TI LMP7701MFX Lmp7701/lmp7702/lmp7704 precision, cmos input, rrio, wide supply range amplifier Datasheet

LMP7701, LMP7702, LMP7704
www.ti.com
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
LMP7701/LMP7702/LMP7704 Precision, CMOS Input, RRIO, Wide Supply Range Amplifiers
Check for Samples: LMP7701, LMP7702, LMP7704
FEATURES
DESCRIPTION
•
The LMP7701/LMP7702/LMP7704 are single, dual,
and quad low offset voltage, rail-to-rail input and
output precision amplifiers each with a CMOS input
stage and a wide supply voltage range. The
LMP7701/LMP7702/LMP7704 are part of the LMP™
precision amplifier family and are ideal for sensor
interface and other instrumentation applications.
1
23
Unless Otherwise Noted,
Typical Values at VS = 5V
– Input Offset Voltage (LMP7701): ±200 µV
(max)
– Input Offset Voltage (LMP7702/LMP7704):
±220 µV (max)
– Input Bias Current: ±200 fA
– Input Bias Current: ±200 fA
– Input Voltage Noise: 9 nV/√Hz
– CMRR: 130 dB
– Open Loop Gain: 130 dB
– Temperature Range: −40°C to 125°C
– Unity Gain Bandwidth: 2.5 MHz
– Supply Current (LMP7701): 715 µA
– Supply Current (LMP7702): 1.5 mA
– Supply Current (LMP7704): 2.9 mA
– Supply Voltage Range: 2.7V to 12V
– Rail-to-Rail Input and Output
APPLICATIONS
•
•
•
•
•
•
High Impedance Sensor Interface
Battery Powered Instrumentation
High Gain Amplifiers
DAC Buffer
Instrumentation Amplifier
Active Filters
The specified low offset voltage of less than ±200 µV
along with the specified low input bias current of less
than ±1 pA make the LMP7701 ideal for precision
applications. The LMP7701/LMP7702/LMP7704 are
built utilizing VIP50 technology, which allows the
combination of a CMOS input stage and a 12V
common mode and supply voltage range. This makes
the LMP7701/LMP7702/LMP7704 great choices in
many applications where conventional CMOS parts
cannot operate under the desired voltage conditions.
The LMP7701/LMP7702/LMP7704 each have a railto-rail input stage that significantly reduces the CMRR
glitch commonly associated with rail-to-rail input
amplifiers. This is achieved by trimming both sides of
the complimentary input stage, thereby reducing the
difference between the NMOS and PMOS offsets.
The output of the LMP7701/LMP7702/LMP7704
swings within 40 mV of either rail to maximize the
signal dynamic range in applications requiring low
supply voltage.
The LMP7701 is offered in the space saving 5-Pin
SOT-23 and 8-Pin SOIC package. The LMP7702 is
offered in the 8-Pin SOIC and 8-Pin VSSOP package.
The quad LMP7704 is offered in the 14-Pin SOIC and
14-Pin TSSOP package. These small packages are
ideal solutions for area constrained PC boards and
portable electronics.
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.
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 © 2005–2013, Texas Instruments Incorporated
LMP7701, LMP7702, LMP7704
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
www.ti.com
TYPICAL APPLICATION
R
R
V1
V
+
-
RS
I = (V2 ± V1)
A1
RS
+
V
-
V
+
Z
R
LOAD
-
R
V2
A2
+
-
V
Figure 1. Precision Current Source
Absolute Maximum Ratings
ESD Tolerance
(3)
(1) (2)
Human Body Model
2000V
Machine Model
200V
Charge-Device Model
1000V
VIN Differential
±300 mV
Supply Voltage (VS = V+ – V−)
13.2V
V++ 0.3V, V− − 0.3V
Voltage at Input/Output Pins
Input Current
10 mA
−65°C to +150°C
Storage Temperature Range
Junction Temperature
(4)
Soldering Information
(1)
(2)
(3)
(4)
2
+150°C
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 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. 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 © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
LMP7701, LMP7702, LMP7704
www.ti.com
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
Operating Ratings
Temperature Range
(1)
(2)
−40°C to +125°C
Supply Voltage (VS = V+ – V−)
2.7V to 12V
Package Thermal Resistance (θJA (2))
(1)
(2)
5-Pin SOT-23
265°C/W
8-Pin SOIC
190°C/W
8-Pin VSSOP
235°C/W
14-Pin SOIC
145°C/W
14-Pin TSSOP
122°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.
The maximum power dissipation is a function of TJ(MAX), θJA. 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.
3V Electrical Characteristics
(1)
Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 3V, V− = 0V, VCM = V+/2, and RL > 10 kΩ to V+/2.
Boldface limits apply at the temperature extremes.
Parameter
VOS
Test Conditions
Input Offset Voltage
TCVOS
IB
Input Offset Voltage Temperature Drift
Min
(2)
(3)
±200
±500
LMP7702/LMP7704
±56
±220
±520
±1
±5
±0.2
±1
±50
±0.2
±1
±400
(4)
(4) (5)
−40°C ≤ TA ≤ 125°C
Input Offset Current
CMRR
Common Mode Rejection Ratio
86
80
130
0V ≤ VCM ≤ 3V
LMP7702/LMP7704
84
78
130
86
82
98
Power Supply Rejection Ratio
2.7V ≤ V+ ≤ 12V, Vo = V+/2
CMVR
Common Mode Voltage Range
CMRR ≥ 80 dB
CMRR ≥ 77 dB
–0.2
–0.2
AVOL
Open Loop Voltage Gain
RL = 2 kΩ (LMP7701)
VO = 0.3V to 2.7V
100
96
114
RL = 2 kΩ (LMP7702/LMP7704)
VO = 0.3V to 2.7V
100
94
114
RL = 10 kΩ
VO = 0.2V to 2.8V
100
96
124
(2)
(3)
(4)
(5)
Units
μV
μV/°C
40
0V ≤ VCM ≤ 3V
LMP7701
PSRR
(1)
(2)
±37
−40°C ≤ TA ≤ 85°C
IOS
Max
LMP7701
(4) (5)
Input Bias Current
Typ
pA
fA
dB
dB
3.2
3.2
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 specification of parametric performance is indicated in the electrical tables under
conditions of internal self-heating where TJ > TA.
Limits are 100% production tested at 25°C. Limits over the operating temperature range are specified through correlations using the
Statistical Quality Control (SQC) method.
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 specified on shipped
production material.
This parameter is specified by design and/or characterization and is not tested in production.
Positive current corresponds to current flowing into the device.
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
Submit Documentation Feedback
3
LMP7701, LMP7702, LMP7704
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
www.ti.com
3V Electrical Characteristics (1) (continued)
Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 3V, V− = 0V, VCM = V+/2, and RL > 10 kΩ to V+/2.
Boldface limits apply at the temperature extremes.
Parameter
VOUT
Test Conditions
Output Voltage Swing High
Output Voltage Swing Low
IOUT
Output Current
IS
Min
+
(6) (7)
Supply Current
(8)
(2)
Typ
(3)
Max
(2)
RL = 2 kΩ to V /2
LMP7701
40
80
120
RL = 2 kΩ to V+/2
LMP7702/LMP7704
40
80
150
RL = 10 kΩ to V+/2
LMP7701
30
40
60
RL = 10 kΩ to V+/2
LMP7702/LMP7704
35
50
100
RL = 2 kΩ to V+/2
LMP7701
40
60
80
RL = 2 kΩ to V+/2
LMP7702/LMP7704
45
100
170
RL = 10 kΩ to V+/2
LMP7701
20
40
50
RL = 10 kΩ to V+/2
LMP7702/LMP7704
20
50
90
Sourcing VO = V+/2
VIN = 100 mV
25
15
42
Sinking VO = V+/2
VIN = −100 mV (LMP7701)
25
20
42
Sinking VO = V+/2
VIN = −100 mV (LMP7702/LMP7704)
25
15
42
Units
mV
from V+
mV
mA
LMP7701
0.670
1.0
1.2
LMP7702
1.4
1.8
2.1
LMP7704
2.9
3.5
4.5
AV = +1, VO = 2 VPP
10% to 90%
0.9
V/μs
2.5
MHz
0.02
%
mA
SR
Slew Rate
GBW
Gain Bandwidth
THD+N
Total Harmonic Distortion + Noise
f = 1 kHz, AV = 1, R.L = 10 kΩ
en
Input Referred Voltage Noise Density
f = 1 kHz
9
nV/√Hz
in
Input Referred Current Noise Density
f = 100 kHz
1
fA/√Hz
(6)
(7)
(8)
4
The maximum power dissipation is a function of TJ(MAX), θJA. 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.
The short circuit test is a momentary test.
The number specified is the slower of positive and negative slew rates.
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
LMP7701, LMP7702, LMP7704
www.ti.com
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
5V Electrical Characteristics
(1)
Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 5V, V− = 0V, VCM = V+/2, and RL > 10 kΩ to V+/2.
Boldface limits apply at the temperature extremes.
Parameter
VOS
Test Conditions
Input Offset Voltage
TCVOS
IB
Input Offset Voltage Temperature Drift
Min
(2)
(3)
±200
±500
LMP7702/LMP7704
±32
±220
±520
±1
±5
±0.2
±1
±50
±0.2
±1
±400
(4)
(4) (5)
−40°C ≤ TA ≤ 125°C
Input Offset Current
CMRR
Common Mode Rejection Ratio
88
83
130
0V ≤ VCM ≤ 5V
LMP7702/LMP7704
86
81
130
86
82
100
Power Supply Rejection Ratio
2.7V ≤ V+ ≤ 12V, VO = V+/2
CMVR
Common Mode Voltage Range
CMRR ≥ 80 dB
CMRR ≥ 78 dB
–0.2
–0.2
AVOL
Open Loop Voltage Gain
RL = 2 kΩ (LMP7701)
VO = 0.3V to 4.7V
100
96
119
RL = 2 kΩ (LMP7702/LMP7704)
VO = 0.3V to 4.7V
100
94
119
RL = 10 kΩ
VO = 0.2V to 4.8V
100
96
130
Output Voltage Swing High
Output Voltage Swing Low
(1)
(2)
(3)
(4)
(5)
Units
μV
μV/°C
pA
40
0V ≤ VCM ≤ 5V
LMP7701
PSRR
VOUT
(2)
±37
−40°C ≤ TA ≤ 85°C
IOS
Max
LMP7701
(4) (5)
Input Bias Current
Typ
fA
dB
dB
5.2
5.2
V
dB
RL = 2 kΩ to V+/2
LMP7701
60
110
130
RL = 2 kΩ to V+/2
LMP7702/LMP7704
60
120
200
RL = 10 kΩ to V+/2
LMP7701
40
50
70
RL = 10 kΩ to V+/2
LMP7702/LMP7704
40
60
120
RL = 2 kΩ to V+/2
LMP7701
50
80
90
RL = 2 kΩ to V+/2
LMP7702/LMP7704
50
120
190
RL = 10 kΩ to V+/2
LMP7701
30
40
50
RL = 10 kΩ to V+/2
LMP7702/LMP7704
30
50
100
mV
from V+
mV
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.
Limits are 100% production tested at 25°C. Limits over the operating temperature range are specified through correlations using the
Statistical Quality Control (SQC) method.
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.
This parameter is specified by design and/or characterization and is not tested in production.
Positive current corresponds to current flowing into the device.
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
Submit Documentation Feedback
5
LMP7701, LMP7702, LMP7704
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
www.ti.com
5V Electrical Characteristics (1) (continued)
Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 5V, V− = 0V, VCM = V+/2, and RL > 10 kΩ to V+/2.
Boldface limits apply at the temperature extremes.
Parameter
IOUT
Output Current
IS
Test Conditions
(6) (7)
Min
+
Supply Current
(8)
(2)
Typ
Sourcing VO = V /2
VIN = 100 mV (LMP7701)
40
28
66
Sourcing VO = V+/2
VIN = 100 mV (LMP7702/LMP7704)
38
25
66
Sinking VO = V+/2
VIN = −100 mV (LMP7701)
40
28
76
Sinking VO = V+/2
VIN = −100 mV (LMP7702/LMP7704)
40
23
76
(3)
Max
(2)
Units
mA
LMP7701
0.715
1.0
1.2
LMP7702
1.5
1.9
2.2
LMP7704
2.9
3.7
4.6
AV = +1, VO = 4 VPP
10% to 90%
1.0
0.02
%
mA
SR
Slew Rate
GBW
Gain Bandwidth
THD+N
Total Harmonic Distortion + Noise
f = 1 kHz, AV = 1, RL = 10 kΩ
en
Input Referred Voltage Noise Density
f = 1 kHz
9
nV/√Hz
in
Input Referred Current Noise Density
f = 100 kHz
1
fA/√Hz
(6)
(7)
(8)
V/μs
2.5
MHz
The maximum power dissipation is a function of TJ(MAX), θJA. 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.
The short circuit test is a momentary test.
The number specified is the slower of positive and negative slew rates.
±5V Electrical Characteristics
(1)
Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 5V, V− = −5V, VCM = 0V, and RL > 10 kΩ to 0V.
Boldface limits apply at the temperature extremes.
Parameter
VOS
Test Conditions
Input Offset Voltage
TCVOS
IB
Input Offset Voltage Temperature Drift
Input Bias Current
Min
(2)
Typ
(3)
±37
±200
±500
LMP7702/LMP7704
±37
±220
±520
±1
±5
±0.2
1
±50
±0.2
1
±400
(4)
(4) (5)
(4) (5)
−40°C ≤ TA ≤ 125°C
Input Offset Current
CMRR
Common Mode Rejection Ratio
(1)
(2)
(3)
(4)
(5)
6
(2)
LMP7701
−40°C ≤ TA ≤ 85°C
IOS
Max
40
−5V ≤ VCM ≤ 5V
LMP7701
92
88
138
−5V ≤ VCM ≤ 5V
LMP7702/LMP7704
90
86
138
Units
μV
μV/°C
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.
Limits are 100% production tested at 25°C. Limits over the operating temperature range are specified through correlations using the
Statistical Quality Control (SQC) method.
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.
This parameter is specified by design and/or characterization and is not tested in production.
Positive current corresponds to current flowing into the device.
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
LMP7701, LMP7702, LMP7704
www.ti.com
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
±5V Electrical Characteristics (1) (continued)
Unless otherwise specified, all limits are ensured for TA = 25°C, V+ = 5V, V− = −5V, VCM = 0V, and RL > 10 kΩ to 0V.
Boldface limits apply at the temperature extremes.
Parameter
Test Conditions
+
Min
(2)
Typ
(3)
PSRR
Power Supply Rejection Ratio
2.7V ≤ V ≤ 12V, VO = 0V
CMVR
Common Mode Voltage Range
CMRR ≥ 80 dB
CMRR ≥ 78 dB
−5.2
−5.2
AVOL
Open Loop Voltage Gain
RL = 2 kΩ (LMP7701)
VO = −4.7V to 4.7V
100
98
121
RL = 2 kΩ (LMP7702/LMP7704)
VO = −4.7V to 4.7V
100
94
121
RL = 10 kΩ (LMP7701)
VO = −4.8V to 4.8V
100
98
134
RL = 10 kΩ (LMP7702/LMP7704)
VO = −4.8V to 4.8V
100
97
134
VOUT
Output Voltage Swing High
Output Voltage Swing Low
IOUT
Output Current
IS
(6) (7)
Supply Current
(8)
86
82
Max
(2)
Units
98
dB
5.2
5.2
dB
RL = 2 kΩ to 0V
LMP7701
90
150
170
RL = 2 kΩ to 0V
LMP7702/LMP7704
90
180
290
RL = 10 kΩ to 0V
LMP7701
40
80
100
RL = 10 kΩ to 0V
LMP7702/LMP7704
40
80
150
RL = 2 kΩ to 0V
LMP7701
90
130
150
RL = 2 kΩ to 0V
LMP7702/LMP7704
90
180
290
RL = 10 kΩ to 0V
LMP7701
40
50
60
RL = 10 kΩ to 0V
LMP7702/LMP7704
40
60
110
Sourcing VO = 0V
VIN = 100 mV (LMP7701)
50
35
86
Sourcing VO = 0V
VIN = 100 mV (LMP7702/LMP7704)
48
33
86
Sinking VO = 0V
VIN = −100 mV
50
35
84
V
mV
from V+
mV
from V–
mA
LMP7701
0.790
1.1
1.3
LMP7702
1.7
2.1
2.5
LMP7704
3.2
4.2
5.0
AV = +1, VO = 9 VPP
10% to 90%
1.1
V/μs
2.5
MHz
0.02
%
mA
SR
Slew Rate
GBW
Gain Bandwidth
THD+N
Total Harmonic Distortion + Noise
f = 1 kHz, AV = 1, RL = 10 kΩ
en
Input Referred Voltage Noise Density
f = 1 kHz
9
nV/√Hz
in
Input Referred Current Noise Density
f = 100 kHz
1
fA/√Hz
(6)
(7)
(8)
The maximum power dissipation is a function of TJ(MAX), θJA. 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.
The short circuit test is a momentary test.
The number specified is the slower of positive and negative slew rates.
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
Submit Documentation Feedback
7
LMP7701, LMP7702, LMP7704
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
www.ti.com
CONNECTION DIAGRAMS
OUT
-
V
5
1
N/C
-IN
2
+
IN+
+
V
-
3
+IN
4
IN-
1
2
3
8
+
4
6
5
V
8
7
N/C
+
V
OUTPUT
N/C
Figure 2. 5-Pin SOT-23 (LMP7701)
Top View
Figure 3. 8-Pin SOIC (LMP7701)
Top View
Figure 4. 8-Pin SOIC/VSSOP (LMP7702)
Top View
Figure 5. 14-Pin SOIC/TSSOP (LMP7704)
Top View
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
LMP7701, LMP7702, LMP7704
www.ti.com
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
Typical Performance Characteristics
Unless otherwise noted: TA = 25°C, VCM = VS/2, RL > 10 kΩ.
Offset Voltage Distribution
TCVOS Distribution
20
25
VS = 3V
VS = 3V
-40°C d TA d 125°C
16
PERCENTAGE (%)
PERCENTAGE (%)
20
TA = 25°C
15
10
12
8
4
5
0
-200
0
-100
0
100
200
-3
-2
-1
0
TCVOS (PV/°C)
Figure 6.
Figure 7.
Offset Voltage Distribution
3
TCVOS Distribution
VS = 5V
VS = 5V
TA = 25°C
-40°C d TA d 125°C
16
PERCENTAGE (%)
20
PERCENTAGE (%)
2
20
25
15
10
12
8
4
5
0
-200
0
-100
0
100
OFFSET VOLTAGE (PV)
200
-3
-2
-1
0
1
2
3
TCVOS (PV/°C)
Figure 8.
Figure 9.
Offset Voltage Distribution
TCVOS Distribution
20
25
VS = 10V
VS = 10V
-40°C d TA d 125°C
TA = 25°C
16
PERCENTAGE (%)
20
PERCENTAGE (%)
1
OFFSET VOLTAGE (PV)
15
10
8
4
5
0
-200
12
0
-100
0
100
OFFSET VOLTAGE (PV)
200
-3
-2
Figure 10.
-1
0
1
2
3
TCVOS (PV/°C)
Figure 11.
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
Submit Documentation Feedback
9
LMP7701, LMP7702, LMP7704
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
www.ti.com
Typical Performance Characteristics (continued)
Unless otherwise noted: TA = 25°C, VCM = VS/2, RL > 10 kΩ.
CMRR
vs.
Frequency
200
0
150
-20
VS = 3V
100
-40
VS = 3V
50
VS = 5V
CMRR (dB)
OFFSET VOLTAGE (PV)
Offset Voltage
vs.
Temperature
0
-50
VS = 5V
VS = 10V
-80
-100
-100
VS = 10V
-120
-150
-200
-140
-40 -20
0
20
40
60
80 100 120125
10
Figure 12.
Figure 13.
Offset Voltage
vs.
Supply Voltage
Offset Voltage
vs.
VCM
200
200
150
150
1M
VS = 3V
100
-40°C
50
0
25°C
-50
-100
125°C
-40°C
100
50
25°C
0
-50
125°C
-100
-150
-200
2
4
6
8
10
-200
-0.5
12
0
0.5 1
1.5
2
2.5
3
3.5
VCM (V)
SUPPLY VOLTAGE (V)
Figure 14.
Figure 15.
Offset Voltage
vs.
VCM
Offset Voltage
vs.
VCM
200
200
VS = 10V
VS = 5V
150
150
OFFSET VOLTAGE (PV)
OFFSET VOLTAGE (PV)
100k
FREQUENCY (Hz)
-150
100
-40°C
50
0
25°C
-50
-100
125°C
-150
100
-40°C
50
0
25°C
-50
-100
-150
125°C
-200
-200
-1
0
1
2
3
4
5
6
-1 0
1
VCM (V)
Submit Documentation Feedback
2
3
4
5
6
7
8
9 10 11
VCM (V)
Figure 16.
10
10k
1k
100
TEMPERATURE (°C)
OFFSET VOLTAGE (PV)
OFFSET VOLTAGE (PV)
-60
Figure 17.
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
LMP7701, LMP7702, LMP7704
www.ti.com
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
Typical Performance Characteristics (continued)
Unless otherwise noted: TA = 25°C, VCM = VS/2, RL > 10 kΩ.
Input Bias Current
vs.
VCM
Input Bias Current
vs.
VCM
300
200
VS = 3V
VS = 3V
200
100
IBIAS (pA)
IBIAS (fA)
100
-40°C
0
85°C
0
-100
-100
-200
125°C
25°C
-300
-200
0
0.5
1
2
1.5
2.5
0
3
0.5
1.5
1
Figure 18.
Figure 19.
Input Bias Current
vs.
VCM
Input Bias Current
vs.
VCM
3
300
300
VS = 5V
VS = 5V
200
200
100
100
IBIAS (pA)
IBIAS (fA)
2.5
2
VCM (V)
VCM (V)
-40°C
0
85°C
0
-100
-100
-200
-200
25°C
125°C
-300
-300
0
1
2
3
4
1
0
5
2
3
4
5
VCM (V)
VCM (V)
Figure 20.
Figure 21.
Input Bias Current
vs.
VCM
Input Bias Current vs. VCM
300
500
VS = 10V
VS = 10V
200
250
IBIAS (pA)
IBIAS (fA)
100
-40°C
0
85°C
0
-100
-250
-200
25°C
125°C
-500
-300
0
2
4
6
8
10
0
VCM (V)
2
4
6
8
10
VCM (V)
Figure 22.
Figure 23.
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
Submit Documentation Feedback
11
LMP7701, LMP7702, LMP7704
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
www.ti.com
Typical Performance Characteristics (continued)
Unless otherwise noted: TA = 25°C, VCM = VS/2, RL > 10 kΩ.
PSRR vs. Frequency
120
Supply Current vs. Supply Voltage (Per Channel)
1.2
VS = 10V
VS = 5V
1
SUPPLY CURRENT (mA)
100
VS = 3V
+PSRR
PSRR (dB)
80
VS = 10V
60
VS = 5V
VS = 3V
40
20
125°C
25°C
0.8
0.6
-40°C
0.4
0.2
-PSRR
0
0
10
10k
1k
100
100k
1M
2
4
6
8
10
FREQUENCY (Hz)
SUPPLY VOLTAGE (V)
Figure 24.
Figure 25.
Sinking Current vs. Supply Voltage
12
Sourcing Current vs. Supply Voltage
120
120
-40°C
100
-40°C
100
25°C
25°C
60
ISOURCE (mA)
ISINK (mA)
80
125°C
40
20
80
125°C
60
40
20
0
0
2
4
6
8
10
12
2
TA = -40°C, 25°C, 125C
AV = +1
1.4
+
(V ) -1
VIN = 2 VPP
+
(V ) -2
|
2
SLEW RATE (V/Ps)
1.3
3V
12
Slew Rate vs. Supply Voltage
1.5
|
10
Figure 27.
+
VOUT FROM RAIL (V)
8
Figure 26.
Output Voltage vs. Output Current
RL = 10 k:
FALLING EDGE
1.2
CL = 10 pF
1.1
1
0.9
RISING EDGE
0.8
0.7
1
VS = 3V, 5V, 10V
0.6
0.5
0
20
40
60
80
100
2
OUTPUT CURRENT (mA)
Submit Documentation Feedback
4
6
8
10
12
SUPPLY VOLTAGE (V)
Figure 28.
12
6
SUPPLY VOLTAGE (V)
V
0
4
SUPPLY VOLTAGE (V)
Figure 29.
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
LMP7701, LMP7702, LMP7704
www.ti.com
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
Typical Performance Characteristics (continued)
Unless otherwise noted: TA = 25°C, VCM = VS/2, RL > 10 kΩ.
Open Loop Frequency Response
100
225
GAIN
80
60
180
80
135
60
90
40
CL = 20 pF, 50 pF, 100 pF 180
RL = 10 k:
VS = 10V
125°C
45
125°C
0
-40°C
-20 VS = 5V
-40
0
25°C
CL = 20 pF
GAIN (dB)
20
25°C
PHASE
PHASE (°)
GAIN (dB)
-40°C
40
CL = 20 pF
PHASE
20
0
-45
-20
-90
-40
1k
-45
VS = 3V
-90
CL = 100 pF
10k
100k
1M
-135
10M 100M
-60
100
1k
10k
100k
1M
-135
10M 100M
FREQUENCY (Hz)
Figure 31.
Large Signal Step Response
Small Signal Step Response
20 mV/DIV
Figure 30.
VS = 5V
f = 10 kHz
VS = 5V
f = 10 kHz
AV = +1
AV = +1
VIN = 2 VPP
VIN = 100 mVPP
RL = 10 k:
RL = 10 k:
CL = 10 pF
CL = 10 pF
10 Ps/DIV
10 Ps/DIV
Figure 32.
Figure 33.
Large Signal Step Response
Small Signal Step Response
200 mV/DIV
500 mV/DIV
90
0
FREQUENCY (Hz)
1V/DIV
135
45
RL = 10 k:
-60
100
225
VS = 3V, 5V, 10V
GAIN
PHASE (°)
Open Loop Frequency Response
100
VS = 5V
f = 10 kHz
VS = 5V
f = 10 kHz
AV = +10
AV = +10
VIN = 400 mVPP
VIN = 100 mVPP
RL = 10 k:
RL = 10 k:
CL = 10 pF
CL = 10 pF
10 Ps/DIV
10 Ps/DIV
Figure 34.
Figure 35.
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
Submit Documentation Feedback
13
LMP7701, LMP7702, LMP7704
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
www.ti.com
Typical Performance Characteristics (continued)
Unless otherwise noted: TA = 25°C, VCM = VS/2, RL > 10 kΩ.
Input Voltage Noise vs. Frequency
Open Loop Gain vs. Output Voltage Swing
150
VS = 10V
100
80
VS = 3V
60
VS = 5V
40
130
120
RL = 10 k:
110
VS = 3V
100
90
80
20
1
10
RL = 2 k:
70
VS = 10V
0
100
1k
10k
60
500
100k
FREQUENCY (Hz)
400
100
0
Output Swing High vs. Supply Voltage
Output Swing Low vs. Supply Voltage
50
50
RL = 10 k:
25°C
40
40
125°C
30
VOUT FROM RAIL (mV)
VOUT FROM RAIL (mV)
200
Figure 37.
RL = 10 k:
-40°C
20
10
0
2
4
6
8
10
-40°C
30
25°C
125°C
20
10
0
12
2
6
8
10
SUPPLY VOLTAGE (V)
Figure 38.
Figure 39.
Output Swing High vs. Supply Voltage
12
Output Swing Low vs. Supply Voltage
100
RL = 2 k:
RL = 2 k:
25°C
25°C
80
80
VOUT FROM RAIL (mV)
125°C
60
-40°C
40
20
0
4
SUPPLY VOLTAGE (V)
100
VOUT FROM RAIL (mV)
300
OUTPUT SWING FROM RAIL (mV)
Figure 36.
14
VS = 5V
140
OPEN LOOP GAIN (dB)
INPUT REFERRED VOLTAGE NOISE
(nV/ Hz)
120
2
4
6
8
10
12
125°C
60
-40°C
40
20
0
2
4
6
8
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Figure 40.
Figure 41.
Submit Documentation Feedback
10
12
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
LMP7701, LMP7702, LMP7704
www.ti.com
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
Typical Performance Characteristics (continued)
Unless otherwise noted: TA = 25°C, VCM = VS/2, RL > 10 kΩ.
THD+N vs. Frequency
THD+N vs. Output Voltage
1
1
VS = 5V
f = 1 kHz
VS = 5V
VO = 4.5 VPP
RL = 100 k:
RL = 100 k:
0.1
THD+N (%)
0.1
AV = +10
THD+N (%)
AV = +10
0.01
0.01
AV = +1
AV = +1
0.001
10
100
1k
10k
0.001
0.001
100k
0.01
0.1
FREQUENCY (Hz)
VOUT (V)
Figure 42.
Figure 43.
1
10
Crosstalk Rejection Ratio vs. Frequency (LMP7702/LMP7704)
140
CROSSTALK REJECTION (dB)
VS = 12V
120
VS = 5V
VS = 3V
100
80
60
40
100
1k
10k
100k
1M
FREQUENCY (Hz)
Figure 44.
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
Submit Documentation Feedback
15
LMP7701, LMP7702, LMP7704
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
www.ti.com
APPLICATION INFORMATION
LMP7701/LMP7702/LMP7704
The LMP7701/LMP7702/LMP7704 are single, dual, and quad low offset voltage, rail-to-rail input and output
precision amplifiers each with a CMOS input stage and wide supply voltage range of 2.7V to 12V. The
LMP7701/LMP7702/LMP7704 have a very low input bias current of only ±200 fA at room temperature.
The wide supply voltage range of 2.7V to 12V over the extensive temperature range of −40°C to 125°C makes
the LMP7701/LMP7702/LMP7704 excellent choices for low voltage precision applications with extensive
temperature requirements.
The LMP7701/LMP7702/LMP7704 have only ±37 μV of typical input referred offset voltage and this offset is
specified to be less than ±500 μV for the single and ±520 μV for the dual and quad, over temperature. This
minimal offset voltage allows more accurate signal detection and amplification in precision applications.
The low input bias current of only ±200 fA along with the low input referred voltage noise of 9 nV/√Hz gives the
LMP7701/LMP7702/LMP7704 superiority for use in sensor applications. Lower levels of noise from the
LMP7701/LMP7702/LMP7704 mean of better signal fidelity and a higher signal-to-noise ratio.
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 LMP7701 is offered in the space saving 5-Pin SOT-23 and 8-Pin SOIC package. The LMP7702 comes in
the 8-Pin SOIC and 8-Pin VSSOP package. The LMP7704 is offered in the 14-Pin SOIC and 14-Pin TSSOP
package. These small packages are ideal solutions for area constrained PC boards and portable electronics.
CAPACITIVE LOAD
The LMP7701/LMP7702/LMP7704 can each be connected as a non-inverting unity gain follower. This
configuration is the most sensitive to capacitive loading.
The combination of a capacitive load placed on the output of an amplifier along with the amplifier's output
impedance creates a phase lag which in turn reduces the phase margin of the amplifier. If the phase margin is
significantly reduced, the response will be either underdamped or it will oscillate.
In order to drive heavier capacitive loads, an isolation resistor, RISO, in Figure 45 should be used. By using this
isolation resistor, the capacitive load is isolated from the amplifier's output, and hence, the pole caused by CL is
no longer in the feedback loop. The larger the value of RISO, the more stable the output voltage will be. If values
of RISO are sufficiently large, the feedback loop will be stable, independent of the value of CL. However, larger
values of RISO result in reduced output swing and reduced output current drive.
Figure 45. Isolating Capacitive Load
INPUT CAPACITANCE
CMOS input stages inherently have low input bias current and higher input referred voltage noise. The
LMP7701/LMP7702/LMP7704 enhance this performance by having the low input bias current of only ±200 fA, as
well as, a very low input referred voltage noise of 9 nV/√Hz. In order to achieve this a larger input stage has been
used. This larger input stage increases the input capacitance of the LMP7701/LMP7702/ LMP7704. The typical
value of this input capacitance, CIN, for the LMP7701/LMP7702/LMP7704 is 25 pF. The input capacitance will
interact with other impedances such as gain and feedback resistors, which are seen on the inputs of the
16
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
LMP7701, LMP7702, LMP7704
www.ti.com
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
amplifier, to form a pole. This pole will have little or no effect on the output of the amplifier at low frequencies and
DC conditions, but will play a bigger role as the frequency increases. At higher frequencies, the presence of this
pole will decrease phase margin and will also cause gain peaking. In order to compensate for the input
capacitance, care must be taken in choosing the feedback resistors. In addition to being selective in picking
values for the feedback resistor, a capacitor can be added to the feedback path to increase stability.
The DC gain of the circuit shown in Figure 46 is simply –R2/R1.
CF
R2
R1
-
+
CIN
VIN
+
+
-
-
AV = -
VOUT
VIN
=-
VOUT
R2
R1
Figure 46. Compensating for Input Capacitance
For the time being, ignore CF. The AC gain of the circuit in Figure 46 can be calculated as follows:
-R2/R1
(s) =
1+
s2
s
+
§ A0 R 1
§ A0
¨
¨C R
+
R
R
2
© 1
© IN 2
§
¨
©
VIN
§
¨
©
VOUT
This equation is rearranged to find the location of the two poles:
-1
2CIN
1
1
+
r
R1
R2
§1
1
+
¨
R2
© R1
§
¨
©
P1,2 =
2
4 A0CIN
-
R2
(1)
As shown in Equation 1, as values of R1 and R2 are increased, the magnitude of the poles is reduced, which in
turn decreases the bandwidth of the amplifier. Whenever possible, it is best to choose smaller feedback resistors.
Figure 47 shows the effect of the feedback resistor on the bandwidth of the LMP7701/LMP7702/LMP7704.
2
VS = 5V
CF = 0 pF
NORMALIZED GAIN (dB)
0
AV = -1
-2
R1 = R2 = 100 k:
-4
R1 = R2 = 30 k:
-6
R1 = R2 = 10 k:
-8
R1 = R2 = 1 k:
-10
1k
10k
100k
1M
10M
FREQUENCY (Hz)
Figure 47. Closed Loop Gain vs. Frequency
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
Submit Documentation Feedback
17
LMP7701, LMP7702, LMP7704
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
www.ti.com
Equation 1 has two poles. In most cases, it is the presence of pairs of poles that causes gain peaking. In order to
eliminate this effect, the poles should be placed in Butterworth position, since poles in Butterworth position do not
cause gain peaking. To achieve a Butterworth pair, the quantity under the square root in Equation 1 should be
set to equal −1. Using this fact and the relation between R1 and R2, R2 = −AV R1, the optimum value for R1 can
be found. This is shown in Equation 2. If R1 is chosen to be larger than this optimum value, gain peaking will
occur.
R1 <
(1 - AV)
2
2A0AVCIN
(2)
In Figure 46, CF is added to compensate for input capacitance and to increase stability. Additionally, CF reduces
or eliminates the gain peaking that can be caused by having a larger feedback resistor. Figure 48 shows how CF
reduces gain peaking.
2
CF = 0 pF
NORMALIZED GAIN (dB)
0
CF = 1 pF
-2
CF = 5 pF
-4
CF = 3 pF
-6
VS = 5V
-8
R1 = R2 = 100 k:
AV = -1
-10
1k
10k
100k
1M
10M
FREQUENCY (Hz)
Figure 48. Closed Loop Gain vs. Frequency with Compensation
DIODES BETWEEN THE INPUTS
The LMP7701/LMP7702/LMP7704 have a set of anti-parallel diodes between the input pins, as shown in
Figure 49. These diodes are present to protect the input stage of the amplifier. At the same time, they limit the
amount of differential input voltage that is allowed on the input pins. A differential signal larger than one diode
voltage drop might damage the diodes. The differential signal between the inputs needs to be limited to ±300 mV
or the input current needs to be limited to ±10 mA.
V
V
D1
ESD
IN
+
+
R1
ESD
R2
+
IN
ESD
ESD
D2
V
-
-
-
V
Figure 49. Input of LMP7701
18
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
LMP7701, LMP7702, LMP7704
www.ti.com
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
PRECISION CURRENT SOURCE
The LMP7701/LMP7702/LMP7704 can each be used as a precision current source in many different
applications. Figure 50 shows a typical precision current source. This circuit implements a precision voltage
controlled current source. Amplifier A1 is a differential amplifier that uses the voltage drop across RS as the
feedback signal. Amplifier A2 is a buffer that eliminates the error current from the load side of the RS resistor that
would flow in the feedback resistor if it were connected to the load side of the RS resistor. In general, the circuit is
stable as long as the closed loop bandwidth of amplifier A2 is greater then the closed loop bandwidth of amplifier
A1. Note that if A1 and A2 are the same type of amplifiers, then the feedback around A1 will reduce its
bandwidth compared to A2.
R
R
V1
V
+
-
RS
I = (V2 ± V1)
A1
RS
+
V
-
V
+
Z
LOAD
-
R
R
V2
A2
+
-
V
Figure 50. Precision Current Source
The equation for output current can be derived as follows:
V2R
R+R
+
(V0 ± IRS)R
R+R
=
V1R
+
R+R
V0R
R+R
Solving for the current I results in the following equation:
I=
V2 ± V1
RS
LOW INPUT VOLTAGE NOISE
The LMP7701/LMP7702/LMP7704 have the very low input voltage noise of 9 nV/√Hz. This input voltage noise
can be further reduced by placing N amplifiers in parallel as shown in Figure 51. 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 51 shows a schematic of this input voltage noise reduction circuit. Typical resistor values are:
RG = 10Ω, RF = 1 kΩ, and RO = 1 kΩ.
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
Submit Documentation Feedback
19
LMP7701, LMP7702, LMP7704
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
www.ti.com
+
V
+
-
VIN
VOUT
-
RG
RO
V
RF
+
V
+
RG
V
-
RO
RF
+
V
+
RG
V
-
RO
RF
+
V
+
RG
V
-
RO
RF
Figure 51. Noise Reduction Circuit
TOTAL NOISE CONTRIBUTION
The LMP7701/LMP7702/LMP7704 have very low input bias current, very low input current noise, and very low
input voltage noise. As a result, these amplifiers are ideal choices for circuits with high impedance sensor
applications.
Figure 52 shows the typical input noise of the LMP7701/LMP7702/LMP7704 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 LMP7701/LMP7702/LMP7704 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 52, at lower RS values, total noise is dominated by the amplifier's input voltage noise.
Once RS is larger than a few kilo-Ohms, 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.
20
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
LMP7701, LMP7702, LMP7704
www.ti.com
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
VOLTAGE NOISE DENSITY (nV/ Hz)
1000
100
eni
en
10
et
ei
1
0.1
10
100
1k
10k
100k
1M
10M
RS (:)
Figure 52. Total Input Noise
HIGH IMPEDANCE SENSOR INTERFACE
Many sensors have high source impedances that may range up to 10 MΩ. The output signal of sensors often
needs to be amplified or otherwise conditioned by means of an amplifier. The input bias current of this amplifier
can load the sensor's output and cause a voltage drop across the source resistance as shown in Figure 53,
where VIN+ = VS – IBIAS*RS
The last term, IBIAS*RS, shows the voltage drop across RS. To prevent errors introduced to the system due to this
voltage, an op amp with very low input bias current must be used with high impedance sensors. This is to keep
the error contribution by IBIAS*RS less than the input voltage noise of the amplifier, so that it will not become the
dominant noise factor.
SENSOR
RS
+
IB
V
VIN+
+
VS
+
-
-
V
Figure 53. Noise Due to IBIAS
pH electrodes are very high impedance sensors. As their name indicates, they are used to measure the pH of a
solution. They usually do this by generating an output voltage which is proportional to the pH of the solution. pH
electrodes are calibrated so that they have zero output for a neutral solution, pH = 7, and positive and negative
voltages for acidic or alkaline solutions. This means that the output of a pH electrode is bipolar and has to be
level shifted to be used in a single supply system. The rate of change of this voltage is usually shown in mV/pH
and is different for different pH sensors. Temperature is also an important factor in a pH electrode reading. The
output voltage of the senor will change with temperature.
Figure 54 shows a typical output voltage spectrum of a pH electrode. Note that the exact values of output voltage
will be different for different sensors. In this example, the pH electrode has an output voltage of 59.15 mV/pH at
25°C.
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
Submit Documentation Feedback
21
LMP7701, LMP7702, LMP7704
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
www.ti.com
ACID
+414 mV
BASE
4
7
10
+177 mV
0 mV
-177 mV
2
0
14 pH
12
-414 mV
Figure 54. Output Voltage of a pH Electrode
The temperature dependence of a typical pH electrode is shown in Figure 55. As is evident, the output voltage
changes with changes in temperature.
mV
600
10°C (74.04 mV/pH)
500
400
25°C (59.15 mV/pH)
300
200
100
2
4
12
10
8
14
pH
0
-100
1
3
5
7
9
11
13
-200
-300
-400
-500
0°C (54.20 mV/pH)
-600
Figure 55. Temperature Dependence of a pH Electrode
The schematic shown in Figure 56 is a typical circuit which can be used for pH measurement. The LM35 is a
precision integrated circuit temperature sensor. This sensor is differentiated from similar products because it has
an output voltage linearly proportional to Celcius measurement, without the need to convert the temperature to
Kelvin. The LM35 is used to measure the temperature of the solution and feeds this reading to the Analog to
Digital Converter, ADC. This information is used by the ADC to calculate the temperature effects on the pH
readings. The LM35 needs to have a resistor, RT in Figure 56, to –V+ in order to be able to read temperatures
below 0°C. RT is not needed if temperatures are not expected to go below zero.
The output of pH electrodes is usually large enough that it does not require much amplification; however, due to
the very high impedance, the output of a pH electrode needs to be buffered before it can go to an ADC. Since
most ADCs are operated on single supply, the output of the pH electrode also needs to be level shifted. Amplifier
A1 buffers the output of the pH electrode with a moderate gain of +2, while A2 provides the level shifting. VOUT at
the output of A2 is given by: VOUT = −2VpH + 1.024V.
The LM4140A is a precision, low noise, voltage reference used to provide the level shift needed. The ADC used
in this application is the ADC12032 which is a 12-bit, 2 channel converter with multiplexers on the inputs and a
serial output. The 12-bit ADC enables users to measure pH with an accuracy of 0.003 of a pH unit. Adequate
power supply bypassing and grounding is extremely important for ADCs. Recommended bypass capacitors are
shown in Figure 56. It is common to share power supplies between different components in a circuit. To minimize
the effects of power supply ripples caused by other components, the op amps need to have bypass capacitors
on the supply pins. Using the same value capacitors as those used with the ADC are ideal. The combination of
these three values of capacitors ensures that AC noise present on the power supply line is grounded and does
not interfere with the amplifiers' signal.
22
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
LMP7701, LMP7702, LMP7704
www.ti.com
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
+
V
pH ELECTRODE TEMPERATURE
0.01 PF
0.01 PF
0.1 PF
0.1 PF
10 PF
10 PF
+
75:
V
1 PF
+
1
A1
R2
10 k:
R1
10 k:
-
V+
+
V
VD
+
V
R3
10 k:
R4
10 k:
VA
+
CH0
-
VOUT
A2
CH1
+
RT
+
V
VOFFSET = 0.5012V
LM35
-V+
2
3
LM4140A
6
R5
10 k:
-
ADC12034
V
R6
3.3 k:
1,4,7,8
AGND
VREFVREF+
DGND
pH ELECTRODE
Figure 56. pH Measurement Circuit
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
Submit Documentation Feedback
23
LMP7701, LMP7702, LMP7704
SNOSAI9H – SEPTEMBER 2005 – REVISED MARCH 2013
www.ti.com
REVISION HISTORY
Changes from Revision G (March 2013) to Revision H
•
24
Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 23
Submit Documentation Feedback
Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LMP7701 LMP7702 LMP7704
PACKAGE OPTION ADDENDUM
www.ti.com
1-Nov-2013
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Op Temp (°C)
Device Marking
(4/5)
LMP7701MA/NOPB
ACTIVE
SOIC
D
8
95
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
LMP77
01MA
LMP7701MAX/NOPB
ACTIVE
SOIC
D
8
2500
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
LMP77
01MA
LMP7701MF
NRND
SOT-23
DBV
5
1000
TBD
Call TI
Call TI
-40 to 125
AC2A
LMP7701MF/NOPB
ACTIVE
SOT-23
DBV
5
1000
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
AC2A
LMP7701MFX
NRND
SOT-23
DBV
5
3000
TBD
Call TI
Call TI
-40 to 125
AC2A
LMP7701MFX/NOPB
ACTIVE
SOT-23
DBV
5
3000
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
AC2A
LMP7702MA/NOPB
ACTIVE
SOIC
D
8
95
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
LMP77
02MA
LMP7702MAX/NOPB
ACTIVE
SOIC
D
8
2500
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
LMP77
02MA
LMP7702MM
NRND
VSSOP
DGK
8
1000
TBD
Call TI
Call TI
-40 to 125
AA3A
LMP7702MM/NOPB
ACTIVE
VSSOP
DGK
8
1000
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
AA3A
LMP7702MMX/NOPB
ACTIVE
VSSOP
DGK
8
3500
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
-40 to 125
AA3A
LMP7704MA/NOPB
ACTIVE
SOIC
D
14
55
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
LMP7704
MA
LMP7704MAX/NOPB
ACTIVE
SOIC
D
14
2500
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
LMP7704
MA
LMP7704MT
NRND
TSSOP
PW
14
94
TBD
Call TI
Call TI
-40 to 125
LMP77
04MT
LMP7704MT/NOPB
ACTIVE
TSSOP
PW
14
94
Pb-Free
(RoHS)
CU SN
Level-1-260C-UNLIM
-40 to 125
LMP77
04MT
LMP7704MTX/NOPB
ACTIVE
TSSOP
PW
14
2500
Pb-Free
(RoHS)
CU SN
Level-1-260C-UNLIM
-40 to 125
LMP77
04MT
(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.
Addendum-Page 1
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
1-Nov-2013
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3)
MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4)
There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5)
Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
(6)
Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish
value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
23-Sep-2013
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) Quadrant
LMP7701MAX/NOPB
SOIC
D
8
2500
330.0
12.4
6.5
5.4
2.0
8.0
12.0
Q1
LMP7701MF
SOT-23
DBV
5
1000
178.0
8.4
3.2
3.2
1.4
4.0
8.0
Q3
LMP7701MF/NOPB
SOT-23
DBV
5
1000
178.0
8.4
3.2
3.2
1.4
4.0
8.0
Q3
LMP7701MFX
SOT-23
DBV
5
3000
178.0
8.4
3.2
3.2
1.4
4.0
8.0
Q3
LMP7701MFX/NOPB
SOT-23
DBV
5
3000
178.0
8.4
3.2
3.2
1.4
4.0
8.0
Q3
LMP7702MAX/NOPB
SOIC
D
8
2500
330.0
12.4
6.5
5.4
2.0
8.0
12.0
Q1
LMP7702MM
VSSOP
DGK
8
1000
178.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
LMP7702MM/NOPB
VSSOP
DGK
8
1000
178.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
LMP7702MMX/NOPB
VSSOP
DGK
8
3500
330.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
LMP7704MAX/NOPB
SOIC
D
14
2500
330.0
16.4
6.5
9.35
2.3
8.0
16.0
Q1
LMP7704MTX/NOPB
TSSOP
PW
14
2500
330.0
12.4
6.95
8.3
1.6
8.0
12.0
Q1
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
23-Sep-2013
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
LMP7701MAX/NOPB
SOIC
D
8
2500
367.0
367.0
35.0
LMP7701MF
SOT-23
DBV
5
1000
210.0
185.0
35.0
LMP7701MF/NOPB
SOT-23
DBV
5
1000
210.0
185.0
35.0
LMP7701MFX
SOT-23
DBV
5
3000
210.0
185.0
35.0
LMP7701MFX/NOPB
SOT-23
DBV
5
3000
210.0
185.0
35.0
LMP7702MAX/NOPB
SOIC
D
8
2500
367.0
367.0
35.0
LMP7702MM
VSSOP
DGK
8
1000
210.0
185.0
35.0
LMP7702MM/NOPB
VSSOP
DGK
8
1000
210.0
185.0
35.0
LMP7702MMX/NOPB
VSSOP
DGK
8
3500
367.0
367.0
35.0
LMP7704MAX/NOPB
SOIC
D
14
2500
367.0
367.0
35.0
LMP7704MTX/NOPB
TSSOP
PW
14
2500
367.0
367.0
35.0
Pack Materials-Page 2
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other
changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest
issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and
complete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of sale
supplied at the time of order acknowledgment.
TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s terms
and conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessary
to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily
performed.
TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products and
applications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or
other intellectual property right relating to any combination, machine, or process in which TI components or services are used. Information
published by TI regarding third-party products or services does not constitute a license to use such products or services or a warranty or
endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the
third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alteration
and is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altered
documentation. Information of third parties may be subject to additional restrictions.
Resale of TI components or services with statements different from or beyond the parameters stated by TI for that component or service
voids all express and any implied warranties for the associated TI component or service and is an unfair and deceptive business practice.
TI is not responsible or liable for any such statements.
Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements
concerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or support
that may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which
anticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might cause
harm and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the use
of any TI components in safety-critical applications.
In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is to
help enable customers to design and create their own end-product solutions that meet applicable functional safety standards and
requirements. Nonetheless, such components are subject to these terms.
No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties
have executed a special agreement specifically governing such use.
Only those TI components which TI has specifically designated as military grade or “enhanced plastic” are designed and intended for use in
military/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI components
which have not been so designated is solely at the Buyer's risk, and that Buyer is solely responsible for compliance with all legal and
regulatory requirements in connection with such use.
TI has specifically designated certain components as meeting ISO/TS16949 requirements, mainly for automotive use. In any case of use of
non-designated products, TI will not be responsible for any failure to meet ISO/TS16949.
Products
Applications
Audio
www.ti.com/audio
Automotive and Transportation
www.ti.com/automotive
Amplifiers
amplifier.ti.com
Communications and Telecom
www.ti.com/communications
Data Converters
dataconverter.ti.com
Computers and Peripherals
www.ti.com/computers
DLP® Products
www.dlp.com
Consumer Electronics
www.ti.com/consumer-apps
DSP
dsp.ti.com
Energy and Lighting
www.ti.com/energy
Clocks and Timers
www.ti.com/clocks
Industrial
www.ti.com/industrial
Interface
interface.ti.com
Medical
www.ti.com/medical
Logic
logic.ti.com
Security
www.ti.com/security
Power Mgmt
power.ti.com
Space, Avionics and Defense
www.ti.com/space-avionics-defense
Microcontrollers
microcontroller.ti.com
Video and Imaging
www.ti.com/video
RFID
www.ti-rfid.com
OMAP Applications Processors
www.ti.com/omap
TI E2E Community
e2e.ti.com
Wireless Connectivity
www.ti.com/wirelessconnectivity
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2013, Texas Instruments Incorporated
Similar pages