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CS8442
CS8442
85mA Dual H-Bridge Odometer Driver with Buffered Speed Signal Output
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 Odead zoneO 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 4.7k1/2 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.
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 (VCC) (continuous) -40uC to +105uC ..................0.5 to 24V (100ms pulse transient) -40uC to +105uC ......................0.5 to 60V Input Voltage (VIN) ..............................................................0.3 to VCC +0.3V Storage Temperature Range (TSTG)......................................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 Block Diagram
Package Options
8L PDIP
Gnd 1 COILA+ COILA SENSOR IN VCC COILB+ COILB 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
CS8442
Electrical Characteristics: Unless otherwise stated, these specifications apply for -40uC to +105uC, 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 TEST CONDITIONS MIN TYP MAX UNIT
s Supply Supply Voltage Range Supply Current Overvoltage Shutdown s 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 s Coil Output Drivers Coil Load Coil Inductance Coil Resistance Temperature * Energized Coil Voltage (Both Polarities) A and B
TA = -40C to +105C TA = -40C to +25C VCC = 15.5 VDC Outputs not loaded
6.5 6.5
15.5 24.0 35 23
a a mA V
16
0 1.6 300 VIN = 0.8VDC to VCC 0 10K Ohm Resistor in Series ICC=1.3mA VCC=5.5V I Clamp at VIN = 0 VDC
400 3.0 1 8 -15 to VCC 0.4 10 -5.0
Hz VDC mV A VDC VDC V A mA
-0.4
+25C Coefficient VCC = 6.5 VDC VCC = 10.0 VDC VCC = 15.5 VDC,TA= -20C to +105C VCC = 15.5 VDC,TA= -40C to -20C
198
210
222 80 0.39
1/2 mH %/C VDC VDC VDC VDC A
VCC -1.50 VCC -1.60 VCC-1.75 VCC-2.00 100
De-Energized Coil Leakage Current s Short Circuit Protection Short Circuit Threshold Coil A + Coil B Short Circuit Turn Off Delay
275 5
400
mA s
* Voltage across the coils shall be measured at the specific voltages, but shall also be within linearly interpolated limits.
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CS8442
Package Pin Description
PACKAGE PIN # PIN SYMBOL FUNCTION
8L PDIP 1 2 3 4 5 6 7 8
Gnd COILA+ COILASENSOR IN SENSOR OUT COILBCOILB+ VCC
Ground connection. Output stage, when active, supplies current to COIL A. Output stage, when active, supplies current to COIL A. Input signal from wheel speed or engine rpm. Buffered and inverted output of SENSOR IN signal. Output stage, when active, supplies current to COIL B. Output stage, when active, supplies current to COIL B. Supply Voltage. Application Information
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 100k1/2 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 4.7k1/2 load connected to a 5V supply.
Table 1: Transition States
State
0 1 2 3 4 5 6 7
Output State Table Coil A
+ OFF OFF + +
Coil B
+ + + OFF OFF
The polarity definition for the coil driver outputs is as follows:
Polarity Positive (+) Negative (-) Connect Coil + VCC Gnd Connect Coil Gnd VCC
Sequencer
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 BOs reversed polarity continues in Stages 5 and 6. COIL AOs 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.
H Bridge Outputs A and B
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.
Short Circuit VCC Q1 Q3 Sense Resistor Overvoltage and Short Circuit Protection
STATE #
0
1
2
3
4
5
6
7
0
+ COIL A
Coil + COIL B Q2 Q4
Short Circuit Gnd Sense Resistor
Figure 1: State Diagram for Coil Outputs
Figure 2: Coil Driver Output
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CS8442
Application Diagram
C1 - 10F C2 - 0.1F C3 - 0.01F R1 - 3.91/2 0.5W R2 - 100k1/2 R3 - 15k1/2 D1 - 1A 600PIV Z1 - 50V 0.5W COIL A - 210121/2, 80mH COIL B - 210121/2, 80mH
COILA+
COILA
COILB+
COILB
CS8442
SENSOR IN
VCC D1 IGN Z1 R3 Buffered Speed Signal (Open Collector Drive) C1 C2 R1
SENSOR OUT
Gnd
R2
C3
Package Specification
PACKAGE DIMENSIONS IN mm (INCHES) PACKAGE THERMAL DATA
D Lead Count 8L PDIP Metric Max Min 10.16 9.02 English Max Min .400 .355
Thermal Data RQJC typ RQJA typ
8L PDIP 52 100
uC/W uC/W
Plastic DIP (N); 300 mil wide
7.11 (.280) 6.10 (.240)
8.26 (.325) 7.62 (.300) 3.68 (.145) 2.92 (.115)
1.77 (.070) 1.14 (.045)
2.54 (.100) BSC
.356 (.014) .203 (.008)
0.39 (.015) MIN. .558 (.022) .356 (.014) Some 8 and 16 lead packages may have 1/2 lead at the end of the package. All specs are the same.
REF: JEDEC MS-001
D
Ordering Information
Part Number CS8442XN8
Rev. 8/2/93
Description 8L PDIP 4
Cherry Semiconductor Corporation reserves the right to make changes to the specifications without notice. Please contact Cherry Semiconductor Corporation for the latest available information.
(c) 1999 Cherry Semiconductor Corporation

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