5

LTC1540

sn1540 1540fas

to 11V.

OUT (Pin 8): Comparator CMOS Output. Swings from

operation.

negative than GND. Connect to ground for single supply

operation.

typically 10pA at 25°C.

10pA at 25°C.

HYST (Pin 5): Hysteresis Input. Connect to REF if not

REF (Pin 6): Reference Output. 1.182V with respect

0.01µF bypass capacitor without oscillation.

1540 • PD

1

2

3

4

8

7

6

5

HYST

REF

OUT

–

+

GND

LTC1540

The LTC1540 is a nanopower comparator with a built-in

1.182V reference. Features include programmable hyster-

esis, wide supply voltage range (2V to 11V) and the ability

of the reference to drive up to a 0.01µF capacitor without

oscillation. The comparator’s CMOS outputs can source

up to 40mA while supply current glitches that normally

occur when switching logic states, have been eliminated.

Power Supplies

The comparator operates from a single 2V to 11V supply.

The LTC1540 includes a separate ground for the compara-

tor output stage, allowing a split supply ranging from ±1V

operation. If the comparator output is required to source

more than 1mA, or the supply source impedance is high,

Comparator Inputs

The comparator inputs can swing from the negative supply,

damage and the typical input leakage current is only ±10pA.

Comparator Output

assure TTL compatibility with a split supply. The output is

capable of sourcing up to 40mA and sinking up to 5mA

while still maintaining nanoampere quiescent currents.

The output stage does not generate crowbar switching

currents during transitions which helps minimize parasitic

feedback through the supply pins.

Voltage Reference

The internal bandgap reference has a voltage of 1.182V

0°C to 70°C. It can source up to 1mA and sink up to 10µA

with a 5V supply. The reference can drive a bypass

capacitor of up to 0.01µF without oscillation and by

inserting a series resistor, capacitance values up to 10µF

can be used (Figure 1).

Figure 2 shows the resistor value required for different

capacitor values to achieve critical damping. Bypassing

the reference can help prevent false tripping of the com-

transients from disturbing the reference output voltage.