DATA SHEET
LND3842A/43A/44A/45A
LND3842B/43B/44B/45B
Current Mode PWM Controller
GENERAL DESCRIPTION
The LND3842B/43B/44B/45B and LND3842A
/43A/44A/45A are fixed frequency current mode
PWM controllers. They are specially designed for
OFF-line and DC to DC converter applications with
a minimal of 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. Protection circuitry
includes undervoltage lockout and current limiting.
The LND3843B, A and LND3844B, A have UVLO
thresholds of 16V(on) and 10 V (off). The
corresponding thresholds for the LND3843B, A/
45B,A are 8.4 V (on) and 7.6(off). The LND3842B,
A and LND3843B, A can operate within 100% duty
cycle. The LND3844B, A and LND3845B, A can
operate within 50% duty cycle.
The LND384XB has Start-Up current of .45mA(typ).
The LND384XA has Start-Up current of .17mA(typ).
FEATURES
•
•
•
•
Low start-up and operating Current
High Current Totem Pole Output
Undervoltage Lockout with Hysterisis
Operating Frequency up to 500KHZ
PIN CONFIGURATION
COMP
V
I
FB
1
2
3
4
8
7
6
5
V
V
REF
CC
SENSE
T
OUT
GND
R /C
T
•
Linear Dimensions, Inc.
•
445 East Ohio Street, Chicago IL 60611 USA
•
tel 312.321.1810
•
fax 312.321.1830
•
•
LINEAR_DIMENSIONS [ LINEAR DIMENSIONS SEMICONDUCTOR ]
