LTC2925

6

2925f

FU CTIO AL BLOCK DIAGRA

10

µA

10

µA

2.6V

0.1V

–

+

RAMPBUF

FB3

TRACK3

GND

2925 FBD

1

×

10

12

9

(6)

REMOTE

17

(14)

10

STATUS

1

11

FB2

TRACK2

14

13

FB1

TRACK1

0.8V

+

–

15

16

+

–

10

µA

CHARGE

PUMP

SQ

0.1V

R

SCTMR

ON

4

(1)

PGTMR

10

µA

23

PGI

22

SCTMR

24

SDx

(15)

FAULT

(17)

(22)

(7, 25)

20

SENSEN

(24)

3

SENSEP

(23)

2

SDTMR

(2)

5

GATE

(16)

19

RAMP

18

1.2V

GATE

GATE > RAMP + 4.9V

4.9V

1.2V

0.4V

ONSIG

–

+

1.2V

1.2V

SQ

R

2

µA

50

µA

50mV

SENSEP > SENSEN + 50mV

(8)

(10)

(13)

(9)

(11)

(12)

(20)

(19)

(21)

Pin numbers in parentheses are for the UF package.

SCTMR (Pin 24/Pin 21): Circuit Breaker Timer. A capaci-

tor from SCTMR to GND programs the maximum time that

a short circuit can be sustained before GATE is pulled low.

When (SENSEP – SENSEN) > 50mV, SCTMR will pull up

with 50

µA, otherwise it pulls down with 2µA. When the

voltage at SCTMR exceeds 1.23V, the GATE will be pulled

to ground with 20mA and the FAULT pin will be pulled low.

The circuit breaker function is reset by pulling ON below

0.4V. The GATE pin will not rise again until SCTMR has

been pulled below 100mV by the 2

µA current source. If

FAULT is tied back to ON the system will automatically

retry after a fault. Tie SCTMR to GND if the circuit breaker

is not used.