CHERRY CS8442

CS8442
CS8442
85mA Dual H-Bridge Odometer Driver
with Buffered Speed Signal Output
Features
Description
The CS8442 is a stepper motor
driver that implements an Hbridge design to drive two coils in
an eight step sequence each revolution. 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 circuit, and over voltage conditions.
If a fault is detected, the IC shuts
down.
The buffered speed signal output
(SENSOR OUT) is an open collector NPN capable of driving a
4.7k½ load connected to a 5V supply. The signal is a buffered,
inverted version of the speed sensor input voltage (SENSOR IN).
The input voltage can be either a
sine or square wave form.
■ Buffered Speed Sensor
Output
■ No Cross-conduction in
either H-bridge
■ Guaranteed Monotonic
■ On Chip Flyback Diodes
■ Fault Protection
Overvoltage
Short Circuit Protection
Load Dump Protection
to 60V
Absolute Maximum Ratings
Supply Voltage (VCC) (continuous) -40ûC to +105ûC ..................Ð0.5 to 24V
(100ms pulse transient) -40ûC to +105ûC ......................Ð0.5 to 60V
Input Voltage (VIN) ..............................................................Ð0.3 to VCC +0.3V
Storage Temperature Range (TSTG)......................................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
Package Options
8L PDIP
Gnd 1
Block Diagram
VCC
COILA+
COILB+
COILAÐ
COILBÐ
SENSOR
IN
SENSOR
IN
Coil
Driver
A
Input
Comp.
Sequencer
SENSOR
OUT
COILA+
COILA-
Overvoltage
and Short
Circuit
Protection
SENSOR
OUT
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
CS8442
Electrical Characteristics: Unless otherwise stated, these specifications apply for -40ûC to +105ûC, VCC = 6.5 to 15.5 VDC. All
voltage shall be referenced to Gnd unless otherwise noted. Overvoltage shutdown of coils occurs when VCC >16V.
PARAMETER
■ Supply
Supply Voltage Range
Supply Current
TEST CONDITIONS
TA = -40¡C to +105¡C
TA = -40¡C to +25¡C
VCC = 15.5 VDC
Outputs not loaded
Overvoltage Shutdown
■ Speed Sensor
Input Frequency Range
Switching Threshold
Hysteresis
Input Bias Current
Input Voltage Range
Operating Input Voltage
Output Saturation Voltage
Output Leakage
Input Clamp Current
■ Coil Output Drivers
Coil Load
Coil Inductance
Coil Resistance Temperature
* Energized Coil Voltage
(Both Polarities) A and B
MIN
TYP
MAX
UNIT
6.5
6.5
15.5
24.0
35
a
a
mA
16
23
V
0
1.6
300
400
3.0
Hz
VDC
mV
µA
VDC
VDC
VIN = 0.8VDC to VCC
±1
8
-15
to VCC
0
10K Ohm Resistor in Series
ICC=1.3mA
VCC=5.5V
I Clamp at VIN = 0 VDC
-0.4
+25¡C
198
210
Coefficient
VCC = 6.5 VDC
VCC = 10.0 VDC
VCC = 15.5 VDC,TA= -20¡C to +105¡C
VCC = 15.5 VDC,TA= -40¡C to -20¡C
275
5
* Voltage across the coils shall be measured at the specific voltages, but shall also be within linearly interpolated limits.
2
V
µA
mA
222
80
0.39
½
mH
%/¡C
±100
VDC
VDC
VDC
VDC
µA
400
mA
VCC -1.50
VCC -1.60
VCC-1.75
VCC-2.00
De-Energized Coil Leakage
Current
■ Short Circuit Protection
Short Circuit Threshold
Coil A + Coil B
Short Circuit Turn Off Delay
0.4
10
-5.0
µs
CS8442
Package Pin Description
PACKAGE PIN #
PIN SYMBOL
8L PDIP
1
FUNCTION
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
VCC
Supply Voltage.
Application Information
Table 1: Transition States
Speed Sensor
SENSOR IN is a PNP comparator input that accepts a sine or
square wave input. Signals in excess of VCC 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 100k½ 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 4.7k½ load connected to a 5V supply.
1
2
3
4
5
6
7
+
OFF
OFF
+
+
+
+
+
OFF
OFF
Connect
Coil +
VCC
Gnd
Polarity
Positive (+)
Negative (-)
Connect
Coil Gnd
VCC
H Bridge Outputs A and B
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 conducting with the same polarity. In State 2, current flows from
COIL A- out through the coil and back in COIL A+. COIL B outputs 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 BÕs
reversed polarity continues in Stages 5 and 6. COIL AÕs 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.
0
Coil B
0
1
2
3
4
5
6
7
The polarity definition for the coil driver outputs is as follows:
Sequencer
STATE #
State
Output State Table
Coil A
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 VCC=15.5V and IOUT = 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.
Protection Circuitry
The CS8442 is protected from short circuit, over voltage and
thermal runaway conditions. When any of these faults is detected, 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.
0
Short
Circuit
VCC
+
Q1
COIL A
Q3
Sense
Resistor
Ð
Coil
+
Q2
COIL B
Q4
Short
Circuit
Gnd
Ð
Sense
Resistor
Figure 1: State Diagram for Coil Outputs
Figure 2: Coil Driver Output
3
Overvoltage
and
Short
Circuit
Protection
CS8442
Application Diagram
C1 - 10µF
C2 - 0.1µF
C3 - 0.01µF
R1 - 3.9½ 0.5W
R2 - 100k½
R3 - 15k½
D1 - 1A 600PIV
Z1 - 50V 0.5W
COIL A - 210±12½, 80mH
COIL B - 210±12½, 80mH
COILA+
COILAÐ
COILB+
CS8442
VCC
D1
COILBÐ
SENSOR IN
SENSOR OUT
Gnd
R1
IGN
C2
C1
Z1
R3
Buffered Speed Signal
(Open Collector Drive)
R2
C3
Package Specification
PACKAGE THERMAL DATA
PACKAGE DIMENSIONS IN mm (INCHES)
D
Lead Count
Metric
Max
Min
10.16
9.02
8L PDIP
Thermal Data
RQJC
typ
English
Max
Min
.400
.355
RQJA
8L PDIP
52
typ
100
ûC/W
ûC/W
Plastic DIP (N); 300 mil wide
7.11 (.280)
6.10 (.240)
8.26 (.325)
7.62 (.300)
1.77 (.070)
1.14 (.045)
2.54 (.100) BSC
3.68 (.145)
2.92 (.115)
.356 (.014)
.203 (.008)
0.39 (.015)
MIN.
.558 (.022)
.356 (.014)
REF: JEDEC MS-001
D
Ordering Information
Part Number
CS8442XN8
Rev. 8/2/93
Some 8 and 16 lead
packages may have
1/2 lead at the end
of the package.
All specs are the same.
Cherry Semiconductor Corporation reserves the
right to make changes to the specifications without
notice. Please contact Cherry Semiconductor
Corporation for the latest available information.
Description
8L PDIP
4
© 1999 Cherry Semiconductor Corporation