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| 8958 LOGIC SUPPLY INHIBIT UV1 UV2 LIMIT GROUND AB GROUND AB PARK VOLTAGE SENSE IN- IN A+ IN A- OUT A 1 2 3 4 5 6 7 8 9 9 B 10 11 12 1.5 V + V CC VOICE COIL MOTOR DRIVER 24 23 22 21 20 19 18 17 SENSE OUT PARK DRIVE PARK GROUND PWR OK GROUNDAB GROUNDAB SENSE IN+ IN B+ IN B- LOAD SUPPLY OUT B Providing control and drive of the voice coil motor used for head positioning in disk drive applications, the A8958CLB is a full-bridge driver which can be configured so that its output current is a direct function of an externally applied control voltage or current. This linear current control function is supplemented by additional circuitry to protect the heads and the data disk during system failure or normal system shutdown. The two 800 mA driver outputs provide very-low saturation voltage drops and precise current control utilizing a single current-sensing resistor connected in series with the load. Under-voltage lockout disables the system in a controlled sequence if a fault condition occurs. When activated by the under-voltage comparator, or a park command, the output power drivers change from a controlled current to a user-determined constant park voltage. Other features include a power ok flag, a limit input to force the outputs to their maximum level in either polarity, an over-riding output disable to shut down both power amplifiers and reduce quiescent supply current, and internal thermal shutdown which disables the load (but still allowing the head to be parked) in the event of excessive junction temperatures. The load is re-enabled when the junction temperature returns to a safe level. The A8958CLB is supplied in a 24-lead power SOIC for surfacemount applications. The copper batwing construction provides for maximum package power dissipation in a minimum package size. It is rated for continuous operation over the temperature range of 0C to +70C. Data Sheet 26300.5A + A - ABSOLUTE MAXIMUM RATINGS at TA = 25C Supply Voltages, VBB and VCC ............... 16 V Output Current, IOUT ............................ 1.0 A Park Drive Output Current, IPARK Continuous ................................ 250 mA Peak .............................................. 1.0 A Amplifier Input Voltage Range, VIN ..................................... -2.0 V to VCC Sense Input Voltage Range, VSENSE IN ............................ -0.3 V to VCC Comparator and Digital Inputs, VIN .................................... -0.3 V to 10 V IIN .............................................. 10 mA Power OK Output, VCEX ......................... 20 V IC ................................................. 30 mA Output Clamp Diode Current, IF (pulsed) ..................................... 1.0 A Package Power Dissipation, PD .. See Graph Operating Temperature Range, TA ...................................... 0C to +70C Junction Temperature, TJ ................... 150C* Storage Temperature Range, TS ................................ -55C to +150C * Fault conditions that produce excessive junction temperature will activate device thermal shutdown circuitry. These conditions can be tolerated but should be avoided. + VBB 16 15 14 13 Dwg. PP-054 FEATURES s Controlled-Velocity Head Parking s Zero Deadband s High Transconductance Bandwidth s User-Adjustable Transconductance Gain s 800 mA Load Current s Dual Under-Voltage Monitors with Flag and User-Selectable Trip Points s Internal Thermal Shutdown Circuitry s Replaces UC3175 Always order by complete part number, e.g., A8958CLB . 8958 VOICE COIL MOTOR DRIVER FUNCTIONAL BLOCK DIAGRAM 14 LOAD SUPPLY 2 PARK VOLTAGE LIMIT 8 5 1.5 V IN A- 11 1.5 V IN A+ 10 GROUNDAB 6, 7 8 k 4 k SENSE IN+ 17 SENSE IN- 9 4 k INHIBIT + - - A 12 OUT A 13 OUT B B V BB TSD 15 IN B- - + + 16 IN B+ 18, 19 GROUND AB 23 PARK DRIVE + - 8 k 24 SENSE OUT 1.5 V BANDGAP REF V CC 1 LOGIC SUPPLY - PARK 22 PWR OK 20 (ACTIVE HIGH) + + - + - 3V 4 1.5 V 3 UV1 21 GROUND UV2 Dwg. FP-020C ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS 5 4 RJT = 6.0C/W 3 2 1 RJA = 55C/W 0 25 50 75 100 TEMPERATURE IN C 125 150 Dwg. GP-033A 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright (c) 1990, 2000 Allegro MicroSystems, Inc. 8958 VOICE COIL MOTOR DRIVER ELECTRICAL CHARACTERISTICS at TA = +25C, VCC = VBB = 12 V Limits Characteristic Logic Supply Voltage Range Logic Supply UV Threshold Logic Supply UV Hysteresis Supply Current Symbol VCC VCC VCC IBB ICC Inhibited Supply Current Thermal Shutdown Temp. Thermal Shutdown Hysteresis Output Power Drivers Output Saturation Voltage VSAT IOUT = 250 mA IOUT = 800 mA IOUT = -250 mA IOUT = -800 mA Total Saturation Voltage (Source + Sink) Input Offset Voltage Input Offset Drift Input Bias Current VSAT ILOAD = 250 mA ILOAD = 800 mA VIO VIO IIN Except INA+, VCM = 6 V INA+ to SENSEIN+ = 12 k, TJ = 25C Input Offset Current Differential Sense Input Current IIO IID INB only, VCM = 6 V IOUT = 5 mA IOUT = 500 mA Large Signal Gain Slew Rate Unity Gain Bandwidth AVS SR BW Amplifier A Amplifier B Common-Mode Rejection Clamp Diode Forward Voltage High-Side Current Limit Power Supply Rejection kCMR VF IOUT kSVR VCM = 1 V to 10 V IF = 800 mA, V2 1.7 V TJ = 25C VCC = 4 V to 15 V, VCM = 1.5 V VOUT = 2 V to 10 V, IOUT = 500 mA VCM = 6 V -- -- -- -- -- -- -- -- -- 69 -- -- -- 1.5 -- 0.5 0.5 70 -- -- 70 250 450 750 950 1.0 1.4 5.0 -- -150 84 -- 300 3.0 5.0 4.0 1.0 2.0 90 1.0 1.0 90 -- -- -- -- 1.4 2.0 8.0 25 -500 105 200 -- -- -- -- 1.7 2.2 -- 1.2 1.2 -- mV mV mV mV V V mV V/C nA A/V nA A mA V/mV V/s MHz MHz dB V A dB -- TJ TJ IBB + ICC, V2 1.7 V VOUT = 6 V, no load Test Conditions Operating High-to-low transition Min. 8.0 -- -- -- -- -- -- -- Typ. 12 2.8 200 2.0 23 3.0 165 8.0 Max. 16 3.0 -- -- -- 8.0 -- -- Units V V mV mA mA mA C C Negative current is defined as coming out of (sourcing) the specified device terminal. Typical Data is for design information only. Continued next page... www.allegromicro.com 8958 VOICE COIL MOTOR DRIVER ELECTRICAL CHARACTERISTICS (continued) Limits Characteristic Current Sense Amplifier Input Offset Voltage Input Offset Drift VIO VIO VCM = 6 V VCM = 0 V to 12 V -- -- -- Voltage Gain Output Saturation Voltage AVS VSAT VID = -1 V to +1 V, VCM = 6 V VOUT, IOUT(SINK) = 1.5 mA VCC - VOUT, IOUT(SOURCE) = -1.5 mA Park Function PARK DRIVE Leakage Current PARK DRIVE Saturation Voltage PARK Input Threshold PARK Input Current PARK VOLTAGE Input Current Under-Voltage Protection UV Threshold UV Threshold Hysteresis UV Input Current PWR OK Saturation Voltage PWR OK Leakage Current Auxiliary Functions LIMIT Input Voltage VLIMIT(L) VLIMIT(H) VLIMIT OUTA forced Low OUTA forced High Limit inactive Open circuit LIMIT Input Resistance INHIBIT Input Threshold INHIBIT Input Current RLIMIT V2 I2 V2 = 1.7 V VLIMIT = 1.2 V to 1.8 V 0.7 -- 1.2 1.45 -- 0.7 -- 0.8 2.2 -- 1.50 10 1.1 -- -- 2.3 1.8 1.55 -- 1.7 200 V V V V k V A VUV VUV IUV VCE(SAT) ICEX VUV = 1 V IC = 5 mA VCEX = 20 V Low-to-High Trans., Other Input = 6 V 1.48 15 -- -- -- 1.50 25 -0.5 -- -- 1.52 45 -1.5 450 5.0 V mV A mV A ICEX VCE(SAT) VPARK IPARK IPARK V VPARK = 1.7 V VCEX = 20 V IC = 200 mA -- -- 0.7 -- -- -- 300 1.1 -- -150 100 500 1.7 100 -500 A mV V A nA 1.95 -- -- -- -- -- 2.00 300 400 2.0 3000 8.0 2.05 500 700 mV V/V V/C -- mV mV Symbol Test Conditions Min. Typ. Max. Units Negative current is defined as coming out of (sourcing) the specified device terminal. Typical Data is for design information only. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 8958 VOICE COIL MOTOR DRIVER TERMINAL FUNCTIONS Term. 1 2 3&4 5 6&7 8 9 10 11 12 13 14 15 16 17 18 & 19 20 21 22 23 24 Terminal Name LOGIC SUPPLY INHIBIT UV1 and UV2 LIMIT GROUNDAB PARK VOLTAGE SENSEIN- INA+ INA- OUTA OUTB LOAD SUPPLY INB- INB+ SENSEIN+ GROUNDAB PWR OK GROUND PARK PARK DRIVE SENSEOUT Function VCC; logic supply voltage. An active-high logic input that inhibits the output stages without initiating a park. Under-voltage detection inputs. If not used, these terminals must be connected to the logic supply (VCC). A tri-state input that forces the output of amplifier A into saturation in either direction, or allows normal linear operation. Power amplifiers' ground and thermal heat sink. Auxiliary inverting input to power amplifier A. Inverting input to current sense error amplifer. Non-inverting input to power amplifier A. Inverting input to power amplifier A. Power amplifier A output to voice coil motor. Power amplifier B output to voice coil motor. VBB; load supply voltage. Inverting input to power amplifier B. Non-inverting input to power amplifier B. Non-inverting input to current sense error amplifer. Power amplifiers' ground and thermal heat sink. A logic low at this output indicates an under-voltage condition. Circuit reference. An active-high logic input that activates the park function. Power transistor for retract current control on power down or park command. Output of current sense error amplifier. www.allegromicro.com 8958 VOICE COIL MOTOR DRIVER CURRENT SENSING 500 pF R FA IN A- 330 k 10 k 10 k IN B- + VS - A RSENSE B OUT A I LOAD - OUT B SENSE IN- - IN A+ + + IN B+ SENSE IN+ RFB 8 k 4 k 4 k + - 8 k SENSE OUT Dwg. EP-034 PARKING FUNCTION PARK VOLTAGE R1 IN B- - A R2 1.5 V RSENSE B OUT A I PARK - OUT B + + IN B+ OPTIONAL PARK CURRENT LIMIT PARK DRIVE UV1 - PARK PWR OK (ACTIVE HIGH) + - + + 1.5 V UV2 3V V CC VOUT A = 1.5 (R1 + R2) R2 - Dwg. EP-039 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 8958 VOICE COIL MOTOR DRIVER Dimensions in Inches (for reference only) 24 13 0.0125 0.0091 0.2992 0.2914 0.491 0.394 0.050 0.016 0.020 0.013 1 2 3 0.6141 0.5985 0.050 BSC NOTE 1 NOTE 3 0 TO 8 0.0926 0.1043 0.0040 MIN. Dwg. MA-008-25 in Dimensions in Millimeters (controlling dimensions) 24 13 0.32 0.23 7.60 7.40 10.65 10.00 1.27 0.40 0.51 0.33 1 2 3 15.60 15.20 1.27 BSC NOTE 1 NOTE 3 0 TO 8 2.65 2.35 0.10 MIN. Dwg. MA-008-25A mm NOTES: 1. Webbed lead frame. Leads 6, 7, 18, and 19 are internally one piece. 2. Lead spacing tolerance is non-cumulative. 3. Exact body and lead configuration at vendor's option within limits shown. www.allegromicro.com 8958 VOICE COIL MOTOR DRIVER The products described here are manufactured under one or more U.S. patents or U.S. patents pending. Allegro MicroSystems, Inc. reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current. Allegro products are not authorized for use as critical components in life-support devices or systems without express written approval. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 |
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