MIC4421/4422
Micrel
5-42
April 1998
MIC4421/4422
9A-Peak Low-Side MOSFET Driver
Bipolar/CMOS/DMOS
Process
General Description
MIC4421 and MIC4422 MOSFET drivers are rugged, effi-
cient, and easy to use. The MIC4421 is an inverting driver,
while the MIC4422 is a non-inverting driver.
Both versions are capable of 9A (peak) output and can drive
the largest MOSFETs with an improved safe operating mar-
gin. The MIC4421/4422 accepts any logic input from 2.4V to
V
S
without external speed-up capacitors or resistor net-
works. Proprietary circuits allow the input to swing negative
by as much as 5V without damaging the part. Additional
circuits protect against damage from electrostatic discharge.
MIC4421/4422 drivers can replace three or more discrete
components, reducing PCB area requirements, simplifying
product design, and reducing assembly cost.
Modern Bipolar/CMOS/DMOS construction guarantees free-
dom from latch-up. The rail-to-rail swing capability of CMOS/
DMOS insures adequate gate voltage to the MOSFET dur-
ing power up/down sequencing. Since these devices are
fabricated on a self-aligned process, they have very low
crossover current, run cool, use little power, and are easy to
drive.
Features
BiCMOS/DMOS Construction
Latch-Up Proof: Fully Isolated Process is Inherently
Immune to Any Latch-up.
Input Will Withstand Negative Swing of Up to 5V
Matched Rise and Fall Times............................... 25ns
High Peak Output Current.............................. 9A Peak
Wide Operating Range.............................. 4.5V to 18V
High Capacitive Load Drive...........................47,000pF
Low Delay Time ........................................... 30ns Typ.
Logic High Input for Any Voltage from 2.4V to V
S
Low Equivalent Input Capacitance (typ).................7pF
Low Supply Current..............450
μ
A With Logic 1 Input
Low Output Impedance ........................................ 1.5
Output Voltage Swing to Within 25mV of GND or V
S
Applications
Switch Mode Power Supplies
Motor Controls
Pulse Transformer Driver
Class-D Switching Amplifiers
Line Drivers
Driving MOSFET or IGBT Parallel Chip Modules
Local Power ON/OFF Switch
Pulse Generators
Functional Diagram
IN
OUT
MIC4421
INVERTING
MIC4422
NON-INVERTING
0.1mA
0.3mA
2k
V
S
GND