1
Features
COILB-
SENSOR
IN
SENSOR
OUT
Coil
Driver
B
Coil
Driver
A
Overvoltage
and Short
Circuit
Protection
Sequencer
COILB
+
COILA-
COILA+
Input
Comp.
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
Package Options
8L PDIP
CS8442
85mA Dual H-Bridge Odometer Driver
with Buffered Speed Signal Output
1
Gnd
COILA+
COILA
SENSOR
IN
V
CC
COILB+
COILB
SENSOR
OUT
Description
Block Diagram
Absolute Maximum Ratings
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
dead zone 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 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.
CS8442
Supply Voltage (V
CC
) (continuous) -40C to +105C ..................0.5 to 24V
(100ms pulse transient) -40C to +105C ......................0.5 to 60V
Input Voltage (V
IN
) ..............................................................0.3 to V
CC
+0.3V
Storage Temperature Range (T
STG
)......................................65C to +150C
Junction Temperature.............................................................40C to +150C
Speed Sensor Output .....................................................................................7V
ESD (Human Body Model) .........................................................................2kV
Lead Temperature Soldering
Wave Solder (through hole styles only)........10 sec. max, 260C peak
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
A Company
Rev. 8/2/93
2
CS8442
Electrical Characteristics:
Unless otherwise stated, these specifications apply for -40C to +105C, V
CC
= 6.5 to 15.5 VDC. All
voltage shall be referenced to Gnd unless otherwise noted. Overvoltage shutdown of coils occurs when V
CC
>16V.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
* Voltage across the coils shall be measured at the specific voltages, but shall also be within linearly interpolated limits.
s Supply
Supply Voltage Range
T
A
= -40C to +105C
6.5
15.5
a
T
A
= -40C to +25C
6.5
24.0
a
Supply Current
V
CC
= 15.5 VDC
35
mA
Outputs not loaded
Overvoltage Shutdown
16
23
V
s Speed Sensor
Input Frequency Range
0
400
Hz
Switching Threshold
1.6
3.0
VDC
Hysteresis
300
mV
Input Bias Current
V
IN
= 0.8VDC to V
CC
1
A
Input Voltage Range
0
8
VDC
Operating Input Voltage
10K Ohm Resistor in Series
-15
VDC
to V
CC
Output Saturation Voltage
I
CC
=1.3mA
0.4
V
Output Leakage
V
CC
=5.5V
10
A
Input Clamp Current
I Clamp at V
IN
= 0 VDC
-0.4
-5.0
mA
s Coil Output Drivers
Coil Load
+25C
198
210
222
Coil Inductance
80
mH
Coil Resistance Temperature
Coefficient
0.39
%/C
* Energized Coil Voltage
(Both Polarities) A and B
V
CC
= 6.5 VDC V
CC
-1.50
VDC
V
CC
= 10.0 VDC V
CC
-1.60
VDC
V
CC
= 15.5 VDC,T
A
= -20C to +105C V
CC
-1.75
VDC
V
CC
= 15.5 VDC,T
A
= -40C to -20C V
CC
-2.00
VDC
De-Energized Coil Leakage
100
A
Current
s Short Circuit Protection
Short Circuit Threshold
275
400
mA
Coil A + Coil B
Short Circuit Turn Off Delay
5
s
3
SENSOR IN is a PNP comparator input that accepts a sine or
square wave input. Signals in excess of V
CC
or Ground will not
damage the input as long as the input current is limited to
1.5mA. An active clamp at 0V prevents negative input voltages
from disrupting normal operation. The input can withstand 150
VDC as long as the input current does not exceed 1.5mA. This is
possible if a 100k resistor is placed in series with the SENSOR
IN.
SENSOR OUT is an open collector NPN transistor that produces
a buffered and inverted version of the SENSOR IN signal. It is
capable of driving a 4.7k load connected to a 5V supply.
The eight step sequencer moves the two H bridge output drivers
through 8 sequential states (Table 1, Figure 1). In State 0, current
flows from COILA+ out through COIL A and back in through
COILA-. The same polarity also holds for COIL B. In State 1,
COIL A outputs turn off while COIL B outputs continue con-
ducting with the same polarity. In State 2, current flows from
COIL A- out through the coil and back in COIL A+. COIL B out-
puts continue with their original polarity. COIL A outputs
maintain this polarity through States 3 and 4 during which
COIL B outputs are first turned off and then reversed. COIL Bs
reversed polarity continues in Stages 5 and 6. COIL As outputs
are turned off in Stage 5 and then turned back on (positive
polarity) in Stage 6. In Stage 7, COIL B is off and COILA outputs
continue with a positive polarity.
Table 1: Transition States
The polarity definition for the coil driver outputs is as follows:
Connect
Connect
Polarity
Coil +
Coil -
Positive (+)
V
CC
Gnd
Negative (-)
Gnd
V
CC
Each H-bridge output stage consists of 4 power NPN transistors
with fly back diodes (Figure 2). Each half bridge has a composite
saturation voltage of 1.5V at V
CC
=15.5V and I
OUT
= 85mA.
The output stage is designed to prevent cross conduction: i.e., at
no time can Q1 and Q2 or Q3 and Q4 conduct. This dead zone
time minimizes fly back energy and helps protect the output
stages from damage.
The CS8442 is protected from short circuit, over voltage and
thermal runaway conditions. When any of these faults is detect-
ed, an internal flip-flop is set and both H bridges are disabled.
When the fault condition is removed, the Flip-Flop is reset after
the first positive going edge from the speed sensor input.
CS8442
Package Pin Description
Application Information
Speed Sensor
Sequencer
H Bridge Outputs A and B
Protection Circuitry
PACKAGE PIN #
PIN SYMBOL
FUNCTION
8L PDIP
1
Gnd
Ground connection.
2
COILA+
Output stage, when active, supplies current to COIL A.
3
COILA-
Output stage, when active, supplies current to COIL A.
4
SENSOR IN
Input signal from wheel speed or engine rpm.
5
SENSOR OUT
Buffered and inverted output of SENSOR IN signal.
6
COILB-
Output stage, when active, supplies current to COIL B.
7
COILB+
Output stage, when active, supplies current to COIL B.
8
V
CC
Supply Voltage.
Short
Circuit
V
CC
Sense
Resistor
Coil
Short
Circuit
Sense
Resistor
Gnd
Q3
Q4
Q1
Q2
Overvoltage
and
Short
Circuit
Protection
Figure 2: Coil Driver Output
Figure 1: State Diagram for Coil Outputs
0
1
2
3
4
5
6
7
0
COIL A
COIL B
+
+
STATE #
Output State Table
State
Coil A
Coil B
0
+
+
1
OFF
+
2
-
+
3
-
OFF
4
-
-
5
OFF
-
6
+
-
7
+
OFF
4
Part Number
Description
CS8442XN8
8L PDIP
Thermal Data
8L PDIP
R
Q
JC
typ
52
C/W
R
Q
JA
typ
100
C/W
Package Specification
Application Diagram
PACKAGE DIMENSIONS IN mm (INCHES)
Ordering Information
PACKAGE THERMAL DATA
Rev. 8/2/93
D
Lead Count
Metric
English
Max
Min
Max
Min
8L PDIP
10.16
9.02
.400
.355
COILA+
COILA
COILB+
COILB
V
CC
SENSOR OUT
Gnd
SENSOR IN
CS8442
IGN
D1
R1
R3
Z1
C1
C2
R2
C3
Buffered Speed Signal
(Open Collector Drive)
CS8442
C1 - 10F
C2 - 0.1F
C3 - 0.01F
R1 - 3.9 0.5W
R2 - 100k
R3 - 15k
D1 - 1A 600PIV
Z1 - 50V 0.5W
COIL A - 21012, 80mH
COIL B - 21012, 80mH
0.39 (.015)
MIN.
2.54 (.100) BSC
1.77 (.070)
1.14 (.045)
D
Some 8 and 16 lead
packages may have
1/2 lead at the end
of the package.
All specs are the same.
.203 (.008)
.356 (.014)
REF: JEDEC MS-001
3.68 (.145)
2.92 (.115)
8.26 (.325)
7.62 (.300)
7.11 (.280)
6.10 (.240)
.356 (.014)
.558 (.022)
Plastic DIP (N); 300 mil wide
1999 Cherry Semiconductor Corporation
Cherry Semiconductor Corporation reserves the
right to make changes to the specifications without
notice. Please contact Cherry Semiconductor
Corporation for the latest available information.
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