LTC1443/LTC1444/LTC1445

8

144345fe

applicaTions inForMaTion

The LTC1443/LTC1444/LTC1445 is a family of quad

micropowercomparatorswithabuilt-inreference(1.182V

for the LTC1443 and 1.221V for the LTC1444/LTC1445).

Features include programmable hysteresis (LTC1444/

LTC1445), wide supply voltage range (2V to 11V) and the

abilityofthereferencetodriveuptoa0.01µFcapacitorwith-

out oscillation. The comparator CMOS outputs (LTC1443/

LTC1445) can source up to 40mA while the LTC1444 has

that normally occur when the comparator output switches

states have been eliminated.

Power Supplies

The comparator family operates from a single 2V to 11V

supply. The LTC1443 includes a separate ground for the

comparator output stage, allowing a split supply ranging

allows single supply operation. If the comparator output

is required to source more than 1mA or the supply source

capacitor.

Comparator Inputs

The comparator inputs can swing from the negative sup-

is only ±10pA.

Comparator Outputs

The LTC1443 comparator output swings between GND

(LTC1443/LTC1445) and sinking up to 5mA while still

maintaining microampere quiescent currents. The output

stage does not generate crowbar switching currents dur-

ing transitions which helps minimize parasitic feedback

through the supply pins.

Voltage Reference

The internal bandgap reference has a voltage of 1.182V for

LTC1443 or 1.221V for LTC1444/LTC1445 referenced to

It can source up to 200µA and sink up to 15µA with a 5V

supply. The reference can drive a bypass capacitor of up to

0.01µFwithoutoscillationandbyinsertingaseriesresistor,

capacitance values up to 100µF can be used (Figure 1).

Figure 2 shows the resistor value required for different

capacitor values to achieve critical damping.

CAPACITOR VALUE (µF)

0.001

0.1

10

1000

0.01

0.1

10

1

144345 F02

1

100

Figure 2. Damping Resistance vs Bypass Capacitor Value

LTC144X

REF

R1

C1

REFERENCE

OUTPUT

144345 F01

1.2V

+–

Figure 1. Damping the Reference Output