Current Mode PWM Controller
KA3843A(AM)
DESCRIPTION
The KA3843AM
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 corresponding thresholds for the
The KA3843AM are 8.4V(on) and 7.6V (off)
The KA3843AM
can operate within 100% duty cycle.
PIN
CONNECTION
(TOP VIEW)
The KA3843AM
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
500KHz
BLOCK DIAGRAM
Absolute Maximum Ratings
Characteristic
Supply Voltage (low impedance
source)
Output Current
Input Voltage (Analog Inputs pins 2,3)
Error Amp Output Sink Current
Power Dissipation (T
A
=25
0
C)
Storage Temperature Range
Lead Temperature (soldering 5 sec.)
Symbol
V
CC
I
O
V
I
I
SINK (E.A)
P
O
Tstg
T
L
Value
30
±1
−0.3
to 5.5
10
1
-65 to150
260
Unit
V
A
V
mA
W
o
C
o
C
1