Voltage Regulators
1
AN8021NS
External excitation flyback AC-DC switching power supply control IC
n Overview
The AN8021S is a switching power supply control IC
that controls the power supply from the primary side. It is
optimal for relatively small switching power supplies. All
rarely used functions have been removed from the
AN8021S and as a result it is an extremely easy-to-use
compact device. Furthermore, internal settings are
implemented as many as we can, cost cut is possible with
reduced external parts.
n Features
• Supports operation at switching frequencies up to
700 kHz and achieves a 35 ns output rise time and a 25
ns output fall time.
• Extremely low pre-startup current consumption of 70
m A (typical) allows a significantly smaller startup resistor
to be used.
• Totem pole circuit structure adopted in the output block.
• Output current absolute maximum rating of – 1.0 A
(peak) for direct driving of power MOSFET.
• Pulse-by-pulse overcurrent protection circuit
•
Low voltage malfunction prevention circuit
On/off: 14.2 V/9.2 V
•
Timer latch and overvoltage protection functions
•
Package: SONF-8D
n Applications
• Switching power supplies
SOP008-P-0225C
Unit: mm
n Block Diagram
OVP Start/Stop
OSC
5
6
3
RT
CT
TIM/OVP
OCL FB
V
REF
PWM4.2 V
Drive
Reset
CLM
1
8
7
V
OUT
GND
CLM
4
IFB
2
V
CC
14
8
5.01±0.20
(1.05)
0.40(0.60)
0.50±0.20
0 to 10
4.30
±0.20
1.75
max.
1.45
±0.10
0.10
±0.10
6.40
±0.20
0.15
+0.10 –0.05
5
Seating plane
1.27
+0.10
–0.05
0.10