10

LT1124/LT1125

S

APPLICATI

TYPICAL

Gain 1000 Amplifier with 0.01% Accuracy, DC to 1Hz

Gain Error vs Frequency Closed-Loop Gain = 1000

–

+

OUTPUT

1124/25 TA03

365

Ω

1%

INPUT

15k

5%

340k

1%

20k

TRIM

15V

1/2 LT1124

–15V

RN60C FILM RESISTORS

THE HIGH GAIN AND WIDE BANDWIDTH OF THE LT1124/LT1125, IS USEFUL IN LOW

FREQUENCY HIGH CLOSED-LOOP GAIN AMPLIFIER APPLICATIONS. A TYPICAL

PRECISION OP AMP MAY HAVE AN OPEN-LOOP GAIN OF ONE MILLION WITH 500kHz

BANDWIDTH. AS THE GAIN ERROR PLOT SHOWS, THIS DEVICE IS CAPABLE OF 0.1%

AMPLIFYING ACCURACY UP TO 0.3Hz ONLY. EVEN INSTRUMENTATION RANGE

SIGNALS CAN VARY AT A FASTER RATE. THE LT1124/LT1125 “GAIN PRECISION —

BANDWIDTH PRODUCT” IS 75 TIMES HIGHER, AS SHOWN.

4

7 (SO-8)

1 (N8)

6 (S0-8)

8 (N8)

3

2

FREQUENCY (Hz)

0.01

0.1

1.0

0.1

10

100

1124/25 TA04

0.001

1

GAIN ERROR =

CLOSED-LOOP GAIN

OPEN-LOOP GAIN

TYPICAL

PRECISION

OP AMP

LT1124/LT1125

LT1124CN8

PARAMETER/UNITS

LT1125CN

OP-27 GP

OP-270 GP

OP-470 GP

UNITS

Voltage Noise, 1kHz

4.2

4.5

–

5.0

nV/

√Hz

100% Tested

Sample Tested

No Limit

Sample Tested

Slew Rate

2.7

1.7

1.7

1.4

V/

µs

100% Tested

Not Tested

Gain Bandwidth Product

8.0

5.0

–

–

MHz

100% Tested

Not Tested

No Limit

No Limit

Offset Voltage

LT1124

100

100

250

–

µV

LT1125

140

–

–

1000

µV

Offset Current

LT1124

20

75

20

–

nA

LT1125

30

–

–

30

nA

Bias Current

30

80

60

60

nA

Supply Current/Amp

2.75

5.67

3.25

2.75

mA

1.5

0.7

0.35

0.4

V/

µV

Common Mode Rejection Ratio

106

100

90

100

dB

Power Supply Rejection Ratio

110

94

104

105

dB

SO-8 Package

Yes - LT1124

Yes

No

–

Table 2 summarizes the performance of the LT1124/

LT1125 compared to the low cost grades of alternate

approaches.

The comparison shows how the specs of the LT1124/

LT1125 not only stand up to the industry standard OP-27,

but in most cases are superior. Normally dual and quad

performance is degraded when compared to singles, for

the LT1124/LT1125 this is not the case.

PERFOR A CE CO PARISO