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Part: 8936
Category:
Description:
Company: Allegro Micro Systems, Inc.
Datasheet: Download 8936 datasheet File size : 421 kB
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Datasheet text preview:
8936DATA SHEET INTERIM
March 16, 1993
VSubjeCtE change without notice) COIL MOTOR DRIVER ( OI c to
8936
VOICE COIL MOTOR DRIVER
Data Sheet 26300.6
A8936CLW
RET REF V FLT V BEMF GROUND UV SET 1 2 3 4 5 28 R S WINDOW COMP. Q 27 26 25 24 23 RET SET V SENS VEL FLT V SENS FB SGND N OUTP
PROTECT CIRCUIT
R OUT P
OUT
EN VEL FLT
IN N VEL IN
RETRACT FAULT MP RESET
SIGNAL SUPPLY
ABSOLUTE
Supply Voltages, VCC and VDD .. 6.0 V Output Current, IOUT (peak) .......... ±600 mA (continuous) ... ±500 mA Analog Input Voltage Range, VIN .. -0.3 V to VCC Logic Input Voltage Range, VIN ....... -0.3 V to +6.0 V 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.
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.
T C UY DL ON RO PE DC EN UE IN ER TF NE OR CR IS O DF --
V REF 6 7 8
Providing control and drive of the voice coil motor used for head positioning in 5 V disk drive applications, the A8936C-- 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. An under- or over-velocity sense disables the system in a controlled sequence if a fault condition occurs. The two ±500 mA MOS driver outputs provide very low saturation voltage and minimal power dissipation. Additional headroom is achieved by the sense-FET structure eliminating the need for an external current-sense resistor. Thermal protection and under-voltage lockout disables the system in a controlled sequence if a fault condition occurs.
+
VREF
VDD
22
LOAD SUPPLY OUT N
21 20
9
SGND P ACT FB
10
19 18 17 16
11
PWR OFF H GAIN
12
PROTECT CIRCUIT
13
14
V CC
+
REFERENCE ACT
15
FEATURES
s s s s s s s s s s s
Dwg. PP-046A
MAXIMUM
RATINGS
Over-Velocity Fault Function Lossless Current Sensing Zero Deadband High Transconductance Bandwidth User-Adjustable Transconductance Gain Digital Transconductance Gain Switch (4:1 Ratio) 5 Volt Monitor with Selectable UV Trip Point Retract Circuitry Functional to 0 Volts Chip Enable/Sleep Mode Function 1 V at 500 mA Output Saturation Voltage Internal Thermal Shutdown Circuitry
Always order by complete part number: Part Number Package A8936CJT A8936CLW
64-Lead Thin Quad Flatpack 28-Lead SOIC
A
TM
MicroSystems, Inc.
8936
VOICE COIL MOTOR DRIVER
FUNCTIONAL
= 'LW' WIDE-BODY SOIC = 'JT' THIN QUAD FLATPACK SIGNAL SUPPLY
14 53
BLOCK
LOAD SUPPLY VDD
DIAGRAM
ACT FB 19 1 ERROR AMP
I SENSE +
ACT 15 55 REFERENCE 16 58 H GAIN 17 60
+
2V POWER CONTROL LOGIC
+
POWER AMP
PWR OFF 18 62
I SENSE
CURRENT-SENSE AMP
V REF
+
WINDOW COMP.
46 10
TSD FAULT 12 50 MP RESET 13 51 PROTECTION CIRCUITRY
33 5 28 3 27 2 23 28
RETRACT CONTROL
25 1 47 11 34 6 19 26
Q Q
S R
30 4
RETRACT
UVSET
VBEMF
V FLT
RET SET
RET REF
R OUT P
VEL FLT
GROUND
ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS
2.0
+ --
V CC PROTECT. CIRCUIT
1.5
1.0
V
DD
V REF
WINDOW
0.5
COMP.
S
R
0
Q
25
50 75 100 125 AMBIENT TEMPERATURE IN °C
150
Dwg. GP-034
Dwg. PP-052-1
A
TM
MicroSystems, Inc.
115 Northeast Cutoff, Box 15036 11orcester, Massachusetts15036 W 5 Northeast Cutoff, Box 01615-0036 (508) 853-5000 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 1992, 1993, Allegro MicroSystems, Inc.
45 9 2 20 13 23 4 21 15 24 16 25 21 27
V CC
V REF
+
35 7
22
8
OUT IN N SGND P OUT P OUT N SGND N V SENS FB V SENS
VEL IN EN VEL FLT
V REF
36 8
Dwg. FP-030A
A8936CJT
/W R, C AI 66° EE = FR JA R
V REF
+
--
RETRACT CONTROL PROTECT. CIRCUIT
8936
VOICE COIL MOTOR DRIVER
ELECTRICAL CHARACTERISTICS at TA = +25°C, VCC = V DD = 5.0 V, VREF = VIN= 2.0 V, Load = 150 µH/3.5 (unless otherwise noted).
Characteristic Error Amplifier Input Offset Voltage Current Gain Current Gain Linearity Reference Voltage Range Current-Sense Amplifier Voltage Gain Input Offset Voltage Output Drivers Output Saturation Voltage (Source + Sink) Retract Output Saturation Voltage Output Current Full Power Bandwidth Window Comparator Lower Trip Point Upper Trip Point Uncommitted Op Amp Voltage Gain Unity Gain Bandwidth Max. Load Capacitance Slew Rate Output Voltage Max. Output Current Input Offset Voltage AVS BW CLOAD SR VO IO V IO VIO = 100 mV -- -- 40 -- 2.5 -- -- 91 1.0 -- 4.2 -- ±250 -- -- -- -- -- 3.5 -- ± 10 dB MHz pF V/ µ s V µA mV V E L IN V E L IN 1.12 2.47 1.25 2.75 1.38 3.03 V V V DS(SAT) ILOAD = 100 mA ILOAD = 500 mA V DS(SAT) IO BW IOUT 150 mA Pulse Test, ±600 mA Limited -3 dB -- -- -- -- 1.0 0.25 1.5 -- -- -- -- -- 1.0 ±500 -- V V V mA kHz A VD ViO Rs = Rgm ILOAD = 0 mA, A i = AiL -- -- 1.0 -- -- ± 25 -- mV V IO A iH A iL E L(adj) VREF ILOAD = 0 mA H GAIN 3.5 V H GAIN 0.7 V IOUT = 5 mA to 500 mA, Ai = A iL IOUT = 5 mA to 500 mA, Ai = A iH -- 7200 1800 -- -- 1.5 -- 8000 2000 -- -- -- 50 8800 2200 ± 10 ± 10 2.5 mV -- -- % % V Symbol Test Conditions Min. Limits Typ. Max. Units
Continued next page ... Negative current is defined as coming out of (sourcing) the specified device terminal. Typical Data is for design information only.
8936
VOICE COIL MOTOR DRIVER
ELECTRICAL CHARACTERISTICS at TA = +25°C, VCC = VDD = 5.0 V, VREF = VIN= 2.0 V, Load = 150 µH/3.5 (unless otherwise noted).
Characteristic Miscellaneous Under-Voltage Lockout Voltage Fault Logic Output VCC V FAULT V CC = V DD V RETRACT 3.5 V V RETRACT 0.7 V I FAULT Power-On Reset V MPRESET V FLT = 2.25 V V RETRACT 3.5 V V RETRACT 0.7 V, IMPRESET = 1.5 mA Total Supply Current ICC + IDD Outputs Balanced, No Load Sleep Mode, PWR OFF = VCC Logic Input Voltage V IN(0) V IN(1) Thermal Shutdown Temperature Thermal Shutdown Hysteresis TJ T J 3.9 -- 4.5 20 4.5 -- -- -- -- 3.5 -- -- 4.2 -- -- -- -- -- -- -- -- -- 165 20 4.35 500 -- -- -- 800 10 2.0 0.7 -- -- -- V mV V µA V mV mA mA V V °C °C Symbol Test Conditions Min. Limits Typ. Max. Units
Negative current is defined as coming out of (sourcing) the specified device terminal. Typical Data is for design information only.
A
TM
MicroSystems, Inc.
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
8936
VOICE COIL MOTOR DRIVER
TERMINAL
"JT" Term."LW" Term. Term. Name 25 27 28 30 33 1 2 3 4 5 RET REF VFLT VBEMF GROUND UVSET R OUT P OUT EN VEL FLT INN VELIN RETRACT FAULT MPRESET Function
FUNCTIONS
The reference supply for setting the voltage across the load during retract. Reservoir (energy storage) capacitor used to operate fault circuitry. Back-EMF voltage from spindle motor used to retract heads during loss of power. Circuit reference. Under-voltage trip point reference input. Set internally to 4.3 V but may be over-ridden by external resistor divider. (Equation 4). Source driver used for retract; externally connected to OUTP. Output of uncommitted operational amplifier. Logic input for over-velocity fault latch. Inverting input to uncommitted operational amplifier. Analog voltage input corresponding to motor speed. An active-low logic input that initiates the retract sequence. A logic low at this MOS output indicates a thermal shutdown, under-voltage fault, or retract command. (Power-On Reset) A logic low at this open-collector output may be used to reset the system on under-voltage fault or power ON.
34 35 36 45 46 47 50 51
6 7 8 9 10 11 12 13
53 55
14 15
SIGNAL SUPPLY VCC ; low-current supply voltage in the range of 4.5 V to 5.5 V. ACT Input which controls the current in the load. Transconductance gain is set with an external resistor in series with this input (Equation 1).
58 60 62 1 2 4 8 13 15 16
16 17 18 19 20 21 22 23 24 25
REFERENCE VREF; reference input for all amplifiers; ac ground. H GAIN PWR OFF ACTFB SGNDP OUT N Logic input to switch the error amplifier transconductance gain: LOW = 2100, HIGH = 8400. An active-high logic input that puts the device in a "sleep mode". All fault circuitry remains active. Input connection for feedback network which sets the error amplifier gain and bandwidth. Power ground for the OUTP sink driver. Power output. Sinks current when VACT < VREF.
LOAD SUPPLY VDD ; high-current supply voltage for the voice-coil motor. OUTP SGNDN V SENS FB VEL FLT V SENS RET SET Power output. Sinks current when VACT > VREF. Power ground for the OUTN sink driver. Input connection for feedback network which sets the current-sense amplifier gain and bandwidth. Also called gm SET. An active-low logic output indicating an over-velocity fault. Voltage output representing load current (Equation 2). Also called MONITOR. An external resistor divider to set the retract voltage across the load. Used in conjunction with VRET-REF (Equation 3).
19 21 23
26 27 28
Others parts begin by 89
89-1
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