THS7303
SLOS479B – OCTOBER 2005 – REVISED MARCH 2011
www.ti.com
2
3-Channel, Low-Power Video Amplifier with I C Control, Selectable Filters, 6-dB Gain,
SAG Correction, 2:1 Input MUX, and Selectable Input Bias Modes
Check for Samples: THS7303
FEATURES
APPLICATIONS
• 3-Video Amplifiers for CVBS, S-Video
,
Y'U'V', SD/ED/HD Y'P'BP'R, and G'B'R' (R'G'B')
• I2C™ Control of All Functions
• Integrated Low-Pass Filters
– 5th-Order Butterworth Characteristics
– Selectable Corner Frequencies of 9-MHz,
16-MHz, 35-MHz, and Bypass (190-MHz)
• Selectable Input Bias Modes
– AC-Coupled with Sync-Tip-Clamp
– AC-Coupled with Bias
– DC-Coupled with 135-mV Input Shift
– DC-Coupled
• 2:1 Input MUX Allows Multiple Input Sources
• Built-in 6-dB Gain (2 V/V)
• SAG Correction Capable
• 2.7-V to 5-V Single Supply Operation
• Low 16.6-mA (3.3 V) Total Quiscent Current
• Individual Disable (< 1 μA) and Mute Control
• Rail-to-Rail Output:
– Output Swings within 100 mV from the
Rails to Allow AC or DC Output Coupling
– Supports Driving Two Lines per Channel
• Low Differential Gain/Phase of 0.13%/0.55°
•
•
•
1
234
Set Top Box Output Video Buffering
PVR/DVDR Output Buffering
USB/Portable Low Power Video Buffering
DESCRIPTION
Fabricated
using
the
new
complementary
silicon-germanium (SiGe) BiCom-3 process, the
THS7303 is a low-power, single-supply, 2.7-V to 5-V,
3-channel integrated video buffer. It incorporates a
selectable fifth-order Butterworth filter to eliminate
data converter images. The 9-MHz filter is a perfect
choice for SDTV video including composite (CVBS),
S-Video, and 480i/576i Y'P'BP'R, and G'B'R' (R'G'B')
signals. The 16-MHz filter is ideal for EDTV
480p/576p Y'P'BP'R, G'B'R', and VGA signals. The
35-MHz filter is useful for HDTV 720p/1080i Y'P'BP'R,
G'B'R', and SVGA/XGA signals. For 1080p or
SXGA/UXGA signals, the filter can be bypassed
allowing a 190-MHz bandwidth, 300-V/μs amplifier to
buffer the signal.
Each channel of the THS7303 is individually I2C
configurable for all functions which makes it flexible
for any application. Its rail-to-rail output stage allows
for both ac and dc coupling applications. The 6-dB
gain along with the built-in SAG correction allows for
maximum flexibility as an output video buffer.
The 16.6-mA total quiescent current (55 mW total
power) makes the THS7303 an excellent choice for
USB powered or portable video applications. While
fully disabled, the THS7303 consumes less than 1 μA
making it ideal for energy sensitive applications.
3.3 V
Bypass
Video
DAC /
Encoder
In A
In B
2 :1
X1
R
DC
135 mV
DC
External
Input
75 W
AC BIAS
SDA
AC
Sync
TIP
Clamp
SCL
+
LPF
9 / 16 /
35-MHz
Out
47 mF
75 W
-
675 W
Video
Out
SAG
MUTE
1 kW
I2C-A1
I2C-A0
150 W
878 W
33 mF
75 W
3.3 V
Figure 1. 3.3-V, Single-Supply, DC-Input/AC-Video Output System with SAG Correction
(1 of 3 Channels Shown)
1
2
3
4
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Windows is a registered trademark of Microsoft Corporation.
2
I C is a trademark of NXP Semiconductors.
All other trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2005–2011, Texas Instruments Incorporated
THS7303
SLOS479B – OCTOBER 2005 – REVISED MARCH 2011
www.ti.com
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
DESCRIPTION (CONTINUED)
As part of the THS7303 flexibility, the 2:1 MUX input can be selected for ac- or dc-coupled inputs. The
ac-coupled modes include a sync-tip-clamp option for CVBS/Y'/G'/B'/R' with sync or a fixed bias for the C'/P'B/P'R
non-sync channels. The dc input options include a dc input or a (dc + 135-mV) input offset shift to allow for a full
sync dynamic range at the output with 0-V input.
PACKAGE/ORDERING INFORMATION (1)
PRODUCT
PACKAGE-LEAD
PACKAGE DESIGNATOR
TSSOP-20
PW
THS7303PW
THS7303PWR
(1)
TRANSPORT MEDIA, QUANTITY
Rails, 70
Tape and Reel, 2000
For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
Web site at www.ti.com.
ABSOLUTE MAXIMUM RATINGS
Over operating free-air temperature range (unless otherwise noted). (1)
PARAMETER
VSS
Supply voltage, VS+ to GND
VI
Input voltage
IO
Output current
UNIT
5.5 V
–0.4 V to VS+
±125 mA
Continuous power dissipation
See Dissipation Ratings Table
TJ
Maximum junction temperature, any condition (2)
TJ
Maximum junction temperature, continuous operation, long term reliability (3)
Tstg
Storage temperature range
+150°C
+125°C
–65°C to +150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds
ESD ratings
(1)
(2)
(3)
+300°C
HBM
2000 V
CDM
750 V
MM
100 V
Stresses above those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied Exposure to absolute maximum rated conditions for extended periods may degrade device reliability.
The absolute maximum junction temperature under any condition is limited by the constraints of the silicon process.
The absolute maximum junction temperature for continuous operation is limited by the package constraints. Operation above this
temperature may result in reduced reliability and/or lifetime of the device.
DISSIPATION RATINGS
POWER RATING (1)
(TJ = +125°C)
PACKAGE
θJC
(°C/W)
θJA
(°C/W)
TA = +25°C
TA = +85°C
TSSOP-20 (PW)
32.3
83 (2)
1.2 W
0.48 W
RECOMMENDED OPERATING CONDITIONS
PARAMETER
MIN
NOM
MAX
UNIT
VSS
Supply voltage, VS+
2.7
5
V
TA
Ambient temperature
–40
+85
°C
(1)
(2)
2
Power rating is determined with a junction temperature of +125°C. This is the point where distortion starts to substantially increase and
long-term reliability starts to be reduced. Thermal management of the final PCB should strive to keep the junction temperature at or
below +125°C for best performance and reliability.
This data was taken with the JEDEC High-K test PCB. For the JEDEC low-K test PCB, the θJA is +125.8°C.
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THS7303
SLOS479B – OCTOBER 2005 – REVISED MARCH 2011
www.ti.com
ELECTRICAL CHARACTERISTICS: VS+ = 3.3 V
RL = 150 Ω to GND, filter select = 9 MHz, input bias = dc, and SAG pin shorted to the output pin (unless otherwise noted).
TYP
PARAMETER
TEST CONDITIONS
+25°C
OVER TEMPERATURE
+25°C
0°C to +70°C
–40°C to +85°C
UNITS
MIN/MAX
AC PERFORMANCE
Small-signal bandwidth
(–3 dB) VO – 0.2 VPP
Large-signal bandwidth
(–3 dB) VO – 2 VPP
Slew rate
Group delay at 100 kHz
Group delay variation with
respect to 100 kHz
Group delay matching
Attenuation with respect to
100 kHz
Filter Select = 9 MHz (1)
9
7.6/10.4
7.4/10.6
7.3/10.7
MHz
Min/Max
Filter select = 16 MHz (1)
16
13.4/18.6
13.1/18.9
13/19
MHz
Min/Max
Filter select = 35 MHz (1)
35
29.4/40.6
29.1/40.9
29/41
MHz
Min/Max
Filter select = bypass
175
MHz
Filter select = 9 MHz
9
MHz
Filter select = 16 MHz
16
MHz
Filter select = 35 MHz
35
MHz
Filter select = bypass
83
MHz
Filter select = bypass, VO = 2 VPP
300
V/μs
Filter select = 9 MHz
54
ns
Filter select = 16 MHz
31.5
ns
Filter select = 35 MHz
17
ns
Filter select = bypass
3
ns
Filter select = 9 MHz, at 5.1 MHz
10.5
ns
Filter select = 16 MHz, at 11 MHz
8
ns
Filter select = 35 MHz, at 27 MHz
4.8
ns
All filters: channel-to-channel
0.5
Filter select = 9 MHz, at 5.75 MHz
0.2
-0.3/0.9
-0.5/1.1
-0.6/1.2
dB
Filter select = 9 MHz, at 27 MHz
43
33
32
31
dB
Min
Filter select = 16 MHz, at 11 MHz
0.25
-0.3/0.9
-0.5/1.1
-0.6/1.2
dB
Min/Max
ns
Filter select = 16 MHz, at 54 MHz
44
33
32
31
dB
Min
Filter select = 35 MHz, at 27 MHz
0.7
-0.3/2.7
-0.5/2.8
-0.6/2.9
dB
Min/Max
15
14
13
dB
Min
Filter select = 35 MHz, at 74 MHz
28
Mute feedthrough
Filter select = bypass, at 30 MHz
-73
dB
Differential gain
Filter select = 9 MHz, NTSC/PAL
0.13/0.27
%
Differential phase
Filter select = 9 MHz, NTSC/PAL
0.55/0.65
°
Filter select = 9 MHz
–59
dB
Filter select = 16 MHz
–62
dB
Filter select = 35 MHz
–58
dB
Filter select = bypass
–60
dB
Filter select = 9 MHz, 480i source
84
dB
Filter select = 16 MHz, 480p source
82
dB
Filter select = 35 MHz, 720p source
79
dB
Filter select = bypass (2), 720p source
67
dB
Filter select = 9 MHz, at 1 MHz
–65
dB
Filter select = 16 MHz, at 1 MHz
–67
dB
Filter select = 35 MHz, at 1 MHz
–69
dB
Filter select = bypass, at 1 MHz
–70
dB
Filter select = 9 MHz, at 5.1 MHz
70
dB
Filter select = 16 MHz, at 11 MHz
69
dB
Filter select = 35 MHz, at 27 MHz
69
dB
Filter select = bypass, at 60 MHz
73
AC gain: all channels
f = 100 kHz
6
Output impedance
f = 10 MHz
0.7
Total harmonic distortion
f = 1 MHz, 2 VPP
Signal-to-noise ratio (unified
weighting per CCIR 576-2
recommendation)
Channel-to-channel crosstalk
(VO = 2 VPP)
MUX isolation
(1)
(2)
Min/Max
dB
5.7/6.3
5.65/6.35
5.65/6.35
dB
Min/Max
Ω
Min/Max values listed are specified by design only. PCB capacitance affects the filter characteristics, especially the 35-MHz and bypass
mode responses.
Bandwidth up to 100-MHz, no weighting, tilt null.
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THS7303
SLOS479B – OCTOBER 2005 – REVISED MARCH 2011
www.ti.com
ELECTRICAL CHARACTERISTICS: VS+ = 3.3 V (continued)
RL = 150 Ω to GND, filter select = 9 MHz, input bias = dc, and SAG pin shorted to the output pin (unless otherwise noted).
TYP
PARAMETER
TEST CONDITIONS
OVER TEMPERATURE
+25°C
+25°C
0°C to +70°C
–40°C to +85°C
35
90
95
UNITS
MIN/MAX
95
mV
Max
20
μV/°C
DC PERFORMANCE
Output offset voltage
Bias = dc
Average offset voltage drift
Bias = dc
Bias = dc + 135 mV, VI = 0 V
290
235/345
215/360
200/375
mV
Min/Max
Bias = ac
1.65
1.5/1.8
1.45/1.85
1.45/1.85
V
Min/Max
Sync-tip-clamp output voltage
Bias = ac STC
290
210/370
200/380
195/385
mV
Min/Max
Input bias current
Bias = dc, implies IB out of the pin
–0.6
–4
–5
–5
μA
Max
Average bias current drift
Bias = dc
10
nA/°C
0.4/3.6
μA
Min/Max
Bias output voltage
Sync-tip-clamp bias current
Bias = ac STC, low bias
1.8
0.6/3.3
0.5/3.5
Bias = ac STC, mid bias
Bias = ac STC, high bias
5.8
4.3/8.2
4.1/8.4
4/8.5
μA
Min/Max
7.8
6.2/10.8
6/11
5.9/11.1
μA
Min/Max
0/1.57
0/1.52
0/1.47
0/1.47
V
Min/Max
INPUT CHARACTERISTICS
Input voltage range
Input resistance
Bias = dc, limited by output
Bias = ac bias mode
19
kΩ
Bias = dc, dc + 135 mV, ac STC
3
MΩ
2
pF
Input capacitance
OUTPUT CHARACTERISTICS
High output voltage swing
Low output voltage swing
Output current
RL = 150 Ω to +1.65V
3.15
2.9
2.8
2.8
V
Min
RL = 150 Ω to GND
3.05
2.85
2.75
2.75
V
Min
RL = 75 Ω to +1.65V
3.05
2.8
2.7
2.7
V
Min
RL = 75 Ω to GND
2.9
2.65
2.55
2.55
V
Min
RL = 150 Ω to +1.65V
0.14
0.24
0.27
0.28
V
Max
RL = 150 Ω to GND
0.09
0.17
0.2
0.21
V
Max
RL = 75 Ω to GND
0.24
0.33
0.36
0.37
V
Max
RL = 75 Ω to GND
0.09
0.17
0.2
0.21
V
Max
RL = 10 Ω to +1.65V, sourcing
70
45
42
40
mA
Min
RL = 10 Ω to +1.65V, sinking
70
45
42
40
mA
Min
3.3
5.5
5.5
5.5
V
Max
3.3
2.6
2.6
2.6
V
Min
6
7.2
7.4
7.5
mA
Max
6
4.8
4.6
4.5
mA
Min
POWER SUPPLY
Maximum operating voltage
Minimum operating voltage
Maximum quiescent current
Per channel VI = 200 mV
Minimum quiescent current
Per channel VI = 200 mV
Total quiescent current
All channels on, VI = 200 mV (3)
Power-supply rejection
(+PSRR)
VS+ = 3.5 V to 3.1 V
16.6
62
mA
37
35
35
dB
Min
DISABLE CHARACTERISTICS
(4)
0.1
μA
5
μs
2
μs
High-level input voltage xxx
VIH
2.3
V
Typ
Low-level input voltage xx x
VIL
1.0
V
Typ
Quiescent current
All 3 channels disabled
Turn-on time delay (tON)
Time reaches 50% of final value after
I2C control is completed
Turn-on time delay (tOFF)
DIGITAL CHARACTERISTICS
(3)
(4)
4
Due to sharing of internal bias circuitry, the quiescent current (with all channels operating) is less than the single individual channel
quiescent currents added together.
Note that the I2C circuitry is still active while in Disable mode. The current shown is while there is no activity with the device I2C circuitry.
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THS7303
SLOS479B – OCTOBER 2005 – REVISED MARCH 2011
www.ti.com
ELECTRICAL CHARACTERISTICS: VS+ = 5 V
RL = 150 Ω to GND, filter select = 9 MHz, input bias = dc, and SAG pin shorted to the output pin (unless otherwise noted).
TYP
PARAMETER
TEST CONDITIONS
+25°C
OVER TEMPERATURE
+25°C
0°C to +70°C
–40°C to +85°C
UNITS
MIN/MAX
AC PERFORMANCE
Small-signal bandwidth
(–3 dB) VO – 0.1 VPP
Large-signal bandwidth
(–3 dB) VO – 2 VPP
Slew rate
Group delay at 100 kHz
Group delay variation with
respect to 100 kHz
Group delay matching
Attenuation with respect to
100 kHz
Filter select = 9 MHz (1)
9
7.6/10.4
7.4/10.6
7.3/10.7
MHz
Min/Max
Filter select = 16 MHz (1)
16
13.4/18.6
13.1/18.9
13/19
MHz
Min/Max
Filter select = 35 MHz (1)
35
29.4/40.6
29.1/40.9
29/41
MHz
Min/Max
Filter select = bypass
190
MHz
Filter select = 9 MHz
9
MHz
Filter select = 16 MHz
16
MHz
Filter select = 35 MHz
35
MHz
Filter select = bypass
90
MHz
Filter select = bypass
320
V/μs
Filter select = 9 MHz
53
ns
Filter select = 16 MHz
31
ns
Filter select = 35 MHz
16.5
ns
Filter select = bypass
2.9
ns
Filter select = 9 MHz, at 5.1 MHz
10.5
ns
Filter select = 16 MHz, at 11 MHz
7.5
ns
Filter select = 35 MHz, at 27 MHz
4.5
ns
All filters: channel-to-channel
0.5
Filter select = 9 MHz, at 5.75 MHz
0.2
-0.3/0.9
-0.5/1.1
-0.6/1.2
dB
Filter select = 9 MHz, at 27 MHz
42
33
32
31
dB
Min
Filter select = 16 MHz, at 11 MHz
0.25
-0.3/0.9
-0.5/1.1
-0.6/1.2
dB
Min/Max
ns
Filter select = 16 MHz, at 54 MHz
44
33
32
31
dB
Min
Filter select = 35 MHz, at 27 MHz
0.7
-0.3/2.7
-0.5/2.8
-0.6/2.9
dB
Min/Max
15
14
13
dB
Min
Filter select = 35 MHz, at 74 MHz
28
Mute feedthrough
Filter select = bypass, at 30 MHz
73
dB
Differential gain
Filter select = 9 MHz, NTSC/PAL
0.2/0.35
%
Differential phase
Filter select = 9 MHz, NTSC/PAL
0.73/0.86
°
Filter select = 9 MHz
–61
dB
Filter select = 16 MHz
–66
dB
Filter select = 35 MHz
–66
dB
Filter select = bypass
–67
dB
Filter select = 9 MHz, 480i source
84
dB
Filter select = 16 MHz, 480p source
82
dB
Filter select = 35 MHz, 720p source
79
dB
Filter select = bypass (2), 720p source
67
dB
Filter select = 9 MHz: at 1 MHz
–65
dB
Filter select = 16 MHz: at 1 MHz
–67
dB
Filter select = 35 MHz: at 1 MHz
–69
dB
Filter select = bypass: at 1 MHz
–70
dB
Filter select = 9 MHz: at 5.1 MHz
70
dB
Filter select = 16 MHz: at 11 MHz
69
dB
Filter select = 35 MHz: at 27 MHz
71
dB
Filter select = bypass: at 60 MHz
68
AC gain: all channels
f = 100 kHz
6
Output impedance
f = 10 MHz
0.7
Total harmonic distortion
f = 1 MHz, 2 VPP
Signal-to-noise ratio (unified
weighting per CCIR 576-2
recommendation)
Channel-to-channel crosstalk
MUX isolation
(1)
(2)
Min/Max
dB
5.7/6.3
5.65/6.35
5.65/6.35
dB
Min/Max
Ω
Min/Max values listed are specified by design only. PCB capacitance affects the filter characteristics, especially the 35-MHz and bypass
mode responses.
Bandwidth up to 100-MHz, no weighting, tilt null.
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THS7303
SLOS479B – OCTOBER 2005 – REVISED MARCH 2011
www.ti.com
ELECTRICAL CHARACTERISTICS: VS+ = 5 V (continued)
RL = 150 Ω to GND, filter select = 9 MHz, input bias = dc, and SAG pin shorted to the output pin (unless otherwise noted).
TYP
PARAMETER
TEST CONDITIONS
OVER TEMPERATURE
+25°C
+25°C
0°C to +70°C
–40°C to +85°C
30
90
95
UNITS
MIN/MAX
95
mV
Max
20
μV/°C
DC PERFORMANCE
Output offset voltage
Bias = dc
Average offset voltage drift
Bias = dc
Bias = dc + 135 mV, VI = 0 V
290
235/345
215/360
200/375
mV
Min/Max
Bias = ac
2.5
2.3/2.7
2.25/2.75
2.25/2.75
V
Min/Max
Sync-tip-clamp output voltage
Bias = ac STC
300
230/375
215/385
210/390
mV
Min/Max
Input bias current
Bias = dc, implies IB out of the pin
–0.6
–4
–5
–5
μA
Max
Average bias current drift
Bias = dc
10
nA/°C
0.4/3.6
μA
Min/Max
Bias output voltage
Bias = ac STC, low bias
Sync-tip-clamp bias current
1.9
0.6/3.3
0.5/3.5
Bias = ac STC, mid bias
6
4.3/8.2
4.1/8.4
4/8.5
μA
Min/Max
Bias = ac STC, high bias
8.2
6.2/10.8
6/11
5.9/11.1
μA
Min/Max
0/2.4
0/2.35
0/2.3
0/2.3
V
Min/Max
INPUT CHARACTERISTICS
Input voltage range
Input resistance
Bias = dc, limited by output
Bias = ac bias mode
19
kΩ
Bias = dc, dc + 135 mV, ac STC
3
MΩ
2
pF
Input capacitance
OUTPUT CHARACTERISTICS
High output voltage swing
Low output voltage swing
Output current
RL = 150 Ω to +2.5V
4.8
4.4
4.3
4.3
V
Min
RL = 150 Ω to GND
4.65
4.2
4.1
4.1
V
Min
RL = 75 Ω to +2.5V
4.7
4.3
4.2
4.2
V
Min
RL = 75 Ω to GND
4.4
4.1
4
4
V
Min
RL = 150 Ω to +2.5V
0.2
0.34
0.37
0.37
V
Max
RL = 150 Ω to GND
0.1
0.23
0.26
0.27
V
Max
RL = 75 Ω to GND
0.35
0.46
0.5
0.5
V
Max
RL = 75 Ω to GND
0.1
0.23
0.26
0.27
V
Max
RL = 10 Ω to +2.5V, sourcing
85
60
57
55
mA
Min
RL = 10 Ω to +2.5V, sinking
85
60
57
55
mA
Min
5
5.5
5.5
5.5
V
Max
POWER SUPPLY
Maximum operating voltage
Minimum operating voltage
5
2.6
2.6
2.6
V
Min
6.6
7.9
8.1
8.2
mA
Max
Per channel VI = 200 mV
6.6
5.3
5.1
5
mA
Min
All channels on, VI = 200 mV (3)
18.9
Maximum quiescent current
Per channel VI = 200 mV
Minimum quiescent current
Total quiescent current
Power-supply rejection
(+PSRR)
VS+ = 5.2 V to 4.8 V
66
mA
38
36
36
dB
Min
DISABLE CHARACTERISTICS
(4)
0.5
μA
5
μs
2
μs
High-level input voltage xxx
VIH
3.5
V
Typ
Low-level input voltage xx x
VIL
1.5
V
Typ
Quiescent current
All 3 channels disabled
Turn-on time delay (tON)
Time reaches 50% of final value after
I2C control is completed
Turn-on time delay (tOFF)
DIGITAL CHARACTERISTICS
(3)
(4)
6
Due to sharing of internal bias circuitry, the quiescent current (with all channels operating) is less than the single individual channel
quiescent currents added together.
Note that the I2C circuitry is still active while in Disable mode. The current shown is while there is no activity with the device I2C circuitry.
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TIMING REQUIREMENTS (1)
At VS+ = 2.7 V to 5 V, unless otherwise noted.
STANDARD MODE
PARAMETER
FAST MODE
MIN
MAX
MIN
MAX
UNIT
fSCL
Clock frequency, SCL
0
100
0
400
kHz
tw(H)
Pulse duration, SCL high
4
0.6
μs
tw(L)
Pulse duration, SCL low
4.7
1.3
μs
tr
Rise time, SCL and SDA
1000
300
ns
tf
Fall time, SCL and SDA
300
300
ns
tsu(1)
Setup time, SDA to SCL
th(1)
Hold time, SCL to SDA
0
0
ns
t(buf)
Bus free time between stop and start conditions
4.7
1.3
μs
tsu(2)
Setup time, SCL to start condition
4.7
0.6
μs
th(2)
Hold time, start condition to SCL
4
0.6
μs
tsu(3)
Setup time, SCL to stop condition
4
0.6
Cb
Capacitive load for each bus line
(1)
250
100
400
ns
μs
400
pF
The THS7303 I2C address = 01011(A1)(A0)(R/W). See the Application Information section for more information.
t w(H)
t w(L)
tr
tf
SCL
t su(1)
t h(1)
SDA
Figure 2. SCL and SDA Timing
SCL
t su(2)
t h(2)
t su(3)
t (buf)
SDA
Start Condition
Stop Condition
Figure 3. Start and Stop Conditions
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FUNCTIONAL BLOCK DIAGRAM
B yp a ss
C h an n e l 1
In p u t A
C h an n e l 2
In p u t A
C h an n e l 3
In p u t A
2 :1
DC
135 mV
X1
DC
ACBIAS
2:1
DC
135 mV
C h an n e l 1
In p u t B
AC
Sync
TIP
Clamp
9 / 16 /
35-MHz
MUTE
ACBIAS
C h an n e l 1
Ou tp u t
-
675 W
1 kW
878 W
150 W
C h an n e l 1
SA G
B yp a ss
X1
DC
+
LP F
AC
Sync
TIP
Clamp
+
LP F
9 / 16 /
35-MHz
-
675 W
878 W
1 kW
MUTE
C h an n e l 2
Ou tp u t
150 W
C h an n e l 2
SA G
B yp ass
C h an n e l 2
In p u t B
C h an n e l 3
In p u t B
2:1
DC
135 mV
X1
AC
Sync
TIP
Clamp
DC
ACBIAS
SD A
SC L
+
LP F
9 / 16 /
35-MHz
1 kW
MUTE
I2C A1
I2 C A0
-
C h an n el 3
Ou tp u t
675 W
878 W
150 W
C h an n e l 3
SA G
Vs+
2
NOTE: The I C address of the THS7303 is 01011(A1)(A0)(R/W).
8
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PIN CONFIGURATION
PW PACKAGE
TSSOP-20
(TOP VIEW)
PIN DESCRIPTIONS
PIN
NAME
NO.
N/C
1, 20
DESCRIPTION
No internal connection. It is recommended, but not required, to connect these pins to GND.
CH. 1 – INPUT A
2
Video input channel 1, input A
CH. 2 – INPUT A
3
Video input channel 2, input A
CH. 3 – INPUT A
4
Video input channel 3, input A
CH. 1 – INPUT B
5
Video input channel 1, input B
CH. 2 – INPUT B
6
Video input channel 2, input B
CH. 3 – INPUT B
7
Video input channel 3, input B
I2C-A1
8
I2C slave address control bit A1. Connect to VS+ for a logic 1 preset value or GND for a logic 0 preset value.
I2C-A0
9
I2C slave address control bit A0. Connect to VS+ for a logic 1 preset value or GND for a logic 0 preset value.
GND
10
Ground reference pin for all internal circuitry.
VS+
11
Positive power-supply input pin. Connect to 2.7 V to 5 V.
SDA
12
Serial data line of the I2C bus. Pull-up resistor should have a minimum value of 2 kΩ and a maximum
value of 19 kΩ. Pull up to VS+.
SCL
13
I2C bus clock line. Pull-up resistor should have a minimum value of 2 kΩ and a maximum value of 19 kΩ.
Pull up to VS+.
CH. 3 – SAG
14
Video output channel 3 SAG correction pin. If SAG is not used, connect directly to CH. 3 – OUTPUT pin.
CH. 3 – OUTPUT
15
Video output channel 3 from either CH. 3 – INPUT A or CH. 3 – INPUT B.
CH. 2 – SAG
16
Video output channel 2 SAG correction pin. If SAG is not used, connect directly to CH. 2 – OUTPUT pin.
CH. 2 – OUTPUT
17
Video output channel 2 from either CH. 2 – INPUT A or CH. 2 – INPUT B.
CH. 1 – SAG
18
Video output channel 1 SAG correction pin. If SAG is not used, connect directly to CH. 1 – OUTPUT pin.
CH. 1 – OUTPUT
19
Video output channel 1 from either CH. 1 – INPUT A or CH. 1 – INPUT B.
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TYPICAL CHARACTERISTICS
RL = 150 Ω to GND and dc-coupled input and output, unless otherwise noted.
TOTAL QUIESCENT CURRENT
vs
SUPPLY VOLTAGE
INPUT BIAS CURRENT
vs
SUPPLY VOLTAGE
9
20
All Channels ON
I IB − Input Bias Current − µ A
I q− Quiescent Current − mA
7
19
18
85 °C
17
STC − High Bias
8
70 °C
0 °C
25 °C
−40 °C
16
STC − Mid Bias
6
TA = 25°C
5
4
3
STC − Low Bias
2
1
DC − Input Bias
0
−1
15
2.6
−2
3
3.4
3.8
4.2
4.6
5
2.6
3
3.4
VS − Supply Voltage − V
Figure 5.
MUTE FEEDTHROUGH
vs
FREQUENCY
CROSSTALK
vs
FREQUENCY
−20
VS = 3.3 V and 5 V
−30
VS = 3.3 V and 5 V
Worst Case
Crosstalk
Referred to Input
RL = 150 W
4.6
5
Filter = 16 MHz
Filter = 9 MHz
−80
Filter = Bypass
Filter = 35 MHz
−40
Filter = 35 MHz
Crosstalk − dB
Mute Feed Through − dB
RL = 150 W || 13 pF
−60
−70
4.2
Figure 4.
−40
−50
3.8
VS − Supply Voltage − V
Filter = 16 MHz
−50
Filter = 9 MHz
−60
−70
−90
−80
Filter = Bypass
−100
0.1
1
10
100
1000
−90
0.1
f − Frequency − MHz
10
100
1000
f − Frequency − MHz
Figure 6.
10
1
Figure 7.
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TYPICAL CHARACTERISTICS: VS+ = 3.3 V
RL = 150 Ω to GND and dc-coupled input and output, unless otherwise noted.
SMALL-SIGNAL FREQUENCY RESPONSE
SMALL-SIGNAL FREQUENCY RESPONSE
10
6.5
Filter =
Bypass
6
Filter =
Bypass
5
Small Signal Gain − dB
Small Signal Gain − dB
0
5.5
Filter =
35 MHz
Filter = 16 MHz
5
Filter = 9 MHz
4.5
4
3.5
3
0.1
Filter = 16 MHz
−10
−15
Filter = 35 MHz
−20
−25
−30
VS = 3.3 V,
VO = 200 mVPP,
RL = 150 W || 13 pF
Filter = 9 MHz
−5
−35
VS = 3.3 V,
VO = 200 mVPP,
RL = 150 W || 13 pF
−40
0.1
f − Frequency − MHz
10
f − Frequency − MHz
Figure 8.
Figure 9.
GROUP DELAY
vs
FREQUENCY
PHASE RESPONSE
vs
FREQUENCY
1
10
100
1000
80
1
Filter = Bypass
0
Filter = 35 MHz
−45
Filter = 9 MHz
−90
Filter = 16 MHz
50
Phase − o
Group Delay − ns
1000
45
VS = 3.3 V,
VO = 200 mVPP,
RL = 150 W || 13 pF
70
60
100
40
Filter = 16 MHz
30
20
−135
Filter = 9 MHz
−180
−225
Filter = 35 MHz
−270
VS = 3.3 V,
VO = 200 mVPP,
RL = 150 W || 13 pF
−315
10
Filter = Bypass
0
0.1
1
10
100
f − Frequency − MHz
−360
0.1
1000
1
10
100
f − Frequency − MHz
1000
Figure 10.
Figure 11.
SMALL- AND LARGE-SIGNAL FREQUENCY RESPONSE
SMALL- AND LARGE-SIGNAL FREQUENCY RESPONSE
6.5
10
Filter = Bypass
VS = 3.3 V,
RL = 150 W || 13 pF
VS = 3.3 V,
RL = 150 W || 13 pF
5
6
0
Signal Gain − dB
Signal Gain − dB
5.5
Filter = 9 MHz
5
Filter = 16 MHz
4.5
Filter = Bypass
−5
Filter = 9 MHz
−10
−15
Filter = 16 MHz
−20
−25
4
−30
Solid Line = 200 mVPP,
Dashed Line = 2.6 VPP
3.5
−35
3
0.1
1
10
f − Frequency − MHz
100
Solid Line = 200 mVPP,
Dashed Line = 2.6 VPP
−40
0.1
Figure 12.
1
10
f − Frequency − MHz
100
1000
Figure 13.
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TYPICAL CHARACTERISTICS: VS+ = 3.3 V (continued)
RL = 150 Ω to GND and dc-coupled input and output, unless otherwise noted.
OUTPUT IMPEDANCE
vs
FREQUENCY
SMALL- AND LARGE-SIGNAL FREQUENCY RESPONSE
6.5
100
VO = 0.2 V PP
VS = 3.3 V
Signal Gain − dB
5.5
Z o − Output Impedance − Ω
6
VO = 0.5 V PP
VO = 1 V PP
5
VO = 2 V PP
4.5
VO = 2.6 V PP
4
10
1
Filter = 9 MHz
0.1
Filter = Bypass
VS = 3.3 V,
Filter = Bypass,
RL = 150 W || 13 pF
3.5
3
0.1
1
10
f − Frequency − MHz
100
0.01
0.1
1000
10
100
f − Frequency − MHz
1
Figure 14.
Figure 15.
3.3-V DIFFERENTIAL GAIN
3.3-V DIFFERENTIAL PHASE
0.30
0.7
Filter = 9 MHz,
RL = 150 W || 13 pF
0.6
PAL
0.20
0.15
0.10
NTSC
NTSC
0.4
0.3
0.1
0
0
2nd
3rd
4th
5th
6th
4th
HD3
vs
FREQUENCY
−30
Filter = Bypass
−35
Filter = 35 MHz
−45
Filter = 9 MHz
−50
−55
−60
Filter = 16 MHz
VS = 3.3 V,
VO = 2 VPP,
RL = 150 W || 13 pF
−40
5th
6th
Filter = Bypass
Filter = 35 MHz
−45
−50
−55
−60
Filter = 16 MHz
−65
−70
Filter = 9 MHz
−75
10
1
100
−80
0.1
1
10
100
f − Frequency − MHz
f − Frequency − MHz
Figure 18.
12
3rd
HD2
vs
FREQUENCY
VS = 3.3 V,
VO = 2 VPP,
RL = 150 W || 13 pF
−65
2nd
Figure 17.
−30
−40
1st
Figure 16.
3rd Order Harmonic distortion − dB
1st
2nd Order Harmonic Distortion − dB
0.5
0.2
0.05
−70
0.1
Filter = 9 MHz,
RL = 150 W || 13 pF
PAL
Differential Phase − °
Differential Gain − %
0.25
−35
1000
Figure 19.
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TYPICAL CHARACTERISTICS: VS+ = 3.3 V (continued)
RL = 150 Ω to GND and dc-coupled input and output, unless otherwise noted.
HD2
vs
OUTPUT VOLTAGE
HD3
vs
OUTPUT VOLTAGE
−40
VS = 3.3 V
F = 1 MHz,
RL = 150 W || 13 pF
−50
3rd Order Harmonic distortion − dB
2nd Order Harmonic Distortion − dB
−40
Filter = 35 MHz
Filter = 9 MHz
−60
−70
Filter = Bypass
VS = 3.3 V
F = 1 MHz,
RL = 150 W || 13 pF
−50
−60
Filter = 9 MHz
−70
Filter = Bypass
Filter = 16 MHz
−80
−90
Filter = 16 MHz
Filter = 35 MHz
−80
−100
0
0.5
1
1.5
2
2.5
3
0
0.5
VO − Output Voltage − VPP
1.5
2
2.5
3
Figure 20.
Figure 21.
SMALL-SIGNAL FREQUENCY RESPONSE
WITH CAPACITIVE LOADING
SMALL-SIGNAL FREQUENCY RESPONSE
WITH 19 pF CAPACITIVE LOAD
20
10
VS = 3.3 V,
Filter = Bypass,
RL = 150 W || CL
18
16
Filter =
Bypass
5
CL = 35 pF
0
Filter = 35 MHz
14
12
CL = 23 pF
10
CL = 19 pF
8
6
Signal Gain − dB
−5
Signal Gain − dB
1
VO − Output Voltage − VPP
−10
Filter = 16 MHz
−15
−20
Filter = 9 MHz
−25
−30
CL = 13 pF
4
−35
VS = 3.3 V,
VO = 200 mVPP,
RL = 150 W || 19 pF
−40
2
−45
0
1
10
100
f − Frequency − MHz
1000
1
Figure 22.
10
100
f − Frequency − MHz
1000
Figure 23.
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TYPICAL CHARACTERISTICS: VS+ = 3.3 V (continued)
RL = 150 Ω to GND and dc-coupled input and output, unless otherwise noted.
SMALL-SIGNAL FREQUENCY RESPONSE
WITH 23 pF CAPACITIVE LOAD
SMALL-SIGNAL FREQUENCY RESPONSE
WITH 35 pF CAPACITIVE LOAD
10
20
Filter =
Bypass
5
10
0
Filter = 35 MHz
Filter = 16 MHz
−10
−15
Filter = 9 MHz
−20
Filter =
Bypass
5
Signal Gain − dB
−5
Signal Gain − dB
VS = 3.3 V,
VO = 200 mVPP,
RL = 150 W || 35 pF
15
−25
0
−5
Filter = 35 MHz
−10
Filter = 16 MHz
−15
−20
Filter = 9 MHz
−25
−30
−30
−35
VS = 3.3 V,
VO = 200 mVPP,
RL = 150 W || 23 pF
−40
−35
−40
−45
1
10
100
f − Frequency − MHz
−45
1000
1
10
100
f − Frequency − MHz
Figure 24.
Figure 25.
SMALL-SIGNAL PULSE RESPONSE
LARGE-SIGNAL PULSE RESPONSE
1.75
1.65
1000
3.25
VS = 3.3 V,
RL = 150 W || 13 pF
VS = 3.3 V,
RL = 150 W || 13 pF
3
1.45
VO − Output Voltage − V
VO - Output Voltage − V
2.75
1.55
Filter = Bypass
1.35
Filter = 9 MHz
Filter = 35 MHz
1.25
Filter = 16 MHz
2.5
2.25
2
Filter = Bypass
1.75
Filter = 9 MHz
1.5
Filter = 35 MHz
1.25
1.15
Filter = 16 MHz
1
0.75
1.05
0.5
0.95
−100
0
100
200
300
400
600
700
0
200
300
400
500
t − Time − ns
Figure 26.
Figure 27.
NTSC - 2T RESPONSE
PAL - 12.5T RESPONSE
VS = 3.3 V
Filter = 9 MHz
250 mV/div
CVBS Input
600
700
VS = 3.3 V
CVBS Input
CVBS Output
CVBS Output
t - Time = 200 ns/div
t - Time = 500 ns/div
Figure 28.
14
100
t − Time − ns
Filter = 9 MHz
250 mV/div
500
0.25
−100
Figure 29.
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TYPICAL CHARACTERISTICS: VS+ = 3.3 V (continued)
RL = 150 Ω to GND and dc-coupled input and output, unless otherwise noted.
576p - 2T PULSE RESPONSE
VS = 3.3 V
VS = 3.3 V
Filter = 35 MHz
143 mV/div
Filter = 16 MHz
143 mV/div
720p - 2T PULSE RESPONSE
P’R Channel Output
P’B Channel Output
P’R Channel Output
P’B Channel Output
Y’ Channel Output
Y’ Channel Output
t - Time = 40 ns/div
t − Time = 200 ns/div
Figure 31.
SLEW RATE
vs
OUTPUT VOLTAGE
POWER-SUPPLY REJECTION RATIO
vs
FREQUENCY
80
VS = 3.3 V,
RL = 150 W || 13 pF
Filter = Bypass
PSRR − Power Supply Rejection Ratio − dB
350
Figure 30.
SR − Slew Rate − V/ms
300
250
Filter = 35 MHz
200
Filter = 16 MHz
150
100
50
Filter = 9 MHz
0
0.5
1
1.5
2
2.5
3
70
VS = 3.3 V
RL = 150 W || 13 pF
Filter = 9 MHz
60
50
Filter = Bypass
40 Filter = 16 MHz
30
Filter = 35 MHz
20
10
0
0.01
VO − Output Voltage − VPP
Figure 32.
0.1
1
10
f − Frequency − MHz
100
Figure 33.
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TYPICAL CHARACTERISTICS: VS+ = 3.3 V (continued)
RL = 150 Ω to GND and dc-coupled input and output, unless otherwise noted.
MUX FEEDTHROUGH
vs
FREQUENCY
INPUT BIAS CURRENT
vs
TEMPERATURE
−40
MUX Feed Through − dB
−50
8
VS = 3.3 V
7
I IB − Input Bias Current − µ A
−45
9
Applied Signal to Unselected MUX
Measured Output of Channel
Referred to Applied Signal Input
−55
Filter = 35 MHz
−60
Filter = 16 MHz
−65
−70
Filter = 9 MHz
−75
−80
−85
−90
0.1
10
100
f − Frequency − MHz
STC − Mid Bias
5
4
3
2
STC − Low Bias
1
Filter = Bypass
1
6
VS = 3.3 V
STC − High Bias
0
−40
1000
−20
0
20
40
60
80
100
TA − Ambient Temperature − 5C
Figure 34.
Figure 35.
TYPICAL CHARACTERISTICS: VS+ = 5 V
RL = 150 Ω to GND and dc-coupled input and output, unless otherwise noted.
SMALL-SIGNAL FREQUENCY RESPONSE
SMALL-SIGNAL FREQUENCY RESPONSE
6.5
10
Filter = Bypass
Filter = Bypass
5
6
0
Filter = 35 MHz
Filter = 16 MHz
5
4.5
Filter = 9 MHz
−15
Filter = 9 MHz
−20
−30
VS = 5 V,
VO = 200 mVPP,
−35
RL = 150 W || 13 pF
3
0.1
Filter = 16 MHz
−10
−25
4
3.5
Filter = 35 MHz
−5
Signal Gain − dB
Signal Gain − dB
5.5
1
10
f − Frequency − MHz
100
1000
VS = 5 V,
VO = 200 mVPP,
RL = 150 W || 13 pF
−40
0.1
10
100
1000
f − Frequency − MHz
Figure 36.
16
1
Figure 37.
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TYPICAL CHARACTERISTICS: VS+ = 5 V (continued)
RL = 150 Ω to GND and dc-coupled input and output, unless otherwise noted.
GROUP DELAY
vs
FREQUENCY
PHASE
vs
FREQUENCY
45
80
Filter = Bypass
VS = 5 V,
VO = 200 mVPP,
70
0
Filter = 35 MHz
RL = 150 W || 13 pF
Filter = 9 MHz
−90
Phase − °
50
40
Filter = 16 MHz
Filter = 9 MHz
−135
Filter = 16 MHz
−180
30
−225
Filter = 35 MHz
20
10
−270
1
VS = 5 V,
VO = 200 mVPP,
RL = 150 W || 13 pF
−315
Filter = Bypass
0
0.1
Signal Gain − dB
−45
10
f − Frequency − MHz
100
−360
0.1
1000
1
10
100
1000
f − Frequency − MHz
Figure 38.
Figure 39.
SMALL- AND LARGE-SIGNAL FREQUENCY RESPONSE
SMALL- AND LARGE-SIGNAL FREQUENCY RESPONSE
6.5
6.5
6
6
VO = 0.2 VPP
5.5
5.5
Signal Gain − dB
Group Delay − ns
60
Filter = 9 MHz
5
Filter = 16 MHz
4.5
VO = 0.5 VPP
5
VO = 1 VPP
4.5
VO = 2 VPP
Filter = 35 MHz
4
4
VS = 5 V
RL = 150 W || 13 pF
Solid Lines = 200 mVPP
Dashed Lines = 2.6 VPP
3.5
3
0.1
3
0.1
1
10
100
VO = 2.6 VPP
VS = 5 V,
Filter = Bypass,
RL = 150 W || 13 pF
3.5
1
10
f − Frequency − MHz
100
1000
f − Frequency − MHz
Figure 40.
Figure 41.
5-V DIFFERENTIAL GAIN
5-V DIFFERENTIAL PHASE
1
0.40
0.35
Filter = 9 MHz,
RL = 150 W || 13 pF
0.9
Filter = 9 MHz,
RL = 150 W || 13 pF
0.25
Differential Phase − °
Differential Gain − %
0.8
0.30
PAL
0.20
0.15
NTSC
0.10
0.7
0.6
PAL
0.5
NTSC
0.4
0.3
0.2
0.05
0.1
0
0
1st
2nd
3rd
4th
5th
6th
Figure 42.
1st
2nd
3rd
4th
5th
6th
Figure 43.
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TYPICAL CHARACTERISTICS: VS+ = 5 V (continued)
RL = 150 Ω to GND and dc-coupled input and output, unless otherwise noted.
HD2
vs
FREQUENCY
HD3
vs
FREQUENCY
−30
VS = 5 V,
VO = 2 VPP,
RL = 150 W || 13 pF
−35
3rd Order Harmonic distortion − dB
2nd Order Harmonic Distortion − dB
−30
Filter = Bypass
−40
−45
Filter = 16 MHz
−50
Filter = 9 MHz
−55
−60
Filter = 35 MHz
−65
−70
0.1
10
1
VS = 5 V,
VO = 2 VPP,
RL = 150 W || 13 pF
−40
Filter = 35 MHz
−50
−60
Filter = 16 MHz
−70
Filter = 9 MHz
−80
Filter = Bypass
−90
−100
0.1
100
1
100
Figure 44.
Figure 45.
HD2
vs
OUTPUT VOLTAGE
HD3
vs
OUTPUT VOLTAGE
−50
−50
VS = 5 V,
F = 1 MHz,
RL = 150 W || 13 pF
−55
3rd Order Harmonic Distortion − dB
2nd Order Harmonic Distortion − dB
10
f − Frequency − MHz
f − Frequency − MHz
Filter = 16 MHz
−60
Filter = 9 MHz
−65
−70
Filter = 35 MHz
Filter = Bypass
−75
VS = 5 V,
F = 1 MHz,
RL = 150 W || 13 pF
−60
Filter = 35 MHz
Filter = 16 MHz
−70
Filter = 9 MHz
−80
−90
Filter = Bypass
−80
−100
0
18
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0
0.5
1
1.5
2
2.5
3
VO − Output Voltage − VPP
VO − Output Voltage − VPP
Figure 46.
Figure 47.
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TYPICAL CHARACTERISTICS: VS+ = 5 V (continued)
RL = 150 Ω to GND and dc-coupled input and output, unless otherwise noted.
SMALL-SIGNAL FREQUENCY RESPONSE
WITH CAPACITIVE LOADING
SMALL-SIGNAL FREQUENCY RESPONSE
WITH 19 pF CAPACITIVE LOAD
20
10
VS = 5 V,
Filter = Bypass,
RL = 150 W || CL
18
16
Filter =
Bypass
5
CL = 35 pF
0
14
Signal Gain − dB
Signal Gain − dB
−5
12
CL = 19 pF
CL = 23 pF
10
8
6
−15
Filter = 16 MHz
−20
−25
Filter = 35 MHz
−30
4
−35
CL = 13 pF
VS = 5 V,
VO = 200 mVPP,
RL = 150 W || 19 pF
−40
2
−45
0
1
10
100
f − Frequency − MHz
1
1000
10
100
f − Frequency − MHz
1000
Figure 48.
Figure 49.
SMALL-SIGNAL FREQUENCY RESPONSE
WITH 23 pF CAPACITIVE LOAD
SMALL-SIGNAL FREQUENCY RESPONSE
WITH 35 pF CAPACITIVE LOAD
10
20
Filter =
Bypass
5
VS = 5 V,
VO = 200 mVPP,
RL = 150 W || 35 pF
15
10
0
Filter =
Bypass
5
−5
Filter = 9 MHz
Signal Gain − dB
Signal Gain − dB
Filter = 9 MHz
−10
−10
−15
Filter = 16 MHz
−20
−25
Filter = 35 MHz
0
−5
Filter = 9 MHz
−10
−15
Filter = 16 MHz
−20
−25
−30
Filter = 35 MHz
−30
−35
VS = 5 V,
VO = 200 mVPP,
RL = 150 W || 23 pF
−40
−35
−40
−45
−45
1
10
100
f − Frequency − MHz
1000
1
10
100
f − Frequency − MHz
Figure 50.
Figure 51.
SMALL-SIGNAL PULSE RESPONSE
1.75
LARGE-SIGNAL PULSE RESPONSE
4
VS = 5 V,
VS = 5 V
RL = 150 W || 13 pF
3.75
RL = 150 W || 13 pF
3.5
1.55
1.45
VO − Output Voltage − V
V O− Output Voltage − V
1.65
1000
Filter = Bypass
1.35
Filter = 9 MHz
1.25
Filter = 35 MHz
Filter = 16 MHz
1.15
3.25
3
Filter = Bypass
2.75
2.5
Filter = 9 MHz
2.25
Filter = 35 MHz
Filter = 16 MHz
2
1.75
1.5
1.05
0.95
−100
1.25
0
100
200
300
400
500
600
700
1
−100
0
100
200
300
400
t − Time − ns
t − Time − ns
Figure 52.
Figure 53.
500
600
700
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TYPICAL CHARACTERISTICS: VS+ = 5 V (continued)
RL = 150 Ω to GND and dc-coupled input and output, unless otherwise noted.
SLEW RATE
vs
OUTPUT VOLTAGE
OUTPUT IMPEDANCE
vs
FREQUENCY
350
100
VS = 5 V
ZO − Output Impedance − W
300
SR − Slew Rate − V/ms
Filter = 35 MHz
Bypass
250
200
Filter = 16 MHz
VS = 5 V
150
RL = 150 W || 13 pF
Filter = 9 MHz
100
10
1
Filter = 9 MHz
0.1
Filter = Bypass
50
0
0.5
1
1.5
2
2.5
3
3.5
4
0.01
0.1
10
100
f − Frequency − MHz
1
VO − Output Voltage − VPP
−45
Figure 55.
MUX FEEDTHROUGH
vs
FREQUENCY
POWER-SUPPLY REJECTION RATIO
vs
FREQUENCY
80
Applied Signal to Unselected MUX
Measured Output of Channel
Referred to Applied Signal Input
PSRR − Power Supply Rejection Ratio − dB
−40
Figure 54.
−50
Feed Through − dB
VS = 5 V
−55
Filter = 35 MHz
−60
−65
Filter = 16 MHz
−70
Filter = 9 MHz
−75
−80
−85
−90
0.1
Filter = Bypass
1
10
100
f − Frequency − MHz
1000
VS = 5 V,
RL = 150 || 13 pF
70
Filter = 9 MHz
60
50
Filter = Bypass
40
Filter = 16 MHz
30
Filter = 35 MHz
20
10
0
0.01
Figure 56.
20
1000
0.1
1
10
f − Frequency − MHz
100
Figure 57.
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APPLICATION INFORMATION
The THS7303 is targeted for video output buffer applications. Although it can be used for numerous other
applications, the needs and requirements of the video signal are the most important design parameters of the
THS7303. Built on the complementary silicon germanium (SiGe) BiCom-3 process, the THS7303 incorporates
many features not typically found in integrated video parts while consuming low power. Each channel
configuration is completely independent of the other channels. This allows for configurations for each channel to
be dictated by the end user and not the device. This results in a highly flexible system for most video systems.
The THS7303 contains the following features:
• I2C Interface for easy interfacing to the system.
• Single-supply 2.7-V to 5-V operation with low total quiescent current of 16.6 mA with 3.3-V supply and 18.9
mA with 5-V supply.
• 2:1 input MUX.
• Input configuration accepting dc, dc + 135 mV shift, ac bias, or ac sync-tip-clamp selection.
• Selectable fifth-order, low-pass filter for DAC reconstruction or ADC image rejection :
– 9-MHz for SDTV NTSC and 480i, PAL/SECAM and 576i, S-Video, and G'B'R' (R'G'B') signals.
– 16-MHz for EDTV 480p and 576p Y’P’BP’R signals, G’B’R’, and VGA signals.
– 35-MHz for HDTV 720p and 1080i Y’P’BP’R signals, G’B’R’, and SVGA/XGA signals.
– Bypass mode for passing HDTV 1080p Y’P’BP’R, G’B’R’, and SXGA/UXGA signals.
• Internal fixed gain of 2 V/V (6 dB) buffer that can drive two video lines per channel with dc coupling,
traditional ac coupling, or SAG corrected ac coupling.
• Disable mode that reduces quiescent current to as low as 0.1-μA or a mute function that keeps the THS7303
powered on, but does not allow a signal to pass through.
• Signal flow-through configuration using a 20-pin TSSOP package that complies with the latest lead-free
(RoHS compatible) and green manufacturing requirements.
OPERATING VOLTAGE
The THS7303 is designed to operate from 2.7 V to 5 V over a –40°C to +85°C temperature range. The impact on
performance over the entire temperature range is negligible due to the implementation of thin film resistors and
low-temperature coefficient capacitors.
The power supply pins should have a 0.1-μF to 0.01-μF capacitor placed as close as possible to these pins.
Failure to do so may result in the THS7303 outputs ringing or oscillating. Additionally, a large capacitor, such as
22 μF to 100 μF, should be placed on the power-supply line to minimize issues with 50/60 Hz line frequencies.
INPUT VOLTAGE
The THS7303 input range allows for an input signal range from ground to (VS+ – 1.4 V). However, as a result of
the internal fixed gain of 2 V/V (6 dB), the output is the limiting factor for the allowable linear input range. For
example, with a 5-V supply, the linear input range is from GND to 3.6 V. Because of the gain, the linear output
range limits the allowable linear input range to be from GND up to 2.5 V.
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INPUT OVERVOLTAGE PROTECTION
The THS7303 is built using a high-speed complementary bipolar and CMOS process. The internal junction
breakdown voltages are low for these very small geometry devices. These breakdowns are reflected in the
Absolute Maximum Ratings table. All input and output device pins are protected with internal ESD protection
diodes to the power supplies, as shown in Figure 58.
VS+
External
Input/
Output
Pin
Internal
Circuitry
Figure 58. Internal ESD Protection
These diodes provide moderate protection to input overdrive voltages above and below the supplies. The
protection diodes can typically support 30-mA of continuous current when overdriven.
TYPICAL CONFIGURATION and VIDEO TERMINOLOGY
A typical application circuit using the THS7303 as a video buffer is shown in Figure 59. It shows a DAC (or
encoder such as the THS8200) driving the three input channels of the THS7303. Although the high-definition
video (HD) or enhanced-definition (ED) Y’P’BP’R (sometimes Y’U’V’ is used or it is incorrectly labeled Y’C’BC’R)
channels are shown, these channels can easily be S-Video Y’C’ channels and the composite video baseband
signal (CVBS) of a standard definition video (SD) system. These signals can also be G’B’R’ (R'G'B') signals or
other variations. Note that for computer signals the sync should be embedded within the signal for a system with
only 3-outputs. This is sometimes labeled as R’G’sB’ (sync on green) or R’sG’sB’s (sync on all signals).
The second set of inputs (B-Channels) shown are being driven from an external input typically used as a
pass-through function. These are either HD, ED, or SD video signals. The flexibility of the THS7303 allows for
almost any input signal to be driven into the THS7303 regardless of the other set of inputs. Control of the I2C
configures each channel of the THS7303 independently of the other channels. For example, the THS7303 can
be configured to have Channel 1 Input connected to input A with 35-MHz LPF while Channels 2 and 3 are
connected to input B with 16-MHz LPF. See the various sections explaining the I2C interface later in this data
sheet for more information.
Note that the Y’ term is used for the luma channels throughout this document rather than the more common
luminance (Y) term. The reason is to account for the definition of luminance as stipulated by the CIE International Commission on Illumination. Video departs from true luminance since a nonlinear term, gamma, is
added to the true RGB signals to form R’G’B’ signals. These R’G’B’ signals are then used to mathematically
create luma (Y’). Thus luminance (Y) is not maintained requiring a difference in terminology.
This rationale is also used for the chroma (C’) term. Chroma is derived from the non-linear R’G’B’ terms and thus
it is nonlinear. Chominance (C) is derived from linear RGB giving the difference between chroma (C’) and
chrominance (C). The color difference signals (P’B / P’R / U’ / V’) are also referenced this way to denote the
nonlinear (gamma corrected) signals.
R’G’B’ (commonly mislabeled RGB) is also called G’B’R’ (again commonly mislabeled as GBR) in professional
video systems. The SMPTE component standard stipulates that the luma information is placed on the first
channel, the blue color difference is placed on the second channel, and the red color difference signal is placed
on the third channel. This is consistent with the Y'P'BP'R nomenclature. Because the luma channel (Y') carries the
sync information and the green channel (G') also carries the sync information, it makes logical sense that G' be
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placed first in the system. Since the blue color difference channel (P'B) is next and the red color difference
channel (P'R) is last, then it also makes logical sense to place the B' signal on the second channel and the R'
signal on the third channel respectfully. Thus hardware compatibility is better achieved when using G'B'R' rather
than R'G'B'. Note that for many G'B'R' systems sync is embeded on all three channels, but may not always be
the case in all systems.
3.3 V
DAC /
Encoder
(THS8200)
HDTV
480i
576i
480p
576p
720p
1080i
1080p
Y’
R
470 mF
+
DC + 135 mV
P’ B
1 NC
R
CH.1 OUT 19
3 CH.2 IN A
CH. 1 SAG 18
4 CH.3 IN A
CH.2 OUT 17
5 CH.1 IN B
CH. 2 SAG 16
6 CH.2 IN B
CH.3 OUT 15
7 CH.3 IN B
CH. 3 SAG 14
DC + 135 mV
DC + 135 mV
P’R
AC STC
R
AC Bias
AC Bias
0.1 mF
Y’
75 W
1 mF
P’B
8 I 2C-A1
SCL 13
9 I 2C-A0
SDA 12
10 GND
Y’
Out
(See Note A)
NC 20
2 CH.1 IN A
75 W
470 mF
+
75 W
75 W
P’B
Out
(See Note A)
75 W
470 mF
+
75 W
P’ R
Out
(See Note A)
75 W
+Vs
VS+ 11
+
75 W
0.01 mF
100 mF
2
IC
Controller
1 mF
P’R
75 W
External
Input
A.
Due to the high frequency content of the video signal, it is recommended, but not required, to add a 0.01-μF capacitor
in parallel with these large capacitors.
Figure 59. Typical Y'P' BP' R Inputs From DC-Coupled Encoder/DAC and
AC-Coupled External Inputs With AC-Coupled Line Driving
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INPUT MODES OF OPERATION: DC
The inputs to the THS7303 allows for both ac-coupled and dc-coupled inputs. Many DACs or video encoders can
be dc-connected to the THS7303. However, one of the drawbacks to dc coupling is when 0 V is applied to the
input of the THS7303. Although the input of the THS7303 allows for a 0-V input signal, the output swing of the
THS7303 cannot yield a 0-V signal. This applies to any traditional single-supply amplifier because of the
limitations of the output transistors. Both CMOS and bipolar transistors cannot go to 0 V while sinking a
significant amount of current. This trait of a transistor is also the same reason why the highest output voltage is
always less than the power-supply voltage when sourcing a significant amount of current.
The internal gain is fixed at 6 dB (2 V/V) regardless of the configuration of the THS7303, and dictates what the
allowable linear input voltage range is without clipping concerns. For example, if the power supply is set to 3 V,
the maximum output is about 2.9 V. Thus, to avoid clipping, the allowable input is 2.9 V / 2 = 1.45 V. This is true
for up to the maximum recommended 5-V power supply that allows about a 4.9 V / 2 = 2.45 V input range while
avoiding clipping on the output.
The input impedance of the THS7303 in this mode of operation is > 1 MΩ. This is a result of the input buffer
being configured as a unity gain amplifier, as shown in Figure 60.
VS+
Input
Internal
Circuitry
Input
Pin
Figure 60. Equivalent DC Input Mode Circuit
The input stage of the THS7303 is designed with PNP bipolar transistors. There is a finite amount of bias current
flowing out of the THS7303 input pin. This bias current (typically about 0.6 μA), must have a path to flow or else
the input stage voltage increases. For example, if there is a 1-MΩ resistance to ground on the input node, the
resulting voltage appearing at the input node is 0.6 μA x 1 MΩ = 0.6 V. Therefore, it should be noted that if a
channel is powered on and has no input termination, the input bias current causes the input stage to float high
until saturation of the input stage exists, approximately 1.4 V from the power supply. Typically, this is not a
concern because most terminations result in an equivalent source impedance of 37.5 Ω to 300 Ω.
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INPUT MODES OF OPERATION: DC + 135-mV SHIFT
Clipping occurs with a 0-V applied input signal when the input mode is set to dc. The clipping can reduce the
sync amplitudes (both horizontal and vertical sync amplitudes) on the video signal. A problem occurs if the
receiver of this video signal uses an AGC loop to account for losses in the transmission line. Some video AGC
circuits derive gain from the horizontal sync amplitude. If clipping occurs on the sync amplitude, then the AGC
circuit can increase the gain too much, resulting in too much luma and/or chroma amplitude gain correction. This
may result in a picture with an overly bright display with too much color saturation.
Other AGC circuits use the chroma burst amplitude for amplitude control, and a reduction in the sync signals
does not alter the proper gain setting. It is good engineering design practice to ensure saturation/clipping does
not take place. Transistors always take a finite amount of time to come out of saturation. This saturation could
possibly result in timing delays or other aberrations on the signals.
To eliminate saturation/clipping problems, the THS7303 has a dc + 135 mV shift input mode. This mode takes
the input voltage and adds an internal +135 mV shift to the signal. Since the THS7303 also has a gain of 6 dB (2
V/V), the resulting output with a 0-V applied input signal is about 270 mV. The THS7303 rail-to-rail output stage
can create this level while connected to a typical video load. This ensures that no saturation/clipping of the sync
signals occurs. This is a constant shift regardless of the input signal. For example, if a 1-V input is applied, the
output is at 2.27 V.
As with the dc-input mode, the input impedance of the THS7303 is > 1 MΩ. Additionally, the same input bias
current of about 0.6 μA appears at the input. Following the same precautions as stipulated with the dc-input
mode of operation minimizes any potential issues. Figure 61 shows the equivalent input circuit while in the dc +
135 mV shift mode of operation. Note that the internal voltage shift does not appear at the input pin, only the
output pin.
VS+
Input
Internal
Circuitry
Input
Pin
Level
Shifter
Figure 61. Equivalent DC + 135 mV Input Mode Circuit
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INPUT MODES OF OPERATION: AC BIAS
Other applications require an ac-coupled input. The ac-coupling ensures that a source dc-input bias level does
not alter, or clip, the resulting output video signal. The first ac-coupling mode is the AC Bias mode, where a
simple internal dc bias voltage is applied to the input signal on the THS7303-side of the external coupling
capacitor.
The applied dc bias voltage is set internally by a simple resistor divider circuit, as shown in Figure 62. The dc
bias voltage is set to VS+ / 4. With a 3.3-V power supply, the input bias voltage is nominally 0.825 V; with 5-V
supply, the input bias voltage is nominally 1.25 V. The input impedance with this mode is approximately 19-kΩ.
With a 1-μF input capacitor, it sets a high-pass corner frequency of about 9 Hz. If a lower frequency is desired,
increasing the capacitor decreases the corner frequency proportionally. For example, using a 4.7-μF capacitor
results in a 1.8-Hz high-pass corner frequency, and results in lower droop (tilt). Using any capacitor value is
acceptable for this mode of operation.
VS+
VS+
Rpu
(See Note A)
75 kW
Input Pin
Input
CI
A.
Internal
Circuitry
VS+
Rpd
(See Note A)
25 kW
Use external pull-up and/or pull-down resistors if changing the ac-bias input voltage is desired.
Figure 62. Equivalent AC Bias Input Mode Circuit
It is sometimes desirable to adjust the bias voltage to another level other than the one dictated by the internal
resistors. There are two ways this adjustment is accomplished:
1. The first method is to add an external resistor between the input pin and either the VS+ or GND. This creates
a new bias voltage equal to VS+× [25 k / {25 k + (75 k || RPU)}] for raising the bias voltage, or VS+ × [(25 k ||
RPD) / {(25 k || RPD) + 75 k}] for reducing the bias voltage.
2. The second method to set the ac bias voltage is to use the RPU and RPD external resistors, but place the
THS7303 in dc input bias mode. Because the dc mode is very high impedance, the resulting bias voltage is
equal to approximately VS+ × (RPD / {RPD + RPU}). Due to the input bias current, there will be a difference
between the true dc bias voltage and the theoretical bias voltage.
This mode of operation is recommended for use with chroma (C’), P’B, P’R, U’, V’, and other non-sync signals.
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INPUT MODES OF OPERATION: AC SYNC-TIP-CLAMP
The last input mode of operation is the ac with sync-tip-clamp (STC), which also requires a capacitor in series
with the input. Note that while the term sync-tip-clamp is used throughout this document, the THS7303 is better
termed as a dc restoration circuit based on the way this function is performed. This circuit is an active clamp
circuit and not a passive diode clamp function. This function should be used when ac coupling is desired with
signals that have sync signals embedded such as CVBS, Y’, and G’ signals.
The input to the THS7303 has an internal control loop which sets the lowest input applied voltage to clamp at
approximately 135 mV. Like the dc + 135 mV input shift, the resulting output voltage low level is about 270 mV. If
the input signal tries to go below the 135-mV level, the internal control loop of the THS7303 sources up to 2 mA
of current to increase the input voltage level on the THS7303 input side of the coupling capacitor. As soon as the
voltage goes above the 135-mV level, the loop stops sourcing current.
One of the concerns about the sync-tip-clamp level is how the clamp reacts to a sync edge that has overshoot
that is common in VCR signals or reflections found in poor PCB layouts. Ideally the STC should not react to the
overshoot voltage of the input signal. Otherwise, this could result in clipping on the rest of the video signal
because there may be too much increase in the bias voltage.
To help minimize this input signal overshoot problem, the patent-pending internal STC control loop in the
THS7303 has an I2C selectable low-pass filter as shown in Figure 63. This filter can be selected to be about
500 kHz, 2.5 MHz, or 5 MHz. The 500-kHz filter is useful when the THS7303 fifth-order low-pass filter is selected
for 9-MHz operation. The effect of this filter is to slow down the response of the control loop so as not to clamp
on the input overshoot voltage, but rather the flat portion of the sync signal when the ringing should be settled
out. The 2.5-MHz filter is best suited for use in conjunction with the 16-MHz signal LPF to account for the faster
sync times associated with the higher rate video signals. For HDTV signals, the 5-MHz STC filter should be
selected to allow for the faster sync rates to properly set the clamp level. Any STC filter can be selected
regardless of the signal or system filter.
VS+
Input
Pin
Input
0.1 mF
VS+
135 mV
STC
LPF
Internal
Circuitry
Comparator
1.8 mA STC
5.8 mA Bias
7.8 mA Select
Figure 63. Equivalent AC Sync-Tip-Clamp Input Mode Circuit
As a result of this selectable delay, the sync has an apparent voltage shift occurring between 15 ns and 2 μs
after the sync falling edge, depending on the STC LPF. The amount of shift depends on the amount of droop in
the signal as dictated by the input capacitor and the STC input bias current selection. Because the sync is
primarily for timing purposes with syncing occurring on the edge of the sync signal, this shift is transparent in
most systems. Note that if the source signal is known to be good, selecting the 5-MHz STC LPF is recommended
for all sources
While this feature may not fully eliminate overshoot issues on the input signal in case of really bad overshoot
and/or ringing, the STC system should help minimize improper clamping levels. As an additional method to help
minimize this issue, an external capacitor (example: 10 pF to 47 pF) to ground in parallel with the external
termination resistors can help filter overshoot problems.
It should be noted that this STC system is dynamic and does not rely upon timing in any way. It only depends on
the voltage appearing at the input pin at any given point in time. The STC filtering helps minimize level shift
problems associated with switching noises or short spikes on the signal line. This helps ensure a robust STC
system.
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When the ac sync-tip-clamp (STC) operation is used, there must also be some finite amount of discharge bias
current. As previously described, if the input signal goes below the 135-mV clamp level, the internal loop of the
THS7303 sources current to increase the voltage appearing at the input pin. As the difference between the signal
level and the 135-mV reference level increases, the amount of source current increases proportionally, supplying
up to 2-mA of current. Thus, the time to re-establish the proper STC voltage can be very fast. If the difference is
small, then the source current is also small to account for minor voltage droop.
What happens if the input signal goes above the 135-mV input level? The problem is the video signal is always
above this level and must not be altered in any way. However, if the sync level of the input signal is above the
135-mV level, then the internal discharge (sink) current reduces the ac-coupled bias signal to the proper 135-mV
level.
This discharge current must not be large enough to alter the video signal appreciably or picture quality issues
may arise. This is often seen by looking at the tilt (droop) of a constant luma signal being applied, and looking at
the resulting output level. The associated change in luma level from the beginning of the video line to the end of
the video line is the amount of line tilt (droop). The amount of tilt can be seen by the general formula:
I = C dV/dt
where I is the discharge current and C is the external coupling capacitor which is typically 0.1 μF. If the current (I)
and the capacitor (C) are constant, then the tilt is governed by:
I/C = dV/dt
If the discharge current is small, then the amount of tilt is low, which is good. However, the amount of time for the
system to capture the sync signal may be too long. This is also termed hum rejection. Hum arises from the ac
line voltage frequency of 50 Hz or 60 Hz. The value of the discharge current and the ac-coupling capacitor
combine to dictate the hum rejection and the amount of line tilt.
Because many users have different thoughts about the proper amount of hum rejection and line tilt, the THS7303
has incorporated a variable sink bias current selectable through the I2C interface. The Low Bias mode selects
approximately 1.8-μA of dc sink bias current for low line tilt. If more hum rejection is desired, then selecting the
Mid Bias mode increases the dc sink bias current to approximately 5.8 μA. For severe environments, the High
Bias mode has about 7.8 μA of dc sink bias current. The drawback to these higher bias modes is an increase in
line tilt, but with an increase in hum rejection. The other method to change the hum rejection and line tilt is to
change the input capacitor used. An increase in the capacitor from 0.1 μF to 0.22 μF decreases the hum
rejection and line tilt by a factor of 2.2. A decrease of this input capacitor accomplishes the opposite effect. Note
that the amplifier input bias current of nominally 0.6 μA has already been taken into account when stipulating the
1.8-μA, 5.8-μA, and 7.8-μA current sink values.
To ensure proper stability of the ac STC control loop, the source impedance must be less than 600-Ω and the
input capacitor must be greater than 0.01 μF. Otherwise, there is a possibility of the control loop ringing. The
ringing appears on the output of the THS7303. Similar to the dc modes of operation, many DACs and encoders
use a resistor to establish the output voltage. These resistors are typically less than 300 Ω. Thus, stability of the
ac STC loop is ensured. If the source impedance looking from the THS7303 input perspective is high or open,
then adding a 300-Ω resistor to GND ensures proper operation of the THS7303.
If a MUX channel is not required in the system, it is recommended to place a 75-Ω resistor to GND. This is not
required, but it helps minimize any potential issues.
28
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OUTPUT MODES OF OPERATION: DC COUPLED
The THS7303 incorporates a rail-to-rail output stage that can be used to drive the line directly without the need
for large ac-coupling capacitors. This is accomplished by connecting the output pin of each channel directly to
the SAG output pin of the corresponding channel as shown in Figure 64. This offers the best line tilt and field tilt
(or droop) performance since there is no ac coupling occurring. Keep in mind that if the input is ac coupled, then
the resulting tilt due to the input ac coupling is still seen on the output regardless of the output coupling. The
70-mA output current drive capability of the THS7303 is designed to drive two video lines simultaneously
(essentially a 75-Ω load), while keeping the output dynamic range as wide as possible.
3.3 V
G’
R
DAC /
Encoder
(THS8200)
75 W
DC + 135 mV
B’
1 NC
R
CH.1 OUT 19
3 CH.2 IN A
CH. 1 SAG 18
4 CH.3 IN A
CH.2 OUT 17
5 CH.1 IN B
CH. 2 SAG 16
6 CH.2 IN B
CH.3 OUT 15
7 CH.3 IN B
CH. 3 SAG 14
DC + 135 mV
R’
AC STC
R
AC STC
AC STC
0.1 mF
G’
75 W
0.1 mF
8 I 2C-A1
SCL 13
9 I 2C-A0
SDA 12
10 GND
75 W
NC 20
2 CH.1 IN A
DC + 135 mV
G’
Out
75 W
B’
Out
75 W
75 W
R’
Out
75 W
+Vs
VS+ 11
+
B’
75 W
0.01 mF
100 mF
2
IC
Controller
0.1 mF
R’
75 W
External
Input
Figure 64. Typical G'B'R' (R'G'B') System With DC-Coupled Line Driving
One concern of dc coupling is if the line is terminated to ground. When the AC-Bias Input mode is selected, the
output of the THS7303 is at mid-rail. With two lines terminated to ground, this creates a dc current path to exist
that results in a slightly decreased high output voltage swing resulting in an increase in power dissipation of the
THS7303. While the THS7303 is designed to operate with a junction temperature of up to +125°C, care must be
taken to ensure that the junction temperature does not exceed this level or else long-term reliability could suffer.
Although this configuration adds less than 10 mW of power dissipation per channel, the overall low power
dissipation of the THS7303 design minimizes potential thermal issues even when using the TSSOP package at
high ambient temperatures.
Note that the THS7303 can drive the line with dc coupling regardless of the input mode of operation. The only
requirement is to make sure the video line has proper termination in series with the output pin (typically 75 Ω).
This helps isolate capacitive loading effects from the THS7303 output. Failure to isolate capacitive loads may
result in instabilities with the output buffer, potentially causing ringing or oscillations to appear. The stray
capacitance appearing directly at the THS7303 output pins should be kept below 25 pF for best performance.
When driving two video lines, each line should have its own 75-Ω source termination resistors to isolate the lines
from each other.
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OUTPUT MODES OF OPERATION: AC-COUPLED
The most common method of coupling the video signal to the line is by using a large capacitor. This capacitor is
typically between 220 μF and 1000 μF, although 470 μF is most common. This value of this capacitor must be
this large to minimize the line tilt (droop) and/or field tilt associated with ac coupling as described previously in
this document. Just like the dc output configuration, connection of the output pin of each channel directly to the
SAG output pin of the corresponding channel should be as close as possible to the output pins of the THS7303.
The most common reason ac coupling is used is to ensure full interoperability with the receiving video system.
This ensures that regardless of the reference dc voltage used on the transmit side of the video signal, the receive
side will re-establish the dc reference voltage to its own requirements without any interaction from the transmit
side dc bias voltage.
As with the dc output mode of operation, each line should have a 75-Ω source termination resistor in series with
the ac-coupling capacitor. If two lines are to be driven, it is best to have each line use its own capacitor and
resistor rather than sharing these components, as shown in Figure 65.This helps ensure line-to-line dc isolation
and other potential problems. Using a single 1000-μF capacitor for two lines can be done, but there is a chance
for interference between the two receivers.
Y’
Out 1
470 mF
(See Note A)
+
3.3 V
75 W
DAC /
Encoder
(THS8200)
Y’
R
75 W
Y’
Out 2
470 mF
(See Note A)
+
DC + 135 mV
75 W
HDTV
480i
576i
480p
576p
720p
1080i
1080p
P’B
1 NC
R
NC 20
2 CH.1 IN A
CH.1 OUT 19
3 CH.2 IN A
CH.1 SAG 18
4 CH.3 IN A
CH.2 OUT 17
5 CH.1 IN B
CH.2 SAG 16
6 CH.2 IN B
CH.3 OUT 15
7 CH.3 IN B
CH.3 SAG 14
470 mF
(See Note A)
+
DC + 135 mV
DC + 135 mV
P’R
AC STC
R
AC Bias
AC Bias
0.1 mF
Y’
75 W
1 mF
8 I2C-A1
SCL 13
9 I2C-A0
SDA 12
10 GND
75 W
P’ B
Out 1
75 W
75 W
P’B
470 mF
(See Note A) Out 2
+
75 W
3.3 V
VS + 11
470 mF
(See Note A)
+
75 W
P’ R
Out 1
75 W
P’B
75 W
100 mF
0.01 mF
1 mF
2
IC
Controller
P’R
470 mF
(See Note A)
+
75 W
P’R
Out 2
75 W
75 W
75 W
External
Input
A.
Due to the high frequency content of the video signal, it is recommended, but not required, to add a 0.01-μF capacitor
in parallel with these large capacitors.
Figure 65. Typical Y'P' BP' R System Driving 2 AC-Coupled Video Lines
Because of the edge rates and frequencies of operation, it is recommended (but not required) to place a 0.1-μF
to 0.01-μF capacitor in parallel with the large 220-μF to 1000-μF capacitors. These large value capacitors are
most commonly aluminum electrolytic. It is well known that these capacitors have significantly large equivalent
series resistance (ESR), and their impedance at high frequencies is large as a result of the associated
inductances involved with their construction. The small 0.1-μF to 0.01-μF capacitors help pass these
high-frequency (> 1 MHz) signals with lower impedance than the large capacitors. This is especially true when
HD and computer R'G'B' signals are being used. Their associated edge rates and frequency content can reach
beyond 30-MHz for HD signals and can be over 100-MHz for R'G'B' signals—frequencies that typical aluminum
electrolytic capacitors typically cannot pass effectively.
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Although it is common to use the same capacitor values for all the video lines, the frequency bandwidth of the
chroma signal in a S-Video system are not required to go as low or as high as the frequency of the luma
channel. Thus, the capacitor values of the chroma line(s) can be smaller, such as 0.1 μF.
OUTPUT MODES OF OPERATION: AC-COUPLED WITH SAG CORRECTION
Other than the line droop issue, ac coupling has two other potential issues: size and cost. A 330-μF to 1000-μF
capacitor is large and can be quite costly in a system. Multiply these items by the number of channels, and the
size and cost can be significant. However, it is still desirable to use ac coupling to insure interoperability among
video devices.
The SAG nomenclature represents signal amplitude gain correction in this document. SAG correction is a
method that is used to ac-couple the video signal while using much smaller value capacitors. SAG correction is
accomplished by manipulating the feedback network of the output buffer. The THS7303 was designed to take
advantage of this compensation scheme, while minimizing the number of external components required.
Figure 66 shows the basic configuration of the output buffer stage along with the SAG configuration driving a
single video line.
Internal
Circuitry
Signal
Out
47 mF
Video
Out
75 W
675 W
33 mF
SAG
878 W
1 kW
150 W
75 W
Figure 66. THS7303 Output Buffer Using SAG Corrected AC-Coupling
SAG compensation can be analyzed by looking at low frequency operation and high frequency operation. At low
frequencies, the impedance of the capacitors are high and the corresponding gain of the amplifier is:
1)
ǒ(675 1k) 878)Ǔ + 2.55 VńV () 8.1 dB).
(1)
At high frequencies, the impedance of the capacitors are low and the resulting gain of the amplifier is:
1)
ǒ
Ǔ
ƪ(675 ø 150) ) 878ƫ
1k
ǒ Ǔ
+ 1 ) 1k + 2 VńV () 6.0 dB)
1k
(2)
which is needed to counteract the doubly-terminated 75-Ω output divider (–6 dB) circuit, resulting in the video-out
signal equaling the input signal amplitude.
When the SAG output pin is connected directly to the amplifier output, as found in the dc-coupled and the
ac-coupled configurations, the gain is configured properly at 2 V/V (6 dB). The SAG pin is part of the negative
feedback network. Thus, the capacitors and traces should be constructed as close as possible to the THS7303 to
minimize parasitic issues. Failure to do so may result in ringing of the video signal.
If these large capacitors must be placed further than 15 mm away from the THS7303, it is recommended that a
0.01-μF capacitor be placed between the output of the channel and the SAG pin. This capacitor should be placed
as close as possible to the THS7303 to minimize stray capacitance and inductance issues. Since SAG correction
targets the low frequency operation area, there is no drawback of adding this high frequency capacitor to the
circuit.
When SAG correction is used, the low-frequency gain is higher than the high-frequency gain (8.1 dB versus 6
dB). This gain counter acts the attenuation of the signal because of the increase in the 47-μF capacitor
impedance. This amplifier gain increase is determined by the 33-μF capacitor (and associated internal resistor
values) and causes a Q enhancement to occur at low frequencies (typically at about 15 Hz). The ratio of these
capacitor values determines the frequency and amplitude of this enhancement.
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The internal resistor values were chosen to optimize the system while using the 47-μF and 33-μF capacitors, and
to approximate the performance of a single 330-μF capacitor. These capacitors can be a different value if
desired, but the characteristics of the system are altered accordingly. For example, if 22-μF capacitors are used
for both sections, then there are increases in line tilt and field tilt. For some systems, this may be considered
acceptable (for example, 720p Y' signals with the associated faster line rates). Using larger values, such as 68
μF and 47 μF respectively, decreases field time distortion even further, and approaches the performance of a
single 470-μF capacitor.
It is important to note that the dc gain is about 2.55 V/V. Thus, if the input has a dc bias, the output dc bias is
2.55 times the input. For example, this results in an output bias point of 355 mV for the dc + 135 mV shift.
Additionally, if the ac bias input mode is selected, the dc operating point is VS+/4 × 2.55, or 2.1 V with 3.3-V
supply and 3.2 V with 5-V supply. This additional offset should not hinder the performance of the THS7303
because there is still plenty of voltage headroom between the dc operating point and the rail-to-rail output
capability.
One possible concern about this configuration is that the low-frequency gain enhancement may cause saturation
of the signal when low power-supply voltages (such as 3 V) are used. The internal resistors were chosen to
minimize the low-frequency gain so that saturation is minimized. Other SAG correction devices have much higher
low-frequency gain (10 dB or higher), which when coupled with low power-supply voltages, can easily create
clipping on the output of the amplifier, both dynamically and at dc. Other SAG correction devices do not use a
resistor in series with the SAG pin. Neglecting this resistor can result in a large Q enhancement causing possible
saturation issues. These systems typically require much larger capacitor values to minimize this problem, which
ultimately minimizes the benefits of SAG correction.
Figure 67 shows a SAG-corrected configuration for the THS7303. If a S-Video chroma channel is being
configured, there is no reason for SAG correction because the coupling capacitor is typically small at 0.1 μF.
Thus, tying the output pin directly to the SAG output pin is recommended along with a 0.1-μF capacitor.
Note that increasing the gain of the THS7303 can be easilly accomplished by using the SAG pin. Simply placing
a resistor, RSAG, between the SAG pin and GND increases the gain by forming a resistor divider on the signal
feedback path. The resulting gain becomes VOUT/VIN = 2.553 + (1268 / (150 + RSAG)).
3.3 V
DAC /
Encoder
(THS8200)
HDTV
480i
576i
480p
576p
720p
1080i
1080p
47 mF
+
Y’
R
R
DC + 135 mV
1
NC
2
CH.1 IN A
CH.1 OUT 19
3
CH.2 IN A
CH. 1 SAG 18
4
CH.3 IN A
CH.2 OUT 17
NC 20
AC STC
R
5
CH.1 IN B
CH. 2 SAG 16
6
CH.2 IN B
CH.3 OUT 15
7
CH.3 IN B
CH. 3 SAG 14
8
I 2C-A1
SCL 13
9
I 2C-A0
SDA 12
AC Bias
AC Bias
0.1 mF
Y’
75 W
1 mF
P’ B
10 GND
75 W
P’B
Out
75 W
47 mF
+
*
33 mF
+
DC + 135 mV
P’R
Y’
Out
33 mF
+
DC + 135 mV
P’B
75 W
75 W
*
47 mF
+
*
33 mF
+
0.01 mF
75 W
+Vs
VS + 11
75 W
75 W
P’R
Out
+
* (See Note A)
100 mF
2
IC
Controller
1 mF
P’R
75 W
External
Input
A.
If the SAG correction capacitors are more than 15 mm from the THS7313, add a 0.01μF capacitor as shown.
Figure 67. Typical Y'P' BP' R System Driving SAG Corrected AC-Coupled Video Lines
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INCREASING GAIN
The gain of the THS7303 can easily be increased by using the SAG pin. As a result of the resistor configuration,
a T-network in the feedback path is formed. This feedback path allows for the SAG function to work properly, but
at the same time it allows for higher gains than the default 2 V/V (6 dB). Figure 68 shows how gain is easily
increased for each channel. Be sure to keep the RG resistor as close as possible to the SAG pin to minimize any
stability concerns.
Internal
Circuitry
Signal
+
Out
-
75 W
470 mF
(Optional)
675 W
75 W
SAG
1 kW
878 W
Video
Out
150 W
RG
Figure 68. Increasing Output Gain of the THS7303
The formula for the gain becomes:
Gain (V/V) = 2.553 +
1268
150 + RG
or
RG (W) =
1268
- 150
Gain (V/V) - 2.553
For example, if the desired gain is 5.6 V/V, then RG should be 267 Ω. Note that the internal resistors do have
tolerances associated with the respective absolute values. Because of the silicon process, resistor-to-resistor
matching is very tight when looked at as a ratio to each other. Compared to an external resistor, however, there
is a greater variation in the gain of the system.
There are a few drawbacks when implementing this feature. One concern is that the SAG functionality no longer
can be used. A second drawback is that the offset voltage increases proportionally with the gain. For example, if
DC + Shift mode is used (normally, this mode has approximately 290-mV offset with 2-V/V gain), then with
5.6-V/V gain the output offset voltage becomes 145 mV × 5.6 V/V = 812 mV. As a result of this higher offset and
the potential risk of clipping of the signal on the high side, using a higher supply voltage, such as 5 V, is
recommended.
One possible option if a 3.3-V supply is desired is to use dc-only input without the level shift. The output offset is
nominally 35 mV × Gain (V/V); or, for this example, 35 mV × 5.6 V/V = 196 mV. Even with a 100%
color-saturated CVBS signal, there should be no clipping on the high side.
One benefit of using the THS7303 for higher gain versus using the THS7353 device is the gain bandwidth
product (GBP) of the output amplifier; this characteristic becomes more important with the THS7353 because the
THS7353 is unity gain while the THS7303 is specified with a 2-V/V gain. For example, the THS7303 has a
bypass mode bandwidth of 190-MHz with a gain of 2 V/V. If the gain is increased to 4 V/V, then the bandwidth
should decrease to approximately 95 MHz. This increase should have minimal impact on any of the filter
characteristics. In comparison, the THS7353 has a bypass mode bandwidth of 150 MHz. If the THS7353 is
configured for a gain of 4 V/V, the bandwidth drops to approximately 37.5 MHz, and has an impact on the
performance of the 35-MHz filter.
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LOW-PASS FILTER AND BYPASS MODES
Each channel of the THS7303 incorporates a fifth-order low-pass filter. These video reconstruction filters
minimize DAC images from being passed onto the video receiver. Depending on the receiver design, failure to
eliminate these DAC images can cause picture quality problems due to aliasing of the ADC. Another benefit of
the filter is smoothing out aberrations in the signal that some DACs produce if their own internal filtering is not
adequate. This smoothing helps with picture quality and insures the signal meets video bandwidth requirements.
Each filter has a Butterworth characteristic associated to it. The benefit of the Butterworth response is that the
frequency response is flat, with a relatively steep initial attenuation at the corner frequency. The problem with this
characteristic is that the group delay rises near the corner frequency. Group delay is defined as the change in
phase (radians/second) divided by a change in frequency. An increase in group delay corresponds to a time
domain pulse response that has overshoot and some possible ringing associated with the overshoot.
The use of other type of filters, such as elliptic or chebyshev, are not recommended for video applications
because of their very large group delay variations near the corner frequency, resulting in significant overshoot
and ringing. While these elliptic or chebyshev filters may help meet the video standard specifications with respect
to amplitude attenuation, their group delay is well beyond the standard specifications. Couple this with the fact
that video can go from a white pixel to a black pixel over and over again, ringing can easily occur. Ringing
typically causes a display to have ghosting or fuzziness appear on the edges of a sharp transition. On the other
hand, a Bessel filter has an ideally flat group delay response, but the rate of attenuation is typically too low for
acceptable image rejection. Thus, the Butterworth filter is a respectable compromise for both attenuation and
group delay.
The THS7303 filter has a slightly lower group delay variation near the corner frequency compared to an ideal
Butterworth filter. This results in a time domain pulse response which still has some overshoot, but not as much
as a true Butterworth filter. Additionally, the initial rate of attenuation in the frequency response is not as fast as
an ideal Butterworth response, but it is an acceptable initial rate of attenuation considering the pulse and group
delay characteristic benefits.
The THS7303 filters have a nominal corner (–3 dB) frequency selectable at 9 MHz, 16 MHz, and 35 MHz along
with a bypass mode. The 9-MHz filter is ideal for standard definition (SD) NTSC, PAL, and SECAM composite
video (CVBS) signals. It is also useful for S-Video signals (Y’C’), 480i / 576i Y’P’BP’R , G'B'R', and Y’U’V’ video
signals. The –3-dB corner frequency was designed to be 9 MHz to allow a maximally flat video signal while
achieving over 40-dB of attenuation at 27 MHz—a common frequency between the ADC second and third
Nyquist zones found in many video receivers. This is important because any signal appearing around this
frequency can appear in the baseband as a result of aliasing effects of an analog-to-digital converter found in a
receiver.
The 9-MHz filter frequency was chosen to account for process variations in the THS7303. To ensure the required
video frequencies are the least affected, the filter corner frequency must be high enough to allow for component
variations. Another consideration is the attenuation must be large enough to ensure the
anti-aliasing/reconstruction filtering meets the system demands. Thus, the selection of the filter frequencies was
not chosen arbitrarily.
The 16-MHz filter was designed to pass 480p and 576p Y’P’BP’R and G'B'R' video signals, sometimes referred as
enhanced definition (ED). Additionally, this filter can be used to pass computer VGA signals with flat frequency
response in the video spectrum. The 16-MHz filter can also be used for SD signals to ensure there is no
amplitude aberration, and to have an exceptional low group delay within the SD video frequency range.
The 35-MHz filter is designed to pass high definition (HD) 720p and 1080i Y’P’BP’R video signals along with
G’B’R’ (R’G’B’) SVGA and XGA signals. If a 4:2:2 system is used, the P’BP’R channels do not require the full
bandwidth as required by the Y’ channel. However, it is still recommended to use the same filter frequency of the
Y’ channel to match the group delay and timing of all three signals. Otherwise, extra delay compensation is
required to minimize timing variations. This filter is also useful for passing 480p/576p signals with little amplitude
or group delay variations within the ED frequency range.
The THS7303 bypass mode has a 190-MHz bandwidth (–3 dB) and a 300 V/μs slew rate to pass G’B’R’ (R’G’B’)
SXGA and UXGA signals with little degradation. This bypass mode is also useful for HDTV 1080p signals that
require a 60-MHz video signal bandwidth.
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The I2C interface of the THS7303 allows each channel to be configured totally independent of the other
channels. One of the benefits is that a multiple output encoder (or DAC) can be routed through one THS7303
with the proper input configuration and low-pass filter required regardless of the signal. This is useful for a
portable system or in a low-cost system where only one set (or two sets in parallel) is desired on the output of
the system. An update of the I2C commands changes the THS7303 channels. An example is shown in Figure 69
where the input MUX allows for one set of HDTV signals to be put into the THS7303, and then through an I2C
update, a SDTV set of signals is sent through the THS7303 with the proper input mode and low-pass filters.
3.3 V
Y’
R
DC + 135 mV
1 NC
P’ B
R
75 W
NC 20
CH.1 OUT 19
3 CH.2 IN A
CH.1 SAG 18
4 CH.3 IN A
CH.2 OUT 17
5 CH.1 IN B
CH.2 SAG 16
6 CH.2 IN B
CH.3 OUT 15
7 CH.3 IN B
CH.3 SAG 14
330 mF
(See Note A)
DC + 135 mV
R
DC + 135 mV
S-Video
Y’
DC + 135 mV
R
S-Video
C’
8 I2C-A1
SCL 13
9 I2C-A0
SDA 12
10 GND
VS +
330 mF
75 W
+
75 W
+Vs
100 mF
2
CVBS
IC
Controller
R
A.
Video
Out 3
(See Note A)
+
0.01 mF
Video
Out 2
75 W
11
R
75 W
+
DC + 135 mV
P’R
75 W
+
2 CH.1 IN A
DC + 135 mV
DAC /
Encoder
Video
Out 1
330 mF
(See Note A)
Due to the high frequency content of the video signal, it is recommended, but not required, to add a 0.01-μF capacitor
in parallel with these large capacitors.
Figure 69. Typical SD/ED/ and HD Video and SDTB Encoder DAC Driving a Single THS7303
Although the circuit of Figure 69 conserves space and cost, the reuse of the output connections may not be the
best solution. For a complete 6-channel system, it is better to use the THS7303 and the THS7313 (see
SLOS483) together, as shown in Figure 70. The THS7313 is targeted for SDTV signals and is limited to an
8-MHz filter. As discussed in the I2C section, it is easy to have both parts in one system because the I2C address
of each part can be one of four discrete addresses by the logic appearing on the I2C-A1 and I2C-A0 lines.
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470 mF
(See Note A)
+
DC + 135 mV
R
(130 W)
THS7303
1 NC
R
(130 W)
DC + 135 mV
DAC /
Encoder
CH.1 OUT 19
3 CH.2 IN A
CH.1 SAG 18
4 CH.3 IN A
CH.2 OUT 17
5 CH.1 IN B
CH.2 SAG 16
6 CH.2 IN B
CH.3 OUT 15
7 CH.3 IN B
CH.3 SAG 14
AC Bias
AC Bias
Y’
Y’
75 W
8 I2C-A1
SCL 13
9 I2C-A0
SDA 12
10 GND
470 mF
(See Note A)
75 W
+
470 mF
(See Note A)
+
P’R
Out
1 mF
75 W
75 W
75 W
3.3 V
VS + 11
+
P’B
0.01 mF
75 W
1 mF
P’R
75 W
P’B
Out
AC STC
0.1 mF
P’B
Y’
Out
NC 20
2 CH.1 IN A
DC + 135 mV
R
(130 W)
3.3 V
75 W
100 mF
2
IC
Controller
2
I C Address = 0101100
P’R
75 W
CVBS
External
Input
(See Note A)
THS7313
1 NC
R
(130 W)
S-Video
C’
CBVS
Out
470 mF
DC + 135 mV
R
(130 W)
S-Video
Y’
DC + 135 mV
75 W
NC 20
2 CH.1 IN A
CH.1 OUT 19
3 CH.2 IN A
CH. 1 SAG 18
4 CH.3 IN A
CH.2 OUT 17
5 CH.1 IN B
CH. 2 SAG 16
6 CH.2 IN B
CH.3 OUT 15
7 CH.3 IN B
CH. 3 SAG 14
470 mF
(See Note A)
AC STC
AC Bias
+VS
CBVS
75 W
8 I2C-A1
SCL 13
9 I2C-A0
SDA 12
10 GND
0.1 mF
0.1 mF
C’
Out
75 W
75 W
75 W
3.3 V
VS+ 11
S-Video Y’
Y’
Out
S-Video
AC STC
0.1 mF
75 W
+
DC + 135 mV
R
(130 W)
75 W
+
+
0.1 mF
75 W
2
0.1 mF
I C Address = 0101110
100 mF
2
IC
Controller
S-Video C’
75 W
External
Input
A.
Due to the high frequency content of the video signal, it is recommended, but not required, to add a 0.01-μF capacitor
in parallel with these large capacitors.
Figure 70. Typical 6-Channel SDTV/EDTV/HDTV Encoder Interfacing to a THS7303 and a THS7313
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BENEFITS OF THS7303 OVER PASSIVE FILTERING
Two key benefits of using an integrated filter system such as the THS7303 over a passive system are PCB area
and filter variations. The small TSSOP-20 package for three video channels is much smaller over a passive RLC
network, especially a 5-pole passive network that cannot easilly change filter corner frequencies. Add in the fact
that inductors normally have ±15% to ±20% tolerance, and capacitors typically have ±10% tolerances or more.
Using a Monte Carlo analysis shows that the filter corner frequency (–3 dB), flatness (–1 dB), Q factor (or
peaking), and channel-to-channel delay have wide variations. These variations can lead to potential performance
and quality issues in mass-production environments. The THS7303 solves most of these problems with the
corner frequency being essentially the only variable.
One concern about an active filter in an integrated circuit is the variation of the filter characteristics when the
ambient temperature and the subsequent die temperature change. To minimize temperature effects, the
THS7303 uses low temperature coefficient resistors and high-quality, low temperature coefficient capacitors
found in the BiCom-3 process. The filters have been specified by design to account for process variations and
temperature variations to maintain proper filter characteristics. This maintains the low channel-to-channel time
delay that is required for proper video signal performance.
Two additional benefits of a THS7303 over a passive RLC filter are the input and output impedances. The input
impedance presented to the DAC varies significantly with a passive network and may cause voltage variations
over frequency. The THS7303 input impedance is very high, depending on the input bias mode configuration.
This impedance, plus the 2-pF input capacitance along with the PCB trace capacitance, has negligible impact on
the input impedance. Therefore, the voltage variation appearing at the DAC output is significantly better
controlled with the THS7303.
On the output side of the filter, a passive filter also has a wide impedance variation over frequency. The EIA770
specifications require that the return loss be at least 25dB over the video frequency range of usage. For a video
system, this condition implies the source impedance (including the source, the series resistor, and the filter) must
be better than 75Ω +9/-8Ω. The THS7303 is an op amp that approximates an ideal voltage source. A voltage
source is desirable because the output impedance is very low and can source and sink current. To properly
match the transmission line characteristic impedance of a video line, a 75-Ω series resistor is placed on the
output. To minimize reflections and maintain a good return loss, this output impedance must maintain a 75-Ω
impedance. The wide impedance variation of a passive filter cannot ensure this consistent performance. The
THS7303 has approximately 0.7-Ω of output impedance at 6.75-MHz with the SD filter, and approximately 2.5-Ω
at 30MHz with the HD filter. Thus, a system is matched much better with a THS7303 compared to a passive
filter.
One last benefit of the THS7303 over a passive filter is power dissipation. A DAC driving a video line must be
able to drive a 37.5-Ω load. This includes the receiver 75-Ω resistor and the 75-Ω impedance matching resistor
next to the DAC to maintain the source impedance requirement. This forces the DAC to drive at least 1.25 VPEAK
(100% Saturation CVBS)/37.5Ω = 33.3mA. A DAC is a current-steering element and this amount of current flows
internally to the DAC even if the output is 0-V. Thus, power dissipation in the DAC may be very high, especially
when three channels are being driven. Using the THS7303, with a high input impedance and the capability to
drive up to two video lines per channel, can reduce the DAC power dissipation significantly because the
resistance the DAC is driving can be substantially increased. It is common to set this in a DAC by a
current-setting resistor on the DAC. Thus, the resistance can be 300-Ω or more. This substantially reduces the
current drive demands from the DAC and saves a substantial amount of power. For example, if driving a 37.5-Ω
load, a 3.3-V, three-channel DAC dissipates 330mW just for the steering current capability (3 ch × 33.3 mA × 3.3
V). With a 300-Ω load, the DAC power dissipation would only be 41mW (3 ch × 4.16 mA × 3.3 V) as a result of
the reduced current steering.
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I2C INTERFACE NOTES
The I2C interface is used to access the internal registers of the THS7303. I2C is a two-wire serial interface
developed by Philips Semiconductor (see the I2C-Bus Specification, Version 2.1, January 2000). The bus
consists of a data line (SDA) and a clock line (SCL) with pull-up structures. When the bus is idle, both SDA and
SCL lines are pulled high. All the I2C compatible devices connect to the I2C bus through open drain I/O pins,
SDA and SCL. A master device, usually a microcontroller or a digital signal processor, controls the bus. The
master is responsible for generating the SCL signal and device addresses. The master also generates specific
conditions that indicate the START and STOP of data transfer. A slave device receives and/or transmits data on
the bus under control of the master device. The THS7303 works as a slave and supports the standard mode
transfer (100 kbps) and fast mode transfer (400 kbps) as defined in the I2C-Bus specification. The THS7303 has
been tested to be fully functional but not ensured with the high-speed mode (3.4 Mbps).
The basic I2C start and stop access cycles are shown in Figure 71.
The basic access cycle consists of:
• A start condition
• A slave address cycle
• Any number of data cycles
• A stop condition
SDA
SCL
S
P
Start
Condition
Stop
Condition
Figure 71. I2C Start and Stop Conditions
GENERAL I2C PROTOCOL
•
•
•
•
38
The master initiates data transfer by generating a start condition (S). A start condition exists when a
high-to-low transition occurs on the SDA line while SCL is high, as shown in Figure 71. All I2C-compatible
devices should recognize the start condition.
The master then generates the SCL pulses and transmits the 7-bit address and the read/write direction bit
R/W on the SDA line. During all transmissions, the master ensures that data are valid. A valid data condition
requires the SDA line to be stable during the entire high period of the clock pulse (see Figure 72). All devices
recognize the address sent by the master and compare it to their internal fixed addresses. Only the slave
device with a matching address generates an acknowledge (see Figure 73) by pulling the SDA line low during
the entire high period of the ninth SCL cycle. On detecting this acknowledge, the master knows that a
communication link with a slave has been established.
The master generates further SCL cycles to either transmit data to the slave (R/W bit 1) or receive data from
the slave (R/W bit 0). In either case, the receiver must acknowledge the data sent by the transmitter. Thus, an
acknowledge signal (A) can either be generated by the master or by the slave, depending on which one is the
receiver. The 9-bit valid data sequences consisting of 8-bit data and 1-bit acknowledge can continue as long
as necessary (see Figure 74).
To signal the end of the data transfer, the master generates a stop condition (P) by pulling the SDA line from
low to high while the SCL line is high (see Figure 71). This releases the bus and stops the communication link
with the addressed slave. All I2C-compatible devices must recognize the stop condition. Upon the receipt of a
stop condition, all devices know that the bus is released, and they wait for a start condition followed by a
matching address.
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SDA
SCL
Data Line
Stable;
Data Valid
Change of Data Allowed
Figure 72. I2C Bit Transfer
Data Output
by Transmitter
Not Acknowledge
Data Output
by Receiver
Acknowledge
SCL From
Master
1
8
2
9
S
Clock Pulse for
Acknowledgement
Start
Condition
Figure 73. I2C Acknowledge
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
SCL
SDA
Stop
MSB
Acknowledge
Slave Address
Acknowledge
Data
Figure 74. I2C Address and Data Cycles
During a write cycle, the transmitting device must not drive the SDA signal line during the acknowledge cycle, so
that the receiving device may drive the SDA signal low. After each byte transfer following the address byte, the
receiving device pulls the SDA line low for one SCL clock cycle. A stop condition is initiated by the transmitting
device after the last byte is transferred. An example of a write cycle can be found in Figure 75 and Figure 76.
Note that the THS7303 does not allow multiple write transfers to occur. See the Example: Writing to the
THS7303 section for the proper procedure on writing to the THS7303.
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During a read cycle, the slave receiver acknowledges the initial address byte if it decodes the address as its
address. Following this initial acknowledge by the slave, the master device becomes a receiver and
acknowledges data bytes sent by the slave. When the master has received all of the requested data bytes from
the slave, the not acknowledge (A) condition is initiated by the master by keeping the SDA signal high just before
it asserts the stop condition. This sequence terminates a read cycle, as shown in Figure 77 and Figure 78. Note
that the THS7303 does not allow multiple read transfers to occur. See the Example: Reading from the THS7303
section for the proper procedure on reading from the THS7303.
From Receiver
S
Slave Address
W
A
DATA
A
DATA
A = No Acknowledge (SDA High)
A = Acknowledge
S = Start Condition
P = Stop Condition
W = Write
R = Read
P
A
From Transmitter
Figure 75. I2C Write Cycle
Acknowledge
(From Receiver)
Start
Condition
A6
A5
A0
A1
R/W ACK
D7
Acknowledge
(Transmitter)
Acknowledge
(Receiver)
D6
D0
D1
ACK
D6
D7
D1
D0
ACK
SDA
2
First Data
Byte
I C Device Address and
Read/Write Bit
Other
Data Bytes
Stop
Condition
Last Data Byte
Figure 76. Multiple Byte Write Transfer
S
Slave Address
R
A
DATA
A
DATA
A
A = No Acknowledge (SDA High)
A = Acknowledge
S = Start Condition
P = Stop Condition
W = Write
R = Read
P
Transmitter
Receiver
Figure 77. I2C Read Cycle
Start
Condition
SDA
Acknowledge
(From
Receiver)
A6
A0
R/W
ACK
I 2 C Device Address and
Read/Write Bit
D7
Not
Acknowledge
(Transmitter)
Acknowledge
(From
Transmitter)
D0
First Data
Byte
ACK
D7
Other
Data Bytes
D6
D1
D0
Last Data Byte
ACK
Stop
Condition
Figure 78. Multiple Byte Read Transfer
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I2C DESIGN NOTES: ISSUES AND SOLUTIONS
The THS7303 requires some special attention to the I2C function that is usually not required. These are known
design issues, but there are simple work-arounds that allow the THS7303 to perform within any I2C system.
The first known I2C issue is with respect to the power-up condition. On power up, the THS7303 registers are in a
random state from device to device. The registers remain in this random state until a valid write sequence is
made to the THS7303. A total of 9 bytes of data completely configure all channels of the THS7303. Therefore,
configuring the THS7303 should be done on power-up of the system. Note that one such random state
(acknowledge state or ACK) can be engaged. While ACK is engaged, the THS7303 pulls the SDA line low and
the master cannot send data to any device on the I2C bus. To circumvent this state, at least one SCL cycle must
be completed and then the acknowledge state disengages.
While one SCL cycle normally eliminates any issues, the internal FIFO buffer may have random bits internally to
the THS7303. To completely clear all eight bits of this buffer, run 8-cycles (or 8-bits or 1-byte) on the SCL line.
While there are several different methods to run SCL cycles, the simplest is to have the master send a 0x00 hex
code to the I2C bus on power-up, ignoring any ACK state. Note that the SCL cycle should occur only after the
power-supply voltage of the THS7303 is at least 2.7 V. Failure to follow this step may cause the THS7303 to
ignore the SCL cycles.
Another known issue with the I2C function is that the internal SDA/SCL buffers are susceptible to high-frequency
noise. This noise can come from switch-mode power supplies, digital processors, or other high-frequency noise
generators. While the THS7303 includes buffers with hysterisis on the front-end, these are placed after a
low-gain CMOS buffer used as an ESD protection element. The noise susceptibility in real-world systems is very
low; however, it can be an issue in some noisy or compact systems. The simple solution, which has shown to
solve the issue, is to place a RC filter on each I2C line. Real-world results show that using a 100-Ω resistor in
series on each SDA/SCL line along with a 22 pF capacitor from each SDA/SCL line to ground eliminates the
noise susceptibility issue. These RC filters should be placed as close as possible to the THS7303 SDA/SCL input
pins. Other solutions have shown that not using a series resistor and only using a larger value capacitor (such as
100 pF to 220 pF) has worked, but the RC solution is more robust.
One last real-world issue that has appeared relates to the value of the pull-up resistor on the SDA and SCL lines.
While the standard allows for between 2 kΩ and 19 kΩ for this pull-up resistor, practice has shown that keeping
this value lower works best. Typical values should be between 2 kΩ and 3.3 kΩ, with 2.7 kΩ being the most
common.
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SLAVE ADDRESS
The slave address byte is the first byte received following the start condition from the master device. The first five
bits (MSBs) of the address are factory preset to '01011'. The next two bits of the THS7303 address are controlled
by the logic levels appearing on the I2C A1 and I2C A0 pins. The I2C A1 and I2C A0 address inputs can be
connected to VS+ for logic 1, GND for logic 0, or can be actively driven by TTL/CMOS logic levels. The device
address is set by the state of these pins and is not latched. Thus, a dynamic address control system can be used
to incorporate several devices on the same system. Up to four THS7303 devices can be connected to the same
I2C bus without requiring additional glue logic. Table 1 lists the possible addresses for the THS7303
Table 1. THS7303 Slave Addresses
SELECTABLE WITH
ADDRESS PINS
FIXED ADDRESS
READ/WRITE
BIT
BIt 7 (MSB)
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2 (A1)
BIT 1 (A0)
BIT 0
0
1
0
1
1
0
0
0
0
1
0
1
1
0
0
1
0
1
0
1
1
0
1
0
0
1
0
1
1
0
1
1
0
1
0
1
1
1
0
0
0
1
0
1
1
1
0
1
0
1
0
1
1
1
1
0
0
1
0
1
1
1
1
1
CHANNEL SELECTION REGISTER DESCRIPTION (SUB-ADDRESS)
The THS7303 operates using only a single-byte transfer protocol similar to Figure 75 and Figure 77. The internal
sub-address registers, and the functionality of each, are found in Table 2. When writing to the device, it is
required to send one byte of data to the corresponding internal sub-address. If control of all three channels is
desired, then the master must cycle through all the sub-addresses (channels) one at a time; see the Example:
Writing to the THS7303 section for the proper procedure of writing to the THS7303.
During a read cycle, the THS7303 sends the data in its selected sub-address (or channel) in a single transfer to
the master device requesting the information. See the Example: Reading from the THS7303 section for the
proper procedure on reading from the THS7303.
Table 2. THS7303 Channel Selection Register Bit Assignments
42
REGISTER NAME
BIT ADDRESS
(b7b6b5....b0)
Channel 1
0000 0001
Channel 2
0000 0010
Channel 3
0000 0011
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CHANNEL REGISTER BIT DESCRIPTIONS
Each bit of the sub-address (channel selection) control register as described in Table 2 allows the user to
individually control the functionality of the THS7303. The benefit of this process allows the functionality of each
channel to be controlled independently of the other channels. The bit description is decoded in Table 3.
Table 3. THS7303 Channel Register Bit Decoder Table
BIT
(MSB)
7, 6
5
4,3
2, 1, 0
(LSB)
FUNCTION
STC Low-Pass Filter Selection
Input MUX Selection
Low-Pass Filter
Frequency Selection
Input Bias Mode Selection and
Disable Control
BIT
VALUE(S)
RESULT
00
500-kHz filter—Useful for 9-MHz video LPF
01
2.5-MHz filter—Useful for 16-MHz video LPF
10
5-MHz filter—Useful for 35-MHz/bypass video LPF
11
5-MHz filter—Useful for 35-MHz/bypass video LPF
0
Input A select
1
Input B select
00
9-MHz LPF—Useful for SDTV, S-Video, 480i/576i
01
16-MHz LPF—Useful for EDTV 480p/576p and VGA
10
35-MHz LPF—Useful for 720p, 1080i, and SVGA/XGA
11
Bypass LPF—Useful for 1080p and SXGA/UXGA
000
Disable channel—Conserves power
001
Channel on—Mute function—No output
010
Channel on—DC bias select
011
Channel on—DC bias + 135 mV offset select
100
Channel on—AC bias select
101
Channel on—Sync-tip-clamp with low bias
110
Channel on—Sync-tip-clamp with mid bias
111
Channel on—Sync-tip-clamp with high bias
Bits 7 (MSB) and 6 – Controls the AC Sync-Tip-Clamp Low-Pass Filter function. If ac STC mode is not used, this
function is ignored.
Bit 5 – Controls the input MUX of the THS7303.
Bits 4 and 3 – Controls the fifth-order low-pass filter –3 dB corner frequency or the bypass mode of operation.
Bits 2, 1, and 0 (LSB) – Selects the input biasing of the THS7303 and the power-savings function. When
sync-tip-clamp is selected, the dc input sink bias current is also selectable.
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EXAMPLE: WRITING TO THE THS7303
To initiate a write operation to the THS7303, an I2C master generates a start condition (S) followed by the
THS7303 I2C address (as shown below) in MSB first bit order, followed by a '0' to indicate a write cycle. After
receiving an acknowledge from the THS7303, the master presents the sub-address (channel) it wants to write
consisting of one byte of data, MSB first. The THS7303 acknowledges the byte after completion of the transfer.
Finally the master presents the data it wants to write to the register (channel) and the THS7303 acknowledges
the byte. The I2C master then terminates the write operation by generating a stop condition (P). Note that the
THS7303 does not support multi-byte transfers. To write to all three channels (or registers), this procedure must
be repeated for each register, one series at a time (that is, repeat steps 1 through 8 for each channel).
Example of THS7303 Write Operation:
Step 1
0
2
I C Start (Master)
S
Step 2
7
6
5
4
3
2
1
0
I2C General Address (Master)
0
1
0
1
1
X
X
0
Where each X logic state is defined by I2C A1 and I2C A0 pins being tied to either VS+ or GND.
Step 3
9
I2C Acknowledge (Slave)
A
Step 4
2
I C Write Channel Address (Master)
7
6
5
4
3
2
1
0
0
0
0
0
0
0
Addr
Addr
Where Addr is determined by the values shown in Table 2.
Step 5
9
2
I C Acknowledge (Slave)
A
Step 6
I2C Write Data (Master)
7
6
5
4
3
2
1
0
Data
Data
Data
Data
Data
Data
Data
Data
Where Data is determined by the values shown in Table 3.
Step 7
9
I2C Acknowledge (Slave)
A
Step 8
0
2
I C Stop (Master)
P
For Step 6, an example of the proper bit control for selecting Input B of the MUX, a 720p Y’ channel signal with
ac STC lowest line tilt and with the shortest sync filter is 1111 0101.
For Step 7, the ACK state means the THS7303 pulls the SDA line low until the next cycle on the SCL line.
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EXAMPLE: READING FROM THE THS7303
The read operation consists of two phases. The first phase is the address phase, where an I2C master initiates a
write operation to the THS7303 by generating a start condition (S) followed by the THS7303 I2C address in MSB
first bit order, followed by a '0' to indicate a write cycle. After receiving acknowledges from the THS7303, the
master presents the sub-address (channel) of the register it wants to read. After the cycle is acknowledged (A),
the master terminates the cycle immediately by generating a stop condition (P).
The second phase is the data phase. In this phase, an I2C master initiates a read operation to the THS7303 by
generating a start condition followed by the THS7303 I2C address in MSB first bit order, followed by a '1' to
indicate a read cycle. After an acknowledge from the THS7303, the I2C master receives one byte of data from
the THS7303. After the data byte has been transferred from the THS7303 to the master, the master generates a
not acknowledge (A) followed by a stop. As with the write function, in order to read all channels, steps 1 through
11 must be repeated for each channel desired.
Example of THS7303 Read Phase 1:
Step 1
0
I2C Start (Master)
S
Step 2
7
6
5
4
3
2
1
0
I2C General Address (Master)
0
1
0
1
1
X
X
0
Where each X logic state is defined by I2C A1 and I2C A0 pins being tied to either VS+ or GND.
Step 3
9
I2C Acknowledge (Slave)
A
Step 4
2
I C Read Channel Address (Master)
7
6
5
4
3
2
1
0
0
0
0
0
0
0
Addr
Addr
Where Addr is determined by the values shown in Table 2.
Step 5
9
I2C Acknowledge (Slave)
A
Step 6
0
I2C Start (Master)
P
Example of THS7303 Read Phase 2:
Step 7
0
I2C Start (Master)
S
Step 8
7
6
5
4
3
2
1
0
I2C General Address (Master)
0
1
0
1
1
X
X
1
Where each X logic state is defined by I2C A1 and I2C A0 pins being tied to either VS+ or GND.
Step 9
9
I2C Acknowledge (Slave)
A
Step 10
I2C Read Data (Slave)
7
6
5
4
3
2
1
0
Data
Data
Data
Data
Data
Data
Data
Data
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Where Data is determined by the logic values contained in the channel register.
Step 11
9
I2C Not-Acknowledge (Master)
A
Step 12
0
2
I C Stop (Master)
46
P
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EVALUATION MODULE
To evaluate the THS7303, an evaluation module (EVM) is available. Because the THS7303 is controlled by the
I2C lines, additional control is required rather than simple switches. To keep the control as easy as possible, a
USB-to-I2C interface was designed onto the EVM. A computer running either Windows® 2000 or XP is then
connected to the EVM through the USB cable. A computer program interface was created for graphical control of
the THS7303 that allows both read and write functions to be performed. The EVM comes with a CD-ROM loaded
with all the required software to install the command software onto the computer.
To program the THS7303, select the channel, the filter, and the mode of operation and then click the Execute
button. The Req Done light on the computer screen is lit to confirm the command was executed by the THS7303.
The same procedure is done for each channel. To read the THS7303 registers, change the switch to Read,
select the channel, and then click the Execute button. The resulting register content appears in hexadecimal
code.
Note that the USB-to-I2C interface circuitry must be powered by a 3.3-V supply only. Additionally, the I2C circuitry
section must be powered on either at the same time as the THS7303 or before power is applied to the THS7303.
This is because the TAS1020 device must complete reading the EEPROM to program its core. The yellow LED
in the I2C section is lit if the TAS1020 was programmed properly. If this LED is not lit, then the power should be
cycled to reset the USB-to-I2C TAS1020 chip.
The communication between the computer and the THS7303 EVM over USB is not plug-and-play. Instead, the
system must be powered up in sequence for proper communication. Follow this procedure to start the program:
1. Make sure the computer program (THS73x3EVM Control program) is not turned on, and make sure there is
no power applied to the EVM (both 3.3 V and the VA (THS7303) power). Check that the USB cable is
plugged into both the computer and the EVM.
2. Apply both 3.3-V and the VA power to the THS73x3 EVM. The USB ACTIVE LED (D2) must be lit yellow. If
D2 s not lit, then there is a EEPROM communication problem between U2 and U3. This must be corrected
before going any further.
NOTE
It is very important to apply power to the THS7303 EVM and have the yellow LED lit
before starting the program on the computer. Failure to follow this step will result in the
computer program not recognizing the EVM and there will be no communication between
the computer and the EVM. If power is removed for any reason, shutdown the computer
program, apply power to the THS7303 EVM with the yellow LED lit, and then restart the
computer program as indicated here.
3. Configure the I2C address jumpers (JP1 and JP2) for the desired I2C addressing. With the jumpers removed,
the two LSBs are 00.
4. With D2 lit, now start the computer program (THS73x3 EVM Control). Configure the program as desired,
making sure that the address of the THS73x3 matches the jumper settings JP1 and JP2. By default, 00
matches the EVM with the jumpers removed.
5. Once configured, pressing the Execute button writes the code to the THS73x3 EVM and sends the proper
I2C codes to the THS73x3. The computer program should show a green light; this light indicates proper
communication to the THS73x3 is occurring.
Table 4 is a bill of materials; the board layout is found in Figure 79 to Figure 82.
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Table 4. Bill of Materials for THS7303 EVM
ITEM
(1)
48
DESCRIPTION
SMD
SIZE
0805
REFERENCE
DESIGNATOR
PCB
QUANTITY
MANUFACTURER
PART NUMBER (1)
DISTRIBUTOR
PART NUMBER
1
BEAD, FERRITE, 2.5A, 80 OHM
FB1, FB2, FB3
3
(TDK) MPZ2012S331A
(DIGI-KEY) 445-1569-1-ND
2
CAP, 22uF, TAN, 6.3V, 10%, LO ESR
A
C30
1
(AVX) TPSA226K006R0900
(DIGI-KEY) 478-1754-1-ND
3
CAP, 100uF, TAN, 10V, 10%, LO ESR
C
C5
1
(AVX) TPSC107K010R0100
(DIGI-KEY) 478-1765-1-ND
4
OPEN
0805
C2, C3, C8, C11, C12,
C14, C17, C21, C23
9
5
CAP, 33pF, CERAMIC, 50V, NPO
0805
C31, C32
2
(AVX) 08055A330JAT2A
(DIGI-KEY) 478-1310-1-ND
6
CAP, 47pF, CERAMIC, 50V, NPO
0805
C27, C29
2
(AVX) 08055A470JAT2A
(DIGI-KEY) 478-1312-1-ND
7
CAP, 100pF, CERAMIC, 50V, NPO
0805
C34
1
(AVX) 08055A101JAT2A
(DIGI-KEY) 478-1316-1-ND
8
CAP, 1000pF, CERAMIC, 100V, NPO
0805
C33
1
(AVX) 08051A102JAT2A
(DIGI-KEY) 478-1290-1-ND
9
CAP, 0.01uF, CERAMIC, 100V, X7R
0805
C19, C28
2
(AVX) 08051C103KAT2A
(DIGI-KEY) 478-1358-1-ND
10
CAP, 0.1uF, CERAMIC, 50V, X7R
0805
C4, C6, C9, C13, C16,
C22, C25, C26, C43, C44,
Z4
11
(AVX) 08055C104KAT2A
(DIGI-KEY) 478-1395-1-ND
11
CAP, 1uF, CERAMIC, 16V, X7R
0805
C18, C35, C36, C37, C38,
C39, C40, C41, C42, Z5,
Z6
11
(TDK) C2012X7R1C105K
(DIGI-KEY) 445-1358-1-ND
12
CAP, ALUM, 470uF, 10V, 20%
F
C1, C10, C20
3
(CORNELL) AFK477M10F24B
(NEWARK) 97C7597
13
CAP, ALUM, 33uF, 25V, 20%
C
C7, C15, C24
3
(CORNELL) AFK336M25C12B
(NEWARK) 97C7564
14
OPEN
0603
R47, R48, R49, R51
4
15
RESISTOR, 0 OHM
0603
R1, R2, R3, R4, R6, R7,
R19, R20, R23
9
(ROHM) MCR03EZPJ000
(DIGI-KEY) RHM0.0GCT-ND
16
RESISTOR, 2.74K OHM, 1/8W, 1%
0603
R41, R61
2
(ROHM) MCR03EZPFX2741
(DIGI-KEY) RHM2.7KHCT-ND
17
OPEN
0805
R15, R16, R28
3
18
RESISTOR, 0 OHM
0805
R9, R13, R21, Z1, Z2, Z3
6
(ROHM) MCR10EZHJ000
(DIGI-KEY) RHM0.0ACT-ND
19
RESISTOR, 10 OHM, 1/8W, 1%
0805
R39, R44, R45, R52
4
(ROHM) MCR10EZHF10R0
(DIGI-KEY) RHM10.0CCT-ND
20
RESISTOR, 27.4 OHM, 1/8W, 1%
0805
R30, R31
2
(ROHM) MCR10EZHF27.4
(DIGI-KEY) RHM27.4CCT-ND
9
(ROHM) MCR10EZHF75.0
(DIGI-KEY) RHM75.0CCT-ND
21
RESISTOR, 75 OHM, 1/8W, 1%
0805
R5, R8, R10, R11, R12,
R14, R17, R18, R22
22
RESISTOR, 100 OHM, 1/8W, 1%
0805
R50
1
(ROHM) MCR10EZHF1000
(DIGI-KEY) RHM100CCT-ND
23
RESISTOR, 200 OHM, 1/8W, 1%
0805
R26, R27
2
(ROHM) MCR10EZHF2000
(DIGI-KEY) RHM200CCT-ND
24
RESISTOR, 649 OHM, 1/8W, 1%
0805
R33, R60
2
(ROHM) MCR10EZHF0649
(DIGI-KEY) RHM649CCT-ND
25
RESISTOR, 1.0K OHM, 1/8W, 1%
0805
R29
1
(ROHM) MCR10EZHF1001
(DIGI-KEY) RHM1.00KCCT-ND
26
RESISTOR, 1.5K OHM, 1/8W, 1%
0805
R32
1
(ROHM) MCR10EZHF1501
(DIGI-KEY) RHM1.50KCCT-ND
27
RESISTOR, 2.21K OHM, 1/8W, 1%
0805
R34, R35
2
(ROHM) MCR10EZHF2211
(DIGI-KEY) RHM2.21KCCT-ND
Manufacturer part numbers are used for test purposes only.
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Table 4. Bill of Materials for THS7303 EVM (continued)
ITEM
DESCRIPTION
SMD
SIZE
REFERENCE
DESIGNATOR
PCB
QUANTITY
MANUFACTURER
PART NUMBER (1)
DISTRIBUTOR
PART NUMBER
28
RESISTOR, 3.09K OHM, 1/8W, 1%
0805
R43
1
(ROHM) MCR10EZHF3091
(DIGI-KEY) RHM3.09KCCT-ND
29
RESISTOR, 10K OHM, 1/8W, 1%
0805
R24, R25, R40, R42
4
(ROHM) MCR10EZHF1002
(DIGI-KEY) RHM10.0KCCT-ND
30
RESISTOR, 20K OHM, 1/8W, 1%
0805
R46
1
(ROHM) MCR10EZHF2002
(DIGI-KEY) RHM20.0KCCT-ND
31
LED, GREEN
0805
D1
1
(LITE-ON) LTST-C171GKT
(DIGI-KEY) 160-1423-1-ND
32
LED, YELLOW
0805
D2
1
(LITE-ON) LTST-C171YKT
(DIGI-KEY) 160-1431-1-ND
33
IC, CONV, SERIAL TO USB
U3
1
(TI) TAS1020BPFB
(DIGI-KEY) TAS1020BPFB
34
IC, SERIAL, EEPROM, 64K
8-SOIC
U2
1
(MICROCHIP) 24LC64-I/SN
(DIGI-KEY) 24LC64-I/SN-ND
35
CRYSTAL, 6.00MHz., SMT
HCM49
X1
1
(CITIZEN) HCM49-6.000MABJT
(DIGI-KEY) 300-6112-1-ND
36
OPEN
SOT-23
U4, U5
2
37
JACK, BANANA RECEPTANCE, 0.25"
DIA. HOLE
J4, J5, J16, J17
4
(SPC) 813
(NEWARK) 39N867
38
SWITCH, SMD GULL WING
S1
1
(BOURNS) 7914G-1-000E
(DIGI-KEY) 7914G-000ETR-ND
39
CONNECTOR, RCA, JACK, R/A
J1, J2, J12
3
(CUI) RCJ-32265
(DIGI-KEY) CP-1446-ND
40
CONNECTOR, USB, RTANG, FEMALE
J15
1
(ASSMANN) AU-Y1007
(DIGI-KEY) AE1085-ND
J3, J6, J7, J8, J9, J10,
J11, J13, J14
9
(AMPHENOL) 31-5329-72RFX
(NEWARK) 93F7554
4MM
B
41
CONNECTOR, BNC, JACK, 75 OHM
42
HEADER, 0.1" CTRS, 0.025" SQ. PINS
JP1, JP2, JP3
3
(SULLINS) PZC36SAAN
(DIGI-KEY) S1011-36-ND
43
SHUNTS
JP1, JP2, JP3
3
(SULLINS) SSC02SYAN
(DIGI-KEY) S9002-ND
44
TEST POINT, RED
TP1, TP2, TP5, TP6, TP7
5
(KEYSTONE) 5000
(DIGI-KEY) 5000K-ND
45
TEST POINT, BLACK
TP3, TP4
2
(KEYSTONE) 5001
(DIGI-KEY) 5001K-ND
46
IC, THS7303
U1
1
(TI) THS7303PW
47
STANDOFF, 4-40 HEX, 0.625"
LENGTH
4
(KEYSTONE) 1808
(NEWARK) 89F1934
48
SCREW, PHILLIPS, 4-40, .250"
4
(BF) PMS 440 0031 PH
(DIGI-KEY) H343-ND
49
BOARD, PRINTED CIRCUIT
1
EDGE # 6469005 REV.B
2 POS.
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EVM BOARD LAYERS
Figure 79. Top Layer: Signal Layer
50
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Figure 80. Layer Two: Ground Layer
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Figure 81. Layer Three: Power and Ground Layer
52
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Figure 82. Bottom Layer: Signal Layer
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REVISION HISTORY
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision A (December, 2008) to Revision B
Page
•
Added Digital Characteristics section specifications to 3.3-V Electrical Characteristics ...................................................... 4
•
Added Digital Characteristics section specifications to 5-V Electrical Characteristics ......................................................... 6
•
Added Increasing Gain section ........................................................................................................................................... 33
•
Updated Evaluation Module section ................................................................................................................................... 47
Changes from Original (October, 2005) to Revision A
Page
•
Changed format and flow of data sheet to match current standard ..................................................................................... 1
•
Changed Package/Ordering Information table quantities ..................................................................................................... 2
54
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Evaluation Board/Kit Important Notice
Texas Instruments (TI) provides the enclosed product(s) under the following conditions:
This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION PURPOSES
ONLY and is not considered by TI to be a finished end-product fit for general consumer use. Persons handling the product(s) must have
electronics training and observe good engineering practice standards. As such, the goods being provided are not intended to be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including product safety and environmental
measures typically found in end products that incorporate such semiconductor components or circuit boards. This evaluation board/kit does
not fall within the scope of the European Union directives regarding electromagnetic compatibility, restricted substances (RoHS), recycling
(WEEE), FCC, CE or UL, and therefore may not meet the technical requirements of these directives or other related directives.
Should this evaluation board/kit not meet the specifications indicated in the User’s Guide, the board/kit may be returned within 30 days from
the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY SELLER TO BUYER
AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF
MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user indemnifies TI from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge.
EXCEPT TO THE EXTENT OF THE INDEMNITY SET FORTH ABOVE, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY
INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
TI currently deals with a variety of customers for products, and therefore our arrangement with the user is not exclusive.
TI assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or
services described herein.
Please read the User’s Guide and, specifically, the Warnings and Restrictions notice in the User’s Guide prior to handling the product. This
notice contains important safety information about temperatures and voltages. For additional information on TI’s environmental and/or
safety programs, please contact the TI application engineer or visit www.ti.com/esh.
No license is granted under any patent right or other intellectual property right of TI covering or relating to any machine, process, or
combination in which such TI products or services might be or are used.
FCC Warning
This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION PURPOSES
ONLY and is not considered by TI to be a finished end-product fit for general consumer use. It generates, uses, and can radiate radio
frequency energy and has not been tested for compliance with the limits of computing devices pursuant to part 15 of FCC rules, which are
designed to provide reasonable protection against radio frequency interference. Operation of this equipment in other environments may
cause interference with radio communications, in which case the user at his own expense will be required to take whatever measures may
be required to correct this interference.
EVM Warnings and Restrictions
It is important to operate this EVM within the input voltage range of 0 V to 3 V and the output voltage range of 0 V to 5 V .
Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the EVM. If there are questions
concerning the input range, please contact a TI field representative prior to connecting the input power.
Applying loads outside of the specified output range may result in unintended operation and/or possible permanent damage to the EVM.
Please consult the EVM User's Guide prior to connecting any load to the EVM output. If there is uncertainty as to the load specification,
please contact a TI field representative.
During normal operation, some circuit components may have case temperatures greater than +100°C. The EVM is designed to operate
properly with certain components above +100° C as long as the input and output ranges are maintained. These components include but are
not limited to linear regulators, switching transistors, pass transistors, and current sense resistors. These types of devices can be identified
using the EVM schematic located in the EVM User's Guide. When placing measurement probes near these devices during operation,
please be aware that these devices may be very warm to the touch.
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2011, Texas Instruments Incorporated
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PACKAGE OPTION ADDENDUM
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14-Oct-2022
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
Samples
(4/5)
(6)
THS7303PW
ACTIVE
TSSOP
PW
20
70
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
HS7303PW
Samples
THS7303PWG4
ACTIVE
TSSOP
PW
20
70
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
HS7303PW
Samples
THS7303PWR
ACTIVE
TSSOP
PW
20
2000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
HS7303PW
Samples
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of