NSC LMP7731MF, LMP7731 Datasheet

July 2007

LMP7731

2.9 nV/sqrt(Hz) Low Noise, Precision, RRIO, Operational
Amplifier in SOT23-5

General Description

The LMP7731 is a single, low noise, low offset voltage, rail­to-rail input and output, low voltage precision amplifier. The
LMP7731 is part of the LMP® precision amplifier family and is
ideal for precision and low noise applications with low voltage
requirements.

This operational amplifier offers low voltage noise of 2.9 nV/

with a 1/f corner of only 3 Hz and low DC offset with a
maximum value of ±40 µV, targeting high accuracy, low fre­quency applications. The LMP7731 has bipolar input stages
with a bias current of only 1.5 nA. This low input bias current,
complemented by the very low AC and DC levels of voltage
noise, makes the LMP7731 an excellent choice for photom­etry applications.

The LMP7731 provides a wide GBW of 22 MHz while con­suming only 2 mA of current. This high gain bandwidth along
with the high open loop gain of 130 dB enables accurate sig­nal conditioning in applications with high closed loop gain
requirements.

The LMP7731 has a supply voltage range of 1.8V to 5.5V,
making it an ideal choice for battery operated portable appli­cations.

The LMP7731 is offered in a 5-pin SOT23 package.

Features

(Typical values, TA = 25°C, VS = 5V)

■

Input voltage noise

—

f = 3 Hz 3.3 nV/√Hz

—

f = 1 kHz 2.9 nV/√Hz

■

Offset voltage (max) ±40 µV

■

Offset voltage drift (max) ±1.0 µV/°C

■

CMRR 130 dB

■

Open loop gain 130 dB

■

GBW 22 MHz

■

Slew rate 2.4 V/µs

■

THD @ f = 10 kHz, AV = +1, RL = 2 kΩ 0.001%

■

Supply current per channel 2.2 mA

■

Supply voltage range 1.8V to 5.5V

■

Operating temperature range −40°C to 125°C

■

Input bias current ±1.5 nA

■

RRIO

■

5-Pin SOT23 package

Applications

■

Thermopile amplifier

■

Gas analysis instruments

■

Photometric instrumentation

■

Medical instrumentation

Typical Application

Thermopile Signal Amplifier

20175201

LMP® is a registered trademark of National Semiconductor Corporation.

© 2007 National Semiconductor Corporation 201752 www.national.com

LMP7731, Low Noise, Precision, RRIO, Amplifier in SOT23–5

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

ESD Tolerance (Note 2)
Human Body Model
Inputs pins only 2000V
All other pins 2000V
Machine Model 200V
Charge Device Model 1000V
VIN Differential

±2V

Supply Voltage (VS = V+ – V−)

6.0V

Storage Temperature Range −65°C to 150°C
Junction Temperature (Note 3) +150°C max
Soldering Information
Infrared or Convection (20 sec) 235°C
Wave Soldering Lead Temp. (10 sec) 260°C

Operating Ratings (Note 1)

Temperature Range −40°C to 125°C
Supply Voltage (VS = V+ – V–)

1.8V to 5.5V

Package Thermal Resistance (θJA)

5-Pin SOT23 265°C/W

2.5V Electrical Characteristics (Note 4)

Unless otherwise specified, all limits are guaranteed for TA = 25°C, V+ = 2.5V, V− = 0V, VCM = V+/2, RL >10 kΩ to V+/2. Bold­face limits apply at the temperature extremes.

Symbol Parameter Conditions Min

(Note 6)

Typ

(Note 5)

Max

(Note 6)

Units

V

OS

Input Offset Voltage
(Note 7)

VCM = 2.0V ±9 ±50

±120

μV

VCM = 0.5V ±9 ±40

±100

TCV

OS

Input Offset Voltage Drift VCM = 2.0V ±0.5 ±1.0

μV/°C

VCM = 0.5V ±0.2 ±0.8

Input Offset Voltage Time Drift VCM = 0.5V and VCM = 2.0V 0.35

μV/month

I

B

Input Bias Current VCM = 2.0V ±1 ±30

±45

nA

VCM = 0.5V ±12 ±50

±75

I

OS

Input Offset Current VCM = 2.0V ±1 ±50

±75

nA

VCM = 0.5V ±11 ±60

±80

TCI

OS

Input Offset Current Drift VCM = 0.5V and VCM = 2.0V 0.0474 nA/°C

CMRR Common Mode Rejection Ratio

0.15V ≤ VCM ≤ 0.7V

0.23V ≤ VCM ≤ 0.7V

101

89

120

dB

1.5V ≤ VCM ≤ 2.35V

1.5V ≤ VCM ≤ 2.27V

105

99

129

PSRR Power Supply Rejection Ratio

2.5V ≤ V+ ≤ 5V

111

105

129

dB

1.8V ≤ V+ ≤ 5.5V

117

CMVR Input Common-Mode Voltage

Range

Large Signal CMRR ≥ 80 dB

0 2.5

V

A

VOL

Large Signal Voltage Gain

RL = 10 kΩ to V+/2
VO = 0.5V to 2.0V

112

104

130

dB

RL = 2 kΩ to V+/2
VO = 0.5V to 2.0V

109

90

119

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LMP7731

Symbol Parameter Conditions Min

(Note 6)

Typ

(Note 5)

Max

(Note 6)

Units

V

O

Output Swing High

RL = 10 kΩ to V+/2

4 50

75

mV

from either

rail

RL = 2 kΩ to V+/2

13 50

75

Output Swing Low

RL = 10 kΩ to V+/2

6 50

75

RL = 2 kΩ to V+/2

9 50

75

I

O

Output Short Circuit Current Sourcing, VO = V+/2

VIN (diff) = 100 mV

22

12

31

mA

Sinking, VO = V+/2
VIN (diff) = −100 mV

15

10

44

I

S

Supply Current
(Per Channel)

VCM = 2.0V 2.0 2.7

3.4

mA

VCM = 0.5V 2.3 3.1

3.9

SR Slew Rate

AV = +1, CL = 10 pF, RL = 10 kΩ to V+/2,
VO = 2 V

PP

2.4

V/μs

GBW Gain Bandwidth Product

CL = 20 pF, RL = 10 kΩ to V+/2

21 MHz

G

M

Gain Margin

CL = 20 pF, RL = 10 kΩ to V+/2

14 dB

Φ

M

Phase Margin

CL = 20 pF, RL = 10 kΩ to V+/2

60 deg

R

IN

Input Resistance Differential Mode 38

kΩ

Common Mode 151

MΩ

THD+N Total Harmonic Distortion AV = 1, f = 1 kHz, Amplitude = 1V 0.002 %

e

n

Input-Referred Voltage Noise f = 1 kHz, VCM = 2.0V 3

nV/

f = 1 kHz, VCM = 0.5V 3

0.1 Hz to 10 Hz 75 nV

PP

i

n

Input-Referred Current Noise f = 1 kHz, VCM = 2.0V 1.1

pA/

f = 1 kHz, VCM = 0.5V 2.3

3.3V Electrical Characteristics (Note 4)

Unless otherwise specified, all limits are guaranteed for TA = 25°C, V+ = 3.3V, V− = 0V, VCM = V+/2, RL > 10 kΩ to V+/2. Bold­face limits apply at the temperature extremes.

Symbol Parameter Conditions Min

(Note 6)

Typ

(Note 5)

Max

(Note 6)

Units

V

OS

Input Offset Voltage
(Note 7)

VCM = 2.5V ±6 ±50

±120

μV

VCM = 0.5V ±6 ±40

±100

TCV

OS

Input Offset Voltage Drift VCM = 2.5V ±0.5 ±1.0

μV/°C

VCM = 0.5V ±0.2 ±0.8

Input Offset Voltage Time Drift VCM = 0.5V and VCM = 2.5V 0.35

μV/month

I

B

Input Bias Current VCM = 2.5V ±1.5 ±30

±45

nA

VCM = 0.5V ±13 ±50

±77

I

OS

Input Offset Current VCM = 2.5V ±1 ±50

±70

nA

VCM = 0.5V ±11 ±60

±80

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LMP7731

Symbol Parameter Conditions Min

(Note 6)

Typ

(Note 5)

Max

(Note 6)

Units

TCI

OS

Input Offset Current Drift VCM = 0.5V and VCM = 2.5V

0.048 nA/°C

CMRR Common Mode Rejection Ratio

0.15V ≤ VCM ≤ 0.7V

0.23V ≤ VCM ≤ 0.7V

101

89

120

dB

1.5V ≤ VCM ≤ 3.15V

1.5V ≤ VCM ≤ 3.07V

105

99

130

PSRR Power Supply Rejection Ratio

2.5V ≤ V+ ≤ 5.0V

111

105

129

dB

1.8V ≤ V+ ≤ 5.5V

117

CMVR Input Common-Mode Voltage

Range

Large Signal CMRR ≥ 80 dB

0 3.3

V

A

VOL

Large Signal Voltage Gain

RL = 10 kΩ to V+/2
VO = 0.5V to 2.8V

112

104

130

dB

RL = 2 kΩ to V+/2
VO = 0.5V to 2.8V

110

92

119

V

O

Output Swing High

RL = 10 kΩ to V+/2

5 50

75

mV

from either

rail

RL = 2 kΩ to V+/2

14 50

75

Output Swing Low

RL = 10 kΩ to V+/2

9 50

75

RL = 2 kΩ to V+/2

13 50

75

I

O

Output Short Circuit Current Sourcing, VO = V+/2

VIN (diff) = 100 mV

28

22

45

mA

Sinking, VO = V+/2
VIN (diff) = -100 mV

25

20

48

I

S

Supply Current
(Per Channel)

VCM = 2.5V 2.1 2.8

3.5

mA

VCM = 0.5V 2.4 3.2

4.0

SR Slew Rate

AV = +1, CL = 10 pF, RL = 10 kΩ to V+/2,
VO = 2 V

PP

2.4

V/μs

GBW Gain Bandwidth Product

CL = 20 pF, RL = 10 kΩ to V+/2

22 MHz

G

M

Gain Margin

CL = 20 pF, RL = 10 kΩ to V+/2

14 dB

Φ

M

Phase Margin

CL = 20 pF, RL = 10 kΩ to V+/2

62 deg

R

IN

Input Resistance Differential Mode 38

kΩ

Common Mode 151

MΩ

THD+N Total Harmonic Distortion AV = 1, f = 1 kHz, Amplitude = 1V, 0.002 %

e

n

Input-Referred Voltage Noise f = 1 kHz, VCM = 2.5V 2.9

nV/

f = 1 kHz, VCM = 0.5V 2.9

0.1 Hz to 10 Hz 65 nV

PP

i

n

Input-Referred Current Noise f = 1 kHz, VCM = 2.5V 1.1

pA/

f = 1 kHz, VCM = 0.5V 2.1

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LMP7731

5V Electrical Characteristics (Note 4)

Unless otherwise specified, all limits are guaranteed for TA = 25°C, V+ = 5V, V− = 0V, VCM = V+/2, RL > 10 kΩ to V+/2. Boldface
limits apply at the temperature extremes.

Symbol Parameter Conditions Min

(Note 6)

Typ

(Note 5)

Max

(Note 6)

Units

V

OS

Input Offset Voltage
(Note 7)

VCM = 4.5V ±6 ±50

±120

μV

VCM = 0.5V ±6 ±40

±100

TCV

OS

Input Offset Voltage Drift VCM = 4.5V ±0.5 ±1.0

μV/°C

VCM = 0.5V ±0.2 ±0.8

Input Offset Voltage Time Drift VCM = 0.5V and VCM = 4.5V 0.35

μV/month

I

B

Input Bias Current VCM = 4.5V ±1.5 ±30

±50

nA

VCM = 0.5V ±14 ±50

±85

I

OS

Input Offset Current VCM = 4.5V ±1 ±50

±70

nA

VCM = 0.5V ±11 ±65

±80

TCI

OS

Input Offset Current Drift VCM = 0.5V and VCM = 4.5V 0.0482 nA/°C

CMRR Common Mode Rejection Ratio

0.15V ≤ VCM ≤ 0.7V

0.23V ≤ VCM ≤ 0.7V

101

89

120

dB

1.5V ≤ VCM ≤ 4.85V

1.5V ≤ VCM ≤ 4.77V

105

99

130

PSRR Power Supply Rejection Ratio

2.5V ≤ V+ ≤ 5V

111

105

129

dB

1.8V ≤ V+ ≤ 5.5V

117

CMVR Input Common-Mode Voltage

Range

Large Signal CMRR ≥ 80 dB

0 5

V

A

VOL

Large Signal Voltage Gain

RL = 10 kΩ to V+/2
VO = 0.5V to 4.5V

112

104

130

dB

RL = 2 kΩ to V+/2
VO = 0.5V to 4.5V

110

94

119

V

O

Output Swing High

RL = 10 kΩ to V+/2

8 50

75

mV

from either

rail

RL = 2 kΩ to V+/2

24 50

75

Output Swing Low

RL = 10 kΩ to V+/2

9 50

75

RL = 2 kΩ to V+/2

23 50

75

I

O

Output Short Circuit Current Sourcing, VO = V+/2

VIN (diff) = 100 mV

33

27

47

mA

Sinking, VO = V+/2
VIN (diff) = -100 mV

30

25

49

I

S

Supply Current
(Per Channel)

VCM = 4.5V 2.2 3.0

3.7

mA

VCM = 0.5V 2.5 3.4

4.2

SR Slew Rate

AV = +1, CL = 10 pF, RL = 10 kΩ to V+/2,
VO = 2 V

PP

2.4

V/μs

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LMP7731

Symbol Parameter Conditions Min

(Note 6)

Typ

(Note 5)

Max

(Note 6)

Units

GBW Gain Bandwidth Product

CL = 20 pF, RL = 10 kΩ to V+/2

22 MHz

G

M

Gain Margin

CL = 20 pF, RL = 10 kΩ to V+/2

12 dB

Φ

M

Phase Margin

CL = 20 pF, RL = 10 kΩ to V+/2

65 deg

R

IN

Input Resistance Differential Mode 38

kΩ

Common Mode 151

MΩ

THD+N Total Harmonic Distortion AV = 1, f = 1 kHz, Amplitude = 1V 0.001 %

e

n

Input-Referred Voltage Noise f = 1 kHz, VCM = 4.5V 2.9

nV/

f = 1 kHz, VCM = 0.5V 2.9

0.1 Hz to 10 Hz 78 nV

PP

i

n

Input-Referred Current Noise f = 1 kHz, VCM = 4.5V 1.1

pA/

f = 1 kHz, VCM = 0.5V 2.2

Note 1: 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 guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics
Tables.

Note 2: 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).

Note 3: The maximum power dissipation is a function of T

J(MAX)

, θJA. The maximum allowable power dissipation at any ambient temperature is

PD = (T

J(MAX)

– TA)/ θJA. All numbers apply for packages soldered directly onto a PC Board.

Note 4: 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 guarantee of parametric performance is indicated in the electrical tables under conditions of internal self-heating where TJ >
TA. Absolute maximum Ratings indicate junction temperature limits beyond which the device maybe permanently degraded, either mechanically or electrically.

Note 5: 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 guaranteed on shipped production material.

Note 6: All limits are guaranteed by testing, statistical analysis or design.

Note 7: Ambient production test is performed at 25°C with a variance of ±3°C.

Connection Diagram

5-Pin SOT23

20175202

Top View

Ordering Information

Package Part Number Package Marking Transport Media NSC Drawing

5-Pin SOT23

LMP7731MF

AY3A

1k Units Tape and Reel

MF05A

LMP7731MFX 3k Units Tape and Reel

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LMP7731