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3966
A3966SLB (SOIC)
DUAL FULL-BRIDGE PWM MOTOR DRIVER
The A3966SA and A3966SLB are designed to drive both windings of a twophase bipolar stepper motor. Each device includes two H-bridges capable of continuous output currents of 650 mA and operating voltages to 30 V. Motor winding current can be controlled by the internal fixed-frequency, pulse-width modulated (PWM), current-control circuitry. The peak load current limit is set by the user's selection of a reference voltage and current-sensing resistors. Except for package style and pinout, the two devices are identical. The fixed-frequency pulse duration is set by a user-selected external RC timing network. The capacitor in the RC timing network also determines a userselectable blanking window that prevents false triggering of the PWM currentcontrol circuitry during switching transitions. To reduce on-chip power dissipation, the H-bridge power outputs have been optimized for low saturation voltages. The sink drivers feature the Allegro(R) patented Satlington(R) output structure. The Satlington outputs combine the low voltage drop of a saturated transistor and the high peak current capability of a Darlington. For each bridge, a PHASE input controls load-current polarity by selecting the appropriate source and sink driver pair. For each bridge, an ENABLE input, when held high, disables the output drivers. Special power-up sequencing is not required. Internal circuit protection includes thermal shutdown with hysteresis, ground-clamp and flyback diodes, and crossover-current protection. The A3966SA is supplied in a 16-pin dual in-line plastic package. The A3966SLB is supplied in a 16-lead plastic SOIC with copper heat sink tabs. The power tab is at ground potential and needs no electrical isolation. The A3966SLB is also available in a lead (Pb) free version, with 100% matte tin leadframe plating.
Data Sheet 29319.25G
OUT1A PHASE 1 ENABLE 1 GROUND SENSE1 OUT 1B LOAD SUPPLY REFERENCE
1 2 3 4 5 6 V 7 8 V
REF BB
16 V BB 15 14 LOGIC LOGIC 13 12 11 VCC RC 10 9
OUT 2A PHASE 2 ENABLE 2 GROUND SENSE 2 OUT 2B LOGIC SUPPLY RC
Dwg. PP-066-1
ABSOLUTE MAXIMUM RATINGS
Load Supply Voltage, VBB ...................... 30 V Output Current, IOUT (peak) ........... 750 mA (continuous) .............................. 650 mA Logic Supply Voltage, VCC .................... 7.0 V Input Voltage, Vin ........ -0.3 V to VCC + 0.3 V Sense Voltage, VS ................................ 1.0 V Package Power Dissipation (TA = 25C), PD A3966SA ..................................... 2.08 W* A3966SLB ................................... 1.87 W* Operating Temperature Range, TA ..................................... -20C to +85C Junction Temperature, TJ .................................................. +150C Storage Temperature Range, TS ................................... -55C to +150C
Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any set of conditions, do not exceed the specified current rating or a junction temperature of 150C. * Per SEMI G42-88 Specification, Thermal Test Board Standardization for Measuring Junction-to-Ambient Thermal Resistance of Semiconductor Packages.
FEATURES
650 mA Continuous Output Current 30 V Output Voltage Rating Internal Fixed-Frequency PWM Current Control Satlington Sink Drivers User-Selectable Blanking Window Internal Ground-Clamp & Flyback Diodes Internal Thermal-Shutdown Circuitry Crossover-Current Protection and UVLO Protection
P a rt N um b e r A 3 9 6 6 S L B -T A 3 9 6 6 S L B T R -T
*
P b -fre e * Ye s Ye s
P ackage 1 6 -L e a d S O IC 1 6 -L e a d S O IC
P a c k ing 4 7 p e r tub e 1 0 0 0 p e r re e l
Pb-based variants are being phased out of the product line. The variants cited in this footnote are in production but have been determined to be LAST TIME BUY. This classification indicates that sale of this device is currently restricted to existing customer applications. The variants should not be purchased for new design applications because obsolescence in the near future is probable. Samples are no longer available. Status change: October 31, 2006. Deadline for receipt fo LAST TIME BUY orders: April 27, 2007. These variants include: A3966SA, A3966SLB, and A3966SLBTR.
3966 DUAL FULL-BRIDGE PWM MOTOR DRIVER
FUNCTIONAL BLOCK DIAGRAM
OUT 1A
OUT 1B
V CC PHASE 1 V BB PHASE 2
+
LOGIC SUPPLY
OUT 2A
OUT 2B
LOAD SUPPLY
UVLO & TSD
CONTROL LOGIC1
CONTROL LOGIC2
UVLO & TSD
ENABLE 1
SOURCE ENABLE 1
ENABLE 2 CURRENT-SENSE COMPARATOR 1 SENSE 1 SENSE 2 CURRENT-SENSE COMPARATOR 2
PWM LATCH 1 R Q S
BLANKING GATE 1
+ -
+ -
BLANKING GATE 2
PWM LATCH 2 R Q S
/4 OSC RC R1S R 2S
SOURCE ENABLE 2
GROUND
RT
CT
REFERENCE
Dwg. FP-036-6
A3966SA (DIP)
SENSE 1 OUT 1B LOAD SUPPLY REFERENCE RC LOGIC SUPPLY OUT 2B SENSE 2 1
LOGIC
TRUTH TABLE
16 15 14 ENABLE 1 PHASE 1 OUT 1A GROUND GROUND OUT 2A PHASE 2 ENABLE 2
2 3 4 5 6 7 8 V REF RC V
PHASE X H L
ENABLE H L L
OUTA Off H L
OUTB Off L H
V BB
13 12 11
X = Irrelevant
CC
LOGIC
10 9
Dwg. PP-066-2
2
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright (c) 1998, 2003 Allegro MicroSystems, Inc.
3966 DUAL FULL-BRIDGE PWM MOTOR DRIVER
ELECTRICAL CHARACTERISTICS at TA = +25C, VBB = 30 V, VCC = 4.75 V to 5.5 V, VREF = 2 V, VS = 0 V, 56 k & 680 pF RC to Ground (unless noted otherwise)
Limits Characteristic Output Drivers
Load Supply Voltage Range Output Leakage Current Output Saturation Voltage V BB ICEX VCE(SAT) Operating, IOUT = 650 mA, L = 3 mH VOUT = 30 V VOUT = 0 V Source Driver, IOUT = -400 mA Source Driver, IOUT = -650 mA Sink Driver, IOUT = +400 mA, VS = 0.5 V Sink Driver, IOUT = +650 mA, VS = 0.5 V Clamp Diode Forward Voltage Motor Supply Current (No Load) VF IBB(ON) IBB(OFF) IF = 4 0 0 m A IF = 6 5 0 m A VENABLE1 = VENABLE2 = 0.8 V VENABLE1 = VENABLE2 = 2.4 V VCC -- -- -- -- -- -- -- -- -- -- -- <1.0 <-1.0 1.7 1.8 0.3 0.7 1.1 1.4 3.0 <1.0 30 50 -50 2.0 2.1 0.5 1.3 1.4 1.6 5.0 200 V A A V V V V V V mA A
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Control Logic
Logic Supply Voltage Range Logic Input Voltage Logic Input Current Reference Input Volt. Range Reference Input Current Reference Divider Ratio Current-Sense Comparator Input Offset Voltage Current-Sense Comparator Input Voltage Range Sense-Current Offset VCC VIN(1) VIN(0) IIN(1) IIN(0) VREF IREF VREF/VTRIP VIO VS ISO VREF = 0 V Operating IS - IOUT, 50 mA IOUT 650 mA VIN = 2.4 V VIN = 0.8 V Operating Operating 4.75 2.4 -- -- -- 0.1 -2.5 3.8 -6.0 -0.3 12 -- -- -- <1.0 <-20 - 0 4.0 0 -- 18 5.50 -- 0.8 20 -200 2.0 1.0 4.2 6.0 1.0 24 V V V A A V A -- mV V mA
NOTES:1. Typical Data is for design information only. 2. Negative current is defined as coming out of (sourcing) the specified device terminal.
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3
3966 DUAL FULL-BRIDGE PWM MOTOR DRIVER
ELECTRICAL CHARACTERISTICS at TA = +25C, VBB = 30 V, VCC = 4.75 V to 5.5 V, VREF = 2 V, VS = 0 V, 56 k & 680 pF RC to Ground (unless noted otherwise) (cont.)
Limits Characteristic Control Logic (continued)
PWM RC Frequency PWM Propagation Delay Time Cross-Over Dead Time Propagation Delay Times fosc t PWM tcodt t pd CT = 680 pF, RT = 56 k Comparator Trip to Source OFF Cycle Reset to Source ON 1 k Load to 25 V IOUT = 650 mA, 50% to 90%: ENABLE ON to Source ON ENABLE OFF to Source OFF ENABLE ON to Sink ON ENABLE OFF to Sink OFF PHASE Change to Sink ON PHASE Change to Sink OFF PHASE Change to Source ON PHASE Change to Source OFF 22.9 -- -- 0.2 -- -- -- -- -- -- -- -- -- -- Increasing VCC VENABLE 1 = VENABLE 2 = 0.8 V VENABLE 1 = VENABLE 2 = 2.4 V -- 0.1 -- -- 25.4 1.0 0.8 1.8 100 500 200 200 2200 200 2200 200 165 15 4.1 0.6 -- -- 27.9 1.4 1.2 3.0 -- -- -- -- -- -- -- -- -- -- 4.6 -- 50 9.0 kHz s s s ns ns ns ns ns ns ns ns C C V V mA mA
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Thermal Shutdown Temp. Thermal Shutdown Hysteresis UVLO Enable Threshold UVLO Hysteresis Logic Supply Current
TJ TJ VT(UVLO)+ VT(UVLO)hys ICC(ON) ICC(OFF)
NOTES:1. Typical Data is for design information only. 2. Negative current is defined as coming out of (sourcing) the specified device terminal.
4
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
3966 DUAL FULL-BRIDGE PWM MOTOR DRIVER
FUNCTIONAL DESCRIPTION
Internal PWM Current Control. The A3966SA and A3966SLB dual H-bridges are designed to drive both windings of a bipolar stepper motor. Load current can be controlled in each motor winding by an internal fixedfrequency PWM control circuit. The current-control circuitry works as follows: when the outputs of the Hbridge are turned on, current increases in the motor winding. The load current is sensed by the current-control comparator via an external sense resistor (RS). Load current continues to increase until it reaches the predetermined value, set by the selection of external currentsensing resistors and reference input voltage (VREF) according to the equation: ITRIP = IOUT + ISO = VREF/(4 RS) where ISO is the sense-current error (typically 18 mA) due to the base-drive current of the sink driver transistor. At the trip point, the comparator resets the sourceenable latch, turning off the source driver of that H-bridge. The source turn off of one H-bridge is independent of the other H-bridge. Load inductance causes the current to recirculate through the sink driver and ground-clamp diode. The current decreases until the internal clock oscillator sets the source-enable latches of both H-bridges, turning on the source drivers of both bridges. Load current increases again, and the cycle is repeated. The frequency of the internal clock oscillator is set by the external timing components RTCT. The frequency can be approximately calculated as: fosc = 1/(RT CT + tblank) where tblank is defined below. The range of recommended values for RT and CT are 20 k to 100 k and 470 pF to 1000 pF respectively. Nominal values of 56 k and 680 pF result in a clock frequency of 25 kHz. Current-Sense Comparator Blanking. When the source driver is turned on, a current spike occurs due to the reverse-recovery currents of the clamp diodes and switching transients related to distributed capacitance in the load. To prevent this current spike from erroneously resetting the source enable latch, the current-control comparator output is blanked for a short period of time when the source driver is turned on. The blanking time is set by the timing component CT according to the equation: tblank = 1900 CT (s). A nominal CT value of 680 pF will give a blanking time of 1.3 s. The current-control comparator is also blanked when the H-bridge outputs are switched by the PHASE or ENABLE inputs. This internally generated blank time is approximately 1 s.
V BB
V PHASE
See Enlargement A
+
I OUT 0 -
BRIDGE ON ALL OFF
BRIDGE ON SOURCE OFF ALL OFF
BRIDGE ON Enlargement A td
I TRIP
SOURCE OFF
t blank INTERNAL OSCILLATOR R TC T
Dwg. WM-003-2
RS
Dwg. EP-006-16
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5
3966 DUAL FULL-BRIDGE PWM MOTOR DRIVER
FUNCTIONAL DESCRIPTION (continued)
Load Current Regulation. Due to internal logic and switching delays (td), the actual load current peak will be slightly higher than the ITRIP value. These delays, plus the blanking time, limit the minimum value the current control circuitry can regulate. To produce zero current in a winding, the ENABLE terminal should be held high, turning off all output drivers for that H-bridge. Logic Inputs. A logic high on the PHASE input results in current flowing from OUTA to OUTB of that H-bridge. A logic low on the PHASE input results in current flowing from OUTB to OUTA. An internally generated dead time (tcodt) of approximately 1 s prevents cross-over current spikes that can occur when switching the PHASE input. A logic high on the ENABLE input turns off all four output drivers of that H-bridge. This results in a fast current decay through the internal ground clamp and flyback diodes. A logic low on the ENABLE input turns on the selected source and sink driver of that H-bridge. The ENABLE inputs can be pulse-width modulated for applications that require a fast current-decay PWM. If external current-sensing circuitry is used, the internal current-control logic can be disabled by connecting the RTCT terminal to ground. The REFERENCE input voltage is typically set with a resistor divider from VCC. This reference voltage is internally divided down by 4 to set up the current-comparator trip-voltage threshold. The reference input voltage range is 0 to 2 V. Output Drivers. To minimize on-chip power dissipation, the sink drivers incorporate a Satlington structure. The Satlington output combines the low VCE(sat) features of a saturated transistor and the high peak-current capability of a Darlington (connected) transistor. A graph showing typical output saturation voltages as a function of output current is on the next page. Miscellaneous Information. Thermal protection circuitry turns off all output drivers should the junction temperature reach +165 C (typical). This is intended only to protect the device from failures due to excessive junction temperatures and should not imply that output short circuits are permitted. Normal operation is resumed when the junction temperature has decreased about 15C. The A3966 current control employs a fixed-frequency, variable duty cycle PWM technique. As a result, the current-control regulation may become unstable if the duty cycle exceeds 50%. To minimize current-sensing inaccuracies caused by ground trace IR drops, each current-sensing resistor should have a separate return to the ground terminal of the device. For low-value sense resistors, the I x R drops in the printed-wiring board can be significant and should be taken into account. The use of sockets should be avoided as their contact resistance can cause variations in the effective value of RS. The LOAD SUPPLY terminal, VBB, should be decoupled with an electrolytic capacitor (47 F recommended) placed as close to the device as physically practical. To minimize the effect of system ground I x R drops on the logic and reference input signals, the system ground should have a low-resistance return to the load supply voltage. The frequency of the clock oscillator will determine the amount of ripple current. A lower frequency will result in higher current ripple, but reduced heating in the motor and driver IC due to a corresponding decrease in hysteretic core losses and switching losses respectively. A higher frequency will reduce ripple current, but will increase switching losses and EMI.
6
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
3966 DUAL FULL-BRIDGE PWM MOTOR DRIVER
2.5 TA = +25C 2.0 SOURCE DRIVER 1.5
Typical output saturation voltages showing Satlington sink-driver operation.
OUTPUT SATURATION VOLTAGE IN VOLTS
1.0
0.5 SINK DRIVER 0
TYPICAL APPLICATION (A3966SLB)
200
300
400
500
600
700
Dwg. GP-064-1A
OUTPUT CURRENT IN MILLIAMPERES
1 PHASE 1 ENABLE 1 2 3 4 0.5 +5 V 6 5 LOGIC LOGIC V
BB
16 15 14 13 12 11 V
BB
PHASE 2 ENABLE 2
0.5
The products described here are manufactured under one or more U.S. patents or U.S. patents pending. Satlington(R) is a registered trademark of Allegro MicroSystems, Inc. (Allegro), and Satlington devices are manufactured under U. S. Patent No. 5,684,427. 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.
39 k
+24 V 7 8 VREF
VCC RC
10 9
+5 V
10 k
Dwg. EP-047-4A
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56 k
47 F
680 pF
+
7
3966 DUAL FULL-BRIDGE PWM MOTOR DRIVER
A3966SA
Dimensions in Inches (controlling dimensions)
16 9 0.014 0.008
0.430 0.280 0.240
MAX
0.300
BSC
1 0.070 0.045
0.100 0.775 0.735
BSC
8 0.005
MIN
0.210
MAX
0.015
MIN
0.150 0.115 0.022 0.014
Dwg. MA-001-16A in
Dimensions in Millimeters (for reference only)
16 9
0.355 0.204
10.92 7.11 6.10
MAX
7.62
BSC
1 1.77 1.15
2.54 19.68 18.67
BSC
8 0.13
MIN
5.33
MAX
0.39
MIN
3.81 2.93 0.558 0.356
Dwg. MA-001-16A mm
NOTES: 1. 2. 3. 4.
Exact body and lead configuration at vendor's option within limits shown. Lead spacing tolerance is non-cumulative. Lead thickness is measured at seating plane or below. Supplied in standard sticks/tubes of 25 devices.
8
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
3966 DUAL FULL-BRIDGE PWM MOTOR DRIVER
A3966SLB
Dimensions in Inches (for reference only)
16 9 0.0125 0.0091
0.2992 0.2914
0.419 0.394
0.050 0.016 0.020 0.013 1 2 3 0.4133 0.3977 0.050
BSC
0 TO 8
0.0926 0.1043 0.0040 MIN.
Dwg. MA-008-16A in
Dimensions in Millimeters (controlling dimensions)
16 9 0.32 0.23
7.60 7.40
10.65 10.00
1.27 0.40 0.51 0.33 1 2 3 10.50 10.10 1.27
BSC
0 TO 8
2.65 2.35 0.10 MIN.
Dwg. MA-008-16A mm
NOTES: 1. Exact body and lead configuration at vendor's option within limits shown.
2. Lead spacing tolerance is non-cumulative. 3. Webbed lead frame. Leads 4 and 13 are internally one piece. 4. Supplied in standard sticks/tubes of 47 devices or add "TR" to part number for tape and reel.
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