CS8442
CS8442
85mA Dual H-Bridge Odometer Driver
with Buffered Speed Signal Output
Description
The CS8442 is a stepper motor
driver that implements an H-
bridge design to drive two coils in
an eight step sequence each revo-
lution. Each H-bridge is capable of
delivering 85mA to the load.
The sequencer function insures
that the odometer is monotonic
and that cross-conduction of each
H bridges does not occur. Before
the beginning of each sequence,
both bridges are turned off. This
Òdead zoneÓ minimizes the fly
back energy generated in the
inductive loads. In addition, on
board clamp diodes across each
output protect the output drive
transistors from excessive fly back
voltages.
The CS8442 is fault protected
against reverse battery, short cir-
cuit, and over voltage conditions.
If a fault is detected, the IC shuts
down.
The buffered speed signal output
(SENSOR OUT) is an open collec-
tor NPN capable of driving a
4.7k�½ load connected to a 5V sup-
ply. The signal is a buffered,
inverted version of the speed sen-
sor input voltage (SENSOR IN).
The input voltage can be either a
sine or square wave form.
Features
s
Buffered Speed Sensor
Output
s
No Cross-conduction in
either H-bridge
s
Guaranteed Monotonic
s
On Chip Flyback Diodes
s
Fault Protection
Overvoltage
Short Circuit Protection
Load Dump Protection
to 60V
Absolute Maximum Ratings
Supply Voltage (V
CC
) (continuous) -40ûC to +105ûC ..................Ð0.5 to 24V
(100ms pulse transient) -40ûC to +105ûC ......................Ð0.5 to 60V
Input Voltage (V
IN
) ..............................................................Ð0.3 to V
CC
+0.3V
Storage Temperature Range (T
STG
)......................................Ð65¡C to +150¡C
Junction Temperature.............................................................Ð40¡C to +150¡C
Speed Sensor Output .....................................................................................7V
ESD (Human Body Model) .........................................................................2kV
Lead Temperature Soldering
Wave Solder (through hole styles only) ........10 sec. max, 260¡C peak
Block Diagram
Package Options
8L PDIP
Gnd
1
COILA+
COILAÐ
SENSOR
IN
V
CC
COILB+
COILBÐ
SENSOR
OUT
SENSOR
IN
Input
Comp.
Coil
Driver
A
COILA+
COILA-
Sequencer
SENSOR
OUT
Overvoltage
and Short
Circuit
Protection
Coil
Driver
B
COILB
+
COILB-
Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885-3600 Fax: (401)885-5786
Email: info@cherry-semi.com
Web Site: www.cherry-semi.com
Rev. 8/2/93
1
A
¨
Company
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
