LT1013, LT1013A, LT1013D

DUAL PRECISION OPERATIONAL AMPLIFIERS

SLOS018H − MAY 1988 − REVISED NOVEMBER 2004

19

POST OFFICE BOX 655303

APPLICATION INFORMATION

comparator applications

The single-supply operation of the LT1013 is well suited for use as a precision comparator with TTL-compatible

output. In systems using both operational amplifiers and comparators, the LT1013 can perform multiple duties

(see Figures 25 and 26).

100 mV

VCC+ = 5 V

VCC− = 0

TA = 25°C

Overdrive

10 mV

5 mV

2 mV

0

50 100 150 200 250 300 350 400 450

5

4

3

2

1

0

t − Time −

µs

Figure 25. Low-to-High-Level Output

Response for Various Input Overdrives

2 mV

5 mV

Overdrive

10 mV

0

50 100 150 200 250 300 350 400 450

5

4

3

2

1

0

t − Time −

µs

VCC+ = 5 V

VCC− = 0

TA = 25°C

100 mV

Figure 26. High-to-Low-Level Output

Response for Various Input Overdrives

low-supply operation

The minimum supply voltage for proper operation of the LT1013 is 3.4 V (three NiCad batteries). Typical supply

current at this voltage is 290

µA; therefore, power dissipation is only 1 mW per amplifier.

offset voltage and noise testing

The test circuit for measuring input offset voltage and its temperature coefficient is shown in Figure 30. This

circuit, with supply voltages increased to

±20 V, also is used as the burn-in configuration.

The peak-to-peak equivalent input noise voltage of the LT1013 is measured using the test circuit shown in

Figure 27. The frequency response of the noise tester indicates that the 0.1-Hz corner is defined by only one

zero. The test time to measure 0.1-Hz to 10-Hz noise should not exceed 10 seconds, as this time limit acts as

an additional zero to eliminate noise contribution from the frequency band below 0.1 Hz.

An input noise voltage test is recommended when measuring the noise of a large number of units. A 10-Hz input

noise voltage measurement correlates well with a 0.1-Hz peak-to-peak noise reading because both results are

determined by the white noise and the location of the 1/f corner frequency.

Current noise is measured by the circuit and formula shown in Figure 28. The noise of the source resistors is

subtracted.