THS4511
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SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
WIDEBAND, LOW-NOISE, LOW-DISTORTION,
FULLY-DIFFERENTIAL AMPLIFIER
Check for Samples: THS4511
FEATURES
DESCRIPTION
•
•
The THS4511 is a wideband, fully-differential
operational amplifier designed for single-supply 5-V
data-acquisition systems. It has very low noise at
2 nV/√Hz, and extremely low harmonic distortion of
–72 dBc HD2 and –87 dBc HD3 at 70 MHz with 2 VPP,
G = 0 dB, and 200-Ω load. Slew rate is very high at
4900 Vµs and with settling time of 3.3 ns to 1% (2 V
step) it is ideal for pulsed applications. It is designed
for minimum gain of 0 dB.
1
2
•
•
•
•
•
•
•
•
•
•
•
•
•
Fully-Differential Architecture
Common-Mode Input Range Includes
the Negative Rail
Unity-Gain Stable
Bandwidth: 1.6 GHz (Gain = 0 dB)
Slew Rate: 4900 V/µs
1% Settling Time: 3.3 ns
HD2: –72 dBc at 70 MHz
HD3: –87 dBc at 70 MHz
OIP2: 76 dBm at 70 MHz
OIP3: 42 dBm at 70 MHz
Input Voltage Noise: 2 nV/√Hz (f > 10 MHz)
Noise Figure: 21.8 dB (50-Ω System, G = 6 dB)
Output Common-Mode Control
5-V Power-Supply Current: 39.2 mA
Power-Down Capability: 0.65 mA
APPLICATIONS
•
•
•
•
•
5-V Data-Acquisition Systems
High Linearity ADC Amplifiers
Wireless Communication
Medical Imaging
Test and Measurement
RELATED PRODUCTS
DEVICE
COMMON-MODE RANGE OF
MIN. GAIN INPUT(1)
THS4508
6 dB
–0.3 V to 2.3 V
THS4509
6 dB
0.75 V to 4.25 V
THS4511
0 dB
–0.3 V to 2.3 V
THS4513
0 dB
0.75 V to 4.25 V
1. Assumes a 5-V single-ended power supply.
To allow for dc coupling to analog-to-digital
converters (ADCs), its unique output common-mode
control circuit maintains the output common-mode
voltage within 5-mV offset (typical) from the set
voltage, when set within ±0.5 V of midsupply. The
common-mode set point is set to midsupply by
internal circuitry, which may be over-driven from an
external source.
The THS4511 is a high-performance amplifier that
has been optimized for use in 5-V single-supply data
acquisition systems. The output has been optimized
for best performance with its common-mode voltages
set to midsupply, and the input has been optimized
for performance over a wide range of common-mode
input voltages. High performance at a low
power-supply voltage enables single-supply 5-V
data-acquisition systems while minimizing component
count.
The THS4511 is offered in a quad, 16-pin leadless
QFN package (RGT), and is characterized for
operation over the full industrial temperature range
from –40°C to +85°C.
Video Buffer, Single-Ended to Differential
Video Source
RS = 75 W
VSignal
VIN
175 W
130 W
348 W
VS+ = 5 V
RO
THS4511
175 W
RO
VOD
+
75 W
130 W
VS-
VCM = 2.5 V
348 W
1
2
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.
PowerPAD is a trademark of Texas Instruments Incorporated.
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 © 2005–2009, Texas Instruments Incorporated
THS4511
SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
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.
ABSOLUTE MAXIMUM RATINGS (1)
Over operating free-air temperature range, unless otherwise noted.
UNIT
VSS
Supply
voltage
VS– to VS+
VI
Input voltage
VID
Differential input voltage
IO
Output current
5.5 V
±VS
4V
200 mA
Continuous power dissipation
See Dissipation Ratings Table
Maximum junction temperature (2)
TJ
+150°C
(3)
TJ
Maximum junction temperature, continuous operation, long term reliability
TA
Operating free-air temperature range
–40°C to +85°C
TSTG
Storage temperature range
–65°C to +150°C
ESD ratings
(1)
(2)
(3)
+125°C
HBM
2000 V
CDM
1500 V
MM
100 V
Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may
degrade device reliability. These are stress ratings only, and functional operation of the device at these or any other conditions beyond
those specified is not implied.
The absolute maximum temperature under any condition is limited by the constraints of the silicon process.
The 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. The THS4511 incorporates a (QFN) exposed thermal pad on the underside
of the chip. This acts as a heatsink and must be connected to a thermally-dissipative plane for proper power dissipation. Failure to do so
may result in exceeding the maximum junction temperature which could permanently damage the device. See TI technical brief
SLMA002 and SLMA004 for more information about using the QFN thermally-enhanced package.
DISSIPATION RATINGS TABLE
(1)
2
PACKAGE (1)
θJC
θJA
RGT (16)
2.4°C/W
39.5°C/W
POWER RATING
TA ≤ +25°C
TA = +85°C
2.3 W
225 mW
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.
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SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
DEVICE INFORMATION
RGT PACKAGE
16-PIN LEADLESS QFN
(TOP VIEW)
VS-
16
15
14
13
NC
1
12
PD
VIN-
2
11
VIN+
VOUT+
3
10
VOUT-
CM
4
9
5
6
7
CM
8
VS+
TERMINAL FUNCTIONS
TERMINAL
(RGT PACKAGE)
NO.
DESCRIPTION
NAME
1
NC
No internal connection
2
VIN–
Inverting amplifier input
3
VOUT+
Noninverting amplifier output
4, 9
CM
Common-mode voltage input
5-8
VS+
Positive amplifier power supply input
10
VOUT–
Inverted amplifier output
11
VIN+
Noninverting amplifier input
12
PD
Power-down; PD = logic low puts part into low power mode, PD = logic high or open for normal operation
13-16
VS–
Negative amplifier power-supply input
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THS4511
SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
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ELECTRICAL CHARACTERISTICS: VS+ – VS– = 5 V
Test conditions unless otherwise noted: VS+ = 5 V, VS– = 0 V, G = 0 dB, CM = open, VO = 2 VPP, RF = 349 Ω, RL = 200 Ω
differential, T = +25°C single-ended input, differential output, input referenced to ground, and output referenced to midsupply.
THS4511
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
TEST
LEVEL (1)
AC PERFORMANCE (see Figure 38)
Small-Signal Bandwidth
G = 0 dB, VO = 100 mVPP
1.6
G = 6 dB, VO = 100 mVPP
1.4
G = 0 dB, VO = 2 VPP
160
G = 6 dB, VO = 2 VPP
620
Gain-Bandwidth Product
Bandwidth for 0.1-dB flatness
Large-Signal Bandwidth
2
G = 10 dB, VO = 2 VPP
Slew Rate (Differential)
Rise Time
GHz
MHz
1.35
GHz
4900
V/µs
0.5
ns
Fall Time
0.5
ns
Settling Time to 1%
3.3
ns
Settling Time to 0.1%
16
ns
2nd Order Harmonic Distortion
3rd Order Harmonic Distortion
VO = 2-V Step
GHz
f = 10 MHz
–117
f = 50 MHz
–80
f = 100 MHz
–64
f = 10 MHz
–106
f = 50 MHz
–92
f = 100 MHz
2nd Order Intermodulation Distortion
3rd Order Intermodulation Distortion
200-kHz tone spacing,
RL = 100 Ω
2nd Order Output Intercept Point
3rd Order Output Intercept Point
200-kHz tone spacing,
RL = 100 Ω
dBc
C
–80
fC = 70 MHz
–78
fC = 140 MHz
–56
fC = 70 MHz
–88
fC = 140 MHz
–71.4
fC = 70 MHz
76.3
fC = 140 MHz
53.4
fC = 70 MHz
42
fC = 140 MHz
dBc
dBm
34
fC = 70 MHz
12.2
fC = 140 MHz
10.8
Noise Figure
50-Ω system, 10 MHz
21.8
dB
Input Voltage Noise
f > 10 MHz
2
nV/√Hz
Input Current Noise
f > 10 MHz
1.5
pA/√Hz
1-dB Compression Point (2)
dBm
DC PERFORMANCE
Open-Loop Voltage Gain (AOL)
Input Offset Voltage
63
TA = +25°C
1
4
TA = –40°C to +85°C
1
5
Average Offset Voltage Drift
Input Bias Current
2.3
TA = +25°C
TA = –40°C to +85°C
Average Bias Current Drift
Input Offset Current
(2)
4
8
15.5
8
18.5
20
TA = +25°C
0.5
3.6
TA = –40°C to +85°C
0.5
7
Average Offset Current Drift
(1)
1.75
7
dB
C
mV
A
µV/°C
B
µA
A
nA/°C
B
µA
A
nA/°C
B
Test levels: (A) 100% tested at +25°C. Over-temperature limits by characterization and simulation. (B) Limits set by characterization and
simulation. (C) Typical value only for information.
The 1-dB compression point is measured at the load with 50-Ω double termination. Add 3 dB to refer to amplifier output.
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SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
ELECTRICAL CHARACTERISTICS: VS+ – VS– = 5 V (continued)
Test conditions unless otherwise noted: VS+ = 5 V, VS– = 0 V, G = 0 dB, CM = open, VO = 2 VPP, RF = 349 Ω, RL = 200 Ω
differential, T = +25°C single-ended input, differential output, input referenced to ground, and output referenced to midsupply.
THS4511
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
TEST
LEVEL (1)
INPUT
Common-Mode Input Range High
2.3
Common-Mode Input Range Low
–0.3
Common-Mode Rejection Ratio
V
90
Differential Input Impedance
18.2 || 1.62
Common-Mode Input Impedance
4.0 || 1.73
B
dB
MΩ || pF
C
OUTPUT
Maximum Output Voltage High
Each output with 100 Ω
to midsupply
Minimum Output Voltage Low
Differential Output Voltage Swing
TA = +25°C
3.7
3.8
TA = –40°C to
+85°C
3.6
3.8
V
TA = +25°C
1.2
1.3
TA = –40°C to
+85°C
1.2
1.4
TA = +25°C
4.8
5.2
TA = –40°C to +85°C
4.4
5.2
A
V
A
Differential Output Current Drive
RL = 10 Ω
96
mA
C
Output Balance Error
VO = 100 mV, f = 1 MHz
–52
dB
C
Closed-Loop Output Impedance
f = 1 MHz
0.3
Ω
C
Small-Signal Bandwidth
250
MHz
Slew Rate
110
V/μs
1
V/V
OUTPUT COMMON-MODE VOLTAGE CONTROL
Gain
Output Common-Mode Offset from CM Input
1.25 V < CM < 3.5 V
5
mV
CM Input Bias Current
1.25 V < CM < 3.5 V
±40
μA
CM Input Voltage Range
CM Input Impedance
CM Default Voltage
CM pins floating
1.25 to 3.75
V
32 || 1.5
kΩ || pF
2.5
V
C
POWER SUPPLY
3.75 (3)
Specified Operating Voltage
Maximum Quiescent Current
Minimum Quiescent Current
TA = +25°C
TA = –40°C to +85°C
TA = +25°C
TA = –40°C to +85°C
5
5.25
39.2
42.5
39.2
43.5
35.9
39.2
35
39.2
Power-Supply Rejection (±PSRR)
To differential output
POWER-DOWN
Referenced to VS–
Enable Voltage Threshold
Device assured on above 2.1 V
> 2.1
Disable Voltage Threshold
Device assured off below 0.7 V
< 0.7
TA = +25°C
0.65
0.9
TA = –40°C to +85°C
0.65
1
Power-Down Quiescent Current
Input Bias Current
PD = VS–
Input Impedance
90
V
C
mA
A
dB
C
V
C
mA
A
100
μA
50 || 2
kΩ || pF
Turn-On Time Delay
Measured to output on
55
ns
Turn-Off Time Delay
Measured to output off
10
µs
(3)
C
See the Application Information section of this data sheet for device operation with full supply voltages less than 5 V.
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TYPICAL CHARACTERISTICS
Small-Signal Frequency
Response
G = 0 dB, VOD = 100 mVPP
Figure 1
G = 6 dB, VOD = 100 mVPP
Figure 2
Large-Signal Frequency
Response
G = 0 dB, VOD = 2 VPP
Figure 3
G = 6 dB, VOD = 2 VPP
Figure 4
HD2, G = 0 dB, VOD = 2 VPP
vs Frequency
Figure 5
HD3, G = 0 dB, VOD = 2 VPP
vs Frequency
Figure 6
HD2, G = 6 dB, VOD = 2 VPP
vs Frequency
Figure 7
HD3, G = 6 dB, VOD = 2 VPP
vs Frequency
Figure 8
HD2, G = 0 dB
vs Output Voltage
Figure 9
HD3, G = 0 dB
vs Output Voltage
Figure 10
HD2, G = 0 dB
vs CM Output Voltage
Figure 11
HD3, G = 0 dB
vs CM Output Voltage
Figure 12
IMD2, G = 0 dB
vs Frequency
Figure 13
IMD3, G = 0 dB
vs Frequency
Figure 14
OIP2
vs Frequency
Figure 15
OIP3
vs Frequency
Figure 16
S-Parameters
vs Frequency
Figure 17
Transition Rate
vs Output Voltage
Figure 18
Harmonic
Distortion
Intermodulation
Distortion
Output Intercept Point
Transient Response
Figure 19
Settling Time
Figure 20
Rejection Ratio
vs Frequency
Figure 21
Output Impedance
vs Frequency
Figure 22
Overdrive Recovery
Differential Output Voltage
Figure 23
Load Resistance
Figure 24
Turn-Off Time
Figure 25
Turn-On Time
Figure 26
Input Offset Voltage
vs Input Common-Mode Voltage
Figure 27
Open-Loop Gain and Phase
vs Frequency
Figure 28
Input-Referred Noise
vs Frequency
Figure 29
Noise Figure
vs Frequency
Figure 30
Quiescent Current
vs Supply Voltage
Figure 31
Output Balance Error
vs Frequency
Figure 32
CM Input Impedance
vs Frequency
Figure 33
CM Small-Signal Frequency Response
Figure 34
CM Input Bias Current
vs CM Input Voltage
Figure 35
Differential Output Offset Voltage
vs CM Input Voltage
Figure 36
Output Common-Mode Offset
vs CM Input Voltage
Figure 37
6
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SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
TYPICAL CHARACTERISTICS: VS+ – VS– = 5 V
Test conditions unless otherwise noted: VS+ = 5 V, VS– = 0 V, G = 0 dB, CM = open, VO = 2 VPP, RF = 349 Ω, RL = 200 Ω
differential, single-ended input, input referenced to ground, and output referenced to midrail.
SMALL-SIGNAL FREQUENCY RESPONSE
SMALL-SIGNAL FREQUENCY RESPONSE
7
5
VO = 100 mV PP
VO = 100 mV PP
G = 0 dB
4
RL = 1 kΩ
RL = 500 Ω
3
6
RL = 200 Ω
G = 6 dB
Signal Gain − dB
Signal Gain − dB
RL = 1 kΩ
RL = 500 Ω
5
2
1
0
−1
RL = 100 Ω
−2
4
RL = 200 Ω
3
RL = 100 Ω
2
−3
−4
1
−5
0
−6
10
100
1000
f− Frequency −MHz
10000
10
100
Figure 1.
LARGE-SIGNAL FREQUENCY RESPONSE
LARGE-SIGNAL FREQUENCY RESPONSE
8
VO = 2 VPP
G = 0 dB
RL = 1 kΩ
RL = 500 Ω
6
1
0
−1
VO = 2 VPP
G = 6 dB
7
Signal Gain − dB
Signal Gain − dB
2
10000
Figure 2.
4
3
1000
f− Frequency −MHz
RL = 100 Ω
RL = 200 Ω
−2
−3
RL = 1 kΩ
RL = 500 Ω
5
4
3
RL = 200 Ω
2
RL = 100 Ω
−4
1
−5
−6
10
0
100
1000
f− Frequency −MHz
10000
10
100
1000
10000
f− Frequency −MHz
Figure 3.
Figure 4.
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TYPICAL CHARACTERISTICS: VS+ – VS– = 5 V (continued)
Test conditions unless otherwise noted: VS+ = 5 V, VS– = 0 V, G = 0 dB, CM = open, VO = 2 VPP, RF = 349 Ω, RL = 200 Ω
differential, single-ended input, input referenced to ground, and output referenced to midrail.
HD2 vs FREQUENCY
HD3 vs FREQUENCY
−70
VO = 2 VPP
G = 0 dB
VO = 2 VPP
G = 0 dB
3rd Order Harmonic Distortion − dBc
2nd Order Harmonic Distortion − dBc
−60
−70
−80
−90
RL = 1 kΩ
RL = 100 Ω
−100
RL = 500 Ω
−110
−80
−90
RL = 1kΩ
RL = 200 Ω
−100
RL = 500 Ω
RL = 200 Ω
RL = 100 Ω
−120
−110
1
10
100
1000
1
10
f − Frequency − MHz
Figure 5.
HD2 vs FREQUENCY
HD3 vs FREQUENCY
−70
G = 6 dB
RF = 348 Ω
RG = 165 Ω
VO = 2 VPP
−60
3rd Order Harmonic Distortion − dBc
2nd Order Harmonic Distortion − dBc
1000
Figure 6.
−50
RL = 500 Ω
−70
−80
RL = 1kΩ
RL = 100 Ω
−90
−100
−110
−120
G = 6 dB
RF = 348 Ω
RG = 165 Ω
VO = 2 VPP
−80
RL = 100 Ω
−90
L
= 200 Ω
RL = 1k Ω
RL = 500 Ω
−100
RL = 200 Ω
−130
−110
1
10
100
f − Frequency − MHz
1000
1
10
100
1000
f − Frequency − MHz
Figure 7.
8
100
f − Frequency − MHz
Figure 8.
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SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
TYPICAL CHARACTERISTICS: VS+ – VS– = 5 V (continued)
Test conditions unless otherwise noted: VS+ = 5 V, VS– = 0 V, G = 0 dB, CM = open, VO = 2 VPP, RF = 349 Ω, RL = 200 Ω
differential, single-ended input, input referenced to ground, and output referenced to midrail.
HD2 vs OUTPUT VOLTAGE
−40
f = 150 MHz
VOD = 2 VPP
f = 150 MHz
VOD = 2 VPP
−50
3rd Order Harmonic Distortion − dBc
2nd Order Harmonic Distortion − dBc
HD3 vs OUTPUT VOLTAGE
−40
f = 100 MHz
−60
f = 64 MHz
−70
−80
f = 32 MHz
−90
f = 8 MHz
f = 16 MHz
−100
−110
−50
f = 100 MHz
−60
f = 64 MHz
−70
f = 8 MHz
−80
f = 32 MHz
−90
f = 16 MHz
−100
−110
−120
−120
0
1
2
3
VO − Output Voltage − VPP
4
0
5
1
2
3
4
5
VO − Output Voltage− V PP
Figure 9.
Figure 10.
HD2 vs CM OUTPUT VOLTAGE
HD3 vs CM OUTPUT VOLTAGE
0
0
3rd Order Harmonic Distortion − dBc
2nd Order Harmonic Distortion − dBc
f = 150 MHz
−20
f = 100 MHz
−40
f = 64 MHz
−60
−80
f = 1 MHz
−100
−120
f = 100 MHz
−40
f = 64 MHz
−60
−100
−120
f = 32 MHz
−140
−1
−0.8
−0.6
−0.4
−0.2
0
0.2
0.4
f = 32 MHz
−80
f = 4 MHz
f = 1 MHz
f = 4 MHz
f = 8 MHz
f = 150 MHz
−20
f = 8 MHz
0.6
0.8
1
−140
−1
VCM − Common-Mode Output Voltage − V
Figure 11.
−0.8 −0.6
−0.4
−0.2
0
0.2
0.4
0.6
0.8
1
VCM − Common-Mode Output Voltage − V
Figure 12.
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TYPICAL CHARACTERISTICS: VS+ – VS– = 5 V (continued)
Test conditions unless otherwise noted: VS+ = 5 V, VS– = 0 V, G = 0 dB, CM = open, VO = 2 VPP, RF = 349 Ω, RL = 200 Ω
differential, single-ended input, input referenced to ground, and output referenced to midrail.
IMD2 vs FREQUENCY
IMD3 vs FREQUENCY
−40
−60
IMD 2 − Intermodulation Distortion − dBc
VOD = 2V PP Envelope
200 kHz Tone Spacing
IMD 3 − Intermodulation Distortion − dBc
−50
RL = 200 Ω
−60
−70
RL = 1 kΩ
−80
RL = 100 Ω
−90
VOD = 2V PP Envelope
200 kHz Tone Spacing
−65
−70
RL = 100 Ω
−75
RL = 1 kΩ
−80
−85
−90
−95
RL = 200 Ω
−100
−105
−110
−100
0
50
100
150
0
200
50
Figure 13.
150
200
Figure 14.
OIP2 vs FREQUENCY
OIP3 vs FREQUENCY
95
50
OIP3 − Output Intercept Point − dBm
RL = 100 Ω
VOD = 2V PP Envelope
200 kHz Tone Spacing
90
OIP2 − Output Intercept Point − dBm
100
f − Frequency − MHz
f − Frequency − MHz
85
80
75
70
65
60
55
RL = 100 Ω
VOD = 2V PP Envelope
200 kHz Tone Spacing
45
40
35
30
50
45
25
0
50
100
150
200
0
Figure 15.
10
50
100
150
200
f − Frequency − MHz
f − Frequency − MHz
Figure 16.
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SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
TYPICAL CHARACTERISTICS: VS+ – VS– = 5 V (continued)
Test conditions unless otherwise noted: VS+ = 5 V, VS– = 0 V, G = 0 dB, CM = open, VO = 2 VPP, RF = 349 Ω, RL = 200 Ω
differential, single-ended input, input referenced to ground, and output referenced to midrail.
S-PARAMETERS vs FREQUENCY
TRANSITION RATE vs OUTPUT VOLTAGE
20
6000
RL = 200 Ω
20% - 80%
10
5000
S21
SR − Transition Rate − V/ms
S−Parameter − dB
0
−10
S22
−20
−30
S11
−40
−50
−60
S12
−70
Falling
4000
Rising
3000
2000
1000
−80
−90
0.1
0
1
10
100
1000
0
f − Frequency − MHz
0.5
1
1.5
2
2.5
3
VOD − Output Voltage − V PP
Figure 17.
Figure 18.
TRANSIENT RESPONSE
SETTLING TIME
4
0.5
3.5
0.3
Percent of Final Value - %
V OD − Differential Output Voltage − V
VOD = 2 VPP
3
2.5
2
0.1
-0.1
-0.3
1.5
1
-0.5
t - Time - 1ns/div
t − Time − 500 ps/div
Figure 19.
Figure 20.
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TYPICAL CHARACTERISTICS: VS+ – VS– = 5 V (continued)
Test conditions unless otherwise noted: VS+ = 5 V, VS– = 0 V, G = 0 dB, CM = open, VO = 2 VPP, RF = 349 Ω, RL = 200 Ω
differential, single-ended input, input referenced to ground, and output referenced to midrail.
REJECTION RATIOS vs FREQUENCY
OUTPUT IMPEDANCE vs FREQUENCY
100
100
PSRR+
90
Z o − Output Impedance − Ω
80
Rejection Ratio −dB
70
CMRR
60
50
40
30
20
10
1
10
0
0.01
0.1
1
10
100
0.1
0.1
1000
f − Frequency − MHz
100
Figure 22.
OVERDRIVE RECOVERY
DIFFERENTIAL OUTPUT VOLTAGE
vs LOAD RESISTANCE
2
2
1.5
0.5
0
−0.5
−1
−2
−1.5
−2
−4
VI − Input Voltage − V
1
Output
0
1000
7
VOD - Differential Output Voltage Swing - V
Input
VO − Differential Output Voltage − V
10
f − Frequency− MHz
Figure 21.
4
6
5
4
3
2
1
0
10
t − Time − 100 ns/div
100
1000
RL - Load Resistance - kW
Figure 23.
12
1
Figure 24.
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TYPICAL CHARACTERISTICS: VS+ – VS– = 5 V (continued)
Test conditions unless otherwise noted: VS+ = 5 V, VS– = 0 V, G = 0 dB, CM = open, VO = 2 VPP, RF = 349 Ω, RL = 200 Ω
differential, single-ended input, input referenced to ground, and output referenced to midrail.
Output
PD Input
0.4
0
Output
t - Time - (2.5 ms/div)
t - Time - (2.5 ms/div)
Figure 25.
Figure 26.
INPUT OFFSET VOLTAGE
vs INPUT COMMON-MODE VOLTAGE
OPEN-LOOP GAIN AND PHASE
vs FREQUENCY
10
9
80
90
70
50
8
10
60
7
Open-loop Gain - dB
VOS - Input Offset Voltage - mV
6.4
6
5.6
5.2
4.8
4.4
4
3.6
3.2
2.8
2.4
2
1.6
1.2
0.8
0.4
0
PD Input
Powerdown Input - V
6.4
6
5.6
5.2
4.8
4.4
4
3.6
3.2
2.8
2.4
2
1.6
1.2
0.8
3
2.8
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
-0.2
6
5
4
3
GAIN
-30
50
PHASE
40
-70
30
-110
20
-150
10
-190
Phase - Degrees
VO - Output Voltage - V
3
2.8
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
VO - Output Voltage - V
TURN-ON TIME
Powerdown Input - V
TURN-OFF TIME
3.2
2
1
0
-0.5
0
0
0.5
1
1.5
2
2.5
3
-230
100
VIC - Commom-Mode Input Voltage - V
Figure 27.
10K
1M
100M
10G
f - Frequency - Hz
Figure 28.
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TYPICAL CHARACTERISTICS: VS+ – VS– = 5 V (continued)
Test conditions unless otherwise noted: VS+ = 5 V, VS– = 0 V, G = 0 dB, CM = open, VO = 2 VPP, RF = 349 Ω, RL = 200 Ω
differential, single-ended input, input referenced to ground, and output referenced to midrail.
INPUT-REFERRED NOISE vs FREQUENCY
NOISE FIGURE vs FREQUENCY
1000
25
24
100
Input Current Noise
NF - Noise Figure - dB
Vn - Voltage Noise - V/rt(Hz)
In - Current Noise - pA/rt(Hz)
50-W System
G = 6 dB
10
Input Voltage Noise
1
0
23
22
21
20
10
100
1k
10k
100k
1M
10M
0
20
40
60
f - Frequency - Hz
80
100
120
140
160
180
200
f - Frequency - MHz
Figure 29.
Figure 30.
QUIESCENT CURRENT vs SUPPLY VOLTAGE
OUTPUT BALANCE ERROR vs FREQUENCY
44
-20
VOD = 500 mVPP
TA = 25o C
42
-25
-30
Balance Error - dB
IQ - Quiescent Current - mA
o
TA = 85 C
40
38
36
TA = -40o C
34
-35
-40
-45
32
-50
30
-55
28
3.75
4
4.25
4.5
4.75
5
5.25
-60
100k
Figure 31.
14
1M
10M
100M
10G
f - Frequency - Hz
VS - Supply Voltage - V
Figure 32.
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TYPICAL CHARACTERISTICS: VS+ – VS– = 5 V (continued)
Test conditions unless otherwise noted: VS+ = 5 V, VS– = 0 V, G = 0 dB, CM = open, VO = 2 VPP, RF = 349 Ω, RL = 200 Ω
differential, single-ended input, input referenced to ground, and output referenced to midrail.
CM INPUT IMPEDANCE vs FREQUENCY
CM SMALL-SIGNAL FREQUENCY RESPONSE
100
2
0
VOCM - Gain - dB
CM Input Impedance − kW
1
10
1
-1
-2
0.1
-3
-4
0.01
100k
1M
10M
f − Frequency − Hz
100M
100k
1G
100M
10G
Figure 33.
Figure 34.
CM INPUT BIAS CURRENT
vs CM INPUT VOLTAGE
DIFFERENTIAL OUTPUT OFFSET VOLTAGE
vs CM INPUT VOLTAGE
5
Differential Output Offset Voltage - mV
Common-Mode Input-Bias Current - mA
10M
f - Frequency - Hz
200
100
0
-100
-200
-300
1M
4
3
2
1
0
-1
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0
VIC - Common-Mode Input Voltage - V
Figure 35.
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
VIC - Common-Mode Input Voltage - V
Figure 36.
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TYPICAL CHARACTERISTICS: VS+ – VS– = 5 V (continued)
Test conditions unless otherwise noted: VS+ = 5 V, VS– = 0 V, G = 0 dB, CM = open, VO = 2 VPP, RF = 349 Ω, RL = 200 Ω
differential, single-ended input, input referenced to ground, and output referenced to midrail.
VOC - Common-Mode Output Offset Voltage - mV
OUTPUT COMMON-MODE OFFSET
vs CM INPUT VOLTAGE
50
40
30
20
10
0
-10
-20
-30
-40
-50
0
0.5
1
1.5
2
2.5
3
3.5
4.5
4
5
VIC - Common-Mode Input Voltage - V
Figure 37.
16
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TEST CIRCUITS
The THS4511 is tested with the following test circuits
built on the evaluation module (EVM). For simplicity,
the power-supply decoupling is not shown—see
Layout in the Application Information section for
recommendations. Depending on the test conditions,
component values are changed per the following
tables, or as otherwise noted. The signal generators
used are ac-coupled 50-Ω sources, and a 0.22-µF
capacitor and 49.9-Ω resistor to ground are inserted
across RIT on the alternate input to balance the
circuit.
From
50 W
Source
VIN
RF
RG
RIT
5V
49.9 W
RG
0.22 mF
THS4511
49.9 W
CM
RIT
100 W
Output Measured
Here With High
Impedance
Differential Probe
Open
0.22 mF
49.9 W
RF
Figure 38. Frequency Response Test Circuit
Distortion and 1-dB Compression
Table 1. Gain Component Values
GAIN
RF
RG
RIT
0 dB
348 Ω
340 Ω
56.2 Ω
6 dB
348 Ω
165 Ω
61.9 Ω
Note the gain setting includes 50-Ω source
impedance. Components are chosen to achieve
gain and 50-Ω input termination.
Table 2. Load Component Values
RL
RO
ROT
ATTEN.
100 Ω
25 Ω
Open
6 dB
200 Ω
86.6 Ω
69.8 Ω
16.8 dB
499 Ω
237 Ω
56.2 Ω
25.5 dB
1 kΩ
487 Ω
52.3 Ω
31.8 dB
Note the total load includes 50-Ω termination by
the test equipment. Components are chosen to
achieve load and 50-Ω line termination through a
1:1 transformer.
Due to the voltage divider on the output formed by
the load component values, the amplifier output is
attenuated. The column Atten in Table 2 shows the
attenuation expected from the resistor divider. When
using a transformer at the output as shown in
Figure 39, the signal will see slightly more loss, and
these numbers will be approximate.
The circuit shown in Figure 39 is used to measure
harmonic distortion, intermodulation distortion, and
1-db compression point of the amplifier.
A signal generator is used as the signal source and
the output is measured with a spectrum analyzer. The
output impedance of the signal generator is 50 Ω. RIT
and RG are chosen to impedance-match to 50 Ω, and
to maintain the proper gain. To balance the amplifier,
a 0.22-µF capacitor and 49.9-Ω resistor to ground are
inserted across RIT on the alternate input.
A low-pass filter is inserted in series with the input to
reduce harmonics generated at the signal source.
The level of the fundamental is measured, then a
high-pass filter is inserted at the output to reduce the
fundamental so that it does not generate distortion in
the input of the spectrum analyzer.
The transformer used in the output to convert the
signal from differential to single ended is an
ADT1-1WT. It limits the frequency response of the
circuit so that measurements cannot be made below
approximately 1 MHz.
From
50 W
Source
VIN
RIT
0.22 mF
The circuit shown in Figure 38 is used to measure the
frequency response of the circuit.
A network analyzer is used as the signal source and
as the measurement device. The output impedance
of the network analyzer is 50 Ω. RIT and RG are
chosen to impedance match to 50 Ω, and to maintain
the proper gain. To balance the amplifier, a 0.22-µF
capacitor and 49.9-Ω resistor to ground are inserted
across RIT on the alternate input.
The output is probed using a high-impedance
differential probe across the 100-Ω resistor. The gain
is referred to the amplifier output by adding back the
6-dB loss due to the voltage divider on the output.
5V
RO
RG
Frequency Response
RF
RG
RIT
THS4511
CM
49.9 W
RO
1:1
VOUT
ROT
To 50 W
Test
Equipment
Open
0.22 mF
RF
Figure 39. Distortion Test Circuit
The 1-dB compression point is measured with a
spectrum analyzer with 50-Ω double termination or
100-Ω termination as shown in Table 2. The input
power is increased until the output is 1 dB lower than
expected. The number reported in the table data is
the power delivered to the spectrum analyzer input.
Add 3 dB to refer to the amplifier output.
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S-Parameter, Slew Rate, Transient Response,
Settling Time, Output Impedance, Overdrive,
Output Voltage, and Turn-On/Off Time
The circuit shown in Figure 40 is used to measure
s-parameters, slew rate, transient response, settling
time, output impedance, overdrive recovery, output
voltage swing, and turn-on/turn-off times of the
amplifier. For output impedance, the signal is injected
at VOUT with VIN left open and the drop across the
49.9-Ω resistor is used to calculate the impedance
seen looking into the amplifier output.
Because S21 is measured single-ended at the load
with 50-Ω double termination, add 12 dB to refer to
the amplifier output as a differential signal.
From V IN
50-W
Source
RG
R IT
5V
VOUT+
THS4511
49.9 W
VOUT-
0.22 mF
R IT
CM
49.9 W
0.22 mF
RIT
5V
49.9 W
49.9 W
VOUT–
RG
0.22 mF
THS4511
49.9 W
VOUT+
CM
RIT
To
50-W
Test
Equipment
RCM
VIN
49.9 W
RCMT
RF
From
50-W
source
Figure 41. CM Input Test Circuit
CMRR and PSRR
The circuit shown in Figure 42 is used to measure the
CMRR and PSRR of VS+ and VS–. The input is
switched appropriately to match the test being
performed.
RF
49.9 W
RG
RF
RG
To 50-W
Test
Equipment
PSRR+
From VIN
50 W
CMRR
Source
Open
0.22 mF
RF
Figure 40. S-Parameter, SR, Transient Response,
Settling Time, ZO, Overdrive Recovery, VOUT
Swing, and Turn-On/Off Test Circuit
348 W
VS+
5V
49.9 W
100 W
100 W
PSRRVS-
THS4511
CM
69.8 W
49.9 W
100 W
Open
0.22 mF
Output
Measured
Here
With High
Impedance
Differential
Probe
348 W
Figure 42. CMRR and PSRR Test Circuit
CM Input
The circuit shown in Figure 41 is used to measure the
frequency response and input impedance of the CM
input. Frequency response is measured single-ended
at VOUT+ or VOUT– with the input injected at VIN, RCM =
0 Ω, and RCMT = 49.9 Ω. The input impedance is
measured with RCM = 49.9 Ω with RCMT = open, and
calculated by measuring the voltage drop across RCM
to determine the input current.
18
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SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
APPLICATION INFORMATION
APPLICATIONS
The following circuits show application information for
the
THS4511.
For
simplicity,
power-supply
decoupling capacitors are not shown in these
diagrams. For more detail on the use and operation
of fully-differential operational amplifiers refer to
application
report
Fully-Differential
Amplifiers
(SLOA054).
Single-Ended
Input
RG
RF
Differential
5V
Output
+
RG
–
VOUT–
THS4511
–
+
VOUT+
Differential Input to Differential Output Amplifier
The THS4511 is a fully-differential operational
amplifier, and can be used to amplify differential input
signals to differential output signals. A basic block
diagram of the circuit is shown in Figure 43 (CM input
not shown). The gain of the circuit is set by RF
divided by RG.
RF
Figure 44. Single-Ended Input to Differential
Output Amplifier
Input Common-Mode Voltage Range
RF
Differential
Input
RG
V IN+
VIN–
RG
Differential
Output
5V
+
–
VOUT–
THS4511
– +
VOUT+
RF
Figure 43. Differential Input to Differential Output
Amplifier
Depending on the source and load, input and output
termination can be accomplished by adding RIT and
RO.
Single-Ended Input to Differential Output
Amplifier
The input common-model voltage of a fully-differential
operational amplifier is the voltage at the (+) and (–)
input pins of the operational amplifier.
It is important to not violate the input common-mode
voltage range (VICR) of the operational amplifier.
Assuming the operational amplifier is in linear
operation the voltage across the input pins is only a
few millivolts at most. So finding the voltage at one
input pin determines the input common-mode voltage
of the operational amplifier.
Treating the negative input as a summing node, the
voltage is given by Equation 1:
ö
ö æ
æ
RG
RF
÷
÷ + ç VIN- ´
VIC = çç VOUT + ´
÷
ç
R G + R F ÷ø
R G + RF ø è
è
(1)
To determine the VICR of the operational amplifier, the
voltage at the negative input is evaluated at the
extremes of VOUT+.
As the gain of the operational amplifier increases, the
input common-mode voltage becomes closer and
closer to the input common-mode voltage of the
source.
The THS4511 can be used to amplify and convert
single-ended input signals to differential output
signals. A basic block diagram of the circuit is shown
in Figure 44 (CM input not shown). The gain of the
circuit is again set by RF divided by RG.
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Setting the Output Common-Mode Voltage
The output common-mode voltage is set by the
voltage at the CM pin(s). The internal common-mode
control circuit maintains the output common-mode
voltage within 5-mV offset (typical) from the set
voltage, when set within 0.5 V of midsupply. If left
unconnected, the common-mode set point is set to
midsupply by internal circuitry, which may be
overdriven from an external source. Figure 45 is
representative of the CM input. The internal CM
circuit has about 700 MHz of –3-dB bandwidth, which
is required for best performance, but it is intended to
be a dc-bias input pin. Bypass capacitors are
recommended on this pin to reduce noise at the
output. The external current required to overdrive the
internal resistor divider is given by Equation 2:
IEXT =
2VCM - (VS + - VS - )
50 kW
(2)
where VCM is the voltage applied to the CM pin, and
VS+ ranges from 3.75 V to 5 V, and VS– is 0 V
(ground).
VS+
50 kW
to internal
CM circuit
I EXT
operational amplifier. Note RS and RIT are added to
the alternate input from the signal input to balance
the amplifier. One resistor that is equal to the
combined value RI = RG + RS || RIT can be placed at
the alternate input.
RS
RG
VSignal
RIT
RF
RPD
VS+ = 3.75 V to 5 V
RO
THS4511
RG
RS
VOUT-
RO
VOUT+
CM
RIT
RPD
VS–
VCM
RF
Figure 46. THS4511 DC-Coupled Single-Source
Supply Range From 3.75 V to 5 V With RPD Used
To Set VIC
Note that in Figure 46, the source is referenced to
ground, as is the input termination resistor RIT. The
proper value of resistance to add can be calculated
from Equation 3:
RPD =
CM
50 kW
1
é
1 ê
1 .6
êV
R F ê S + - 1 .6
êë 2
ù
ú
1
ú RI
ú
úû
(3)
where RI = RG + RS || RIT.
V S–
Figure 45. CM Input Circuit
Device Operation with Single Power Supplies
Less than 5 V
The THS4511 is optimized to work in systems using
5-V single supplies, and the characterization data
presented in this data sheet were taken with 5-V
single-supply inputs. For ac-coupled systems or
dc-coupled systems operating with supplies less than
5 V and greater than 3.75 V, the amplifier input
common-mode range is maximized by adding
pull-down resistors at the device inputs. The
pull-down resistors provide additional loading at the
input, and lower the common-mode voltage that is fed
back into the device input through resistor RF.
Figure 46 shows the circuit configuration for this
mode of operation where RPD is added to the
dc-coupled circuit to avoid violating the VICR of the
20
VS+ is the power-supply voltage, RF is the feedback
resistance, RG is the gain-setting resistance, RS is the
signal source resistance, and RIT is the termination
resistance.
Table 3 is a modification of Table 1 to add the proper
values with RPD assuming VS+ = 3.75 V, a dc-coupled
50-Ω source impedance, and setting the output
common-mode voltage to midsupply.
Table 3. RPD Values for Various Gains,
VS+ = 3.75 V, DC-coupled Signal Source
GAIN
RF
RG
RIT
RPD
0 dB
348 Ω
340 Ω
56.2 Ω
422 Ω
6 dB
348 Ω
169 Ω
64.9 Ω
86.6 Ω
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If the signal originates from an ac-coupled 50-Ω
source (see Figure 47), the equivalent dc-source
resistance is an open circuit and RI = RG + RIT.
Table 4 is a modification of Table 1 to add the proper
values with RPD assuming VS+ = 3.75 V, an
ac-coupled 50-Ω source impedance, and setting the
output common-mode voltage to midsupply.
Video Source
RS = 75 W
VSignal
VIN
175 W
130 W
348 W
VS+ = 5 V
RO
-
RO
THS4511
175 W
VOD
+
Table 4. RPD Values for Various Gains,
VS+ = 3.75 V, AC-Coupled Signal Source
75 W
GAIN
RF
RG
RIT
RPD
0 dB
348 Ω
340 Ω
56.2 Ω
390 Ω
6 dB
348 Ω
169 Ω
64.9 Ω
80.6 Ω
C
RS
RIT
V Signal
RPD
VCM = 2.5 V
VS-
348 W
Figure 48. Single-Supply Video Buffer, Gain = 2
RF
RG
130 W
0.8
VS+ = 3.75 V to 5 V
0.6
RO
V OUTV OUT+
C
RS
RIT
RO
RPD
V S-
CM
0.4
Voltage - V
THS4511
RG
0.2
0
RF
-0.2
Figure 47. THS4511 AC-Coupled Single-Source
Supply Range From 3.75 V to 5 V With RPD Used
To Set VIC
Figure 48 shows a possible application of the
THS4508 as a dc-coupled video buffer with a gain of
2. Figure 49 shows a plot of the Y' signal originating
from an HDTV 720p video system. The input signal
includes a 3-level sync (minimum level at –0.3 V) and
the portion of a video signal with maximum amplitude
of 0.7 V. Although the buffer draws its power from a
5-V single-ended power supply, internal level shifters
allow the buffer to support input signals which are as
much as –0.3 V below ground. This allows maximum
design flexibility while maintaining a minimum parts
count. Figure 50 shows the differential output of the
buffer. Note that the dc-coupled amplifier can
introduce a dc offset on a signal applied at its input.
0
5
10
15
20
t - Time - ms
Figure 49. Y' Signal with 3-Level Sync and Video
Signal
1.5
VOD - Video Buffer Output - V
Video Buffer
-0.4
1
0.5
0
-0.5
-1
0
5
10
15
20
t - Time - ms
Figure 50. Video Buffer Differential Output Signal
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THS4511 and ADS5500 Combined Performance
THS4511 and ADS5424 Combined Performance
The THS4511 is designed to be a high-performance
drive amplifier for high-performance data converters
like the ADS5500 14-bit 125-MSPS ADC. Figure 51
shows a circuit combining the two devices. The
THS4511 amplifier circuit provides 0 dB of gain, and
converts the single-ended input signal to a differential
output signal. The default common-mode output of
the THS4511 (2.5 V) is not compatible with the
required common-mode input of the ADS5500
(1.55 V), so dc-blocking capacitors are added (0.22
µF). Note that a biasing circuit (not shown in
Figure 51) is needed to provide the required
common-mode, dc-input for the ADS5500. The 100-Ω
resistors and 2.7-pF capacitor between the THS4511
outputs and ADS5500 inputs along with the input
capacitance of the ADS5500 limit the bandwidth of
the signal to 115 MHz (–3 dB). For testing, a signal
generator is used for the signal source. The
generator is an ac-coupled 50-Ω source. A band-pass
filter is inserted in series with the input to reduce
harmonics and noise from the signal source. Input
termination is accomplished via the 69.8-Ω resistor
and 0.22-µF capacitor to ground in conjunction with
the input impedance of the amplifier circuit. A 0.22-µF
capacitor and 49.9-Ω resistor is inserted to ground
across the 69.8-Ω resistor and 0.22-µF capacitor on
the alternate input to balance the circuit. Gain is a
function of the source impedance, termination, and
348-Ω feedback resistor. See Table 1 for component
values to set proper 50-Ω termination for other
common gains.
Figure 52 shows the THS4511 driving the ADS5424
ADC.
From
50-W
source
VIN
The 225-Ω resistors and 2.7-pF capacitor between
the THS4511 outputs and ADS5424 inputs (along
with the input capacitance of the ADC) limit the
bandwidth of the signal to about 100 MHz (–3 dB).
When the THS4511 is operated from a single power
supply with VS+ = 5 V and VS– = ground, the 2.5-V
output common-mode voltage is compatible with the
recommended value of the ADS5424 input
common-mode voltage (2.4 V).
From
50-W
source
V IN
348 W
340 W
56.2 W
5V
225 W
340
49 .9 W
56.2 W
THS4511
225 W
2 .7 pF
CM
0.22 mF
348 W
14-bit,
105 MSPS
A IN+
ADS5424
A IN– VBG
49.9 W
0.1 mF
0.1 mF
Figure 52. THS4511 and ADS5424 Circuit
348 W
340 W
56.2 W
As before, the THS4511 amplifier provides 0 dB of
gain, converts the single-ended input to differential,
and sets the proper input common-mode voltage to
the ADS5424. Input termination and circuit testing is
the same as described above for the THS4511 and
ADS5500 circuit.
5V
0.22 mF
100 W
14-bit,
125 MSPS
A IN +
340 W
49.9 W
56.2 W
THS4511
2.7 pF
ADS5500
A IN - CM
CM
0.22 mF
0.22 mF
100 W
0.1 mF
348 W
Figure 51. THS4511 and ADS5500 Circuit
22
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SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
Layout Recommendations
It is recommended to follow the layout of the external
components near the amplifier, ground plane
construction, and power routing of the EVM as
closely as possible. General guidelines are:
1. Signal routing should be direct and as short as
possible into and out of the operational amplifier
circuit.
2. The feedback path should be short and direct;
avoid vias.
3. Ground or power planes should be removed from
directly under the amplifier input and output pins.
4. An output resistor is recommended on each
output, as near to the output pin as possible.
5. Two 10-µF and two 0.1-µF power-supply
decoupling capacitors should be placed as near
to the power-supply pins as possible.
6. Two 0.1-µF capacitors should be placed between
the CM input pins and ground. This configuration
limits noise coupled into the pins. One each
should be placed to ground near pin 4 and pin 9.
7. It is recommended to split the ground pane on
layer 2 (L2) as shown below and to use a solid
ground on layer 3 (L3). A single-point connection
should be used between each split section on L2
and L3.
8. A single-point connection to ground on L2 is
recommended for the input termination resistors
R1 and R2. This configuration should be applied
to the input gain resistors if termination is not
used.
9. The recommended printed circuit board (PCB)
footprint for the THS4511 is shown in Figure 54.
as a thermal pad on the underside of the package
(see Figure 53c). Because this thermal pad has direct
thermal contact with the die, excellent thermal
performance can be achieved by providing a good
thermal path away from the thermal pad.
Note that the THS4511 has no electrical connection
between the PowerPAD and circuitry on the die.
Connecting the PowerPAD to any potential voltage
between VS+ and VS– is acceptable. It is most
important that it be connected for maximum heat
dissipation.
The PowerPAD package allows both assembly and
thermal management in one manufacturing operation.
During the surface-mount solder operation (when the
leads are being soldered), the thermal pad can also
be soldered to a copper area underneath the
package. Through the use of thermal paths within this
copper area, heat can be conducted away from the
package into either a ground plane or other heat
dissipating device.
The PowerPAD package represents a breakthrough
in combining the small area and ease of assembly of
surface-mount with the heretofore awkward
mechanical methods of heatsinking.
DIE
Side View (a)
DIE
End View (b)
Bottom View (c)
Figure 53. Views of Thermally-Enhanced Package
PowerPAD™ DESIGN CONSIDERATIONS
The THS4511 is available in a thermally-enhanced
PowerPAD family of packages. These packages are
constructed using a downset leadframe on which the
die is mounted (see Figure 53a and Figure 53b). This
arrangement results in the lead frame being exposed
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THS4511
SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
PowerPAD PCB LAYOUT
CONSIDERATIONS
Although there are many ways to properly heatsink
the PowerPAD package, the following steps illustrate
the recommended approach.
0.144
0.049
0.012
Pin 1
0.0095
0.015
0.144
0.0195 0.0705
0.010
vias
0.032
0.030
0.0245
Top View
Figure 54. PowerPAD PCB Etch and Via Pattern
1. Prepare the PCB with a top side etch pattern as
shown in Figure 54. There should be etch for the
leads as well as etch for the thermal pad.
2. Place five holes in the area of the thermal pad.
The holes should be 13 mils (0.013 in, 0.33 mm)
in diameter. Keep them small so that solder
wicking through the holes is not a problem during
reflow.
3. Additional vias may be placed anywhere along
the thermal plane outside of the thermal pad
area. They help dissipate the heat generated by
the IC. These additional vias may be larger than
the 13-mil diameter vias directly under the
thermal pad. They can be larger because they
are not in the thermal pad area to be soldered, so
that wicking is not a problem.
4. Connect all holes to the internal ground plane.
5. When connecting these holes to the ground
plane, do not use the typical web or spoke via
connection methodology. Web connections have
a high thermal resistance connection that is
24
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useful for slowing the heat transfer during
soldering operations. This resistance makes the
soldering of vias that have plane connections
easier. In this application, however, low thermal
resistance is desired for the most efficient heat
transfer. Therefore, the holes under the IC
PowerPAD package should make the connection
to the internal ground plane, with a complete
connection around the entire circumference of the
plated-through hole.
6. The top-side solder mask should leave the
terminals of the package and the thermal pad
area with its five holes exposed. The bottom-side
solder mask should cover the five holes of the
thermal pad area. This configuration prevents
solder from being pulled away from the thermal
pad area during the reflow process.
7. Apply solder paste to the exposed thermal pad
area and all of the IC terminals.
8. With these preparatory steps in place, the IC is
simply placed in position and run through the
solder reflow operation as any standard
surface-mount component. This process results
in a part that is properly installed.
The next consideration is the package constraints.
The two sources of heat within an amplifier are
quiescent power and output power. The designer
should never forget about the quiescent heat
generated within the device, especially multi-amplifier
devices. Because these devices have linear output
stages (Class AB), most of the heat dissipation is at
low output voltages with high output currents.
The other key factor when dealing with power
dissipation is how the devices are mounted on the
PCB. The PowerPAD devices are extremely useful
for heat dissipation. But the device should always be
soldered to a copper plane to fully use the heat
dissipation properties of the PowerPAD. The SOIC
package, on the other hand, is highly dependent on
how it is mounted on the PCB. As more trace and
copper area is placed around the device,
θJA
decreases and the heat dissipation capability
increases. For a single package, the sum of the RMS
output currents and voltages should be used to
choose the proper package.
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SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
THS4511 EVM
Figure 55 is the THS4511 EVAL1 EVM schematic, layers 1 through 4 of the PCB are shown in Figure 56, and
Table 5 is the bill of materials for the EVM as supplied from TI.
GND
TP1
VS+
J6
J5
VCC
J8
R5
348 W
R1
56.2 W
R3
J1
C15
R12
49.9 W
12
2
3
VO+
-
U1 11
+
R4
VOPwrPad 10
4
340 W
R2
56.2 W
TP2
C14
0.1 mF
R7
86.6 W
R8
86.6 W
C5
6
C12
C13
1
5
4
0.1 mF
VCC
3
XFMR_ADT1-1WT
Vocm
9
0.1 mF
J3
T1
R11
69.8 W
10 mF
C3
R9
open
7
PD
340 W
0.22 mF
J2
VCC
8
6
5
10 mF
15 13
14 16
R10
open
R6
C1
open
J7
C8
open
348 W
TP3
C7
open
C2
open
C11
0.1 mF
Figure 55. THS4511 EVAL1 EVM Schematic
Figure 56. THS4511 EVAL1 EVM Layer 1 Through 4
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THS4511
SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
www.ti.com
Table 5. THS4511RGT EVM Bill of Materials
ITEM
(1)
DESCRIPTION
SMD
SIZE
REFERENCE
DESIGNATOR
PCB
QTY
MANUFACTURER
PART NUMBER (1)
1
CAP, 10.0 µF, Ceramic, X5R, 6.3V
0805
C3, C5
2
(AVX) 08056D106KAT2A
2
CAP, 0.1 µF, Ceramic, X5R, 10V
0402
C11-C14
4
(AVX) 0402ZD104KAT2A
3
CAP, 0.22 µF, Ceramic, X5R, 6.3V
0402
C15
1
(AVX) 04026D224KAT2A
4
OPEN
0402
C1, C2, C7-C10
6
5
OPEN
0402
R9, R10
2
6
Resistor, 49.9 Ω, 1/16W, 1%
0402
R12
1
7
Resistor, 56.2 Ω, 1/16W, 1%
0402
R1, R2
8
Resistor, 69.8 Ω, 1/16W, 1%
0402
R11
3
(KOA) RK73H1ETTP69R8F
9
Resistor, 86.6 Ω, 1/16W, 1%
0402
R7, R8
2
(KOA) RK73H1ETTP86R6F
10
Resistor, 340 Ω, 1/16W, 1%
0402
R3, R4
2
(KOA) RK73H1ETTP3400F
11
Resistor, 348 Ω, 1/16W, 1%
0402
R5, R6
2
(KOA) RK73H1ETTP3480F
12
Resistor, 0 Ω, 5%
0805
C4, C6
2
(KOA) RK73Z2ATTD
13
Transformer, RF
T1
1
(MINI-CIRCUITS) ADT1-1WT
14
Jack, banana receptance, 0.25" diameter
hole
J5, J6
15
OPEN
J1, J7, J8
3
16
Connector, edge, SMA PCB Jack
J2, J3
2
(JOHNSON) 142-0701-801
17
Test point, Red
TP1, TP2, TP3
3
(KEYSTONE) 5000
18
IC, THS4511
U1
1
(TI) THS4511RGT
19
Standoff, 4-40 HEX, 0.625" length
4
(KEYSTONE) 1808
20
SCREW, PHILLIPS, 4-40, 0.250"
4
SHR-0440-016-SN
21
Printed circuit board
1
(TI) EDGE# 6475513
(KOA) RK73H1ETTP49R9F
(KOA) RK73H1ETTP56R2F
2
(HH SMITH) 101
The manufacturer's part numbers were used for test purposes only.
EVM WARNINGS AND RESTRICTIONS
It is important to operate this EVM within the input and output voltage ranges as specified in the table provided
below.
INPUT RANGE, VS+ TO VS–
3.0 V TO 6.0 V
Input Range, VI
3.0 V to 6.0 V NOT TO EXCEED VS+ or VS–
Output Range, VO
3.0 V to 6.0 V NOT TO EXCEED VS+ or VS–
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 product data sheet or EVM user's guide (if user's guide is
available) 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 +30°C. The EVM is
designed to operate properly with certain components above +50°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 material provided. 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
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SLOS471E – SEPTEMBER 2005 – REVISED NOVEMBER 2009
REVISION HISTORY
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision D (May 2007) to Revision E
Page
•
Updated document format to match current standards ........................................................................................................ 1
•
Deleted title and conditions of Typical Conditions table of graphs ....................................................................................... 6
•
Added title and conditions to Typical Characteristics plots ................................................................................................... 7
•
Changed item 9 in the Layout Recommendations section ................................................................................................. 23
•
Added PowerPAD Design Considerations section ............................................................................................................. 23
•
Added PowerPAD PCB Layout Considerations section ..................................................................................................... 24
•
Moved Figure 54 and associated paragraph to PowerPAD PCB Layout Considerations section ..................................... 24
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PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
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)
(4/5)
(6)
THS4511RGTT
ACTIVE
VQFN
RGT
16
250
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
4511
(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
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