3965 PRELIMINARY DATASHEET - 12/4/2002 (Subject to change without notice) ABSOLUTE MAXIMUM RATINGS at TA = +25°C Load Supply Voltage, VBB ..........................20 V Output Current, IOUT............................ ±500 mA* Logic Supply Voltage, VDD ..........................7.0 V Logic Input Voltage Range, VIN ......................-0.3 V to VDD + 0.3 V (tW<30ns) ..................-1.0V to VDD +1V Sense Voltage, VSENSE ..................................0.5 V Reference Voltage, VREF .................................3 V Package Power Dissipation (TA = +25°C), PD A3965SLB........................... 50°C/W** Operating Temperature Range, TA ................................ -20°C to +85°C Junction Temperature, TJ ......................... +150°C Storage Temperature Range, TS............................... -55°C to +150°C * 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 150°C. *Measured with 062" thick FR4, two sided PCB with 1 sq inch copper area. 1 DMOS DUAL FULL-BRIDGE PWM MOTOR DRIVER Designed for Pulse Width Modulated (PWM) current control of low voltage stepper motors, the A3965S is capable of output currents to ± 500 mA and operating voltages to 20 V. The A3965 is particularly attractive for low power or battery operated motors where minimal power consumption is desired. A SLEEP mode disables all circuitry and typically draws less than 1µA supply current from motor and logic supply. During operation the fixed frequency ON pulses of each H-bridge are 180 degrees out of phase to minimize the peak demand required of the motor supply allowing savings in size and cost of external power supply components. PHASE and ENABLE input terminals are provided for use in controlling the speed and direction of a stepper motor with externally applied PWM control signals. Internal circuit protection includes thermal shutdown with hysteresis, undervoltage monitoring of VDD and charge pump, and crossover current protection. Special power up sequencing is not required. The A3965 is supplied in a 24-lead plastic SOIC with a copper batwing tab (suffix ‘LB’). FEATURES ±500 mA, 20 V Output Rating 2.85 to 5.5V Logic Supply Operation Sleep Mode for Minimum Power Consumption Fixed Frequency PWM Offset On Pulses to Minimize Peak Supply Transient Currents Internal UVLO and Thermal Shutdown Circuitry Crossover-Current Protection 3965 DMOS Dual Full Bridge PWM Motor Driver CP2 CP1 .22uf VREG .22uf Functional Block Diagram VDD REGULATOR CHARGE PUMP VCP BANDGAP VBB .22uf UVLO AND FAULT DETECT DMOS H-BRIDGE VCP OUT1A SLEEP OUT1B PHASE2 PHASE1 CONTROL LOGIC ENABLE1 SENSE1 ENABLE2 GATE DRIVE DMOS H-BRIDGE VBB OUT2A OSC RC OUT2B S 1/6 R S 1/6 Q R SENSE2 - REF1 + SENSE1 Q - REF2 + SENSE2 .1uF GROUND 2 3965 DMOS Dual Full Bridge PWM Motor Driver ELECTRICAL CHARACTERISTICS at TA = +25°C, VBB = 20 V, VDD = 3.0 V, VSENSE = 0.5 V, fPWM < 50KHz (unless noted otherwise) Limits Characteristics Symbol Test Conditions Min. Typ. Max. Units Operating, IOUT = ±500 mA 6 – 20 V During Sleep Mode 0 20 V VOUT = VBB – <1.0 20 µA VOUT = 0 V – <–1.0 -20 µA Source Driver, IOUT = -500 mA – 1.2 1.35 Ω Sink Driver, IOUT = 500 mA – .75 .9 Ω Source Driver, IOUT = -500 mA; VBB=6V 1.3 1.5 Ω Sink Driver, IOUT = 500 mA, VBB=6V .85 1.0 Ω Output Drivers Load Supply Voltage Range Output Leakage Current Output On Resistance Body Diode Forward Voltage Motor Supply Current Logic Supply Current VBB IDSS RDSON VF IBB IDD Source Diode, IF = -500 mA – 1 – V Sink Diode, IF = 500mA – 1 – V fPWM < 50 kHz – 3.5 7 mA Charge Pump On, Outputs Disabled – 1.5 3 mA Sleep Mode – – 10 uA fPWM < 50 kHz 4.5 mA Outputs Off 3.6 mA 10 µA 5.5 V Sleep Mode (Inputs below .5V) <1 Control Logic Logic Supply Voltage Range VDD Logic Input Voltage VIN(1) Operating 2.85 VDD*.7 VIN(0) Logic Input Current 3 – V – VDD*.3 V IIN(1) VIN = VDD*.7 -20 <1.0 20 µA IIN(0) VIN = VDD*.3 -20 <1.0 20 µA 3965 DMOS Dual Full Bridge PWM Motor Driver ELECTRICAL CHARACTERISTICS at TA = +25°C, VBB = 20V, VDD = 3.0 V, VSENSE = 0.5 V (unless noted otherwise) Limits Characteristics Symbol Test Conditions Min. Typ. Max. Units -1 0 1 µA Control Logic Reference Input Current IREF VREF input voltage range VREF Reference Divider Ratio GM Error Propagation Delay VREF = VDD 0 VREF/VS 6 VERR VREF = 1.5V -5 5 % (Note 3) VREF = .5V -10 10 % tPD PWM CHANGE TO SOURCE OFF – 150 – ns PWM CHANGE TO SINK OFF – 150 – ns PWM CHANGE TO SOURCE ON – 1000 – ns PWM CHANGE TO SINK ON – 1000 – ns DISABLE TO SOURCE ON – 200 – ns DISABLE TO SINK ON – 200 – ns 300 850 1200 ns tCOD PWM RC Frequency Blank Time Thermal Shutdown Temp. Thermal Shutdown Hysteresis fOSC R = 1000pf, C = 20K tBLANK R = 1000pf, C = 20K Khz TJ – 165 ∆TJ – 15 – °C 2.5 2.8 V 0.10 – V Rising VDD Typical Data is for design information only. Negative current is defined as coming out of (sourcing) the specified device pin. VERR =((VREF/6) – VSENSE)/(VREF/6) 0.05 1.6 µs 1.21 UVLO Hysteresis 4 47.4 .8 UVLO Enable Threshold NOTES: 1. 2. 3. VDD- .1 °C 3965 DMOS Dual Full Bridge PWM Motor Driver Functional Description Sleep Mode. The input pin SLEEP is dedicated to put the device into a minimum current draw mode. All circuits are disabled including the VDD undervoltage monitor. Fixed Frequency PWM. Selection of an external RC sets the oscillator frequency as follows: Shutdown. In the event of a fault due to excessive junction temperature, or low voltage on VCP or VREG, the outputs of the device are disabled until the fault condition is removed. At power up, and in the event of low VDD, the UVLO circuit disables the drivers Blank Time. When a source driver turns on, a current spike occurs due to the reverse recovery currents of the clamp diodes and/or switching transients related to distributed capacitance in the load. To prevent this current spike from erroneously resetting the source enable latch, the sense comparator is blanked. The blank duration is determined by the time it takes to charge the external RC .38*VDD volts with a 1mA current source. Current Regulation. Load current is regulated by a fixed frequency PWM control circuit. When the outputs of the DMOS H-bridge are turned on, current increases in the motor winding until it reaches a value given by: ITRIP = VREF/(6*RSENSE) At the trip point, the sense comparator resets the source enable latch, turning off the source. At this point, load inductance causes the current to recirculate until the end fixed frequency cycle. (see timing diagram) VREF. The VREF voltage is divided down by 6 and compared to the voltage across the sense resistor to set the value of bridge current that will trip the PWM comparator. The VREF input is a high impedance input and can be connected to VDD, if desired, as well as via resistor divider. Note: When connected to VDD, the VBB voltage must be 1.8V greater than VDD to allow proper headroom for the buffer output. fOSC = 1/ ( 850ns + tBLANK+RTCT)) tBLANK = CT*.38*VDD/ ( 1mA – ( .41*VDD/RT)) VREG. This supply voltage is used to run the sink side DMOS outputs. VREG is internally monitored and in the case of a fault condition, the outputs of the device are disabled. The VREG pin should be decoupled with a 0.22 µF capacitor to ground. Charge Pump. The Charge Pump is used to generate a supply above VBB to drive the source side DMOS gates. A 0.22 uF ceramic monolithic capacitor should be connected between CP1 and CP2 for pumping purposes. A 0.22 uF ceramic monolithic capacitor should be connected between VCP and VBB to act as a reservoir to run the high side DMOS devices. The VCP Voltage is internally monitored and in the case of a fault condition the outputs of the device are disabled. Thermal protection. Circuitry turns OFF all drivers when the junction temperature reaches 165°C typically. It is intended only to protect the device from failures due to excessive junction temperatures and should not imply that output short circuits are permitted. Thermal shutdown has a hysteresis of approximately 15°C. 5 3965 DMOS Dual Full Bridge PWM Motor Driver Control Logic Phase Enable Sleep X X 0 0 1 1 X 1 0 0 0 0 0 1 1 1 1 1 Chopping (Vs>VREF/6) X X 0 1 0 1 OUTA OUTB Function Off Off L L H L Off Off H L L L Sleep Fast Decay Forward Slow Decay Chop Reverse Slow Decay Chop Typical PWM Waveforms (Phase = 1) RC BLANK1 OUT1A IOUT1 VSENSE1 BLANK2 OUT2A IOUT2 VSENSE2 6 3965 DMOS Dual Full Bridge PWM Motor Driver Terminal List Pin Name VREG RC SLEEP VDD OUT1B GND SENSE1 OUT1A ENABLE1 PHASE1 REF1 REF2 PHASE2 ENABLE2 OUT2B SENSE2 GND OUT2A VCP CP2 CP1 VBB 7 Pin Description Regulator decoupling Terminal Analog Input for fixed frequency Logic input for SLEEP mode Logic Supply Voltage DMOS H – Bridge 1 Output B Ground Sense Resistor Terminal for Bridge 2 DMOS H – Bridge 1 Output A Logic Input for Bridge 1 Enable Control Logic Input for Bridge 1 PHASE Control Gm Reference Input Voltage Bridge 2 Gm Reference Input Voltage Bridge 1 Logic Input for Bridge 2 PHASE Control Logic Input for Bridge 2 Enable Control DMOS H – Bridge 2 Output B Sense Resistor Terminal for Bridge 1 Ground DMOS H – Bridge 2 Output A Reservoir Capacitor Terminal Charge Pump Capacitor Terminal Charge Pump Capacitor Terminal Load Supply SOIC 24 1 2 3 4 5 6,7 8 9 10 11 12 13 14 15 16 17 18,19 20 21 22 23 24