* 1844A and 1845A series only.

Values in brackets are for IP1845 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

PIN NUM BERS

1st Num ber

2nd Num ber

– N, J and 8 Pin D Packages

– 14 Pin D Package.

I

SENSE

/C

R

T

T

OUTPUT

POW ER

GROUND

V

REF

V

C

3/5

5/9

7/12

2/3

1/1

4/7

6/10

7/11

5/8

8/14

TOGGLE

FLIP

FLOP *

T

Q

LAB

SEME

IP1842A SERIES

IP1843A SERIES

Prelim. 2/95

Output Current

Analog Inputs

(pins 2 and 3)

Error Amp Output Sink Current

IP1842A , IP1843A

Operating Ambient Temperature Range

IP2842A , IP2843A

IP3842A , IP3843A

≤ 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.

DESCRIPTION

The IP1842A/IP1843A 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 standard IP1842/3 parts these devices offer improved performance in several

areas. They also offer tighter specification and improved performance over the IP and UC1842/3 series, whilst

retaining complete compatibility.

BLOCK DIAGRAM

RECOMMENDED OPERATING CONDITIONS