IP1842 SERIES

IP1843 SERIES

Prelim.3/00

Website: http://www.semelab.co.uk

DESCRIPTION

The IP1842 and IP1843 series of switching regulator control circuits contain all the functions necessary to

implement off–line, current mode switching regulators, using a minimum number of external parts. Functions

included are voltage reference, error amplifier, current sense comparator, oscillator, totem pole output driver and

under-voltage lockout circuitry.

Although pin compatible with the UC1842 and 1843 series, SEMELAB has incorporated several improvements in

the IP1842 and IP1843 series allowing tighter and more complete specification of electrical performance.

BLOCK DIAGRAM

Values in brackets are for IP1843 series.

3.6V

ERROR

AMP

OSCILLATOR

2R

R

1V

R

S

PW M

LATCH

CURRENT

SENSE

COM PARATOR

16V

(8.4V)

6V

(0.5V)

2.5V

UNDER–VOLTAGE

LOCKOUT

ENABLE

REFERENCE

REGULATOR

5V

INTERNAL

BIAS

34V

REG

R

S

V

STATUS

LATCH

REF

OUTPUT

V

REF

/C

R

T

T

POW ER

GROUND

V

C

PIN NUM BERS

1st Num ber

2nd Num ber

– N, J and 8 Pin D Packages

– 14 Pin D Package.

3/5

5/9

7/12

2/3

1/1

4/7

6/10

7/11

5/8

8/14

Output Current

Analog Inputs

(pins 2 and 3)

Error Amp Output Sink Current

IP1842 , IP1843

Operating Ambient Temperature Range

IP2842 , IP2843

IP3842 , IP3843

£ 30V

0 to ±200mA

–0.3V to 3V

0 to 2mA

–55 to 125°C

–25 to 85°C

0 to 70°C

Notes:

1.

Lower limit set by under voltage lockout specification.

RECOMMENDED OPERATING CONDITIONS