LMP7732
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SNOSAZ0E – AUGUST 2007 – REVISED MARCH 2013
2.9 nV/sqrt(Hz) Low Noise, RRIO Amplifier
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FEATURES
DESCRIPTION
•
•
The LMP7732 is a dual low noise, rail-to-rail input
and output, low voltage amplifier. The LMP7732 is
part of the LMP™ amplifier family and is ideal for
precision and low noise applications with low voltage
requirements.
1
23
•
•
•
•
•
•
•
•
•
•
(Typical Values, TA = 25°C, VS = 5V)
Input Voltage Noise
– f = 3 Hz 3.3 nV/√Hz
– f = 1 kHz 2.9 nV/√Hz
CMRR 130 dB
Open Loop Gain 130 dB
GBW 22 MHz
Slew Rate 2.4 V/µs
THD 0.001% @ f = 10 kHz, AV = 1, RL = 2 kΩ
Supply Current 4.4 mA
Supply Voltage Range 1.8V to 5.5V
Operating Temperature Range −40°C to 125°C
Input Bias Current ±1.5 nA
RRIO
The LMP7732 provides a wide GBW of 22 MHz while
consuming only 4 mA of current. This high gain
bandwidth along with the high open loop gain of 130
dB enables accurate signal conditioning in
applications with high closed loop gain requirements.
The LMP7732 has a supply voltage range of 1.8V to
5.5V, making it an ideal choice for battery operated
portable applications.
APPLICATIONS
•
•
•
This operational amplifier offers low voltage noise of
2.9 nV/√Hz with a 1/f corner of only 3 Hz. The
LMP7732 has bipolar junction input stages with a
bias current of only 1.5 nA. This low input bias
current, complemented by the very low level of
voltage noise, makes the LMP7732 an excellent
choice for photometry applications.
Gas Analysis Instruments
Photometric Instrumentation
Medical Instrumentation
The LMP7732 is offered in the 8-Pin SOIC and
VSSOP packages.
The LMP7731 is the single version of this product
and is offered in the 5-Pin SOT-23 and 8-Pin SOIC
packages.
Typical Performance Characteristics
Input Voltage Noise vs. Frequency
Input Current Noise vs. Frequency
100
100
10
VS = 2.5V, 3.3V, 5V
CURRENT NOISE (pA/ Hz)
VOLTAGE NOISE (nV/ Hz)
VS = 2.5V, 3.3V, 5V
VCM = 0.5V
VCM = 2.5V
VCM = 0.5V
10
VCM = 2.5V
1
0.1
1
10
100
1k
FREQUENCY (Hz)
10k
1
0.1
1
10
100
1k
10k
FREQUENCY (Hz)
1
2
3
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.
LMP is a trademark of Texas Instruments.
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 © 2007–2013, Texas Instruments Incorporated
LMP7732
SNOSAZ0E – AUGUST 2007 – REVISED MARCH 2013
www.ti.com
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
Absolute Maximum Ratings (1) (2)
Human Body Model
ESD Tolerance (3)
For inputs pins only
2000V
For all other pins
2000V
Machine Model
200V
Charge Device Model
1000V
VIN Differential
±2V
Supply Voltage (VS = V+ – V−)
6.0V
−65°C to 150°C
Storage Temperature Range
Junction Temperature (4)
+150°C max
Soldering Information
(1)
(2)
(3)
(4)
Infrared or Convection (20 sec)
235°C
Wave Soldering Lead Temp. (10 sec)
260°C
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is intended to be functional, but specific performance is not ensured. For ensured specifications and the test
conditions, see the Electrical Characteristics Tables.
If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and
specifications.
Human Body Model, applicable std. MIL-STD-883, Method 3015.7. Machine Model, applicable std. JESD22-A115-A (ESD MM std. of
JEDEC) Field-Induced Charge-Device Model, applicable std. JESD22-C101-C (ESD FICDM std. of JEDEC).
The maximum power dissipation is a function of TJ(MAX), θJA, and TA. The maximum allowable power dissipation at any ambient
temperature is PD = (TJ(MAX) - TA)/ θJA. All numbers apply for packages soldered directly onto a PC board.
Operating Ratings (1)
−40°C to 125°C
Temperature Range
Supply Voltage (VS = V+ – V–)
Package Thermal Resistance (θJA)
(1)
2
1.8V to 5.5V
8-Pin SOIC
190 °C/W
8-Pin VSSOP
235°C/W
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is intended to be functional, but specific performance is not ensured. For ensured specifications and the test
conditions, see the Electrical Characteristics Tables.
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2.5V Electrical Characteristics (1)
Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 2.5V, V− = 0V, VCM = V+/2, RL >10 kΩ to V+/2. Boldface
limits apply at the temperature extremes.
Symbol
Typ (3)
Max (2)
VCM = 2.0V
±9
±500
±600
VCM = 0.5V
±9
±500
±600
VCM = 2.0V
±0.5
±5.5
VCM = 0.5V
±0.2
±5.5
VCM = 2.0V
±1
±30
±45
VCM = 0.5V
±12
±50
±75
VCM = 2.0V
±1
±50
±75
VCM = 0.5V
±11
±60
±80
Parameter
Conditions
Min (2)
Input Offset Voltage (4)
VOS
TCVOS
IB
Input Offset Voltage Temperature Drift
Input Bias Current
IOS
Input Offset Current
TCIOS
Input Offset Current Drift
CMRR
Common Mode Rejection Ratio
PSRR
Power Supply Rejection Ratio
VCM = 0.5V and VCM = 2.0V
0.0474
0.15V ≤ VCM ≤ 0.7V
0.23V ≤ VCM ≤ 0.7V
101
89
120
1.5V ≤ VCM ≤ 2.35V
1.5V ≤ VCM ≤ 2.27V
105
99
129
2.5V ≤ V+ ≤ 5V
105
101
113
1.8V ≤ V+ ≤ 5.5V
CMVR
Common Mode Voltage Range
Large Signal CMRR ≥ 80 dB
+
AVOL
Open Loop Voltage Gain
0
112
104
130
RL = 2 kΩ to V+/2
VOUT = 0.5V to 2.0V
109
90
119
(1)
(2)
(3)
(4)
dB
50
75
RL = 2 kΩ to V+/2
13
50
75
RL = 10 kΩ to V /2
6
50
75
RL = 2 kΩ to V+/2
9
50
75
Sourcing, VOUT = V+/2
VIN (diff) = 100 mV
22
12
31
Sinking, VOUT = V+/2
VIN (diff) = −100 mV
15
10
44
V
dB
4
mV from
either rail
mA
VCM = 2.0V
4.0
5.4
6.8
VCM = 0.5V
4.6
6.2
7.8
AV = +1, CL = 10 pF, RL = 10 kΩ to V+/2
VOUT = 2 VPP
2.4
Supply Current
Slew Rate
nA
nA/°C
RL = 10 kΩ to V+/2
Output Voltage Swing Low
SR
nA
2.5
RL = 10 kΩ to V /2
VOUT = 0.5V to 2.0V
+
IS
μV/°C
dB
VOUT
Output Current
μV
111
Output Voltage Swing High
IOUT
Units
mA
V/μs
Electrical Table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very
limited self-heating of the device such that TJ = TA. No ensured specification of parametric performance is indicated in the electrical
tables under conditions of internal self-heating where TJ > TA. Absolute maximum Ratings indicate junction temperature limits beyond
which the device maybe permanently degraded, either mechanically or electrically.
All limits are specified by testing, statistical analysis or design.
Typical values represent the most likely parametric norm as determined at the time of characterization. Actual typical values may vary
over time and will also depend on the application and configuration. The typical values are not tested and are not ensured on shipped
production material.
Ambient production test is performed at 25°C with a variance of ±3°C.
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2.5V Electrical Characteristics(1) (continued)
Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 2.5V, V− = 0V, VCM = V+/2, RL >10 kΩ to V+/2. Boldface
limits apply at the temperature extremes.
Symbol
GBW
Parameter
Gain Bandwidth
Min (2)
Conditions
Typ (3)
+
21
+
CL = 20 pF, RL = 10 kΩ to V /2
Max (2)
Units
MHz
GM
Gain Margin
CL = 20 pF, RL = 10 kΩ to V /2
14
dB
ΦM
Phase Margin
CL = 20 pF, RL = 10 kΩ to V+/2
60
deg
RIN
Input Resistance
THD+N
Total Harmonic Distortion + Noise
en
Input Referred Voltage Noise Density
Input Voltage Noise
in
4
Input Referred Current Noise Density
Differential Mode
38
kΩ
Common Mode
151
MΩ
0.002
%
AV = 1, fO = 1 kHz, Amplitude = 1V
f = 1 kHz, VCM = 2.0V
3.0
f = 1 kHz, VCM = 0.5V
3.0
0.1 Hz to 10 Hz
75
f = 1 kHz, VCM = 2.0V
1.1
f = 1 kHz, VCM = 0.5V
2.3
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nV/√Hz
nVPP
pA/√Hz
Copyright © 2007–2013, Texas Instruments Incorporated
Product Folder Links: LMP7732
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SNOSAZ0E – AUGUST 2007 – REVISED MARCH 2013
3.3V Electrical Characteristics (1)
Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 3.3V, V− = 0V, VCM = V+/2, RL > 10 kΩ to V+/2. Boldface
limits apply at the temperature extremes.
Symbol
Typ (3)
Max (2)
VCM = 2.5V
±6
±500
±600
VCM = 0.5V
±6
±500
±600
VCM = 2.5V
±0.5
±5.5
VCM = 0.5V
±0.2
±5.5
VCM = 2.5V
±1.5
±30
±45
VCM = 0.5V
±13
±50
±77
VCM = 2.5V
±1
±50
±70
VCM = 0.5V
±11
±60
±80
Parameter
Conditions
Min (2)
Input Offset Voltage (4)
VOS
TCVOS
IB
Input Offset Voltage Temperature
Drift
Input Bias Current
IOS
Input Offset Current
TCIOS
CMRR
PSRR
Input Offset Current Drift
Common Mode Rejection Ratio
VCM = 0.5V and VCM = 2.5V
0.048
0.15V ≤ VCM ≤ 0.7V
0.23V ≤ VCM ≤ 0.7V
101
89
120
1.5V ≤ VCM ≤ 3.15V
1.5V ≤ VCM ≤ 3.07V
105
99
130
2.5V ≤ V+ ≤ 5.0V
105
101
Power Supply Rejection Ratio
1.8V ≤ V+ ≤ 5.5V
CMVR
Common Mode Voltage Range
Large Signal CMRR ≥ 80 dB
+
AVOL
Open Loop Voltage Gain
RL = 10 kΩ to V /2
VOUT = 0.5V to 2.8V
+
RL = 2 kΩ to V /2
VOUT = 0.5V to 2.8V
0
(1)
(2)
(3)
(4)
nA/°C
3.3
112
104
130
110
92
119
V
dB
RL = 10 kΩ to V+/2
5
50
75
RL = 2 kΩ to V+/2
14
50
75
RL = 10 kΩ to V /2
9
50
75
RL = 2 kΩ to V+/2
13
50
75
Sourcing, VOUT = V+/2
VIN (diff) = 100 mV
28
22
45
Sinking, VOUT = V+/2
VIN (diff) = −100 mV
25
20
48
mV from
either rail
mA
VCM = 2.5V
4.2
5.6
7.0
VCM = 0.5V
4.8
6.4
8.0
AV = +1, CL = 10 pF, RL = 10 kΩ to
V+/2
VOUT = 2 VPP
2.4
Supply Current
Slew Rate
nA
dB
Output Voltage Swing Low
SR
nA
111
+
IS
μV/°C
113
VOUT
Output Current
μV
dB
Output Voltage Swing High
IOUT
Units
mA
V/μs
Electrical Table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very
limited self-heating of the device such that TJ = TA. No ensured specification of parametric performance is indicated in the electrical
tables under conditions of internal self-heating where TJ > TA. Absolute maximum Ratings indicate junction temperature limits beyond
which the device maybe permanently degraded, either mechanically or electrically.
All limits are specified by testing, statistical analysis or design.
Typical values represent the most likely parametric norm as determined at the time of characterization. Actual typical values may vary
over time and will also depend on the application and configuration. The typical values are not tested and are not ensured on shipped
production material.
Ambient production test is performed at 25°C with a variance of ±3°C.
Submit Documentation Feedback
Copyright © 2007–2013, Texas Instruments Incorporated
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3.3V Electrical Characteristics(1) (continued)
Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 3.3V, V− = 0V, VCM = V+/2, RL > 10 kΩ to V+/2. Boldface
limits apply at the temperature extremes.
Symbol
GBW
Parameter
Gain Bandwidth
Min (2)
Conditions
Typ (3)
+
22
+
CL = 20 pF, RL = 10 kΩ to V /2
Max (2)
Units
MHz
GM
Gain Margin
CL = 20 pF, RL = 10 kΩ to V /2
14
dB
ΦM
Phase Margin
CL = 20 pF, RL = 10 kΩ to V+/2
62
deg
THD+N
Total Harmonic Distortion + Noise
AV = 1, fO = 1 kHz, Amplitude = 1V
RIN
0.002
%
Differential Mode
38
kΩ
Common Mode
151
MΩ
Input Referred Voltage Noise
Density
f = 1 kHz, VCM = 2.5V
2.9
nV/√Hz
f = 1 kHz, VCM = 0.5V
2.9
Input Voltage Noise
0.1 Hz to 10 Hz
75
nVPP
Input Referred Current Noise
Density
f = 1 kHz, VCM = 2.5V
1.1
pA/√Hz
f = 1 kHz, VCM = 0.5V
2.1
Input Resistance
en
in
5V Electrical Characteristics (1)
Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 5V, V− = 0V, VCM = V+/2, RL > 10 kΩ to V+/2. Boldface
limits apply at the temperature extremes.
Symbol
Typ (3)
Max (2)
VCM = 4.5V
±6
±500
±600
VCM = 0.5V
±6
±500
±600
VCM = 4.5V
±0.5
±5.5
VCM = 0.5V
±0.2
±5.5
VCM = 4.5V
±1.5
±30
±50
VCM = 0.5V
±14
±50
±85
VCM = 4.5V
±1
±50
±70
VCM = 0.5V
±11
±65
±80
Parameter
Conditions
Min (2)
Input Offset Voltage (4)
VOS
TCVOS
IB
Input Offset Voltage Temperature Drift
Input Bias Current
IOS
Input Offset Current
TCIOS
CMRR
PSRR
Input Offset Current Drift
Common Mode Rejection Ratio
VCM = 0.5V and VCM = 4.5V
0.0482
0.15V ≤ VCM ≤ 0.7V
0.23V ≤ VCM ≤ 0.7V
101
89
120
1.5V ≤ VCM ≤ 4.85V
1.5V ≤ VCM ≤ 4.77V
105
99
130
2.5V ≤ V+ ≤ 5V
105
101
113
Power Supply Rejection Ratio
1.8V ≤ V+ ≤ 5.5V
CMVR
AVOL
(1)
(2)
(3)
(4)
6
Common Mode Voltage Range
Open Loop Voltage Gain
Large Signal CMRR ≥ 80 dB
Units
μV
μV/°C
nA
nA
nA/°C
dB
dB
111
0
5
RL = 10 kΩ to V+/2
VOUT = 0.5V to 4.5V
112
104
130
RL = 2 kΩ to V+/2
VOUT = 0.5V to 4.5V
110
94
119
V
dB
Electrical Table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very
limited self-heating of the device such that TJ = TA. No ensured specification of parametric performance is indicated in the electrical
tables under conditions of internal self-heating where TJ > TA. Absolute maximum Ratings indicate junction temperature limits beyond
which the device maybe permanently degraded, either mechanically or electrically.
All limits are specified by testing, statistical analysis or design.
Typical values represent the most likely parametric norm as determined at the time of characterization. Actual typical values may vary
over time and will also depend on the application and configuration. The typical values are not tested and are not ensured on shipped
production material.
Ambient production test is performed at 25°C with a variance of ±3°C.
Submit Documentation Feedback
Copyright © 2007–2013, Texas Instruments Incorporated
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5V Electrical Characteristics(1) (continued)
Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 5V, V− = 0V, VCM = V+/2, RL > 10 kΩ to V+/2. Boldface
limits apply at the temperature extremes.
Symbol
Typ (3)
Max (2)
RL = 10 kΩ to V+/2
8
50
75
RL = 2 kΩ to V+/2
24
50
75
RL = 10 kΩ to V+/2
9
50
75
RL = 2 kΩ to V+/2
23
50
75
Parameter
Min (2)
Conditions
Output Voltage Swing High
VOUT
Output Voltage Swing Low
IOUT
Output Current
IS
Supply Current
SR
GBW
Slew Rate
Gain Bandwidth
Sourcing, VOUT = V+/2
VIN (diff) = 100 mV
33
27
47
Sinking, VOUT = V+/2
VIN (diff) = −100 mV
30
25
49
mV from
either rail
mA
VCM = 4.5V
4.4
6.0
7.4
VCM = 0.5V
5.0
6.8
8.4
AV = +1, CL = 10 pF, RL = 10 kΩ to V+/2
VOUT = 2 VPP
Units
mA
2.4
V/μs
+
22
MHz
+
CL = 20 pF, RL = 10 kΩ to V /2
GM
Gain Margin
CL = 20 pF, RL = 10 kΩ to V /2
12
dB
ΦM
Phase Margin
CL = 20 pF, RL = 10 kΩ to V+/2
65
deg
RIN
Input Resistance
THD+ N Total Harmonic Distortion + Noise
en
Input Referred Voltage Noise Density
Input Voltage Noise
in
Input Referred Current Noise Density
Differential Mode
38
kΩ
Common Mode
151
MΩ
0.001
%
AV = 1, fO = 1 kHz, Amplitude = 1V
f = 1 kHz, VCM = 4.5V
2.9
f = 1 kHz, VCM = 0.5V
2.9
0.1 Hz to 10 Hz
75
f = 1 kHz, VCM = 4.5V
1.1
f = 1 kHz, VCM = 0.5V
2.2
nV/√Hz
nVPP
pA/√Hz
Connection Diagram
8-Pin SOIC/VSSOP
1
A
3
B
+
+IN A
7
+
2
-IN A
V
8
-
4
6
-
OUT A
5
+
V
OUT B
-IN B
+IN B
Figure 1. Top View
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Typical Performance Characteristics
Unless otherwise noted: TA = 25°C, RL > 10 kΩ, VCM = VS/2.
Offset Voltage Distribution
10
9
TCVOS Distribution
25
VS = 2.5V
VS = 2.5V, 3.3V
VCM = 0.5V
VCM = 0.5V
20
PERCENTAGE (%)
PERCENTAGE (%)
8
7
6
5
4
3
15
10
5
2
1
0
-40 -30
-20
-10
0
10
20
30
0
-0.5
40
0
VOS (PV)
Figure 2.
Offset Voltage Distribution
1.5
TCVOS Distribution
25
VS = 3.3V, 5V
VS = 5V
VCM = 0.5V
VCM = 0.5V
20
PERCENTAGE (%)
PERCENTAGE (%)
8
1
Figure 3.
10
9
0.5
TCVOS (PV/°C)
7
6
5
4
3
15
10
5
2
1
0
-40 -30
-20
-10
0
10
20
30
0
-0.5
40
0
VOS (PV)
Figure 4.
1
1.5
Figure 5.
Offset Voltage Distribution
TCVOS Distribution
14
9
VS = 2.5V
VS = 2.5V, 5V
8
12 VCM = 2V
VCM = VS - 0.5V
PERCENTAGE (%)
7
PERCENTAGE (%)
0.5
TCVOS (PV/°C)
6
5
4
3
10
8
6
4
2
2
1
0
-40 -30 -20
8
-10
0
10
20
30
40
0
-0.5
0
0.5
VOS (PV)
TCVOS (PV/°C)
Figure 6.
Figure 7.
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1
1.5
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Typical Performance Characteristics (continued)
Unless otherwise noted: TA = 25°C, RL > 10 kΩ, VCM = VS/2.
Offset Voltage Distribution
TCVOS Distribution
14
8
VS = 3.3V, 5V
VS = 3.3V
7
12 VCM = 2.5V, 4.5V
VCM = 2.5V
10
PERCENTAGE (%)
PERCENTAGE (%)
6
5
4
3
8
6
4
2
2
1
0
-40 -30 -20 -10
0
10
20
30
0
-0.5
40
0
Figure 8.
Figure 9.
Offset Voltage vs. Temperature
1.5
Offset Voltage vs. Temperature
100
VS = 2.5V, 3.3V, 5V
75
VCM = 0.5V
5 TYPICAL PARTS
50
20
10
0
VS = 2.5V, 3.3V, 5V
VCM = 2V, 2.5V, 4.5V
5 TYPICAL PARTS
25
VOS (PV)
VOS (PV)
1
TCVOS (PV/°C)
40
30
0.5
VOS (PV)
0
-25
-10
-50
-20
-75
-30
-40 -20
0
20
40
-100
-40 -20
80 100 120
60
0
TEMPERATURE (°C)
20
40
60
80
100 120
TEMPERATURE (°C)
Figure 10.
Figure 11.
PSRR vs. Frequency
CMRR vs. Frequency
160
0
VS = 2.5V, 3.3V, 5V
140
-20
-PSRR
120
CMRR (dB)
PSRR (dB)
-40
-60
VS = 2.5V
-80
+PSRR
100
-100
60
40
-120
20
VS = 3.3V
-140
10
80
100
VS = 5V & 3.3V
1k
10k
100k
1M
10M
0
100
1k
10k
100k
1M
10M
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 12.
Figure 13.
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Typical Performance Characteristics (continued)
Unless otherwise noted: TA = 25°C, RL > 10 kΩ, VCM = VS/2.
Offset Voltage vs. Supply Voltage
Offset Voltage vs. VCM
5
100
VS = 2.5V
50
-5
VOS (PV)
OFFSET VOLTAGE (PV)
75
25°C
0
-40°C
-10
125°C
25
85°C
25°C
0
-15
-40°C
-25
85°C
-20
-50
-25
1.5
125°C
2
2.5
3
3.5
4
4.5
5
-75
5.5
0
0.5
1
SUPPLY VOLTAGE (V)
Figure 14.
Offset Voltage vs. VCM
Offset Voltage vs. VCM
VS = 5V
VS = 3.3V
75
50
50
VOS (PV)
125°C
VOS (PV)
2.5
100
75
85°C
25
25°C
0
-40°C
-25
125°C
25
85°C
25°C
0
-40°C
-25
-50
-50
-75
-75
0
0.5
1
1.5
2
2.5
3 3.3
0
1
2
3
4
5
VCM (V)
VCM (V)
Figure 16.
Figure 17.
Input Offset Voltage Time Drift
Slew Rate vs. Supply Voltage
3.4
5.0
RISING EDGE
3.2
4.0
SLEW RATE (V/Ps)
OFFSET VOLTAGE DRIFT (PV)
2
Figure 15.
100
3.0
2.0
3
2.8
FALLING EDGE
2.6
AV = +1
2.4
VIN = 1 VPP
VS = 5V
1.0
RL = 2 k:
5 TYPICAL UNITS
2.2
0.0
0
50
100
150
200
250
300
TIME (s)
2
1.5
RL = 10 k:
CL = 10 pF
2
2.5
3
3.5
4
4.5
5
5.5
SUPPLY VOLTAGE (V)
Figure 18.
10
1.5
VCM (V)
Figure 19.
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Typical Performance Characteristics (continued)
Unless otherwise noted: TA = 25°C, RL > 10 kΩ, VCM = VS/2.
Time Domain Voltage Noise
Time Domain Voltage Noise
Figure 20.
Figure 21.
Time Domain Voltage Noise
Output Voltage vs. Output Current
1000
VS = 2.5V, 3.3V, 5V
VOUT FROM RAIL (mV)
800
VS = 2.5V
600
400
SINK
200
0
-200
-400
SOURCE
-600
-800
0
5
10
15
20
25
30
OUTPUT CURRENT (mA)
Figure 22.
Figure 23.
Input Bias Current vs. VCM
Input Bias Current vs. VCM
100
100
VS = 2.5V
125°C
60
85°C
40
25°C
20
0
-20
-40
-40°C
-60
60
85°C
40
25°C
20
0
-20
-40°C
-40
-60
-80
-80
-100
VS = 3.3V
125°C
80
INPUT BIAS CURRENT (nA)
INPUT BIAS CURRENT (nA)
80
-100
0
0.5
1
1.5
2
2.5
0
0.5
1
1.5
2
VCM (V)
VCM (V)
Figure 24.
Figure 25.
2.5
3
3.5
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Typical Performance Characteristics (continued)
Unless otherwise noted: TA = 25°C, RL > 10 kΩ, VCM = VS/2.
Input Bias Current vs. VCM
Open Loop Frequency Response Over Temperature
100
100
INPUT BIAS CURRENT (nA)
225
VS = 5V
125°C
80
GAIN
80
180
60
60
20
GAIN (dB)
25°C
0
-20
-40
PHASE
20
45
VS = 2.5V, TA = 25°C
-40°C
0
0
VS = 2.5V, 3.3V, 5V
-20 RL = 10 k:
TA = -40°C, 25°C, 85°C, 125°C
-40
1M
10M
100k
1k
10k
-80
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
VCM (V)
FREQUENCY (Hz)
Figure 26.
Figure 27.
Open Loop Frequency Response
Open Loop Frequency Response
225
VS = 5V
GAIN
GAIN
180
80
135
60
RL = 10 k: 180
CL = 20 pF
135
-40°C
90
25°C
90
40
PHASE
20 V = 2.5V, C = 100 pF,
S
L
45
RL = 10 k:
GAIN (dB)
GAIN (dB)
RL = 2 k:
PHASE (°)
VS = 5V, CL = 20 pF,
60
40
PHASE
20
45
85°C
0
0
VS = 2.5V, 3.3V, 5V
-20
-40
RL = 2 k:, 10 k:
1k
10k
100k
1M
10M
-90
100M
-40
1k
10k
100k
Figure 28.
THD+N vs. Frequency
-90
100M
THD+N vs. Output Voltage
1
RL = 100 k:
RL = 100 k:
CL = 10 pF
CL = 10 pF
f = 1 kHz
VO = VS -1V
0.1
VS = 2.5V
THD+N (%)
THD+N (%)
10M
Figure 29.
1
0.01
1M
-45
FREQUENCY (Hz)
FREQUENCY (Hz)
0.1
0
125°C
-20
-45
CL = 20 pF, 50 pF, 100 pF
-90
100M
100
225
80
-45
PHASE (°)
100
0
135
90
40
-60
-100
VS = 5V, TA = -40°C
PHASE (°)
85°C
40
VS = 3.3V
0.001
0.01
VS = 2.5V
0.001
VS = 3.3V
VS = 5V
VS = 5V
0.0001
10
100
1k
10k
100k
0.0001
FREQUENCY (Hz)
1
10
VOUT (VPP)
Figure 30.
12
0.1
Figure 31.
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Typical Performance Characteristics (continued)
Unless otherwise noted: TA = 25°C, RL > 10 kΩ, VCM = VS/2.
Small Signal Step Response
20 mV/DIV
500 mV/DIV
Large Signal Step Response
VS = 5V
VIN = 2 VPP
f = 10 kHz
VS = 5V
VIN = 100 mVPP
f = 10 kHz
AV = +1
AV = +1
RL = 10 k:
RL = 10 k:
CL = 10 pF
CL = 10 pF
Figure 32.
Figure 33.
Large Signal Step Response
Small Signal Step Response
200 mV/DIV
10 Ps/DIV
1 V/DIV
10 Ps/DIV
VS = 5V
VIN = 400 mVPP
f = 10 kHz
VS = 5V
VIN = 100 mVPP
f = 10 kHz
AV = +10
AV = +10
RL = 10 k:
RL = 10 k:
CL = 10 pF
CL = 10 pF
10 Ps/DIV
10 Ps/DIV
Figure 34.
Figure 35.
Supply Current vs. Supply Voltage
Output Swing High vs. Supply Voltage
7
40
6
35
125°C
VOUT FROM RAIL (mV)
SUPPLY CURRENT (mA)
RL = 2 k:
5
25°C
4
-40°C
3
2
30
85°C
20
-40°C
15
25°C
10
1
0
1.5
125°C
25
5
2
2.5
3
3.5
4
4.5
5
5.5
0
1.5
2
2.5
3
3.5
4
4.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Figure 36.
Figure 37.
5
5.5
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Typical Performance Characteristics (continued)
Unless otherwise noted: TA = 25°C, RL > 10 kΩ, VCM = VS/2.
Output Swing Low vs. Supply Voltage
Sinking Current vs, Supply Voltage
60
40
-40°C
RL = 2 k:
25°C
50
125°C
30
25
ISINK (mA)
VOUT FROM RAIL (mV)
35
85°C
20
15
85°C
40
125°C
30
-40°C
25°C
10
20
5
0
1.5
2
2.5
3
3.5
4
4.5
5
10
1.5
5.5
2
2.5
3
3.5
4
4.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Figure 38.
Figure 39.
5
5.5
Sourcing Current vs. Supply Voltage
60
-40°C
ISOURCE (mA)
50
25°C
40
125°C
30
85°C
20
10
1.5
2
2.5
3
3.5
4
4.5
5
5.5
SUPPLY VOLTAGE (V)
Figure 40.
14
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APPLICATION NOTES
LMP7732
The LMP7732 is a dual low noise, rail-to-rail input and output, low voltage amplifier.
The low input voltage noise of only 2.9 nV/√Hz with a 1/f corner at 3 Hz makes the LMP7732 ideal for sensor
applications where DC accuracy is of importance.
The LMP7732 has high gain bandwidth of 22 MHz. This wide bandwidth enables the use of the amplifier at
higher gain settings while retaining ample usable bandwidth for the application. This is particularly beneficial
when system designers need to use sensors with very limited output voltage range as it allows larger gains in
one stage which in turn increases signal to noise ratio.
The LMP7732 has a proprietary input bias cancellation circuitry on the input stages. This allows the LMP7732 to
have only about 1.5 nA bias current with a bipolar input stage. This low input bias current, paired with the
inherent lower input voltage noise of bipolar input stages makes the LMP7732 an excellent choice for precision
applications. The combination of low input bias current, low input offset voltage, and low input voltage noise
enables the user to achieve unprecedented accuracy and higher signal integrity.
Texas Instruments is heavily committed to precision amplifiers and the market segment they serve. Technical
support and extensive characterization data is available for sensitive applications or applications with a
constrained error budget.
The LMP7732 comes in the 8-Pin SOIC and VSSOP packages. These small packages are ideal solutions for
area constrained PC boards and portable electronics.
INPUT BIAS CURRENT CANCELLATION
The LMP7732 has proprietary input bias current cancellation circuitry on its input stage.
The LMP7732 has rail-to-rail input. This is achieved by having a p-input and n-input stage in parallel. Figure 41
only shows one of the input stages as the circuitry is symmetrical for both stages.
Figure 41 shows that as the common mode voltage gets closer to one of the extreme ends, current I1
significantly increases. This increased current shows as an increase in voltage drop across resistor R1 equal to
I1*R1 on IN+ of the amplifier. This voltage contributes to the offset voltage of the amplifier. When common mode
voltage is in the mid-range, the transistors are operating in the linear region and I1 is significantly small. The
voltage drop due to I1 across R1 can be ignored as it is orders of magnitude smaller than the amplifier's input
offset voltage. As the common mode voltage gets closer to one of the rails, the offset voltage generated due to I1
increases and becomes comparable to the amplifiers offset voltage.
IBIAS CANCELLATION CIRCUIT
V
+
INPUT STAGE
+
V
R
R
C1 C2
R1
IN
+
I1
Q1
Q2
R2
IN
-
Figure 41. Input Bias Current Cancellation
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INPUT VOLTAGE NOISE MEASUREMENT
The LMP7732 has very low input voltage noise. The peak-to-peak input voltage noise of the LMP7732 can be
measured using the test circuit shown in Figure 42.
0.1 PF
100 k:
-
½
LMP7732
10:
+
VOLTAGE GAIN = 50,000
2 k:
4.7 PF
+ ½
LMP7732
-
100 k:
4.3 k:
22 PF
2.2 PF
110 k:
SCOPE
x1
RIN = 1M
24.3 k:
0.1 PF
Figure 42. 0.1 Hz to 10 Hz Noise Test Circuit
The frequency response of this noise test circuit at the 0.1 Hz corner is defined by only one zero. The test time
for the 0.1 Hz to 10 Hz noise measurement using this configuration should not exceed 10 seconds, as this time
limit acts as an additional zero to reduce or eliminate the contributions of noise from frequencies below 0.1 Hz.
Figure 43 shows typical peak-to-peak noise for the LMP7732 measured with the circuit in Figure 42.
Figure 43. 0.1 Hz to 10 Hz Input Voltage Noise
Measuring the very low peak-to-peak noise performance of the LMP7732, requires special testing attention. In
order to achieve accurate results, the device should be warmed up for at least five minutes. This is so that the
input offset voltage of the op amp settles to a value. During this warm up period, the offset can typically change
by a few µV because the chip temperature increases by about 30°C. If the 10 seconds of the measurement is
selected to include this warm up time, some of this temperature change might show up as the measured noise.
Figure 44 shows the start-up drift of five typical LMP7732 units.
16
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OFFSET VOLTAGE DRIFT (PV)
5.0
4.0
3.0
2.0
VS = 5V
1.0
RL = 2 k:
5 TYPICAL UNITS
0.0
0
50
100
150
200
250
300
TIME (s)
Figure 44. Start-Up Input Offset Voltage Drift
During the peak-to-peak noise measurement, the LMP7732 must be shielded. This prevents offset variations due
to airflow. Offset can vary by a few nV due to this airflow and that can invalidate measurements of input voltage
noise with a magnitude which is in the same range. For similar reasons, sudden motions must also be restricted
in the vicinity of the test area. The feed-through which results from this motion could increase the observed noise
value which in turn would invalidate the measurement.
DIODES BETWEEN THE INPUTS
The LMP7732 has a set of anti-parallel diodes between their input pins, as shown in Figure 45. These diodes are
present to protect the input stage of the amplifiers. At the same time, they limit the amount of differential input
voltage that is allowed on the input pins. A differential signal larger than the voltage needed to turn on the diodes
might cause damage to the diodes. The differential voltage between the input pins should be limited to ±3 diode
drops or the input current needs to be limited to ±20 mA.
V
ESD
IN
+
+
V
R1
ESD
R2
+
IN
-
ESD
ESD
-
-
V
V
Figure 45. Anti-Parallel Diodes between Inputs
DRIVING AN ADC
Analog to Digital Converters, ADCs, usually have a sampling capacitor on their input. When the ADC's input is
directly connected to the output of the amplifier a charging current flows from the amplifier to the ADC. This
charging current causes a momentary glitch that can take some time to settle. There are different ways to
minimize this effect. One way is to slow down the sampling rate. This method gives the amplifier sufficient time to
stabilize its output. Another way to minimize the glitch, caused by the switch capacitor, is to have an external
capacitor connected to the input of the ADC. This capacitor is chosen so that its value is much larger than the
internal switching capacitor and it will hence provide the charge needed to quickly and smoothly charge the
ADC's sampling capacitor. Since this large capacitor will be loading the output of the amplifier as well, an
isolation resistor is needed between the output of the amplifier and this capacitor. The isolation resistor, RISO,
separates the additional load capacitance from the output of the amplifier and will also form a low-pass filter and
can be designed to provide noise reduction as well as anti-aliasing. The draw back of having RISO is that it
reduces signal swing since there is some voltage drop across it.
Figure 46 (a) shows the ADC directly connected to the amplifier. To minimize the glitch in this setting, a slower
sample rate needs to be used. Figure 46 (b) shows RISO and an external capacitor used to minimize the glitch.
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FEEDBACK
NETWORK
(a)
ADC
V+
SENSOR
INPUT
NETWORK
V-
(b)
FEEDBACK
NETWORK
V+
ADC
RISO
SENSOR
INPUT
NETWORK
V-
C
Figure 46. Driving An ADC
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REVISION HISTORY
Changes from Revision D (March 2013) to Revision E
•
Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 18
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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)
LMP7732MA/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LMP77
32MA
LMP7732MAX/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LMP77
32MA
LMP7732MM/NOPB
ACTIVE
VSSOP
DGK
8
1000
RoHS & Green
SN
Level-1-260C-UNLIM
AZ3A
LMP7732MME/NOPB
ACTIVE
VSSOP
DGK
8
250
RoHS & Green
SN
Level-1-260C-UNLIM
AZ3A
LMP7732MMX/NOPB
ACTIVE
VSSOP
DGK
8
3500
RoHS & Green
SN
Level-1-260C-UNLIM
AZ3A
(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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