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| Page 1 of 6 3976 PRELIMINARY DATASHEET - 12/20/01 (Subject to change without notice) DUAL FULL BRIDGE PROTECTED MOTOR DRIVER The A3976 is designed to drive both windings of a bipolar stepper motor or bidirectionally control two DC Motors. Both H-Bridges are capable of continuous output currents of up to +/- 500 mA and operating voltages to 27V. Free wheeling, substrate isolated diodes are included for output transient suppression when switching motors or other inductive loads. For each bridge the PHASE input controls load current polarity by selecting the appropriate source and sink driver pair. The ENABLE input, when held high, enables the respective output H-bridge. When both ENABLE pins are held low the device will enter SLEEP mode and consume less than 100A. The A3976 is protected to ensure safe operation in harsh operating environments and was designed specifically for automotive applications. Protection circuitry will check for open or shorted load, motor lead short to ground or supply, VBB overvoltage, VCC undervoltage, and thermal shutdown. If any of these conditions are detected the outputs will be disabled and fault information will be output to diagnostic pins FAULT1 and FAULT2. The A3976 is supplied in a 24-lead plastic SOIC with a copper batwing tab (suffix `LB'). V BB 1 ENABLE1 PHASE1 NC NC GROUND GROUND n/c OUT1A 2 3 4 5 6 7 8 9 2 4 V CC 2 3 ENABLE2 2 2 PHASE2 2 1 NC 2 0 NC A3976KLB 1 9 GROUND 1 8 GROUND 1 7 n/c 1 6 OUT2A 1 5 n/c 1 4 FAULT2 1 3 OUT2B n/c 1 0 FAULT1 OUT1B 11 12 ABSOLUTE MAXIMUM RATINGS at TA = +25C Operating Supply Voltage, VBB .................... 27 V Non-Operating Supply Voltage .................... 35 V Output Current, IOUT ............................500 mA* Logic Supply Voltage, VCC .......................... 7.0 V Fault Output Voltage ................................... 7.0 V Logic Input Voltage Range, VIN ......................... -0.3 V to VCC + 0.3 V Package Power Dissipation (TA = +25C), PD A3976KLB.................................. 2.2 W Operating Temperature Range, TA .............................. -40C to +125C 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. T T T T T T T T T T T FEATURES 500 mA Continuous Output Rating 35V Load Dump Survival Output Short Circuit Protection Coded Fault Diagnostic Outputs Low Current Standby Mode Open Load Monitor Low Current Standby Mode VBB Over Voltage Shutdown Internal Thermal Shutdown Circuitry Internal Low Parasitic Free Wheeling Diodes Crossover Current Protection Page 2 of 6 3976 - DUAL FULL BRIDGE PROTECTED MOTOR DRIVER Functional Block Diagram (one of two bridges shown) V CC Thermal Shutdown Over/Under Voltage Monitor Short to Supply Monitor V BB FAULT1 Diagnostic Logic FAULT2 To Bridge 2 PHASE1 OUT1A ENABLE1 PHASE2 CONTROL LOGIC OUT1B ENABLE2 OUT2A Input Pull Down To Bridge 2 OUT2B GROUND Short to Ground Monitor Input Logic PHASE X 0 1 ENABLE 0 1 1 OUTA Off Low High OUTB Off High Low Fault Logic Fault Condition Thermal Shutdown Short to Battery or Open Load Short to Ground Normal Operation FAULT1 Low Low High High FAULT2 Low High Low High Page 3 of 6 3976 - DUAL FULL BRIDGE PROTECTED MOTOR DRIVER ELECTRICAL CHARACTERISTICS at TA = -40C to +125C, VBB = 16V, VCC = 4.5 to 5.5 V (Unless noted otherwise) Limits Characteristics Output Drivers Load Supply Voltage Range Logic Supply Range Output Current Limit VBB VCC ICL Operating Operating Outputs A or B = GROUND Outputs A or B = VBB Output Leakage Current ICEX VOUT = VBB VOUT = 0 V Output Saturation Voltage VCE(SAT) Source Driver, IOUT = -350 mA Source Driver, IOUT = -500 mA Sink Driver, IOUT = +350 mA Sink Driver, IOUT = +500 mA Clamp Diode Forward Voltage (Flyback or Ground Clamp) Control Logic Motor Supply Current (No Load) Logic Supply Current ICC IBB ENABLE1 = ENABLE2 = High Sleep Mode ENABLE1 = ENABLE2 = Low ENABLE1 = ENABLE2 = High Sleep Mode, ENABLE1 = ENABLE2 = Low Logic Input Voltage VIN(1) VIN(0) Logic Input Current IIN(1) IIN(0) VIN = 5 V VIN = 0 V - - - - 0.7VCC - - - 7 - 45 - - - 50 -1.0 10 25 50 75 .3VCC 100 -2.0 mA A mA A V V A A VF IF = 500 mA (Sink / Ground Clamp) IF = 500 mA (Source / Flyback) 6 4.5 0.7 0.7 - - - - - - - - 1.1 1.1 <1.0 <1.0 1.0 1.2 0.2 0.4 1.2 1.55 - 27 5.5 - - 50 -50 1.2 1.3 0.4 0.6 1.5 2.0 V V V V V V A A A A V Symbol Test Conditions Min. Typ. Max. Units Page 4 of 6 3976 - DUAL FULL BRIDGE PROTECTED MOTOR DRIVER ELECTRICAL CHARACTERISTICS at TA = -40C to +125C, VBB = 16 V, VCC = 4.5 to 5.5 V (Unless noted otherwise) Limits Characteristics Symbol Test Conditions Min. Typ. Max. Units Fault Circuitry Fault Output Leakage Current Fault Output Voltage Fault Output Current Output Open Load Current Thermal Fault Temp. Thermal Fault Hysteresis OVLO Enable Threshold OVLO Hysteresis UVLO Enable Threshold UVLO Hysteresis Timing Open Fault to Reset Delay PHASE_X Delay to OPEN Fault PHASE_X Delay to S.C. Fault ENABLE_X Delay to Fault Propagation Delay Times trs tof tSC tof tpd VBB = 12 V VBB = 12 V VBB = 12 V VBB = 12 V IOUT = 0.35A, 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 Cross Over Dead Time tCODT 1K (1k+1k) Load (VBB to OUT to GND) - - - - - - - - 0.5 0.3 0.4 0.3 0.2 4.0 0.3 4.0 0.4 3.0 6.0 s s s s s s s s s - - - - - 8 5 5 25 - - - s s s s VCC rising 3.5 - IF-LEAK VFL IF I OUT-O.L. TF TFHYS VBB rising VF = 5 V, No Faults Fault Condition Asserted, IF = 25 A VF = 5 V, ENABLE = High VBB = 12 V 25 - - - 27 - 50 2 170 10 30 1.5 4 400 4.49 - 10 0.8 75 - - - 33 A V A mA C C V V V mV Page 5 of 6 3976 - DUAL FULL BRIDGE PROTECTED MOTOR DRIVER APPLICATION NOTES Open Load Protection. During normal PWM operation, diagnostic circuitry will look for a minimum source current level after a bridge is signalled on. Additionally, the diode flyback is monitored on the proper output. The logic will signal a fault and disable the outputs if it determines that the current is below the minimum level AND no flyback is occurring. If the inductive load is too large, the current would take too long to reach the minimal level and a false open load would be reported. It is recommended that the inductive load be less than 38 mH. Short Circuit Protection. Internal sense resistors in series with VBB and ground will trip the fault circuitry if greater than 1.1 A is detected. To prevent false overcurrent events due to reverse recovery spikes of the clamp diodes, the current monitor is blanked for 5s after a high side is signalled to turn on. If an additional input command follows after the initial fault, the selected pair of drivers will pulse on for the 5s blanking duration. The short circuit fault will remember the input state where the fault occurred and will wait for that particular logic state after the short has been removed before normal operation is allowed to resume. Layout. The printed wiring board should use a heavy ground plane. For optimum electrical and thermal performance, the driver should be soldered directly onto the board. The load supply terminal, VBB, should be decoupled with an electrolytic capacitor (> 47 F is recommended) placed as close to the device as possible. Thermal Protection. Circuitry turns OFF all drivers when the junction temperature reaches 170C typically. It is intended only to protect the device from failures due to excessive junction temperatures and has a hysteresis of approximately 15C. Page 6 of 6 3976 - DUAL FULL BRIDGE PROTCTED MOTOR DRIVER Terminal List Name VBB ENABLE1 PHASE1 GROUND OUT1A FAULT1 OUT1B OUT2B FAULT2 OUT2A PHASE2 ENABLE2 VCC NC Description Motor Supply Voltage Control Logic - Bridge 1 Control Logic - Bridge 1 Power Ground Return Bridge 1 Output A Diagnostic Output Bridge 1 Output B Bridge 2 Output B Diagnostic Output Bridge 2 Output A Control Logic - Bridge 2 Control Logic - Bridge 2 Logic Supply No Connect SOIC - 24 1 2 3 18,19,6,7 9 11 12 13 14 16 22 23 24 4,5,8,15,17,20,21 |
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