KA3842 View Datasheet(PDF) - Unspecified

Part Name

Description

View to exact match

KA3842

Linear Integrated Circuit(CURRENT-MODE PWM CONTROLLER)

Unspecified 

Description

The 3842A(AM)/43A(AM)/44A(AM)/45A(AM) are fixed frequency current mode PWM controller. They are specially designed for

OFF−Line and DC to DC converter applications with a minimal external components. Internally implemented circuits include a trimmed

oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator,

and a high current totempole output ideally suited for driving a power MOSFET. Protection circuitry includes built undervoltage lockout

and current limiting. The 3842A(AM) and 3844A(AM) have UVLO thresholds of 16 V (on) and 10 V (off). The corresponding

thresholds for the 3843A(AM)/45A(AM) are 8.4V (on) and 7.6V (off). The MIK3842A(AM) and MIK3843A(AM) can operate within 100% duty

cycle. The 3844A(AM) and UC3845A(AM) can operate within 50% duty cycle.

The 384XA(AM) has Start-Up Current 0.17mA (typ).

Features

• Low Start-Up and Operating Current

• High Current Totem Pole Output

• Undervoltage Lockout With Hysteresis

•Operating Frequency Up To 300KHz (384XA)

500KHz (384XAM)

Pin Connection

Block diagram

(toggle flip flop used only in MIK3844, MIK3845)

Top view

V

8

5V

VREF

SET/

RESET

UVLO

7

36V

GND

5

INTERNAL

BIAS

VRE GOODF

LOGIC

1/2 VREF

+

2R

2 VFB

ERR

R

COMP

1

CURRENT

SENSE

3

R /CT

OSCILLATOR

C.S.

COMP

1V

R

PWM

LATCH

S

T

POWER VCC

7

OUT

6

5

POWER GND

Absolute Maximum Ratings

Symbol

Parameter

VCC

IO

VI

ISINK (E.A)

Po

Tstg

TL

Supply Voltage (low impedance source)

Output Current

Input Voltage (Analog Inputs pins 2,3)

Error Amp Output Sink Current

Power Dissipation (TA=250C)

Storage Temperature Range

Lead Temperature (soldering 5 sec.)

Maximum

30

±1

−0.3 to 5.5

10

1

-65 to150

260

Units

V

A

V

mA

W

oC

oC

BEIJING ESTEK ELECTRONICS CO.,LTD

1

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