Data Sheet
AZ3842/3/4/5
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
General Description
Features
The AZ3842/3/4/5 are high performance fixed fre-
quency current-mode PWM controller series.
·
Robust V
Line/Load Regulation
REF
Low Line Regulation : 4mV
Low Load Regulation : 4mV
These integrated circuits are optimized for off-line and
DC-DC converter applications with minimum external
components. They feature under-voltage lockout
(UVLO) circuit for low start-up current, trimmed
oscillator for precise duty cycle control, current sense
comparator providing maximum current limiting and a
totem pole output stage for increasing output current.
In addition, these ICs also feature accurate protection
against over-temperature, over-current and maximal
output power.
·
High Stability of Reference Voltage over a Full
o
Temperature Range: 0.2mV/ C
·
·
Operating Frequency up to 500KHz
High PWM Frequency Stability over a Full Tem-
perature Range: 2.5%
High PWM Frequency Stability under a Full Sup-
ply Voltage Range: 0.2%
Accurate Over-temperature Protection with Hys-
teresis
UVLO with Hysteresis
·
·
·
The AZ3842 and AZ3844 have UVLO thresholds of
15.5V(on) and 10V(off); The corresponding thresholds
for AZ3843 and AZ3845 are 8.4 V(on) and 7.8V(off).
Applications
·
·
·
·
·
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Off-line Converter
DC-DC Converter
Voltage Adapter
CRT Monitor Power Supply
Desktop Power Supply
DVD/STB Power Supply
The AZ3842 and AZ3843 can operate approaching
100% duty cycle; AZ3844 and AZ3845 can operate
from zero to 50% duty cycle.
These ICs are available in 3 packages: SOIC-8, DIP-8
and SOIC-14.
SOIC-8
DIP-8
SOIC-14
Figure 1. Package Types of AZ3842/3/4/5
March 2003
Rev: 1.0
1