CURRENT MODE PWM CONTROLLER
FEATURES
●
●
●
●
●
●
Automatic feed forward compensation
Optimized for offline converter
Double pulse suppression
Current mode operation to 500 KHz
High gain totem pole output
Internally trimmed bandgap reference
LM3842A/3A/4A/5A
8 SOP/ 8 DIP PIN Configulation
Compen
sation
8
7
6
5
V
REF
1
2
3
4
SOP-8 PKG
Voltage
Feedback
Current
Sense
Vcc
OUTPUT
GND
● Undervoltage lockout with hysteresis
● Low start up current :
＜ 0.3 mA
● Moisture Sensitivity Level 3
DIP-8 PKG
R
T
/C
T
ORDERING INFORMATION
Device
LM3842A/3A/4A/5A D
Package
8 SOP
8 DIP
DESCRIPTION
LM3842A/3A/4A/5A N
The LM384xA are fixed frequency current-mode PWM controller. They are specially designed for Off-Line and
DC-to-DC converter applications with minimal external components.
These integrated circuits features 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 in under-voltage lockout and current limiting.
SIMPLIFIED BLOCK DIAGRAM
V
REF
⑧
R
R
RT/CT ④
VFB ②
COMP ①
+
-
V
REF
Undervoltage
Lockout
Oscillator
5V
Reference
Vcc
Undervoltage
Lockout
⑦ Vcc
Latching
PWM
⑥ Output
⑤ Ground
③ Current
Sense
Input
Error
Amplifie
r
ABSOLUTE MAXIMUM RATINGS (T
A
= 25℃)
Characteristic
Power Supply Voltage
Output Current
Analog Inputes Voltage
Error Amp Output Sink Current
Power Dissipation
Storage Temperature Range
Lead Temperature (soldering 5 sec)
2008 - Ver. 1.0
Symbol
V
cc
I
o
V
IN
I
SINK
P
D
T
stg
T
L
Value
30
±1
-0.3 to 5.5V
10
1
-65 to 150
260
Unit
V
A
V
mA
W
℃
℃
−
1
−
HTC
HTC [ HTC KOREA TAEJIN TECHNOLOGY CO. ]
