9

LT1007/LT1037

sn100737 100737fbs

General

The LT1007/LT1037 series devices may be inserted

directly into OP-07, OP-27, OP-37 and 5534 sockets with

or without removal of external compensation or nulling

components. In addition, the LT1007/LT1037 may be

fitted to 741 sockets with the removal or modification of

external nulling components.

Offset Voltage Adjustment

The input offset voltage of the LT1007/LT1037 and its drift

with temperature, are permanently trimmed at wafer

testing to a low level. However, if further adjustment of

will not degrade drift with temperature. Trimming to a

1

µV/°C (Figure 1).

The adjustment range with a 10k

Ω pot is approximately

±2.5mV.Iflessadjustmentrangeisneeded,thesensitivity

and resolution of the nulling can be improved by using a

smaller pot in conjunction with fixed resistors. The ex-

ample has an approximate null range of

±200µV

(Figure 2).

Offset Voltage and Drift

Thermocouple effects, caused by temperature gradients

across dissimilar metals at the contacts to the input

terminals, can exceed the inherent drift of the amplifier

unless proper care is exercised. Air currents should be

minimized, package leads should be short, the two input

leads should be close together and maintained at the same

temperature.

The circuit shown to measure offset voltage is also used

as the burn-in configuration for the LT1007/LT1037, with

the supply voltages increased to

±20V (Figure 3).

Figure 2. Improved Sensitivity Adjustment

1007/37 F02

1k

4.7k

OUTPUT

8

7 6

4

1

2

3

15V

–15V

LT1007

LT1037

4.7k

1007/37 F01

10k

OUTPUT

INPUT

8

7

6

4

1

2

3

15V

–15V

LT1007

LT1037

Figure 1. Standard Adjustment

Unity-Gain Buffer Application (LT1007 Only)

signal pulse (>1V), the output waveform will look as

shown in the pulsed operation diagram (Figure 4).

During the fast feedthrough-like portion of the output, the

input protection diodes effectively short the output to the

input and a current, limited only by the output short-circuit

protection, will be drawn by the signal generator. With

in its active mode and a smooth transition will occur.

1007/37 F04

LT1007

OUTPUT

2.8V/

µs

Figure 4. Pulsed Operation

1007/37 F03

*RESISTORS MUST HAVE LOW

THERMOELECTRIC POTENTIAL

7

6

4

2

3

15V

–15V

LT1007

LT1037

50k*

100

Ω*

50k*

Figure 3. Test Circuit for Offset Voltage and

Offset Voltage Drift with Temperature