19-3750; Rev 0; 7/05
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
The MAX9504A/MAX9504B 3V/5V, ground-sensing
amplifiers with a fixed gain of 6dB provide high output
current while consuming only 10nA of current in shutdown mode. The MAX9504A/MAX9504B are ideal for
amplifying DC-coupled video inputs from current digital-to-analog converters (DACs). The output can drive
two DC-coupled 150Ω back-terminated video loads in
portable media players, security cameras, and automotive video applications. The MAX9504B features an
internal 160mV input offset to prevent output sync tip
clipping when the input signal is close to ground.
The MAX9504A/MAX9504B have -3dB large-signal
bandwidth of 42MHz and -3dB small-signal bandwidth
of 47MHz.
The MAX9504A/MAX9504B operate from a single +2.7V
to +5.5V supply and consume only 5mA of supply current. The low-power shutdown mode reduces supply
current to 10nA, making the MAX9504A/MAX9504B ideal
for low-voltage, battery-powered video applications.
The MAX9504A/MAX9504B are available in tiny 6-pin
µDFN (2mm x 2mm) and 6-pin SOT23 packages, and
are specified over the -40°C to +85°C extended temperature range.
Applications
Features
♦ DC-Coupled Input/Output
♦ Drives Two DC-Coupled Video Loads
♦ Direct Connection to Ground-Referenced DAC
♦
♦
♦
♦
♦
42MHz Large-Signal Bandwidth
47MHz Small-Signal Bandwidth
Internal 160mV Input Offset (MAX9504B)
Single-Supply Operation from +2.7V to +5.5V
10nA Shutdown Supply Current
♦ Small µDFN (2mm x 2mm) and SOT23 Packages
Ordering Information
PINPACKAGE
PKG
CODE
MAX9504AELT-T
6 µDFN-6
L622-1
0
AAJ
MAX9504AEUT+T
6 SOT23-6
U65-3
0
ABWC
MAX9504BELT-T
MAX9504BEUT+
6 µDFN-6
L622-1
160
AAK
6 SOT23-6
U65-3
160
ABWD
PART
OFFSET TOP
(mV)
MARK
Note: All devices specified over the -40°C to +85°C operating
range.
+Denotes lead-free package.
Car Navigation Systems
Security Cameras
Portable Media Players
Block Diagram
Low-Power Video Applications
Y/C-to-CVBS Mixer
VCC
Pin Configurations
SHDN
MAX9504A
MAX9504B
TOP VIEW
FB
SHDN
160mV OFFSET
OUT
IN
6
5
4
OUT
MAX9504B
ONLY
2.3kΩ
MAX9504A
MAX9504B
1
VCC
FB
2
3
GND
IN
580Ω
780Ω
1.2kΩ
µDFN
Pin Configurations continued at end of data sheet.
GND
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
1
MAX9504A/MAX9504B
General Description
MAX9504A/MAX9504B
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
ABSOLUTE MAXIMUM RATINGS
VCC to GND ..............................................................-0.3V to +6V
IN, OUT, FB, SHDN to GND .......................-0.3V to (VCC + 0.3V)
OUT Short-Circuit Duration to VCC or GND ..............Continuous
Continuous Power Dissipation (TA = +70°C)
6-Pin SOT23 (derate 8.7mW/°C above +70°C)............695mW
6-Pin µDFN (derate 4.7mW/°C above +70°C) .............377mW
Operating Temperature Range ..........................-40°C to +85°C
Junction Temperature .....................................................+150°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................+300°C
Stresses beyond 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 in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS
(VCC = 3.0V, GND = 0V, VIN = 0.5V, RL = infinity to GND, FB connected to OUT, SHDN = VCC, TA = -40°C to +85°C. Typical values
are at TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Supply Voltage Range
SYMBOL
VCC
CONDITIONS
Guaranteed by PSRR
9
Input Voltage Range
VIN
Inferred from
voltage gain
Input Offset Voltage
VOS
Input Bias Current
IBIAS
0.01
0.10
1.25
MAX9504B
0
1.10
-25
0
+25
MAX9504B
120
160
200
5
20
VIN = 0V
0 < VIN < 1.45V
4
RL = 150Ω
(Note 2),
MAX9504B
1.9
2.0
2.1
VCC = 3.0V,
0.1V < VIN < 1.25V
1.9
2.0
2.1
Output Short-Circuit Current
ISC
SHDN Logic-Low Threshold
VIL
SHDN Logic-High Threshold
VIH
SHDN Input Current
IIN
Shutdown Output
Impedance
2
ROUT
(Disabled)
1.9
2.0
2.1
VCC = 3.0V,
0 < VIN < 1.10V
1.9
2.0
2.1
mV
µA
2
MAX9504A
60
80
MAX9504B
50
61
45
85
Sinking, RL = 20Ω to VCC
40
110
OUT shorted to VCC or GND
dB
mA
130
mA
VCC x 0.3
V
1.000
µA
VCC x 0.7
SHDN = 0V
V
V/V
VCC = 2.7V,
0 < VIN < 0.95V
Sourcing, RL = 20Ω to GND
SHDN = 0V or VCC
µA
2
VCC = 4.5V,
0 < VIN < 1.75V
2.7V < VCC < 5.5V
mA
MΩ
VCC = 2.7V,
0.1V < VIN < 1.10V
VCC = 4.5V,
0.1V < VIN < 1.90V
AV
IOUT
1
MAX9504A
MAX9504A
RL = 150Ω
(Note 2),
MAX9504A
Output Current
V
5
SHDN = 0V
PSRR
5.5
VCC = 5V
ISHDN
Power-Supply Rejection
Ratio
UNITS
9
Shutdown Supply Current
Voltage Gain
2.7
MAX
5
ICC
RIN
TYP
VCC = 3V
Quiescent Supply Current
Input Resistance
MIN
V
0.003
4
_______________________________________________________________________________________
kΩ
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
(VCC = 3.0V, GND = 0V, VIN = 0.5V, RL = 150Ω to GND, FB connected to OUT, SHDN = VCC, TA = +25°C, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Small-Signal -3dB
Bandwidth
BWSS
VOUT = 100mVP-P
47
MHz
Large-Signal -3dB
Bandwidth
BWLS
VOUT = 2VP-P
42
MHz
Small-Signal 0.1dB Gain
Flatness
BW0.1dBSS VOUT = 100mVP-P
10
MHz
Large-Signal 0.1dB Gain
Flatness
BW0.1dBLS VOUT = 2VP-P
12
MHz
Slew Rate
SR
VOUT = 2V step
165
V/µs
Settling Time to 1%
tS
VOUT = 2V step
25
ns
Power-Supply Rejection
Ratio
PSRR
f = 100kHz
Output Impedance
ZOUT
f = 5MHz
Differential Gain
DG
NTSC
Differential Phase
DP
NTSC
MAX9504A
75
MAX9504B
49
VCC = 3V
0.1
VCC = 5V
0.1
VCC = 3V
0.3
VCC = 5V
0.3
2.5
dB
Ω
%
degrees
2T Pulse-to-Bar K Rating
2T = 250ns, bar time is 18µs, the beginning
2.5% and the ending 2.5% of the bar time
are ignored
0.2
K%
2T Pulse Response
2T = 250ns
0.1
K%
2T Bar Response
2T = 250ns, bar time is 18µs, the beginning
2.5% and the ending 2.5% of the bar time
are ignored
0.1
K%
5-step staircase
Nonlinearity
0.1
%
Group Delay Distortion
D/dT
f = 100kHz to 5.5MHz
2
ns
Peak Signal-to-RMS Noise
SNR
VIN = 1VP-P, 100kHz < f < 5MHz
65
dB
Enable Time
tON
VIN = 1V, VOUT settled to 1% of nominal
300
ns
Disable Time
tOFF
VIN = 1V, VOUT settled to 1% of nominal
85
ns
Note 1: All devices are 100% production tested at TA = +25°C. Specifications over temperature limits are guaranteed by design.
Note 2: Voltage gain (AV) is referenced to the input offset voltage; i.e., an input voltage of VIN would produce an output voltage of
VOUT = AV x (VIN + VOS).
_______________________________________________________________________________________
3
MAX9504A/MAX9504B
AC ELECTRICAL CHARACTERISTICS
Typical Operating Characteristics
(VCC = 3.0V, GND = 0V, VIN = 0.5V, RL = 150Ω to GND, FB connected to OUT, SHDN = VCC, TA = +25°C, unless otherwise noted.)
1
0.1
-2
1
0
-0.1
-0.2
-1
-2
-3
-0.3
-3
-4
-0.4
-4
-5
-0.5
-5
-6
-0.6
-6
1
10
0.1
1
10
100
0.1
FREQUENCY (MHz)
SMALL-SIGNAL GAIN FLATNESS
vs. FREQUENCY
LARGE-SIGNAL GAIN
vs. FREQUENCY
LARGE-SIGNAL GAIN FLATNESS
vs. FREQUENCY
2
0.1
-0.2
0
0
GAIN (dB)
GAIN (dB)
-0.1
-1
-2
-0.3
-3
-0.4
-4
-0.1
-0.2
-0.3
-0.4
-0.5
-5
-0.5
-0.6
-6
-0.6
0.1
1
10
0.1
100
VOUT = 2VP-P
VCC = 3V
0.2
1
0
MAX9504 toc06
VOUT = 2VP-P
VCC = 3V
3
0.3
MAX9504 toc05
4
MAX9504 toc04
0.1
1
10
100
0.01
0.1
1
10
FREQUENCY (MHz)
FREQUENCY (MHz)
FREQUENCY (MHz)
LARGE-SIGNAL GAIN
vs. FREQUENCY
LARGE-SIGNAL GAIN FLATNESS
vs. FREQUENCY
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
2
VOUT = 2VP-P
VCC = 5V
0.2
0.1
1
10
0
-20
-2
PSRR (dB)
GAIN (dB)
-1
-0.1
-0.2
-30
-40
-50
-3
-0.3
-4
-0.4
-70
-5
-0.5
-80
-6
10
FREQUENCY (MHz)
100
MAX9504B
-60
-0.6
1
VCC = 3V
-10
0
0
100
MAX9504 toc09
VOUT = 2VP-P
VCC = 5V
MAX9504 toc08
0.3
MAX9504 toc07
4
0.1
100
10
FREQUENCY (MHz)
VOUT = 100mVP-P
VCC = 5V
3
1
FREQUENCY (MHz)
0.3
0.2
100
VOUT = 100mVP-P
VCC = 5V
2
GAIN (dB)
-1
0.1
GAIN (dB)
3
0
GAIN (dB)
GAIN (dB)
0
4
VOUT = 100mVP-P
VCC = 3V
0.2
SMALL-SIGNAL GAIN
vs. FREQUENCY
MAX9504 toc02
VOUT = 100mVP-P
VCC = 3V
2
0.3
MAX9504 toc01
3
SMALL-SIGNAL GAIN FLATNESS
vs. FREQUENCY
MAX9504 toc03
SMALL-SIGNAL GAIN
vs. FREQUENCY
GAIN (dB)
MAX9504A/MAX9504B
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
0.1
1
10
FREQUENCY (MHz)
100
-90
0.001
MAX9504A
0.01
0.1
FREQUENCY (MHz)
_______________________________________________________________________________________
1
10
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
(VCC = 3.0V, GND = 0V, VIN = 0.5V, RL = 150Ω to GND, FB connected to OUT, SHDN = VCC, TA = +25°C, unless otherwise noted.)
SUPPLY CURRENT (mA)
-10
-30
-40
MAX9504B
-60
-70
MAX9504A
-80
-90
0.001
0.01
0.1
0.18
VCC = 5V
0.17
0.16
VCC = 3V
VCC = 3V
0.15
0.14
-40
10
1
0.19
VCC = 5V
-15
FREQUENCY (MHz)
10
35
60
-40
85
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
VOLTAGE GAIN
vs. TEMPERATURE
LARGE-SIGNAL STEP RESPONSE
MAX9504 toc14
MAX9504 toc13
2.10
VCC = 3V and 5V
2.05
VIN
500mV/div
2.00
1.95
VOUT
1V/div
1.90
-15
10
35
60
85
10ns/div
TEMPERATURE (°C)
DIFFERENTIAL GAIN AND PHASE
SMALL-SIGNAL STEP RESPONSE
MAX9504 toc15
VIN
25mV/div
VOUT
50mV/div
10ns/div
0.2
MAX9504 toc16
-40
DIFFERENTIAL PHASE (degrees) DIFFERENTIAL GAIN (%)
-50
GAIN (V/V)
PSRR (dB)
-20
5.50
5.45
5.40
5.35
5.30
5.25
5.20
5.15
5.10
5.05
5.00
4.95
4.90
4.85
4.80
VOS (V)
VCC = 5V
MAX9504 toc11
MAX9504 toc10
10
0
MAX9504B INPUT OFFSET VOLTAGE
vs. TEMPERATURE
QUIESCENT SUPPLY CURRENT
vs. TEMPERATURE
MAX9504 toc12
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
0.1
0
-0.1
-0.2
1
2
3
4
5
6
1
2
3
4
5
6
0.4
0.2
0
-0.2
-0.4
_______________________________________________________________________________________
5
MAX9504A/MAX9504B
Typical Operating Characteristics (continued)
MAX9504A/MAX9504B
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
Typical Operating Characteristics (continued)
(VCC = 3.0V, GND = 0V, VIN = 0.5V, RL = 150Ω to GND, FB connected to OUT, SHDN = VCC, TA = +25°C, unless otherwise noted.)
OUT RESPONSE TO NTC-7
TEST SIGNAL (MAX9504B)
OUT RESPONSE TO NTC-7
TEST SIGNAL (MAX9504B)
MAX9504 toc18
MAX9504 toc17
VIN
500mV/div
GND
VIN
500mV/div
GND
VOUT
1V/div
GND
VOUT
1V/div
GND
VCC = 5V
VCC = 3V
10µs/div
10µs/div
OUT RESPONSE TO A FIELD
SQUARE WAVE (MAX9504B)
OUT RESPONSE TO A FIELD
SQUARE WAVE (MAX9504B)
MAX9504 toc19
MAX9504 toc20
VCC = 3V
VCC = 5V
VIN
500mV/div
GND
VIN
500mV/div
GND
VOUT
1V/div
GND
VOUT
1V/div
GND
2ms/div
2ms/div
Pin Description
PIN
6
NAME
FUNCTION
SOT23
µDFN
1
4
OUT
Video Output
2
2
GND
Ground
3
3
IN
4
1
VCC
5
5
SHDN
6
6
FB
Video Input
Power-Supply Input. Bypass VCC with a 0.1µF capacitor to ground as close as possible to VCC.
Shutdown Input. Pull SHDN low to place the device in low-power shutdown mode.
Feedback. Connect FB to OUT.
_______________________________________________________________________________________
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
VCC
2.7V TO 5.5V
0.1µF
VCC
3-POLE RECONSTRUCTION LPF
SHDN
C3
MAX9504A
MAX9504B
75Ω
VIDEO
CURRENT
DAC
Z0 = 75Ω
160mV OFFSET
L1
IN
OUT
R1
C1
C2
R2
75Ω
MAX9504B
ONLY
75Ω
Z0 = 75Ω
FB
75Ω
GND
Detailed Description
The MAX9504A/MAX9504B 3V/5V, 6dB video amplifiers
with low-power shutdown mode accept DC-coupled
inputs and drive up to two DC-coupled, 150Ω back-terminated video loads. The MAX9504B provides an internal input offset voltage of 160mV, which allows
DC-coupled input signals down to ground without clipping the output sync tip.
The MAX9504A/MAX9504B operate from a single +2.7V
to +5.5V supply and consume only 5mA of supply current. The low-power shutdown mode reduces supply current to less than 1µA, making the MAX9504A/MAX9504B
ideal for low-voltage, battery-powered video applications.
Output Current Capability
As shown in the Typical Application Circuit, the
MAX9504A/MAX9504B can drive up to two 150Ω loads
to ground at the same time because the outputs can
source guaranteed 45mA (min) current. Two 150Ω loads
to ground is the same as a single 75Ω load to ground.
Since the MAX9504A/MAX9504B can also sink guaranteed 40mA (min) current, they can also drive two, AC-coupled 150Ω loads. When VCC > 3V, the output can swing
2.4VP-P. When VCC > 4.5V, the output can swing 2.8VP-P.
Input Offset (MAX9504B)
The MAX9504A/MAX9504B amplify DC-coupled video
signals with a gain of +2V/V (+6dB). The MAX9504B
features a 160mV input offset voltage (VOS) that allows
a video signal input range to ground without clipping
the output sync tip. The MAX9504B output voltage is
the sum of the input voltage and the input offset voltage
gained up by a factor of 2.
VOUT = 2 x (VIN + VOS)
For example, if VIN = 1V and VOS = 0.16V then:
VOUT = 2 x (1V + 0.16V) = 2.32V
Shutdown Mode
The MAX9504A/MAX9504B feature a low-power shutdown mode (I SHDN < 1µA) for battery-powered/
portable applications. Driving SHDN high enables the
output. Driving SHDN low disables the output and
places the MAX9504A/MAX9504B into a low-power
shutdown mode. In shutdown, the output resistance is
4kΩ (typ) due to the combination of feedback resistors
from OUT to ground with FB connected to OUT.
_______________________________________________________________________________________
7
MAX9504A/MAX9504B
Typical Application Circuit
MAX9504A/MAX9504B
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
Applications Information
Using the MAX9504A/MAX9504B
with Video Current DACs
Video current DACs source current into a resistor connected to ground. The output voltage range for composite video and luma (Y) is usually from ground up to
1V (see Figure 1). Notice that the sync tip is quite close
to ground. Standard single-supply amplifiers with railto-rail outputs have difficulty amplifying input signals at
or near ground because their output stages enter a
nonlinear mode of operation when the output is pulled
close to ground.
The MAX9504B level shifts the input signal up by
160mV so that the output has a positive DC offset of
320mV. As a result, the MAX9504B output stage always
operates in the linear mode. Even if the input signal is
at ground, the MAX9504B output is at 320mV.
At the output of a video current DAC, the blank level of
the chroma signal is usually between 500mV to 650mV.
The voltage swing above and below the blank level is
approximately ±350mV (see Figure 1). If the blank level
is 550mV, then the lowest voltage for the chroma signal
is 200mV. For the case of chroma signals, no input
level shift is needed because 200mV gained up by two
is 400mV, which is well within the linear output range of
the MAX9504A or MAX9504B. Since the MAX9504A
does not have an input level shift, the MAX9504A
should be used with chroma signals. In summary, use
the MAX9504B with composite video and luma signals
from a DAC, and use the MAX9504A with chroma signals from a DAC.
MAX9504 fig01
Using the MAX9504A/MAX9504B with a
Video Reconstruction Filter
In most video applications, the video signal generated
from the DAC requires a reconstruction filter to smooth
out the steps and reduce the spikes. The MAX9504 has
a high-impedance, DC-coupled input that can be connected directly to the reconstruction filter.
LUMA
500mV/div
GND
For standard-definition video, the video passband is
approximately 6MHz, and the DAC sampling clock is
27MHz. Normally, a 9MHz lowpass filter can be used
for the reconstruction filter. This section demonstrates
the methods to build simple 2nd- and 3rd-order passive Butterworth lowpass filters with 9MHz cutoff frequency. See Figures 2 and 3.
CHROMA
500mV/div
GND
10µs/div
Figure 1. Oscilloscope Trace of Luma and Chroma Signals
from Video Current DAC
VCC
C7
0.1µF
2-POLE RECONSTRUCTION LPF
L1
3.9µH
VIDEO
CURRENT
DAC
IN
R1
150Ω
C1
150pF
R3
75Ω
VCC
OUT
MAX9504
R2
150Ω
FB
SHDN
VCC
GND
Figure 2. 2nd-Order Butterworth LPF with MAX9504
8
_______________________________________________________________________________________
VOUT
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
VCC
C3
6.8pF
C7
0.1µF
L1
4.7µH
VIDEO
CURRENT
DAC
R3
75Ω
VCC
IN
R1
150Ω
MAX9504A/MAX9504B
3-POLE RECONSTRUCTION LPF
C1
120pF
C2
120pF
VOUT
OUT
MAX9504
R2
150Ω
FB
SHDN
GND
VCC
Figure 3. 3rd-Order Butterworth LPF with MAX9504
2nd-Order Butterworth Lowpass Filter Realization
Table 1 shows the normalized 2nd-order Butterworth
LPF component values at 1 rad/s with a source/load
impedance of 1Ω.
With the following equations, the L and C can be calculated for the cutoff frequency (f C) at 9MHz. Table 2
shows the appropriate L and C values for different
source/load impedances, the bench measurement values for the -3dB frequency and the attenuation at
27MHz. There is approximately 20dB attenuation at
27MHz, which decreases the spikes at the sampling
frequency.
Table 2. Bench Measurement Values
(2nd-Order LPF)
R1 = R2
(Ω)
C1
(pF)
L1
(µH)
3dB
FREQUENCY
(MHz)
ATTENUATION AT
27MHz (dB)
75
330
1.8
8.7
20
150
150
3.9
9.0
20
200
120
4.7
9.3
22
300
82
8.2
8.7
20
Cn1
2πfcR1
Ln1R1
L1 =
2πfc
FREQUENCY RESPONSE
C1 =
0
-10
Table 1. 2nd-Order Butterworth Lowpass
Filter Normalized Values
Rn1 = Rn2 (Ω)
Cn1 (F)
Ln1 (H)
1
1.414
1.414
-20
GAIN (dB)
Figure 4 shows the frequency response for R1 = R2 =
150Ω. At 6MHz, the attenuation is about 1.4dB. The
attenuation at 27MHz is about 20dB. Figure 5 shows
the multiburst response for R1 = R2 = 150Ω.
-30
-40
-50
-60
0.1
1
10
100
FREQUENCY (MHz)
Figure 4. Frequency Response for 2nd-Order Lowpass Filter
_______________________________________________________________________________________
9
FREQUENCY RESPONSE
0
-10
VIN
500mV/div
-20
GAIN (dB)
MAX9504A/MAX9504B
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
-30
-40
VOUT
1V/div
-50
-60
0.1
10µs/div
1
10
100
FREQUENCY (MHz)
Figure 5. Multiburst Response
Figure 6. Frequency Response for 3rd-Order Lowpass Filter
3rd-Order Butterworth Lowpass Filter Realization
If a flatter passband and more stopband attenuation
are desired, a 3rd-order lowpass filter can be used.
The design procedures are similar to the 2nd-order
Butterworth lowpass filter.
Table 3 shows the normalized 3rd-order Butterworth
lowpass filter with the cutoff frequency at 1 rad/s and
the stopband frequency at 3 rad/s. Table 4 shows the
appropriate L and C values for different source/load
impedances, the bench measurement values for the -3dB
frequency and the attenuation at 27MHz. The attenuation is over 40dB at 27MHz. At 6MHz, the attenuation is
approximately 0.6dB for R1 = R2 = 150Ω (Figure 6).
Table 3. 3rd-Order Butterworth Lowpass
Filter Normalized Values
Rn1 = Rn2
(Ω)
Cn1 (F)
Cn2 (F)
Cn3 (F)
Ln1 (H)
1
0.923
0.923
0.06
1.846
Y/C-to-Composite Mixer and Driver Circuit
The Y/C-to-composite mixer and driver use two lowpass filters, the MAX9504A and the MAX9504B. In
Figure 7, the top video DAC generates a luma signal,
which is filtered through the passive RLC network and
then amplified by the MAX9504B. The bottom video
DAC generates a chroma signal, which is filtered and
then amplified by the MAX9504A.
LUMA OUT is directly connected to the output of the
MAX9504B through a 75Ω back-termination resistor;
likewise, CHROMA OUT to the output of the MAX9504A.
CVBS OUT (the composite video with blanking and
sync output) is created by AC-coupling the chroma signal to the luma signal through the 470pF capacitor,
which looks like an AC short at the color subcarrier frequency of 3.58MHz for NTSC or 4.43MHz for PAL.
This circuit relies upon the feature that the MAX9504A/
MAX9504B can drive two loads at the same time.
Table 4. Bench Measurement Values—3rd Order LPF
R1 = R2 (Ω)
C1 (pF)
C2 (pF)
C3 (pF)
10
L (µH)
3dB FREQUENCY (MHz)
ATTENUATION AT 27MHz (dB)
75
220
220
15.0
2.2
9.3
43
150
120
120
6.8
4.7
8.9
50
300
56
56
3.3
10.0
9.0
45
______________________________________________________________________________________
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
VCC
6.8pF
0.1µF
LUMA
VCC
4.7µH
VIDEO
CURRENT
DAC
IN
150Ω
120pF
120pF
75Ω
LUMA OUT
OUT
MAX9504B
150Ω
FB
SHDN
GND
75Ω
CHROMA OUT
75Ω
3-POLE RECONSTRUCTION LPF
CVBS OUT
6.8pF
0.1µF
CHROMA
VCC
4.7µH
VIDEO
CURRENT
DAC
IN
150Ω
120pF
120pF
75Ω
470pF
OUT
MAX9504A
150Ω
FB
SHDN
GND
VCC
Figure 7. Y/C-to-Composite Mixer and Driver Circuit
______________________________________________________________________________________
11
MAX9504A/MAX9504B
3-POLE RECONSTRUCTION LPF
MAX9504A/MAX9504B
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
AC Output Coupling and Sag Correction
The MAX9504 can use the sag configuration if the output requires AC-coupling and VCC ≥ 4.5V. Sag correction refers to the low-frequency compensation for the
highpass filter formed by the 150Ω load and the output
capacitor. In video applications, the cutoff frequency
must be less than 5Hz in order to pass the vertical sync
interval and avoid field time distortion (field tilt). In the
simplest configuration, a very large coupling capacitor
(> 220µF typically) is used to achieve the 5Hz cutoff
frequency. In the sag configuration, two smaller capacitors are used to replace the very large coupling capacitor (see Figure 8). For VCC ≥ 4.5V, C5 and C6 are 22µF
capacitors.
Layout and Power-Supply Bypassing
The MAX9504A/MAX9504B operate from a single 2.7V
to 5.5V supply. Bypass the supply with a 0.1µF capacitor as close to VCC possible. Maxim recommends using
microstrip and stripline techniques to obtain full bandwidth. To ensure that the PC board does not degrade
the device’s performance, design it for a frequency
greater than 1GHz. Pay careful attention to inputs and
outputs to avoid large parasitic capacitance. Whether
or not you use a constant-impedance board, observe
the following design guidelines:
• Do not use wire-wrap boards; they are too inductive.
• Do not use IC sockets; they increase parasitic capacitance and inductance.
• Use surface-mount instead of through-hole components for better, high-frequency performance.
• Use a PC board with at least two layers; it should be
as free from voids as possible.
• Keep signal lines as short and as straight as possible.
Do not make 90° turns; round all corners.
3-POLE RECONSTRUCTION LPF
VCC
C3
6.8pF
C7
0.1µF
L1
4.7µH
VIDEO
CURRENT
DAC
IN
R1
150Ω
C1
120pF
C5
22µF
VCC
C2
120pF
R2
150Ω
OUT
C6
22µF
MAX9504
FB
SHDN
VCC
GND
Figure 8. SAG Correction Configuration
12
______________________________________________________________________________________
R3
75Ω
VOUT
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
VCC
2.7V TO 5.5V
0.1µF
VCC
3-POLE RECONSTRUCTION LPF
C3
6.8pF
VIDEO
CURRENT
DAC
SHDN
MAX9504A
MAX9504B
75Ω
L1
4.7µH
Z0 = 75Ω
160mV OFFSET
IN
OUT
R1
150Ω
C2
120pF
C1
120pF
R2
150Ω
MAX9504B
ONLY
75Ω
2.3kΩ
FB
580Ω
75Ω
Z0 = 75Ω
75Ω
780Ω
1.2kΩ
GND
Chip Information
Pin Configurations (continued)
PROCESS: BiCMOS
TOP VIEW
OUT 1
GND 2
+
MAX9504A
MAX9504B
IN 3
6
FB
5
SHDN
4
VCC
SOT23-6
______________________________________________________________________________________
13
MAX9504A/MAX9504B
Typical Operating Circuit
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
6LSOT.EPS
MAX9504A/MAX9504B
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
14
______________________________________________________________________________________
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
XXXX
XXXX
XXXX
b
e
N
SOLDER
MASK
COVERAGE
E
PIN 1
0.10x45∞
L
PIN 1
INDEX AREA
6, 8, 10L UDFN.EPS
A
D
L1
1
SAMPLE
MARKING
A
A
(N/2 -1) x e)
7
CL
b
L
A
A2
A1
CL
L
e
EVEN TERMINAL
e
ODD TERMINAL
PACKAGE OUTLINE,
6, 8, 10L uDFN, 2x2x0.80 mm
-DRAWING NOT TO SCALE-
21-0164
A
1
2
______________________________________________________________________________________
15
MAX9504A/MAX9504B
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
MAX9504A/MAX9504B
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
COMMON DIMENSIONS
SYMBOL
MIN.
NOM.
A
0.70
0.75
0.80
A1
0.15
0.20
0.25
0.035
A2
0.020
0.025
D
1.95
2.00
E
1.95
2.00
L
0.30
0.40
L1
MAX.
-
2.05
2.05
0.50
0.10 REF.
PACKAGE VARIATIONS
PKG. CODE
N
e
b
(N/2 -1) x e
L622-1
6
0.65 BSC
0.30±0.05
1.30 REF.
L822-1
8
0.50 BSC
0.25±0.05
1.50 REF.
L1022-1
10
0.40 BSC
0.20±0.03
1.60 REF.
PACKAGE OUTLINE,
6, 8, 10L uDFN, 2x2x0.80 mm
21-0164
-DRAWING NOT TO SCALE-
A
2
2
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2005 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products, Inc.
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