8

LTC1443/LTC1444/LTC1445

Bypassing the reference can help prevent false tripping of

reference output voltage. Figure 3 shows the bypassed

Resistors R1 and R2 set 10mV of hysteresis, while R3

damps the reference response. Note that the comparator

output doesn’t trip.

Hysteresis

Hysteresis can be added to the LTC1444/LTC1445 by

connecting a resistor (R1) between the REF and HYST

The difference between the upper and lower threshold volt-

voltage difference between the REF and HYST pins. When

more hysteresis is added, the upper threshold increases the

same amount as the lower threshold decreases. The maxi-

mum voltage allowed between REF and HYST is 50mV,

producing a maximum hysteresis voltage band of 100mV. If

hysteresis is not wanted, the HYST pin should be shorted to

2.4M is chosen for R2, then R1(k

5

OUT

R1

10k

R3

430

Ω

R2

2.4M

C1

1.0

µF

HYST

REF

4

14

8

5V

TO 8V

LTC1443/44/45 • F03

LTC1445

3

9

2

–

+

LTC1443/1444/1445 • TA02

8V

5V

OUT

2ms/DIV

Figure 4. Programmable Hysteresis

8

R2

HYST

REF

14

R1

LTC1443/44/45 • F04

LTC1445

9

R1 =

R2 =

2

()

1.221V –

APPLICATIO S I FOR ATIO