![](http://datasheet.mmic.net.cn/370000/MIC3832_datasheet_16722088/MIC3832_1.png)
April 1998
4-135
MIC3832/3833
Micrel
Features
15.9V startup, up to 21V operation (MIC3832)
8.3V startup, up to 21V operation (MIC3833)
9.8V undervoltage lockout (MIC3832)
7.8V undervoltage lockout (MIC3833)
0.5mA maximum startup current (40
μ
A typical)
17mA typical operating current
50ns maximum rise and fall times
30kHz to 500kHz RC oscillator
Voltage or current-mode control
Cycle-by-cycle current limit
Soft start function
5V 2% reference sources 20mA
Totem-pole output drive stages
1A peak output drive current
22V zener clamp on supply pin
PWM latch eliminates false outputs from noise or ringing
Adjustable maximum duty-cycle limit
5MHz bandwidth error amplifier
Applications
High-power, multiple-output, switched-mode
power supplies and dc-to-dc Converters
Current-fed, push-pull, switched-mode
power supplies or dc-to-dc converters
Isolated high-voltage supplies
Ordering Information
Part Number
MIC3832BN
MIC3832BWM
MIC3833BN
MIC3833BWM
Temperature Range
–40
°
C to +85
°
C
–40
°
C to +85
°
C
–40
°
C to +85
°
C
–40
°
C to +85
°
C
Package
16-pin Plastic DIP
16-pin Wide SOIC
16-pin Plastic DIP
16-pin Wide SOIC
General Description
The MIC3832 and MIC3833 are unique PWM controllers
designed for current-fed, multiple-output or push-pull,
switched-mode power supply applications.
The MIC3832/3 features UVLO (undervoltage lockout) with
hysteresis, soft start with a programmable time constant,
cycle-by-cycle current limiting, a PWM latch to prevent mul-
tiple outputs due to noise or ringing, and front-edge blanking.
Current-fed topologies eliminate core saturation problems
caused by shoot through (cross conduction) of push-pull
circuits and reduce stress on the switching transistors.
The MIC3832/3 has one PWM stage capable of operating up
to 500kHz and two output stages, Q and Q, that operate at
one-half of the system frequency at a fixed 50% duty cycle.
The MIC3832 UVLO circuit permits startup when the supply
is above 15.9V and forces shutdown when the supply drops
below 9.8V. The MIC3833 starts up above 8.3V and shuts
down below 7.8V. An internal 22V zener diode provides low
power overvoltage protection.
The three output stages are totem-pole drivers capable of 1A
peak current to external power MOSFETs, BJTs, or IGBTs.
The Q and Q outputs have an intentional 50ns overlap (no
dead time).
MIC3832/3833
Current-Fed PWM Controllers
Not Recommended for New Designs
Pin Configuration
1
14
2
3
4
5
6
7
13
12
10
9
11
GND
C
T
Q
V
DD
5V REF
EA –
EA +
EA OUT
R
T
SYNC
CMR
MDC/SS
SHDN
NC
PWM
Q
8
15
16
DIP (N) or Wide SOIC (WM)