Data Sheet 26300.5A 8958 VOICE COIL MOTOR DRIVER LOGIC SUPPLY 1 INHIBIT 2 V CC 1.5 V + 24 SENSE OUT 23 PARK DRIVE 22 PARK UV1 3 UV2 4 21 GROUND LIMIT 5 20 PWR OK GROUND AB 6 19 GROUNDAB GROUND AB 7 18 GROUNDAB PARK VOLTAGE 8 17 SENSE IN+ SENSE IN– 99 16 IN B+ IN A+ 10 - 15 IN B– VBB 14 LOAD SUPPLY 13 OUT B + B + A IN A– OUT A 11 12 - Dwg. PP-054 ABSOLUTE MAXIMUM RATINGS at TA = 25°C 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 ...................................... 0°C to +70°C Junction Temperature, TJ ................... 150°C* Storage Temperature Range, TS ................................ -55°C to +150°C * Fault conditions that produce excessive junction temperature will activate device thermal shutdown circuitry. These conditions can be tolerated but should be avoided. 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 0°C to +70°C. FEATURES ■ Controlled-Velocity Head Parking ■ Zero Deadband ■ High Transconductance Bandwidth ■ User-Adjustable Transconductance Gain ■ ±800 mA Load Current ■ Dual Under-Voltage Monitors with Flag and User-Selectable Trip Points ■ Internal Thermal Shutdown Circuitry ■ 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 8 LIMIT 5 + 1.5 V TSD – V BB – IN A– 11 1.5 V IN A+ 10 GROUNDAB A 13 12 + OUT B OUT A – 15 IN B– + 16 IN B+ B 6, 7 18, 19 GROUND AB 23 PARK DRIVE 8 kΩ 4 kΩ SENSE IN+ 17 + 9 – SENSE IN– INHIBIT 4 kΩ 24 1.5 V BANDGAP REF SENSE OUT 8 kΩ V CC 1 LOGIC SUPPLY 4 UV1 3 UV2 – PARK 22 + PWR OK 20 (ACTIVE HIGH) 3V + – 21 GROUND + 1.5 V – ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS Dwg. FP-020C 5 RθJT = 6.0°C/W 4 3 2 RθJA = 55°C/W 1 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 © 1990, 2000 Allegro MicroSystems, Inc. 8958 VOICE COIL MOTOR DRIVER ELECTRICAL CHARACTERISTICS at TA = +25°C, VCC = VBB = 12 V Limits Characteristic Symbol Test Conditions Min. Typ. Max. Units Logic Supply Voltage Range VCC Operating 8.0 12 16 V Logic Supply UV Threshold VCC High-to-low transition — 2.8 3.0 V Logic Supply UV Hysteresis ∆VCC — 200 — mV — 2.0 — mA — 23 — mA — 3.0 8.0 mA Supply Current IBB VOUT = 6 V, no load ICC IBB + ICC, V2 ≥ 1.7 V Inhibited Supply Current — Thermal Shutdown Temp. TJ — 165 — °C ∆TJ — 8.0 — °C IOUT = 250 mA — 250 — mV IOUT = 800 mA — 450 — mV IOUT = -250 mA — 750 — mV IOUT = -800 mA — 950 — mV ILOAD = 250 mA — 1.0 1.4 V ILOAD = 800 mA — 1.4 2.0 V VCM = 6 V — 5.0 8.0 mV — — 25 µV/°C Except INA+, VCM = 6 V — -150 -500 nA INA+ to SENSEIN+ = 12 kΩ, TJ = 25°C 69 84 105 µA/V Thermal Shutdown Hysteresis Output Power Drivers Output Saturation Voltage Total Saturation Voltage (Source + Sink) Input Offset Voltage Input Offset Drift Input Bias Current VSAT VSAT VIO ∆VIO IIN Input Offset Current IIO INB only, VCM = 6 V — — 200 nA Differential Sense Input Current IID IOUT = 5 mA — ±300 — µA IOUT = 500 mA — 3.0 — mA VOUT = 2 V to 10 V, IOUT = ±500 mA 1.5 5.0 — V/mV — 4.0 — V/µs Amplifier A 0.5 1.0 1.7 MHz Amplifier B 0.5 2.0 2.2 MHz VCM = 1 V to 10 V 70 90 — dB IF = 800 mA, V2 ≥ 1.7 V — 1.0 1.2 V Large Signal Gain AVS Slew Rate SR Unity Gain Bandwidth BW Common-Mode Rejection Clamp Diode Forward Voltage kCMR VF High-Side Current Limit IOUT TJ = 25°C — 1.0 1.2 A Power Supply Rejection kSVR VCC = 4 V to 15 V, VCM = 1.5 V 70 90 — dB Negative current is defined as coming out of (sourcing) the specified device terminal. Typical Data is for design information only. www.allegromicro.com Continued next page... 8958 VOICE COIL MOTOR DRIVER ELECTRICAL CHARACTERISTICS (continued) Limits Characteristic Symbol Test Conditions Min. Typ. Max. Units VCM = 6 V — — 2.0 mV VCM = 0 V to 12 V — — 3000 µV/V — — 8.0 µV/°C 1.95 2.00 2.05 — Current Sense Amplifier Input Offset Voltage Input Offset Drift VIO ∆VIO Voltage Gain AVS VID = -1 V to +1 V, VCM = 6 V Output Saturation Voltage VSAT VOUT, IOUT(SINK) = 1.5 mA — 300 500 mV VCC - VOUT, IOUT(SOURCE) = -1.5 mA — 400 700 mV ICEX VCEX = 20 V — — 100 µA VCE(SAT) IC = 200 mA — 300 500 mV 0.7 1.1 1.7 V — — 100 µA — -150 -500 nA 1.48 1.50 1.52 V 15 25 45 mV Park Function PARK DRIVE Leakage Current PARK DRIVE Saturation Voltage PARK Input Threshold VPARK PARK Input Current IPARK PARK VOLTAGE Input Current VPARK = 1.7 V IPARK V Under-Voltage Protection UV Threshold UV Threshold Hysteresis UV Input Current PWR OK Saturation Voltage PWR OK Leakage Current VUV Low-to-High Trans., Other Input = 6 V ∆VUV IUV VUV = 1 V — -0.5 -1.5 µA VCE(SAT) IC = 5 mA — — 450 mV VCEX = 20 V — — 5.0 µA VLIMIT(L) OUTA forced Low 0.7 0.8 — V VLIMIT(H) OUTA forced High — 2.2 2.3 V Limit inactive 1.2 — 1.8 V Open circuit 1.45 1.50 1.55 V — 10 — kΩ 0.7 1.1 1.7 V — — 200 µA ICEX Auxiliary Functions LIMIT Input Voltage VLIMIT LIMIT Input Resistance RLIMIT INHIBIT Input Threshold V2 INHIBIT Input Current I2 VLIMIT = 1.2 V to 1.8 V V2 = 1.7 V 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. Terminal Name Function 1 LOGIC SUPPLY VCC; logic supply voltage. 2 INHIBIT An active-high logic input that inhibits the output stages without initiating a park. 3&4 UV1 and UV2 Under-voltage detection inputs. If not used, these terminals must be connected to the logic supply (VCC). 5 LIMIT 6&7 GROUNDAB 8 PARK VOLTAGE Auxiliary inverting input to power amplifier A. 9 SENSEIN– Inverting input to current sense error amplifer. 10 INA+ Non-inverting input to power amplifier A. 11 INA– Inverting input to power amplifier A. 12 OUTA Power amplifier A output to voice coil motor. 13 OUTB Power amplifier B output to voice coil motor. 14 LOAD SUPPLY 15 INB– Inverting input to power amplifier B. 16 INB+ Non-inverting input to power amplifier B. 17 SENSEIN+ 18 & 19 GROUNDAB 20 PWR OK A logic low at this output indicates an under-voltage condition. 21 GROUND Circuit reference. 22 PARK 23 PARK DRIVE 24 SENSEOUT www.allegromicro.com 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. VBB; load supply voltage. Non-inverting input to current sense error amplifer. Power amplifiers’ ground and thermal heat sink. 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. 8958 VOICE COIL MOTOR DRIVER CURRENT SENSING 500 pF 330 kΩ 10 kΩ 10 kΩ R FA IN B– IN A– + RSENSE – VS – A OUT A + – B I IN A+ OUT B LOAD IN B+ SENSE IN– SENSE IN+ 4 kΩ 4 kΩ RFB + + – 8 kΩ 8 kΩ SENSE OUT Dwg. EP-034 PARKING FUNCTION PARK VOLTAGE R1 IN B– RSENSE – – A R2 1.5 V + B OUT A I OUT B PARK IN B+ + OPTIONAL PARK CURRENT LIMIT PARK DRIVE UV1 – PARK + PWR OK (ACTIVE HIGH) – 1.5 V UV2 + + VOUT A = 1.5 (R1 + R2) – 3V V CC 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 0.491 0.394 0.2992 0.2914 0.050 0.016 0.020 0.013 1 2 3 0.050 0.6141 0.5985 0° TO 8 BSC NOTE 1 NOTE 3 0.0926 0.1043 0.0040 MIN. Dwg. MA-008-25 in Dimensions in Millimeters (controlling dimensions) 24 13 0.32 0.23 10.65 10.00 7.60 7.40 1.27 0.40 0.51 0.33 1 2 3 15.60 15.20 1.27 BSC 0° TO 8 NOTE 1 NOTE 3 2.65 2.35 0.10 MIN. 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 Dwg. MA-008-25A mm 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