Linear Technology LT1920 Datasheet

FEATURES

■

Single Gain Set Resistor: G = 1 to 10,000

■

Gain Error: G = 10, 0.3% Max

■

Gain Nonlinearity: G = 10, 30ppm Max

■

Input Offset Voltage: G = 10, 225µV Max

■

Input Offset Voltage Drift: 1µV/°C Max

■

Input Bias Current: 2nA Max

■

PSRR at G = 1: 80dB Min

■

CMRR at G = 1: 75dB Min

■

Supply Current: 1.3mA Max

■

Wide Supply Range: ±2.3V to ±18V

■

1kHz Voltage Noise: 7.5nV/√Hz

■

0.1Hz to 10Hz Noise: 0.28µV

■

Available in 8-Pin PDIP and SO Packages

■

Meets IEC 1000-4-2 Level 4 ESD Tests with

P-P

Two External 5k Resistors

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APPLICATIO S

■

Bridge Amplifiers

■

Strain Gauge Amplifiers

■

Thermocouple Amplifiers

■

Differential to Single-Ended Converters

■

Medical Instrumentation

LT1920

Single Resistor Gain

Programmable, Precision

Instrumentation Amplifier

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DESCRIPTIO

The LT®1920 is a low power, precision instrumentation
amplifier that requires only one external resistor to set gains
of 1 to 10,000. The low voltage noise of 7.5nV/√Hz (at 1kHz)
is not compromised by low power dissipation (0.9mA typical
for ±2.3V to ±15V supplies).

The high accuracy of 30ppm maximum nonlinearity and

0.3% max gain error (G = 10) is not degraded even for load
resistors as low as 2k (previous monolithic instrumentation
amps used 10k for their nonlinearity specifications). The
LT1920 is laser trimmed for very low input offset voltage
(125µV max), drift (1µV/°C), high CMRR (75dB, G = 1) and
PSRR (80dB, G = 1). Low input bias currents of 2nA max are
achieved with the use of superbeta processing. The output
can handle capacitive loads up to 1000pF in any gain configu­ration while the inputs are ESD protected up to 13kV (human
body). The LT1920 with two external 5k resistors passes the
IEC 1000-4-2 level 4 specification.

The LT1920, offered in 8-pin PDIP and SO packages, is a pin
for pin and spec for spec improved replacement for the
AD620. The LT1920 is the most cost effective solution for
precision instrumentation amplifier applications. For even
better guaranteed performance, see the LT1167.

, LTC and LT are registered trademarks of Linear Technology Corporation.

TYPICAL APPLICATIO

Single Supply Barometer

V

S

LT1634CCZ-1.25

392k

R5

3

8

+

2

R8

100k

–

1/2

LT1490

5

6

4

+

LT1490

–

50k

50k

1

2

R4

R3

1

R6
1k

1/2

LUCAS NOVA SENOR

NPC-1220-015-A-3L

4

5k

5k

2

6

R

SET

7

R7

50k

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Gain Nonlinearity

V

S

R1
825Ω

R2
12Ω

–

2
1

8
3

7

5

VOLTS

2.800

3.000

3.200

6

INCHES Hg

TO
4-DIGIT
DVM

28.00

30.00

32.00

1920 TA01

NONLINEARITY (100ppm/DIV)

OUTPUT VOLTAGE (2V/DIV)

G = 1000

= 1k

R

L

= ±10V

V

OUT

1167 TA02

LT1920

G = 60

+

4

1

–

5k

5k

3

+

5

VS = 8V TO 30V

1

LT1920

WW

W

ABSOLUTE MAXIMUM RATINGS

(Note 1)

Supply Voltage ...................................................... ±20V

Differential Input Voltage (Within the

Supply Voltage) ..................................................... ±40V

Input Voltage (Equal to Supply Voltage) ................±20V

Input Current (Note 3) ........................................ ±20mA

Output Short-Circuit Duration..........................Indefinite

Operating Temperature Range ................ – 40°C to 85°C

Specified Temperature Range

LT1920C (Note 4)....................................0°C to 70°C

LT1920I .............................................. – 40°C to 85°C

Storage Temperature Range ................. – 65°C to 150°C

Lead Temperature (Soldering, 10 sec).................. 300°C

ELECTRICAL CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS (Note 6) MIN TYP MAX UNITS

G Gain Range G = 1 + (49.4k/RG) 1 10k

Gain Error G = 1 0.008 0.1 %

G/T Gain vs Temperature G < 1000 (Note 2) ● 20 50 ppm/°C

Gain Nonlinearity (Note 5) VO = ±10V, G = 1 10 ppm

V

OST

V

OSI

V

/T Input Offset Drift (RTI) (Note 3) ● 1 µV/°C

OSI

V

OSO

V

/T Output Offset Drift (Note 3) ● 515µV/°C

OSO

I

OS

I

B

e

n

Total RTI Noise = √e
e

ni

e

no

i

n

R

IN

C

IN(DIFF)

Total Input Referred Offset Voltage V
Input Offset Voltage G = 1000, VS = ±5V to ±15V 30 125 µV

Output Offset Voltage G = 1, VS = ±5V to ±15V 400 1000 µV

Input Offset Current 0.3 1 nA
Input Bias Current 0.5 2 nA
Input Noise Voltage, RTI 0.1Hz to 10Hz, G = 1 2.00 µV

2

+ (eno/G)

ni

Input Noise Voltage Density, RTI fO = 1kHz 7.5 nV/√Hz
Output Noise Voltage Density, RTI fO = 1kHz 67 nV/√Hz
Input Noise Current fO = 0.1Hz to 10Hz 10 pA
Input Noise Current Density fO = 10Hz 124 fA/√Hz
Input Resistance VIN = ±10V 200 GΩ
Differential Input Capacitance fO = 100kHz 1.6 pF

2

U

U

W

PACKAGE/ORDER INFORMATION

TOP VIEW



R

1

G

–IN
+IN

–V

T

JMAX

T

JMAX

Consult factory for Military grade parts.

–

2

+

3
4

S

N8 PACKAGE
8-LEAD PDIP

S8 PACKAGE

8-LEAD PLASTIC SO

= 150°C, θJA = 130°C/ W (N8)
= 150°C, θJA = 190°C/ W (S8)

8
7
6
5



RG



+V

S

OUTPUT
REF

VS = ±15V, VCM = 0V, TA = 25°C, RL = 2k, unless otherwise noted.

G = 10 (Note 2) 0.010 0.3 %
G = 100 (Note 2) 0.025 0.3 %
G = 1000 (Note 2) 0.040 0.35 %

V

= ±10V, G = 10 and 100 10 30 ppm

O

V

= ±10V, G = 100 and 1000 20 ppm

O

= V

+ V

OST

OSI

G = 1000, V

G = 1, V

0.1Hz to 10Hz, G = 10 0.50 µV

0.1Hz to 10Hz, G = 100 and 1000 0.28 µV

= ±5V to ±15V ● 1500 µV

S

/G

OSO

= ±5V to ±15V ● 185 µV

S

ORDER PART

NUMBER

LT1920CN8
LT1920CS8
LT1920IN8
LT1920IS8

S8 PART MARKING

1920
1920I

P-P
P-P
P-P

P-P

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2

LT1920

ELECTRICAL CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS (Note 6) MIN TYP MAX UNITS

C

IN(CM)

V

CM

CMRR Common Mode Rejection Ratio 1k Source Imbalance,

PSRR Power Supply Rejection Ratio VS = ±2.3 to ±18V

I

S

V

OUT

I

OUT

BW Bandwidth G = 1 1000 kHz

SR Slew Rate G = 1, V

R

REFIN

I

REFIN

V

REF

A

VREF

The ● denotes specifications that apply over the full specified
temperature range.

Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.

Note 2: Does not include the effect of the external gain resistor R
Note 3: This parameter is not 100% tested.
Note 4: The LT1920C is designed, characterized and expected to meet the

industrial temperature limits, but is not tested at –40°C and 85°C. I-grade
parts are guaranteed.

Common Mode Input Capacitance fO = 100kHz 1.6 pF
Input Voltage Range G = 1, Other Input Grounded

V

S

V

S

V

S

V

S

V

= 0V to ±10V

CM

G = 1 75 95 dB
G = 10 95 115 dB
G = 100 110 125 dB
G = 1000 110 140 dB

G = 1 80 120 dB
G = 10 100 135 dB
G = 100 120 140 dB

G = 1000 120 150 dB
Supply Current VS = ±2.3V to ±18V 0.9 1.3 mA
Output Voltage Swing RL = 10k

V

S

V

S

V

S

V

S

Output Current 20 27 mA

G = 10 800 kHz
G = 100 120 kHz
G = 1000 12 kHz

Settling Time to 0.01% 10V Step

G = 1 to 100 14 µs

G = 1000 130 µs
Reference Input Resistance 20 kΩ
Reference Input Current V
Reference Voltage Range –VS + 1.6 +VS – 1.6 V
Reference Gain to Output 1 ± 0.0001

REF

VS = ±15V, VCM = 0V, TA = 25°C, RL = 2k, unless otherwise noted.

= ±2.3V to ±5V –VS + 1.9 +VS – 1.2 V
= ±5V to ±18V –VS + 1.9 +VS – 1.4 V
= ±2.3V to ±5V ● –VS + 2.1 +VS – 1.3 V
= ±5V to ±18V ● –VS + 2.1 +VS – 1.4 V

= ±2.3V to ±5V –VS + 1.1 +VS – 1.2 V
= ±5V to ±18V –VS + 1.2 +VS – 1.3 V
= ±2.3V to ±5V ● –VS + 1.4 +VS – 1.3 V
= ±5V to ±18V ● –VS + 1.6 +VS – 1.5 V

= ±10V 1.2 V/µs

OUT

= 0V 50 µA

Note 5: This parameter is measured in a high speed automatic tester that
does not measure the thermal effects with longer time constants. The
magnitude of these thermal effects are dependent on the package used,
heat sinking and air flow conditions.

.

G

Note 6: Typical parameters are defined as the 60% of the yield parameter
distribution.

3

LT1920

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Gain Nonlinearity, G = 1

NONLINEARITY (1ppm/DIV)

OUTPUT VOLTAGE (2V/DIV)G = 1

= 2k

R

L

= ±10V

V

OUT

Gain Nonlinearity, G = 1000

NONLINEARITY (100ppm/DIV)

OUTPUT VOLTAGE (2V/DIV)

G = 1000
R

= 2k

L

= ±10V

V

OUT

1167 G01

1167 G04

Gain Nonlinearity, G = 10

NONLINEARITY (10ppm/DIV)

G = 10
R
V

OUTPUT VOLTAGE (2V/DIV)

= 2k

L

= ±10V

OUT

Gain Error vs Temperature

0.20

0.15

0.10

0.05

0

–0.05

VS = ±15V

GAIN ERROR (%)

–0.10

–0.15

–0.20

= ±10V

V

OUT

= 2k

R

L

*DOES NOT INCLUDE
 TEMPERATURE EFFECTS
 OF R

G

–50

0

–25

TEMPERATURE (°C)

1167 G02

G = 1

G = 10*

G = 100*

G = 1000*

25 100

75

50

1920 G06

Gain Nonlinearity, G = 100

NONLINEARITY (10ppm/DIV)

OUTPUT VOLTAGE (2V/DIV)

G = 100
R

= 2k

L

= ±10V

V

OUT

Warm-Up Drift

14

VS = ±15V

= 25°C

T

A

12

G = 1

10

8

6

4

CHANGE IN OFFSET VOLTAGE (µV)

2

0

12 5

0

TIME AFTER POWER ON (MINUTES)

1167 G03

S8

N8

34

1920 G09

Input Bias Current
vs Common Mode Input Voltage

500
400
300
200
100

0

–100

–200

INPUT BIAS CURRENT (pA)

–300
–400
–500

–12 12

–15

COMMON MODE INPUT VOLTAGE (V)

–9

–6

85°C

0°C

–40°C

–3

0

4

3

70°C

25°C

Common Mode Rejection Ratio
vs Frequency

160

G = 1000

140

G = 100
G = 10

120

G = 1

100

80

60

40

20

COMMON MODE REJECTION RATIO (dB)

0

6

9

15

1920 G13

110 1k

0.1
FREQUENCY (Hz)

100

VS = ±15V

= 25°C

T

A

1k SOURCE
IMBALANCE

10k

1920 G14

100k

Negative Power Supply Rejection
Ratio vs Frequency

160

G = 100

140

G = 10

120

G = 1

100

80

60

40

20

0

NEGATIVE POWER SUPPLY REJECTION RATIO (dB)

110 1k

0.1
FREQUENCY (Hz)

100

V+ = 15V

= 25°C

T

A

G = 1000

10k

1920 G15

100k