A3974SED-T

A3974 DMOS Dual Full-Bridge PWM Motor Driver Last Time Buy These parts are in production but have been determined to be LAST TIME BUY. This classification indicates that the product is obsolete and notice has been given. Sale of this device is currently restricted to existing customer applications. The device should not be purchased for new design applications because of obsolescence in the near future. Samples are no longer available. Date of status change: November 2, 2009 Deadline for receipt of LAST TIME BUY orders: April 30, 2010 Recommended Substitutions: For existing customer transition, and for new customers or new applications, refer to the A3992. NOTE: For detailed information on purchasing options, contact your local Allegro field applications engineer or sales representative. Allegro MicroSystems, Inc. reserves the right to make, from time to time, revisions to the anticipated product life cycle plan for a product to accommodate changes in production capabilities, alternative product availabilities, or market demand. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use. A3974 DMOS Dual Full-Bridge PWM Motor Driver Features and Benefits Description ▪ ±1.5 A, 50 V continuous output rating ▪ Low rDS(on) DMOS output drivers ▪ Programmable slow, fast, and mixed current-decay modes ▪ Serial-interface controls chip functions ▪ Synchronous rectification for low power dissipation ▪ Internal UVLO and thermal shutdown circuitry ▪ Crossover-current protection ▪ Sleep and idle modes Designed for pulse width modulated (PWM) current control of two DC motors, the A3974 is capable of output currents to ±1.5 A and operating voltages to 50 V. Internal fixed off-time PWM current-control timing circuitry can be programmed via a serial interface to operate in slow, fast, and mixed currentdecay modes. Independent ENABLE input terminals are provided for use in controlling the speed and torque of each DC motor with externally applied PWM control signals. Synchronous rectification circuitry allows the load current to flow through the low rDS(on) of the DMOS output driver during the current decay. This feature will eliminate the need for external clamp diodes in most applications, saving cost and external component count, while minimizing power dissipation. Package: 44-pin PLCC with internally fused pins (suffix ED) Internal circuit protection includes thermal shutdown with hysteresis, undervoltage monitoring of VDD and the charge pump, and crossover-current protection. Special power-up sequencing is not required. Not to scale The A3974 is supplied in a 44-pin plastic PLCC with 3 internally fused pins on each side, for maximum heat dissipation. The fused pins are at ground potential and need no electrical isolation. ENABLE1 NC OUT1B 42 41 40 GND LOAD 43 SUPPLY1 GND 1 GND 2 44 NC SENSE1 4 NC 5 3 OUT1A 6 Pin-out Diagram VBB1 NC 7 STROBE 8 CP2 37 CP1 36 CP GND 11 35 GND GND 12 34 GND GND 13 33 GND CLOCK 9 DATA 10 PROGRAM PWM TIMER CHARGE PUMP NC 38 SERIAL PORT 39 LOGIC REF1 14 REF2 15 LOGIC 16 SUPPLY NC PROGRAM PWM TIMER LOGIC VDD 17 32 OSC 31 SLEEP 30 VREG 29 NC 29319.35C OUT2B 28 NC 27 25 ENABLE2 26 LOAD SUPPLY2 23 GND 24 GND GND 22 21 NC 20 SENSE2 NC 19 OUT2A 18 VBB2 Dwg. PP-073 A3974 DMOS Dual Full-Bridge PWM Motor Driver Selection Guide Part Number A3974SED-T A3974SEDTR-T Packing 27 pieces per tube 450 pieces per reel Absolute Maximum Ratings Characteristic Symbol Notes Rating Units Load Supply Voltage VBB 50 V Logic Supply Voltage VDD 7.0 V Logic Input Voltage Range VIN Continuous –0.3 to VDD+ 0.3 V Pulsed, tw < 30 ns –1.0 to VDD+ 1.0 V Reference Voltage Sense Voltage (DC) Output Current VREF VS IOUT 3 V Continuous 0.5 V Pulsed, tw < 1 μs 2.5 V 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. ±1.5 A Operating Ambient Temperature TA –20 to 85 ºC Maximum Junction Temperature TJ(max) 150 ºC Tstg –55 to 150 ºC Storage Temperature Range S Thermal Characteristics may require derating at maximum conditions, see application information Characteristic Package Thermal Resistance Test Conditions* Symbol RθJA 4-layer PCB based on JEDEC standard RθJT Value Units 22 ºC/W 6 ºC/W *Additional thermal information available on the Allegro website. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 A3974 DMOS Dual Full-Bridge PWM Motor Driver FUNCTIONAL BLOCK DIAGRAM VBB1 VDD UNDERVOLTAGE & FAULT DETECT CP2 CP1 CHARGE PUMP BANDGAP VDD CREG TSD CP + LOGIC SUPPLY LOAD SUPPLY1 CHARGE PUMP BANDGAP REGULATOR ENABLE1 OUT1A GATE DRIVE PHASE SYNC RECT MODE SYNC RECT DISABLE MODE CONTROL LOGIC VREG OUT1B SENSE1 CS1 ZERO CURRENT DETECT FIXED OFF PROGRAMMABLE BLANK DECAY RS1 PWM TIMER CURRENT SENSE FIXED OFF ENABLE2 PHASE ENABLE SYNC RECT MODE SYNC RECT DISABLE PWM MODE INT PWM MODE EXT PROGRAMMABLE BLANK DECAY PWM TIMER SLEEP MODE REFERENCE BUFFER & DIVIDER SERIAL PORT REF1 VREF LOAD SUPPLY2 CHARGE PUMP + VBB2 OUT2A GATE DRIVE OSC CLOCK DATA STROBE OUT2B CONTROL LOGIC SENSE2 TO PWM TIMER CS2 ZERO CURRENT DETECT RS2 CURRENT SENSE REFERENCE BUFFER & DIVIDER REF2 VREF2 Dwg. FP-048-1 Copyright © 2001 Allegro MicroSystems, Inc. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 A3974 DMOS Dual Full-Bridge PWM Motor Driver ELECTRICAL CHARACTERISTICS at TA = +25°C, VBB = 50 V, VDD = 5.0 V, fPWM < 50 kHz (unless otherwise noted). Characteristic Symbol Test Conditions Min. Limits Typ. Max. Units Output Drivers Load Supply Voltage Range Output Leakage Current Output ON Resistance Body Diode Forward Voltage Load Supply Current VBB IDSS rDS(on) VF IBB Operating 15 — 50 V During sleep mode 0 — 50 V VOUT = VBB —