LMP2232
www.ti.com
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
LMP2232 Dual Micropower, 1.6V, Precision, Operational Amplifier with CMOS Input
Check for Samples: LMP2232
FEATURES
1
(For VS = 5V, Typical Unless Otherwise Noted)
23
•
•
•
•
•
•
•
•
•
•
•
•
Supply Current at 1.8V 16 µA
Operating Voltage Range 1.6V to 5.5V
Low TCVOS ±0.5 µV/°C (max)
VOS ±150 µV (max)
Input Bias Current 20 fA
PSRR 120 dB
CMRR 97 dB
Open Loop Gain 120 dB
Gain Bandwidth Product 130 kHz
Slew Rate 58 V/ms
Input Voltage Noise, f = 1 kHz 60 nV/√Hz
Temperature Range –40°C to 125°C
APPLICATIONS
•
•
•
•
•
Precision Instrumentation Amplifiers
Battery Powered Medical Instrumentation
High Impedance Sensors
Strain Gauge Bridge Amplifier
Thermocouple Amplifiers
DESCRIPTION
The LMP2232 is a dual micropower precision
amplifier designed for battery powered applications.
The 1.6V to 5.5V operating supply voltage range and
quiescent power consumption of only 26 μW extend
the battery life in portable systems. The LMP2232 is
part of the LMP™ precision amplifier family. The high
impedance CMOS input makes it ideal for
instrumentation
and
other
sensor
interface
applications.
The LMP2232 has a maximum offset voltage of 150
μV and maximum offset voltage drift of only 0.5 μV/°C
along with low bias current of only ±20 fA. These
precise specifications make the LMP2232 a great
choice for maintaining system accuracy and long term
stability.
The LMP2232 has a rail-to-rail output that swings 15
mV from the supply voltage, which increases system
dynamic range. The common mode input voltage
range extends 200 mV below the negative supply,
thus the LMP2232 is ideal for ground sensing in
single supply applications.
The LMP2232 is offered in 8-pin SOIC and VSSOP
packages.
The LMP2231 is the single version of this product
and the LMP2234 is the quad version of this product.
Both of these products are available on Texas
Instruments' website.
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 © 2008–2013, Texas Instruments Incorporated
LMP2232
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
www.ti.com
Typical Application
+
+
V
V
3
½ LMP2232
+
2
6 LM4140A
1 PF
1,4,7,8
V
+
0.1 PF
V
+
+
½
LMP2232
-
R+'R
10 k:
12 k:
R
+
-
V
VA
½
LMP2232
1 k:
R
10 PF
40 k:
IN
+
ADC121S021
R+'R
+
V
-
12 k:
½
LMP2232
+
GND
10 k:
40 k:
Figure 1. Strain Gauge Bridge Amplifier
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
ESD Tolerance
(1) (2)
(3)
Human Body Model
Machine Model
Differential Input Voltage
2000V
100V
±300 mV
Supply Voltage (VS = V+ - V–)
6V
Voltage on Input/Output Pins
V+ + 0.3V, V– – 0.3V
Storage Temperature Range
−65°C to 150°C
Junction Temperature
(4)
150°C
Mounting Temperature
Infrared or Convection (20 sec.)
+235°C
Wave Soldering Lead Temperature (10 sec.)
(1)
(2)
(3)
(4)
2
+260°C
Absolute Maximum Ratings indicate limits beyond which damage 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 test conditions, see the Electrical
Characteristics.
If Military/Aerospace specified devices are required, please contact the TI 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.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
LMP2232
www.ti.com
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
Operating Ratings
(1)
Operating Temperature Range
+
(2)
−40°C to 125°C
–
Supply Voltage (VS = V - V )
Package Thermal Resistance (θJA) (2)
(1)
(2)
1.6V to 5.5V
8-Pin SOIC
111.2 °C/W
8-Pin VSSOP
147.4 °C/W
Absolute Maximum Ratings indicate limits beyond which damage 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 test conditions, see the Electrical
Characteristics.
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.
5V DC Electrical Characteristics (1)
Unless otherwise specified, all limits ensured for TA = 25°C, V+ = 5V, V− = 0V, VCM = VO = V+/2, and RL > 1 MΩ. Boldface
limits apply at the temperature extremes.
Symbol
Typ (3)
Max (2)
Units
±10
±150
±230
μV
LMP2232A
±0.3
±0.5
LMP2232B
±0.3
±2.5
0.02
±3
±125
Parameter
VOS
Input Offset Voltage
TCVOS
Input Offset Voltage Drift
Conditions
Min (2)
IBIAS
Input Bias Current
IOS
Input Offset Current
CMRR
Common Mode Rejection Ratio
0V ≤ VCM ≤ 4V
81
80
97
PSRR
Power Supply Rejection Ratio
1.6V ≤ V+ ≤ 5.5V
V− = 0V, VCM = 0V
83
83
120
CMVR
Common Mode Voltage Range
CMRR ≥ 80 dB
CMRR ≥ 79 dB
−0.2
−0.2
AVOL
Large Signal Voltage Gain
VO = 0.3V to 4.7V
RL = 10 kΩ to V+/2
110
108
VO
Output Swing High
IO
IS
(1)
(2)
(3)
(4)
Output Current
(4)
pA
5
RL = 10 kΩ to V+/2
VIN(diff) = 100 mV
17
Sourcing, VO to V−
VIN(diff) = 100 mV
27
19
30
Sinking, VO to V+
VIN(diff) = −100 mV
17
12
22
Supply Current
dB
dB
V
120
17
RL = 10 kΩ to V /2
VIN(diff) = −100 mV
fA
4.2
4.2
+
Output Swing Low
μV/°C
19
dB
50
50
50
50
mV
from either
rail
mA
27
28
μA
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 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 may be permanently degraded, either mechanically or electrically.
All limits are specified by testing, statistical analysis or design.
Typical values represent the most likely parametric norm 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.
The short circuit test is a momentary open loop test.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
3
LMP2232
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
www.ti.com
5V AC Electrical Characteristics (1)
Unless otherwise specified, all limits ensured for TA = 25°C, V+ = 5V, V− = 0V, VCM = VO = V+/2, and RL > 1 MΩ. Boldface
limits apply at the temperature extremes.
Symbol
Parameter
Conditions
GBW
Gain-Bandwidth Product
CL = 20 pF, RL = 10 kΩ
SR
Slew Rate
AV = +1
Min (2)
Typ (3)
Max (2)
130
Falling Edge
33
32
58
Rising Edge
33
32
48
Units
kHz
V/ms
θm
Phase Margin
CL = 20 pF, RL = 10 kΩ
68
Gm
Gain Margin
CL = 20 pF, RL = 10 kΩ
27
dB
en
Input-Referred Voltage Noise Density
f = 1 kHz
60
nV/√Hz
deg
Input Referred Voltage Noise
0.1 Hz to 10 Hz
2.3
μVPP
in
Input-Referred Current Noise
f = 1 kHz
10
fA/√Hz
THD+N
Total Harmonic Distortion + Noise
f = 100 Hz, RL = 10 kΩ
0.002
%
(1)
(2)
(3)
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 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 may be permanently degraded, either mechanically or electrically.
All limits are specified by testing, statistical analysis or design.
Typical values represent the most likely parametric norm 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.
3.3V DC Electrical Characteristics (1)
Unless otherwise specified, all limits ensured for T A = 25°C, V+ = 3.3V, V− = 0V, VCM = VO = V+/2, and RL > 1 MΩ. Boldface
limits apply at the temperature extremes.
Symbol
Typ (3)
Max (2)
Units
±10
±160
±250
μV
LMP2232A
±0.3
±0.5
LMP2232B
±0.3
±2.5
0.02
±3
±125
Parameter
VOS
Input Offset Voltage
TCVOS
Input Offset Voltage Drift
Conditions
Min (2)
IBIAS
Input Bias Current
IOS
Input Offset Current
CMRR
Common Mode Rejection Ratio
0V ≤ VCM ≤ 2.3V
79
77
92
PSRR
Power Supply Rejection Ratio
1.6V ≤ V+ ≤ 5.5V
V− = 0V, VCM = 0V
83
83
120
CMVR
Common Mode Voltage Range
CMRR ≥ 78 dB
CMRR ≥ 77 dB
−0.2
−0.2
AVOL
Large Signal Voltage Gain
VO = 0.3V to 3V
RL = 10 kΩ to V+/2
108
107
VO
Output Swing High
5
+
RL = 10 kΩ to V /2
VIN(diff) = 100 mV
Output Swing Low
(1)
(2)
(3)
4
RL = 10 kΩ to V /2
VIN(diff) = −100 mV
dB
dB
120
+
14
pA
fA
2.5
2.5
14
μV/°C
V
dB
50
50
50
50
mV
from either
rail
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 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 may be permanently degraded, either mechanically or electrically.
All limits are specified by testing, statistical analysis or design.
Typical values represent the most likely parametric norm 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.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
LMP2232
www.ti.com
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
3.3V DC Electrical Characteristics(1) (continued)
Unless otherwise specified, all limits ensured for T A = 25°C, V+ = 3.3V, V− = 0V, VCM = VO = V+/2, and RL > 1 MΩ. Boldface
limits apply at the temperature extremes.
Symbol
IO
Output Current
IS
(4)
Conditions
Min (2)
Typ (3)
−
Sourcing, VO to V
VIN(diff) = 100 mV
11
8
14
Sinking, VO to V+
VIN(diff) = −100 mV
8
5
11
Parameter
(4)
Supply Current
17
Max (2)
Units
mA
25
26
μA
The short circuit test is a momentary open loop test.
3.3V AC Electrical Characteristics (1)
Unless otherwise is specified, all limits ensured for TA = 25°C, V+ = 3.3V, V− = 0V, VCM = VO = V+/2, and RL > 1 MΩ. Boldface
limits apply at the temperature extremes.
Symbol
Parameter
Conditions
Min (2)
Typ (3)
GBW
Gain-Bandwidth Product
CL = 20 pF, RL = 10 kΩ
128
SR
Slew Rate
AV = +1, CL = 20 pF
RL = 10 kΩ
Falling Edge
58
Rising Edge
48
Max (2)
Units
kHz
V/ms
θm
Phase Margin
CL = 20 pF, RL = 10 kΩ
66
Gm
Gain Margin
CL = 20 pF, RL = 10 kΩ
26
dB
en
Input-Referred Voltage Noise Density
f = 1 kHz
60
nV/√Hz
Input-Referred Voltage Noise
0.1 Hz to 10 Hz
2.4
μVPP
in
Input-Referred Current Noise
f = 1 kHz
10
fA/√Hz
THD+N
Total Harmonic Distortion + Noise
f = 100 Hz, RL = 10 kΩ
0.003
%
(1)
(2)
(3)
deg
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 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 may be permanently degraded, either mechanically or electrically.
All limits are specified by testing, statistical analysis or design.
Typical values represent the most likely parametric norm 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.
2.5V DC Electrical Characteristics (1)
Unless otherwise specified, all limits ensured for TA = 25°C, V+ = 2.5V, V− = 0V, VCM = VO = V+/2, and RL > 1MΩ. Boldface
limits apply at the temperature extremes.
Symbol
VOS
Input Offset Voltage
TCVOS
Input Offset Voltage Drift
IBias
Input Bias Current
IOS
Input Offset Current
CMRR
Common Mode Rejection Ratio
(1)
(2)
(3)
Typ (3)
Max (2)
Units
±10
±190
±275
μV
LMP2232A
±0.3
±0.5
LMP2232B
±0.3
±2.5
0.02
±3
±125
Parameter
Conditions
Min (2)
μV/°C
5
0V ≤ VCM ≤ 1.5V
77
76
91
pA
fA
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 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 may be permanently degraded, either mechanically or electrically.
All limits are specified by testing, statistical analysis or design.
Typical values represent the most likely parametric norm 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.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
5
LMP2232
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
www.ti.com
2.5V DC Electrical Characteristics(1) (continued)
Unless otherwise specified, all limits ensured for TA = 25°C, V+ = 2.5V, V− = 0V, VCM = VO = V+/2, and RL > 1MΩ. Boldface
limits apply at the temperature extremes.
Symbol
Parameter
Conditions
+
Min (2)
Typ (3)
83
83
120
Max (2)
PSRR
Power Supply Rejection Ratio
1.6V ≤ V ≤ 5.5V
V– = 0V, VCM = 0V
CMVR
Common Mode Voltage Range
CMRR ≥ 77 dB
CMRR ≥ 76 dB
−0.2
−0.2
AVOL
Large Signal Voltage Gain
VO = 0.3V to 2.2V
RL = 10 kΩ to V+/2
104
104
VO
Output Swing High
RL = 10 kΩ to V+/2
VIN(diff) = 100 mV
12
50
50
Output Swing Low
RL = 10 kΩ to V+/2
VIN(diff) = –100 mV
13
50
50
IO
Output Current
IS
(4)
(4)
dB
1.7
1.7
120
Sourcing, VO to V–
VIN(diff) = 100 mV
5
4
8
Sinking, VO to V+
VIN(diff) = –100 mV
3.5
2.5
7
Supply Current
Units
V
dB
mV
from either
rail
mA
16
24
25
µA
The short circuit test is a momentary open loop test.
2.5V AC Electrical Characteristics (1)
Unless otherwise specified, all limits specified for TA = 25°C, V+ = 2.5V, V− = 0V, VCM = VO = V+/2, and RL > 1MΩ. Boldface
limits apply at the temperature extremes.
Symbol
Parameter
Min (2)
Conditions
GBW
Gain-Bandwidth Product
CL = 20 pF, RL = 10 kΩ
SR
Slew Rate
AV = +1, CL = 20 pF
RL = 10 kΩ
Typ (3)
128
Falling Edge
58
Rising Edge
48
Max (2)
Units
kHz
V/ms
θm
Phase Margin
CL = 20 pF, RL = 10 kΩ
64
deg
Gm
Gain Margin
CL = 20 pF, RL = 10 kΩ
26
dB
en
Input-Referred Voltage Noise Density
f = 1 kHz
60
nV/√Hz
Input-Referred Voltage Noise
0.1 Hz to 10 Hz
2.5
μVPP
in
Input-Referred Current Noise
f = 1 kHz
10
fA/√Hz
THD+N
Total Harmonic Distortion + Noise
f = 100 Hz, RL = 10 kΩ
0.005
%
(1)
(2)
(3)
6
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 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 may be permanently degraded, either mechanically or electrically.
All limits are specified by testing, statistical analysis or design.
Typical values represent the most likely parametric norm 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.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
LMP2232
www.ti.com
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
1.8V DC Electrical Characteristics
(1)
Unless otherwise specified, all limits ensured for T A = 25°C, V+ = 1.8V, V− = 0V, VCM = VO = V+/2, and RL > 1 MΩ. Boldface
limits apply at the temperature extremes.
Symbol
Typ (3)
Max (2)
Units
±10
±230
±325
μV
LMP2232A
±0.3
±0.5
LMP2232B
±0.3
±2.5
0.02
±3
±125
Parameter
VOS
Input Offset Voltage
TCVOS
Input Offset Voltage Drift
Min (2)
Conditions
IBIAS
Input Bias Current
IOS
Input Offset Current
CMRR
Common Mode Rejection Ratio
0V ≤ VCM ≤ 0.8V
76
75
92
PSRR
Power Supply Rejection Ratio
1.6V ≤ V+ ≤ 5.5V
V− = 0V, VCM = 0V
83
83
120
CMVR
Common Mode Voltage Range
CMRR ≥ 76 dB
CMRR ≥ 75 dB
−0.2
0
AVOL
Large Signal Voltage Gain
VO = 0.3V to 1.5V
RL = 10 kΩ to V+/2
103
103
VO
Output Swing High
fA
dB
dB
1.0
1.0
dB
12
RL = 10 kΩ to V /2
VIN(diff) = −100 mV
IS
(1)
(2)
(3)
(4)
(4)
V
120
RL = 10 kΩ to V+/2
VIN(diff) = 100 mV
Output Swing Low
Output Current
pA
5
50
50
+
IO
μV/°C
50
50
13
Sourcing, VO to V–
VIN(diff) = 100 mV
2.5
2
5
Sinking, VO to V+
VIN(diff) = −100 mV
2
1.5
5
Supply Current
mV
from either
rail
mA
24
25
16
µA
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 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 may be permanently degraded, either mechanically or electrically.
All limits are specified by testing, statistical analysis or design.
Typical values represent the most likely parametric norm 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.
The short circuit test is a momentary open loop test.
1.8V AC Electrical Characteristics
(1)
Unless otherwise is specified, all limits ensured for TA = 25°C, V+ = 1.8V, V− = 0V, VCM = VO = V+/2, and RL > 1 MΩ. Boldface
limits apply at the temperature extremes.
Symbol
Parameter
Conditions
Min (2)
Typ
(3)
GBW
Gain-Bandwidth Product
CL = 20 pF, RL = 10 kΩ
127
SR
Slew Rate
AV = +1, CL = 20 pF
RL = 10 kΩ
Falling Edge
58
Rising Edge
48
Max (2)
Units
kHz
V/ms
θm
Phase Margin
CL = 20 pF, RL = 10 kΩ
60
Gm
Gain Margin
CL = 20 pF, RL = 10 kΩ
25
dB
en
Input-Referred Voltage Noise Density
f = 1 kHz
60
nV/√Hz
Input-Referred Voltage Noise
0.1 Hz to 10 Hz
2.4
μVPP
(1)
(2)
(3)
deg
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 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 may be permanently degraded, either mechanically or electrically.
All limits are specified by testing, statistical analysis or design.
Typical values represent the most likely parametric norm 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.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
7
LMP2232
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
www.ti.com
1.8V AC Electrical Characteristics (1) (continued)
Unless otherwise is specified, all limits ensured for TA = 25°C, V+ = 1.8V, V− = 0V, VCM = VO = V+/2, and RL > 1 MΩ. Boldface
limits apply at the temperature extremes.
Symbol
Parameter
Conditions
in
Input-Referred Current Noise
f = 1 kHz
THD+N
Total Harmonic Distortion + Noise
f = 100 Hz, RL = 10 kΩ
Min (2)
Typ
(3)
Max (2)
Units
10
fA/√Hz
0.005
%
Connection Diagram
Figure 2. 8-Pin VSSOP/SOIC (Top View)
Package Numbers DGK0008A and D0008A
8
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
LMP2232
www.ti.com
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
Typical Performance Characteristics
Unless otherwise Specified: TA = 25°C, VS = 5V, VCM = VS/2, where VS = V+ - V−
Offset Voltage Distribution
TCVOS Distribution
10
16
VS = 5V
VCM = VS/2
14
TA = 25°C
12
VCM = VS/2
8
PERCENTAGE (%)
PERCENTAGE (%)
VS = 5V
10
8
6
4
-40°C d TA d 125°C
6
4
2
2
0
-150
-100
-50
0
50
100
0
-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5
150
VOS (PV)
TCVOS (PV/°C)
Figure 3.
Figure 4.
Offset Voltage Distribution
TCVOS Distribution
10
14
VS = 3.3V
VS = 3.3V
8 VCM = VS/2
TA = 25°C
VCM = VS/2
10
PERCENTAGE (%)
PERCENTAGE (%)
12
-40°C d TA d 125°C
8
6
4
6
4
2
2
0
-150
-100
-50
0
50
100
0
-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5
150
VOS (PV)
TCVOS (PV/°C)
Figure 5.
Figure 6.
Offset Voltage Distribution
TCVOS Distribution
10
14
VS = 2.5V
8
VCM = VS/2
10
VS = 2.5V
VCM = VS/2
TA = 25°C
PERCENTAGE (%)
PERCENTAGE (%)
12
8
6
4
-40°C d TA d 125°C
6
4
2
2
0
-150
-100
-50
0
50
100
150
0
-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5
VOS (PV)
TCVOS (PV/°C)
Figure 7.
Figure 8.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
9
LMP2232
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
www.ti.com
Typical Performance Characteristics (continued)
Unless otherwise Specified: TA = 25°C, VS = 5V, VCM = VS/2, where VS = V+ - V−
Offset Voltage Distribution
TCVOS Distribution
25
12
VS = 1.8V
VS = 1.8V
TA = 25°C
10
VCM = VS/2
20
PERCENTAGE (%)
PERCENTAGE (%)
VCM = VS/2
8
6
4
15
10
5
2
0
-150
-40°C d TA d 125°C
-100
-50
0
50
100
0
-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5
150
TCVOS (PV/°C)
VOS (PV)
Figure 9.
Figure 10.
Offset Voltage vs. VCM
Offset Voltage vs. VCM
250
250
VS = 3.3V
150
150
25°C
-40°C
25°C
85°C
50
VOS (PV)
OFFSET VOLTAGE (PV)
VS = 5V
-40°C
125°C
-50
-150
-250
-0.2
50
85°C
125°C
-50
-150
0.8
1.8
2.8
3.8
-250
-0.2 0.2
4.3
0.6
1
1.4
VCM (V)
1.8
Figure 11.
Offset Voltage vs. VCM
Offset Voltage vs. VCM
VS = 1.8V
150
-40°C
-40°C
85°C
50
VOS (PV)
VOS (PV)
25°C
-50
125°C
25°C
50
85°C
-50
125°C
-150
-150
0.2
0.6
1
1.4
1.8
2.2
-250
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
VCM (V)
VCM (V)
Figure 13.
10
3
250
VS = 2.5V
-250
-0.2
2.6
Figure 12.
250
150
2.2
VCM (V)
Figure 14.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
LMP2232
www.ti.com
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
Typical Performance Characteristics (continued)
Unless otherwise Specified: TA = 25°C, VS = 5V, VCM = VS/2, where VS = V+ - V−
Offset Voltage vs. Temperature
Offset Voltage vs. Supply Voltage
120
VS = 1.8V, 2.5V, 3.3V, 5V
100
VCM = 0V
5 TYPICAL PARTS
80
80
OFFSET VOLTAGE (PV)
OFFSET VOLTAGE (PV)
100
60
40
20
0
-20
-40
60
-40°C
40
25°C
20
0
85°C
-20
-60
-80
-40 -20
125°C
0
20
40
60
80 100 120
TEMPERATURE (°C)
-40
1.5
2
2.5
3
3.5
4
4.5
5
5.5
SUPPLY VOLTAGE (V)
Figure 15.
Figure 16.
0.1 Hz to 10 Hz Voltage Noise
0.1 Hz to 10 Hz Voltage Noise
Figure 17.
Figure 18.
0.1 Hz to 10 Hz Voltage Noise
0.1 Hz to 10 Hz Voltage Noise
Figure 19.
Figure 20.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
11
LMP2232
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
www.ti.com
Typical Performance Characteristics (continued)
Unless otherwise Specified: TA = 25°C, VS = 5V, VCM = VS/2, where VS = V+ - V−
Input Bias Current vs. VCM
Input Bias Current vs. VCM
10
40
VS = 2V
INPUT BIAS CURRENT (pA)
INPUT BIAS CURRENT (fA)
25°C
20
10
0
-40°C
-10
-20
6
4
85°C
2
0
-2
-6
-8
-40
-10
0.25
0.5
1
0.75
1.25
125°C
-4
-30
0
VS = 2V
8
30
0
1.5
0.5
0.75
1
VCM (V)
Figure 21.
Figure 22.
Input Bias Current vs. VCM
1.25
10
VS = 2.5V
20
-40°C
10
0
-10
-20
25°C
VS = 2.5V
8
INPUT BIAS CURRENT (pA)
30
-30
6
4
85°C
2
0
-2
-4
125°C
-6
-8
-40
0
0.5
1
1.5
-10
2
0
0.5
1
1.5
VCM (V)
VCM (V)
Figure 23.
Figure 24.
Input Bias Current vs. VCM
20
VS = 3.3V
VS = 3.3V
15
50
INPUT BIAS CURRENT (pA)
75
INPUT BIAS CURRENT (fA)
2
Input Bias Current vs. VCM
100
25°C
25
0
-40°C
-25
-50
-75
10
125°C
5
0
85°C
-5
-10
-15
-100
-20
0
0.5
1
1.5
2
0
2.5
VCM (V)
0.5
1
1.5
2
2.5
VCM (V)
Figure 25.
12
1.5
Input Bias Current vs. VCM
40
INPUT BIAS CURRENT (fA)
0.25
VCM (V)
Figure 26.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
LMP2232
www.ti.com
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
Typical Performance Characteristics (continued)
Unless otherwise Specified: TA = 25°C, VS = 5V, VCM = VS/2, where VS = V+ - V−
Input Bias Current vs. VCM
Input Bias Current vs. VCM
600
30
VS = 5V
400
300
200
25°C
100
0
-100
-40°C
-200
1
3
2
20
125°C
15
10
5
0
-5
85°C
-10
-15
-20
-25
-30
-300
0
VS = 5V
25
INPUT BIAS CURRENT (pA)
INPUT BIAS CURRENT (fA)
500
4
0
1
2
VCM (V)
3
4
VCM (V)
Figure 27.
Figure 28.
PSRR vs. Frequency
Supply Current vs. Supply Voltage (per channel)
11
0
VS = 2V, 2.5V, 3.3V, 5V
-20
PSRR (dB)
SUPPLY CURRENT (PA)
10
-40
+PSRR
-60
-80
-100
VS = 2V
-PSRR
-120
-140
-160
10
9
25°C
8
-40°C
7
6
VS = 5V
100
1k
10k
5
1.5
100k
FREQUENCY (Hz)
2.5
3.5
4.5
5.5
SUPPLY VOLTAGE (V)
Figure 29.
Figure 30.
Sinking Current vs. Supply Voltage
Sourcing Current vs. Supply Voltage
30
40
35
25
30
-40°C
-40°C
ISOURCE (mA)
20
ISINK (mA)
125°C
85°C
25°C
15
85°C
10
25°C
20
15
85°C
125°C
125°C
10
5
0
1.5
25
5
2.5
3.5
4.5
5.5
0
1.5
2.5
3.5
4.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Figure 31.
Figure 32.
5.5
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
13
LMP2232
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
www.ti.com
Typical Performance Characteristics (continued)
Unless otherwise Specified: TA = 25°C, VS = 5V, VCM = VS/2, where VS = V+ - V−
Output Swing High vs. Supply Voltage
Output Swing Low vs. Supply Voltage
30
25
RL = 10 k:
RL = 10 k:
VOUT FROM RAIL (mV)
VOUT FROM RAIL (mV)
125°C
20
85°C
25°C
15
85°C
20
15
10
2.5
3.5
-40°C
25°C
-40°C
10
1.5
125°C
25
4.5
5
1.5
5.5
2.5
3.5
4.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Figure 33.
Figure 34.
Open Loop Frequency Response
100
Open Loop Frequency Response
120
PHASE
5.5
100
120
PHASE
-40°C
25°C
75
90
75
90
-40°C
25
30
60
50
GAIN
30
25
PHASE (°)
60
GAIN
GAIN (dB)
125°C
50
PHASE (°)
GAIN (dB)
85°C
25°C
0
125°C
VS = 5V
0
0
RL = 10 k:
10k
1k
100
100k
CL = 20 pF, 50 pF, 100 pF
-25
10k
1k
10
100
-30
1M
FREQUENCY (Hz)
Slew Rate vs. Supply Voltage
60
VS = 5V
RL = 100 k:
14
SLEW RATE (V/ms)
PHASE MARGIN (°)
VS = 1.8V
VS = 2.5V
60
VS = 3.3V
40
52
48
RISING EDGE
44
RL = 10 k:
60
FALLING EDGE
56
80
50
20
-30
1M
Figure 36.
Phase Margin vs. Capacitive Load
70
100k
FREQUENCY (Hz)
Figure 35.
90
0
RL = 10 k:, 100 k:, 10 M:
85°C
CL = 20 pF
-25
10
VS = 1.8V, 2.5V, 3.3V, 5V
80
100
40
1.5
2
2.5
3
3.5
4
4.5
CAPACITIVE LOAD (pF)
SUPPLY VOLTAGE (V)
Figure 37.
Figure 38.
Submit Documentation Feedback
5
5.5
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
LMP2232
www.ti.com
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
Typical Performance Characteristics (continued)
Unless otherwise Specified: TA = 25°C, VS = 5V, VCM = VS/2, where VS = V+ - V−
THD+N vs. Amplitude
THD+N vs. Frequency
10
1
RL = 10 k:
CL = 20 pF
0.1
1
VS = 2V
VS = 2.5V
THD+N (%)
THD+N (%)
VS = 2V
0.1
0.01
VS = 3.3V
RL = 10 k:
VO = VS ± 1V
VS = 2.5V
0.01
0.001
VS = 3.3V
VS = 5V
VS = 5V
CL = 20 pF
f = 1 kHz
0.001
0.01
0.1
1
10
0.0001
1
100
1k
10k
100k
Figure 40.
Large Signal Step Response
Small Signal Step Response
50 mV/DIV
Figure 39.
VS = 5V
VIN = 2 VPP
f = 1 kHz
AV = +1
VS = 5V
VIN = 200 mVPP
f = 1 kHz
AV = +1
RL = 10 k:
RL = 10 k:
CL = 20 pF
CL = 20 pF
100 Ps/DIV
100 Ps/DIV
Figure 41.
Figure 42.
Large Signal Step Response
Small Signal Step Response
100 mV/DIV
500 mV/DIV
1V/DIV
10
FREQUENCY (Hz)
VOUT (VPP)
VS = 5V
VIN = 400 mVPP
f = 1 kHz
AV = +10
VS = 5V
VIN = 50 mVPP
f = 1 kHz
AV = +10
RL = 10 k:
RL = 10 k:
CL = 20 pF
CL = 20 pF
100 Ps/DIV
100 Ps/DIV
Figure 43.
Figure 44.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
15
LMP2232
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
www.ti.com
Typical Performance Characteristics (continued)
Unless otherwise Specified: TA = 25°C, VS = 5V, VCM = VS/2, where VS = V+ - V−
CMRR vs. Frequency
Input Voltage Noise vs. Frequency
140
1000
VS = 5V
VS = 2.5V
120
VOLTAGE NOISE nV/ Hz)
VS = 3.3V
CMRR (dB)
100
80
VS = 5V
60
40
20
0
10
100
1k
10k
100k
10
1
1
10
100
1k
10k
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 45.
16
100
Figure 46.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
LMP2232
www.ti.com
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
APPLICATION INFORMATION
LMP2232
The LMP2232 is a quad CMOS precision amplifier that offers low offset voltage, low offset voltage drift, and high
gain while consuming less than 10 μA of supply current per channel.
The LMP2232 is a micropower op amp, consuming only 36 μA of current. Micropower op amps extend the run
time of battery powered systems and reduce energy consumption in energy limited systems. The ensured supply
voltage range of 1.8V to 5.0V along with the ultra-low supply current extend the battery run time in two ways. The
extended ensured power supply voltage range of 1.8V to 5.0V enables the op amp to function when the battery
voltage has depleted from its nominal value down to 1.8V. In addition, the lower power consumption increases
the life of the battery.
The LMP2232 has input referred offset voltage of only ±150 μV maximum at room temperature. This offset is
ensured to be less than ±230 μV over temperature. This minimal offset voltage along with very low TCVOS of only
0.3 µV/°C typical allows more accurate signal detection and amplification in precision applications.
The low input bias current of only ±20 fA gives the LMP2232 superiority for use in high impedance sensor
applications. Bias current of an amplifier flows through source resistance of the sensor and the voltage resulting
from this current flow appears as a noise voltage on the input of the amplifier. The low input bias current enables
the LMP2232 to interface with high impedance sensors while generating negligible voltage noise. Thus the
LMP2232 provides better signal fidelity and a higher signal-to-noise ratio when interfacing with high impedance
sensors.
Texas Instruments is heavily committed to precision amplifiers and the market segments they serve. Technical
support and extensive characterization data is available for sensitive applications or applications with a
constrained error budget.
The operating voltage range of 1.6V to 5.5V over the extensive temperature range of −40°C to 125°C makes the
LMP2232 an excellent choice for low voltage precision applications with extensive temperature requirements.
The LMP2232 is offered in the 8-pin VSSOP and 8-pin SOIC packages. These small packages are ideal
solutions for area constrained PC boards and portable electronics.
TOTAL NOISE CONTRIBUTION
The LMP2232 has very low input bias current, very low input current noise, and low input voltage noise for
micropower amplifiers. As a result, these amplifiers make great choices for circuits with high impedance sensor
applications.
Figure 47 shows the typical input noise of the LMP2232 as a function of source resistance where:
en denotes the input referred voltage noise
ei is the voltage drop across source resistance due to input referred current noise or ei = RS * in
et shows the thermal noise of the source resistance
eni shows the total noise on the input.
Where:
eni =
2
2
2
en + ei + et
The input current noise of the LMP2232 is so low that it will not become the dominant factor in the total noise
unless source resistance exceeds 300 MΩ, which is an unrealistically high value. As is evident in Figure 47, at
lower RS values, total noise is dominated by the amplifier’s input voltage noise. Once RS is larger than a 100 kΩ,
then the dominant noise factor becomes the thermal noise of RS. As mentioned before, the current noise will not
be the dominant noise factor for any practical application.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
17
LMP2232
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
www.ti.com
VOLTAGE NOISE DENSITY (nV/ Hz)
1000
eni
en
100
et
10
ei
1
0.1
10
100
1k
10k
100k
1M
10M
RS (:)
Figure 47. Total Input Noise
VOLTAGE NOISE REDUCTION
The LMP2232 has an input voltage noise of 60nV/√Hz . While this value is very low for micropower amplifiers,
this input voltage noise can be further reduced by placing N amplifiers in parallel as shown in Figure 48. The total
voltage noise on the output of this circuit is divided by the square root of the number of amplifiers used in this
parallel combination. This is because each individual amplifier acts as an independent noise source, and the
average noise of independent sources is the quadrature sum of the independent sources divided by the number
of sources. For N identical amplifiers, this means:
REDUCED INPUT VOLTAGE NOISE =
1
N
en1+en2+
=
1
N
Nen =
=
1
2
2
2
2
+enN
N
en
N
en
N
Figure 48 shows a schematic of this input voltage noise reduction circuit. Typical resistor values are: RG = 10Ω,
RF = 1 kΩ, and RO = 1 kΩ.
18
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
LMP2232
www.ti.com
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
+
V
+
-
VIN
VOUT
-
RG
RO
V
RF
+
V
+
RG
V
-
RO
RF
+
V
+
RG
V
-
RO
RF
+
V
+
RG
V
-
RO
RF
Figure 48. Noise Reduction Circuit
PRECISION INSTRUMENTATION AMPLIFIER
Measurement of very small signals with an amplifier requires close attention to the input impedance of the
amplifier, gain of the signal on the inputs, and the gain on each input of the amplifier. This is because the
difference of the input signal on the two inputs is of the interest and the common signal is considered noise. A
classic circuit implementation is an instrumentation amplifier. Instrumentation amplifiers have a finite, accurate,
and stable gain. They also have extremely high input impedances and very low output impedances. Finally they
have an extremely high CMRR so that the amplifier can only respond to the differential signal. A typical
instrumentation amplifier is shown in Figure 49.
V1
+
V01
-
R2
KR2
R1
R1
R11 = a
+
R1
V2
+
VOUT
V02
R2
KR2
Figure 49. Instrumentation Amplifier
There are two stages in this amplifier. The last stage, output stage, is a differential amplifier. In an ideal case the
two amplifiers of the first stage, the input stage, would be set up as buffers to isolate the inputs. However they
cannot be connected as followers because of mismatch of amplifiers. That is why there is a balancing resistor
between the two. The product of the two stages of gain will give the gain of the instrumentation amplifier. Ideally,
the CMRR should be infinite. However the output stage has a small non-zero common mode gain which results
from resistor mismatch.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
19
LMP2232
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
www.ti.com
In the input stage of the circuit, current is the same across all resistors. This is due to the high input impedance
and low input bias current of the LMP2232.
GIVEN: I R = I R
11
1
(1)
By Ohm’s Law:
VO1 - VO2 = (2R1 + R11) IR
11
= (2a + 1) R11 x IR
11
= (2a + 1) V R
11
(2)
However:
VR
11 = V1 - V2
(3)
So we have:
VO1–VO2 = (2a+1)(V1–V2)
(4)
Now looking at the output of the instrumentation amplifier:
KR2
VO =
R2
(VO2 - VO1)
= -K (VO1 - VO2)
(5)
Substituting from Equation 4:
VO = -K (2a + 1) (V1 - V2)
(6)
This shows the gain of the instrumentation amplifier to be:
−K(2a+1)
(7)
Typical values for this circuit can be obtained by setting: a = 12 and K= 4. This results in an overall gain of −100.
SINGLE SUPPLY STRAIN GAGE BRIDGE AMPLIFIER
Strain gauges are popular electrical elements used to measure force or pressure. Strain gauges are subjected to
an unknown force which is measured as the deflection on a previously calibrated scale. Pressure is often
measured using the same technique; however this pressure needs to be converted into force using an
appropriate transducer. Strain gauges are often resistors which are sensitive to pressure or to flexing. Sense
resistor values range from tens of ohms to several hundred kilo-ohms. The resistance change which is a result of
applied force across the strain gauge might be 1% of its total value. An accurate and reliable system is needed
to measure this small resistance change. Bridge configurations offer a reliable method for this measurement.
Bridge sensors are formed of four resistors, connected as a quadrilateral. A voltage source or a current source is
used across one of the diagonals to excite the bridge while a voltage detector across the other diagonal
measures the output voltage.
Bridges are mainly used as null circuits or to measure differential voltages. Bridges will have no output voltage if
the ratios of two adjacent resistor values are equal. This fact is used in null circuit measurements. These are
particularly used in feedback systems which involve electrochemical elements or human interfaces. Null systems
force an active resistor, such as a strain gauge, to balance the bridge by influencing the measured parameter.
Often in sensor applications at lease one of the resistors is a variable resistor, or a sensor. The deviation of this
active element from its initial value is measured as an indication of change in the measured quantity. A change in
output voltage represents the sensor value change. Since the sensor value change is often very small, the
resulting output voltage is very small in magnitude as well. This requires an extensive and very precise
amplification circuitry so that signal fidelity does not change after amplification.
Sensitivity of a bridge is the ratio of its maximum expected output change to the excitation voltage change.
20
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
LMP2232
www.ti.com
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
Figure 50(a) shows a typical bridge sensor and Figure 50(b) shows the bridge with four sensors. R in
Figure 50(b) is the nominal value of the sense resistor and the deviations from R are proportional to the quantity
being measured.
R1
R + 'R
R2
EXCITATION
SOURCE
VOUT
R3
R - 'R
EXCITATION
SOURCE
VOUT
R4
R - 'R
R + 'R
(b)
(a)
§
R
¨1 + 3
¨
R1
©
R4
-
VOUT =
R2
§
¨
¨
©
VOUT =
R1
§
R
¨1 + 4
¨
R2
©
§
¨
¨
©
R3
'R
R
x VSOURCE
x VSOURCE
Figure 50. Bridge Sensor
Instrumentation amplifiers are great for interfacing with bridge sensors. Bridge sensors often sense a very small
differential signal in the presence of a larger common mode voltage. Instrumentation amplifiers reject this
common mode signal.
Figure 51 shows a strain gauge bridge amplifier. In this application one of the LMP2232 amplifiers is used to
buffer the LM4140A's precision output voltage. The LM4140A is a precision voltage reference. The other three
amplifiers in the LMP2232 are used to form an instrumentation amplifier. This instrumentation amplifier uses the
LMP2232's high CMRR and low VOS and TCVOS to accurately amplify the small differential signal generated by
the output of the bridge sensor. This amplified signal is then fed into the ADC121S021 which is a 12-bit analog to
digital converter. This circuit works on a single supply voltage of 5V.
+
+
V
V
3
½ LMP2232
+
2
6 LM4140A
1 PF
1,4,7,8
V
+
0.1 PF
V
+
+
½
LMP2232
-
R+'R
10 k:
12 k:
R
+
-
V
½
LMP2232
1 k:
R
10 PF
40 k:
+
R+'R
VA
IN
ADC121S021
+
V
-
12 k:
½
LMP2232
+
GND
10 k:
40 k:
Figure 51. Strain Gage Bridge Amplifier
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
21
LMP2232
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
www.ti.com
PORTABLE GAS DETECTION SENSOR
Gas sensors are used in many different industrial and medical applications. They generate a current which is
proportional to the percentage of a particular gas sensed in an air sample. This current goes through a load
resistor and the resulting voltage drop is measured. Depending on the sensed gas and sensitivity of the sensor,
the output current can be in the order of tens of microamperes to a few milliamperes. Gas sensor datasheets
often specify a recommended load resistor value or they suggest a range of load resistors to choose from.
Oxygen sensors are used when air quality or oxygen delivered to a patient needs to be monitored. Fresh air
contains 20.9% oxygen. Air samples containing less than 18% oxygen are considered dangerous. Oxygen
sensors are also used in industrial applications where the environment must lack oxygen. An example is when
food is vacuum packed. There are two main categories of oxygen sensors, those which sense oxygen when it is
abundantly present (i.e. in air or near an oxygen tank) and those which detect very small traces of oxygen in
ppm.
Figure 52 shows a typical circuit used to amplify the output signal of an oxygen detector. The LMP2232 makes
an excellent choice for this application as it draws only 36 µA of current and operates on supply voltages down to
1.8V. This application detects oxygen in air. The oxygen sensor outputs a known current through the load
resistor. This value changes with the amount of oxygen present in the air sample. Oxygen sensors usually
recommend a particular load resistor value or specify a range of acceptable values for the load resistor. Oxygen
sensors typically have a life of one to two years. The use of the micropower LMP2232 means minimal power
usage by the op amp and it enhances the battery life. Depending on other components present in the circuit
design, the battery could last for the entire life of the oxygen sensor. The precision specifications of the
LMP2232, such as its very low offset voltage, low TCVOS, low input bias current, low CMRR, and low PSRR are
other factors which make the LMP2232 a great choice for this application..
99 k:
+
V
1 k:
VOUT
1 k:
+
V
-
RL
OXYGEN SENSOR
Figure 52. Precision Oxygen Sensor
22
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
LMP2232
www.ti.com
SNOSB02C – JANUARY 2008 – REVISED MARCH 2013
REVISION HISTORY
Changes from Revision B (March 2013) to Revision C
•
Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 22
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: LMP2232
23
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)
LMP2232AMA/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LMP22
32AMA
LMP2232AMAE/NOPB
ACTIVE
SOIC
D
8
250
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LMP22
32AMA
LMP2232AMAX/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LMP22
32AMA
LMP2232AMM/NOPB
ACTIVE
VSSOP
DGK
8
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
AK5A
LMP2232AMME/NOPB
ACTIVE
VSSOP
DGK
8
250
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
AK5A
LMP2232AMMX/NOPB
ACTIVE
VSSOP
DGK
8
3500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
AK5A
LMP2232BMA/NOPB
ACTIVE
SOIC
D
8
95
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LMP22
32BMA
LMP2232BMAE/NOPB
ACTIVE
SOIC
D
8
250
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LMP22
32BMA
LMP2232BMAX/NOPB
ACTIVE
SOIC
D
8
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
LMP22
32BMA
LMP2232BMM/NOPB
ACTIVE
VSSOP
DGK
8
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
AK5B
LMP2232BMME/NOPB
ACTIVE
VSSOP
DGK
8
250
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
AK5B
(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
工商网监
湘ICP备2023018690号
