Linear Technology LTC1250 Datasheet

LTC1250

Very Low Noise

Zero-Drift Bridge Amplifier

EATU

F

■

Very Low Noise: 0.75µV

■

DC to 1Hz Noise Lower Than OP-07

■

Full Output Swing into 1k Load

■

Offset Voltage: 10µV Max

■

Offset Voltage Drift: 50nV/°C Max

■

Common-Mode Rejection Ratio: 110dB Min

■

Power Supply Rejection Ratio: 115dB Min

■

No External Components Required

■

Pin-Compatible with Standard 8-Pin Op Amps

PPLICATI

A

■

Electronic Scales

■

Strain Gauge Amplifiers

■

Thermocouple Amplifiers

■

High Resolution Data Acquisition

■

Low Noise Transducers

■

Instrumentation Amplifiers

RE

S

O

U
S

Typ, 0.1Hz to 10Hz

P-P

DUESCRIPTIO

The LTC®1250 is a high performance, very low noise zero­drift operational amplifier. The LTC1250’s combination of
low front-end noise and DC precision makes it ideal for use
with low impedance bridge transducers. The LTC1250
features typical input noise of 0.75µV
10Hz, and 0.2µ V
DC to 1Hz noise of 0.35µ V

from 0.1Hz to 1Hz. The LTC1250 has

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, surpassing that of low noise

P-P

bipolar parts including the OP-07, OP-77, and LT1012.
The LTC1250 uses the industry-standard single op amp
pinout, and requires no external components or nulling
signals, allowing it to be a plug-in replacement for bipolar
op amps.

The LTC1250 incorporates an improved output stage
capable of driving 4.3V into a 1k load with a single 5V
supply; it will swing ±4.9V into 5k with ±5V supplies. The
input common mode range includes ground with single
power supply voltages above 12V. Supply current is 3mA
with a ±5V supply, and overload recovery times from
positive and negative saturation are 0.5ms and 1.5ms,
respectively. The internal nulling clock is set at 5kHz for
optimum low frequency noise and offset drift; no external
connections are necessary.

from 0.1Hz to

P-P

and LTC are registered trademarks and LT is a trademark of Linear Technology Corporation.

U

O

A

PPLICATITYPICAL

Differential Bridge Amplifier

2

3

18.2k

–

LTC1250

+

5V

1000pF

18.2k

7

6

4

–5V

5V

350Ω

STRAIN

GAUGE

–5V

50Ω
GAIN
TRIM

0.1µF

1000pF

The LTC1250 is available in standard 8-pin ceramic and
plastic DIPs, as well as an 8-pin SOIC package.

Input Referred Noise 0.1Hz to 10Hz

2

VS = ±5V

= 10k

A

V

1

0

µV

A

= 100

V

1250 TA01

–2

–1

2

0

4

TIME (s)

6

8

10

LT1250 TA02

1

LTC1250

W

O

A

LUTEXI T

S

Total Supply Voltage (V+ to V–) ............................. 18V

Input Voltage ........................ (V+ + 0.3V) to (V– – 0.3V)

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

Operating Temperature Range

LTC1250M..................................... – 55°C to 125°C

LTC1250C .......................................... 0°C TO 70°C

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

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

LECTRICAL C CHARA TERIST

E

SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

V

OS

∆V

e

n

i

n

I

B

I

OS

CMRR Common-Mode Rejection Ratio VCM = –4V to 3V ● 110 130 110 130 dB
PSRR Power Supply Rejection Ratio VS = ±2.375V to ±8V ● 115 130 115 130 dB
A

VOL

SR Slew Rate RL = 10k, CL = 50pF 10 10 V/µs
GBW Gain-Bandwidth Product 1.5 1.5 MHz
I

S

f

S

Input Offset Voltage TA = 25°C (Note 1) ±5 ±10 ±5 ±10 µV
Average Input Offset Drift (Note 1) ● ±0.01 ±0.05 ±0.01 ±0.05 µV/°C

OS

Long Term Offset Drift 50 50 nV/√Mo
Input Noise Voltage (Note 2) TA = 25°C, 0.1Hz to 10Hz 0.75 1.0 0.75 1.0 µV

Input Noise Current f = 10Hz 4.0 4.0 fA/√Hz
Input Bias Current TA = 25°C (Note 3) ±50 ±150 ±50 ±200 pA

Input Offset Current TA = 25°C (Note 3) ±100 ±300 ±100 ±400 pA

Large-Signal Voltage Gain RL = 10k, V
Maximum Output Voltage Swing R

Supply Current No Load, TA = 25°C 3.0 4.0 3.0 4.0 mA

Internal Sampling Frequency TA = 25°C 4.75 4.75 kHz

A

WUW

ARB

TA = 25°C, 0.1Hz to 1Hz 0.2 0.2 µV

= 1k ● ±4.0 4.3/–4.7 ±4.0 4.3/–4.7 V

L

RL = 100k ±4.92 ±4.95 V

U

/

G

S

I

ICS

VIN = ±5V, TA = Operating Temperature Range, unless otherwise noted.

= ±4V ● 125 170 125 170 dB

OUT

PACKAGE

NC

1

–IN

2

+IN

3

–

V

4

J8 PACKAGE

8-LEAD CERAMIC DIP

8-LEAD PLASTIC SOIC

T

JMAX

T

JMAX

T

JMAX

● ±950 ±450 pA

● ±500 ±500 pA

● 7.0 5.0 mA

O

RDER I FOR ATIO

TOP VIEW

NC

8

+



V

7

OUT

6

NC

5



N8 PACKAGE

8-LEAD PLASTIC DIP

S8 PACKAGE

= 150°C, θJA = 100°CW (J8)
= 110°C, θJA = 130°CW (N8)
= 110°C, θJA = 200°CW (S8)

LTC1250M LTC1250C

S8 PART MARKING

WU

ORDER PART

NUMBER

LTC1250MJ8
LTC1250CJ8
LTC1250CN8
LTC1250CS8

1250

U

P-P
P-P

VIN = 5V, TA = Operating Temperature Range, unless otherwise noted.

LTC1250M LTC1250C

SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

V
∆V
e

I
I

OS

n

B
OS

Input Offset Voltage TA = 25°C (Note 1) ±2 ±5 ±2 ±5 µV
Average Input Offset Drift (Note 1) ● ±0.01 ±0.05 ±0.01 ±0.05 µV/°C

OS

Input Noise Voltage (Note 2) TA = 25°C, 0.1Hz to 10Hz 1.0 1.0 µV

TA = 25°C, 0.1Hz to 1Hz 0.3 0.3 µV
Input Bias Current TA = 25°C (Note 3) ±20 ±100 ±20 ±100 pA
Input Offset Current TA = 25°C (Note 3) ±40 ±200 ±40 ±200 pA

P-P
P-P

2

LTC1250

TEMPERATURE (°C)

–50

SAMPLING FREQUENCY (kHz)

4

5

6

25

LTC1250 G06

3

2

–25 0 50

1

0

8

7

75 100 150

VS = ±5V

TOTAL SUPPLY VOLTAGE, V+ TO V– (V)

4

2

SAMPLING FREQUENCY (kHz)

3

4

681012

LTC1250 G03

5

6

14

16

TA = 25°C

LECTRICAL C CHARA TERIST

E

ICS

VIN = 5V, TA = Operating Temperature Range, unless otherwise noted.

LTC1250M LTC1250C

SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

Maximum Output Voltage Swing R

= 1k 4.0 4.3 4.0 4.3 V

L

RL = 100k 4.95 4.95 V

I

S

f

S

The ● denotes specifications which apply over the full operating
temperature range.

Note 1: These parametes are guaranteed by design. Thermocouple effects
preclude measurement of these voltage levels during automated testing.

Supply Current TA = 25°C 1.8 2.5 1.8 2.5 mA
Sampling Frequency TA = 25°C 3 3 kHz

filter at 0.1Hz. The LTC1250 is sample tested for noise; for 100% tested
parts contact LTC Marketing Dept.

Note 3: At T ≤ 0°C these parameters are guaranteed by design and not
tested.

Note 2: 0.1Hz to 10Hz noise is specified DC coupled in a 10s window;

0.1Hz to 1Hz noise is specified in a 100s window with an RC high-pass

UW

LPER

F

O

Input Noise vs Supply Voltage

1.6

1.4

1.2

)

P-P

1.0

0.8

0.6

INPUT NOISE (µV

0.4

0.2

0

681012

4

TOTAL SUPPLY VOLTAGE, V+ TO V– (V)

R

TA = 25°C

0.1Hz TO 10Hz

0.1Hz TO 1Hz

14

LTC1250 G01

ATYPICA

CCHARA TERIST

E

C

Supply Current vs Supply Voltage

4.0
TA = 25°C

3.5

3.0

2.5

2.0

1.5

SUPPLY CURRENT (mA)

1.0

0.5

0

16

4

TOTAL SUPPLY VOLTAGE, V+ TO V– (V)

681012

ICS

14

LTC1250 G02

Sampling Frequency vs Supply
Voltage

16

1.2
VS = ±5V

1.0

)

P-P

0.8

0.6

0.4

INPUT NOISE (µV

0.2



0

–50

–25 0

0.1Hz TO 10Hz

0.1Hz TO 1Hz

25 75

TEMPERATURE (°C)

50 100 125

LTC1250 G04

Supply Current vs TemperatureInput Noise vs Temperature

4.5

4.0

3.5

3.0

SUPPLY CURRENT (mA)

2.5

2.0
–50

–25

0

TEMPERATURE (°C)

Sampling Frequency vs
Temperature

VS = ±5V

50

25

75

100

LTC1250 G05

125

3