Data Sheet 26300.2A 8932-A VOICE-COIL MOTOR DRIVER Providing control and drive of the voice-coil motor used for head positioning in 5 V disk drive applications, the second-generation RET REF 1 28 RET SET A8932CLWA is a full-bridge driver that can be configured so that its V FLT 2 27 V SENS PROTECT output current is a direct function of an externally applied control CIRCUIT 3 26 V V BEMF LOAD + voltage or current. This linear current control function is supplemented 4 25 V GROUND SENS FB by additional circuitry to protect the heads and the data disk during 24 UV 5 SGND N SET system failure or normal system shutdown. 6 23 OUT R P OUT P The two 500 mA MOS driver outputs provide very low saturation LOAD 7 22 OUT V DD SUPPLY voltage and minimal power dissipation. Additional headroom is SWITCH 8 21 OUT N achieved by the sense-FET structure eliminating the need for an exter- + SGND 9 20 P IN N + nal current-sense resistor. Internal circuitry can be configured to V REF 10 ACT OUT 19 2 V FB provide closed-loop velocity control of the actuator by utilizing the SW 11 RETRACT 18 PWR OFF generated back-EMF of the voice-coil motor. Thermal protection and under-voltage lockout disables the system in a controlled sequence if a 12 FAULT 17 H GAIN PROTECT CIRCUIT fault condition occurs. 13 16 MP REFERENCE RESET + SIGNAL 14 V 15 ACT CC SUPPLY FEATURES Dwg. PP-042B Class-B, 2 r at 500 mA Output DS(on) ABSOLUTE MAXIMUM RATINGS Lossless Current Sensing Supply Voltages, V and V ............ 6.0 V CC DD Zero Current-Loop Deadband Output Current, I (peak) ........... 600 mA OUT High Transconductance Bandwidth (continuous) ........................... 500 mA User-Adjustable Transconductance Gain Analog Input Voltage Range, V .................................... -0.3 V to V Digital Transconductance Gain Switch (4:1 Ratio) IN CC Logic Input Voltage Range, 5 Volt Monitor with Selectable UV Trip Point V ............................... -0.3 V to +6.0 V IN Retract Circuitry Functional to 0 Volts Package Power Dissipation, Sleep Mode Function P ......................................... See Graph D Internal Back-EMF Velocity Loop Option Operating Temperature Range, T ..................................... 0C to +70C A Internal Thermal Shutdown Circuitry Junction Temperature, T ............... +150C J Storage Temperature Range, T ................................ -55C to +150C S Fault conditions that produce excessive junction temperature will activate device thermal shutdown circuitry. These conditions can be tolerated, but should be avoided. Output current rating may be restricted to a value determined by system concerns and factors. These include: system duty cycle and timing, ambient temperature, and use of any heatsinking and/or forced cooling. For reliable operation the specified maximum junction temperature should not be exceeded. Always order by complete part number, e.g., A8932CLWA . NO LONGER AVAILABLE FOR GENERAL SALEFREE AIR, R = 66C/W JA 8932-A VOICE-COIL MOTOR DRIVER FUNCTIONAL BLOCK DIAGRAM SIGNAL LOAD SUPPLY SUPPLY VOLTAGE-SENSE 14 22 AMP V V CC DD 19 ACT FB I SENSE + 26 V LOAD + ERROR POWER 20 AMP SGND 15 P ACT REF. AMP + 23 16 + OUT REFERENCE P 21 OUT N 17 2 V H GAIN 24 SGND N POWER CURRENT-SENSE 18 CONTROL 25 PWR OFF AMP V SENS FB I LOGIC SENSE 27 V SENS REF. + TSD 9 IN N 7 OUT 12 FAULT PROTECTION RETRACT 10 OUT SW CIRCUITRY CONTROL 13 MP REF. + RESET 53 2 1611 8 28 4 GROUND SWITCH Dwg. FP-024D 2.0 1.5 1.0 0.5 0 25 50 75 100 125 150 AMBIENT TEMPERATURE IN C Dwg. GP-034 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright 1992, 2001 Allegro MicroSystems, Inc. ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS UV SET V BEMF V FLT RET SET RET REF RETRACT R OUT P