MIC5021
Micrel
MIC5021
High-Speed High-Side MOSFET Driver
General Description
The MIC5021 high-side MOSFET driver is designed to oper-
ate at frequencies up to 100kHz (5kHz PWM for 2% to 100%
duty cycle) and is an ideal choice for high speed applications
such as motor control, SMPS (switch mode power supplies),
and applications using IGBTs. The MIC5021 can also
operate as a circuit breaker with or without automatic retry.
A rising or falling edge on the input results in a current source
pulse or sink pulse on the gate output. This output current
pulse can turn on a 2000pF MOSFET in approximately
550ns. The MIC5021 then supplies a limited current (< 2mA),
if necessary, to maintain the output state.
An overcurrent comparator with a trip voltage of 50mV makes
the MIC5021 ideal for use with a current sensing MOSFET.
An external low value resistor may be used instead of a
sensing MOSFET for more precise overcurrent control. An
optional external capacitor placed from the C
T
pin to ground
may be used to control the current shutdown duty cycle (dead
time) from 20% to < 1%. A duty cycle from 20% to about 75%
is possible with an optional pull-up resistor from C
T
to V
DD
.
The MIC5021 is available in 8-pin SOIC and plastic DIP
packages.
Other members of the MIC502x family include the MIC5020
low-side driver and the MIC5022 half-bridge driver with a
cross-conduction interlock.
Features
12V to 36V operation
550ns rise/fall time driving 2000pF
TTL compatible input with internal pull-down resistor
Overcurrent limit
Gate to source protection
Internal charge pump
100kHz operation guaranteed over full temperature and
operating voltage range
• Compatible with current sensing MOSFETs
• Current source drive reduces EMI
•
•
•
•
•
•
•
Applications
•
•
•
•
•
•
Lamp control
Heater control
Motor control
Solenoid switching
Switch-mode power supplies
Circuit breaker
Ordering Information
Part Number
MIC5021BM
MIC5021BN
Temperature Range
–40°C to +85°C
–40°C to +85°C
Package
8-pin SOIC
8-pin Plastic DIP
5
Typical Application
+12V to +36V
MIC5021
10µF
TTL Input
optional*
1
2
3
4
V
DD
Input
C
T
Gnd
V
BOOST
Gate
Sense
Sense
8
7
6
5
2.7
nF
R
SENSE
R
SENSE =
50mV
I
TRIP
* increases time before retry
N-Channel
Power MOSFET
High-Side Driver with Overcurrent Trip and Retry
October 1998
5-169
Load