A3981KLPTR-T Allegro Microsystems Inc, A3981KLPTR-T Datasheet

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Features and Benefits • Typical application up to ±750 mA • Low R outputs, 0.5 Ω source and sink, typical DS(on) • Automatic current decay mode detection/selection • Mixed, Fast, and Slow current decay modes • Synchronous rectification ...

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... A3981 Selection Guide Part Number A3981KLP-T A3981KLPTR-T *Contact Allegro ® for additional packing information. Absolute Maximum Ratings With respect to GND Characteristic Load Supply Voltage Logic Supply Voltage Pin CP1 Pins CP2, VCP Pins STEP, DIR, ENABLE, DIAG Pin VREG Pin RESETn ...

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A3981 3.3V VDD REF DAC 6-bit DAC STEP DIR MS1 MS0 RESETn System ENABLE Control and Registers SDI SDO SCK STRn 6-bit DAC Cold Warning, Hot Warning, Overtemperature DIAG A G Automotive, Programmable Stepper Driver Functional Block Diagram OSC VREG ...

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A3981 ELECTRICAL CHARACTERISTICS Characteristics Supplies Load Supply Voltage Range 3 Load Supply Quiescent Current Logic Supply Voltage Range Logic Supply Quiescent Current Charge Pump Voltage Internal Regulator Voltage Internal Regulator Dropout Voltage Motor Bridge Output High-Side On-Resistance High-Side Body Diode ...

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A3981 ELECTRICAL CHARACTERISTICS Characteristics Current Control (continued) Reference Input Current Maximum Sense Voltage Current Trip Point Error 5 Logic Input And Output – DC Parameters Input Low Voltage Input High Voltage Input Hysteresis Input Current (Except RESETn) Input Pull-Down Resistor ...

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A3981 ELECTRICAL CHARACTERISTICS Characteristics Diagnostics and Protection VBB Overvoltage Threshold VBB Overvoltage Hysteresis V VREG Undervoltage Threshold VREG Undervoltage Hysteresis VDD Undervoltage Threshold VDD Undervoltage Hysteresis V OSC Timeout High-Side Overcurrent Threshold High-Side Current Limit Low-Side Overcurrent Sense Voltage Overcurrent ...

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A3981 STEP STRn C SCK J SDI X F SDO Z Figure 1. Serial Interface Timing Diagram Key A Clock High Time B Clock Low Time C Strobe Lead Time D Strobe Lag Time E Strobe High Time F Data ...

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A3981 The A3981 is an automotive stepper motor driver suitable for high temperature applications such as headlamp bending and leveling, throttle control, and gas recirculation control also suitable for other low current stepper applications such as air con- ...

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A3981 impedance allowing multiple SDI slaves to have common SDI, SCK, and SDO connections. DIAG Diagnostic output. Function selected via the serial inter- face, setting Configuration Register 1. Default is Fault output. OSC With bit 13 in Configuration Register 1 ...

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A3981 starts and the bridge is switched into one of two decay modes, slow decay or fast decay: • Slow decay is most effective when the current is rising from step to step, and it occurs when the phase winding ...

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A3981 Alternative to the Fault Output flag, the DIAG output can be pro- grammed via the serial interface to output: the stall detect signal, which goes low when a stall is detected; the phase A PWM-on signal, which is high ...

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A3981 Hot Warning If the chip temperature rises above the Hot Tem- perature Warning Threshold the Fault flag will go low and JWH the Hot Warning bits will be set in the diagnostic registers. No action will be ...

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A3981 next occurrence of: the next rising edge on the STEP input, the RESETn input is pulsed low, or until the diagnostic registers are reset by writing to one of the registers through the serial interface. At the next STEP ...

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A3981 A three wire synchronous serial interface, compatible with SPI, can be used to configure and control all the features of the A3981. A fourth wire can be used to provide diagnostic feedback. The registers that are accessible through the ...

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A3981 If there are more than 16 rising edges on SCK STRn goes high and there are fewer than 16 rising edges on SCK, the write will be cancelled without writing data to the configuration and control registers. ...

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A3981 An optional simple odd parity scheme is included to provide some measure of error checking, if required. Each 6-bit value can be supplemented with an additional parity bit, PTP, to ensure an odd number the transmission. ...

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A3981 15 14 CONFIG Configuration Register 0 Synchronous rectification SYR SYR Synchronous Rectification 0 Diode recirculation 1 Synchronous Microstep mode for external STEP input control MS[1..0] MS1 MS0 Microstep Mode 0 0 Full Step 0 1 Half ...

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A3981 15 14 CONFIG RUN 1 0 Configuration Register 1 Selects clock source OSC OSC Clock Source 0 Internal 1 External Overcurrent fault delay Assumes 4-MHz clock TSC[1..0] TSC1 TSC0 Detect Delay Time 0 0 0.5 μs ...

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A3981 15 14 TBLLD 1 1 Fault 0 FF TW1 Fault 1 FF TW1 Table Load Register Parity bit (odd parity) PTP Phase Table Value PT(0..15)[5..0] Table Load Register Mapping Step Angle Number Phase PT(0) 1 ...

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A3981 Motor Movement Control The A3981 provides two independent methods to control the movement of a stepper motor. The simpler is the Step and Direc- tion method, which only requires two control signals to control the stepper motor in either ...

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A3981 The magnitude of the resultant will be the square root of the sum of the squares of these two currents:     1406 the ...

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A3981 In half step and in quarter step, the single phase active positions are used to preserve symmetry. However, if the motor is required to stop with a significant holding torque for any length of time it is recommended that ...

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A3981 arithmetic operators to be used, within the microcontroller, to determine the size of the next step increment. Table 6 shows the binary equivalent of each decimal number between –16 and +16. Each increase in the Step Angle Number represents ...

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A3981 high when writing to the Run register. The motor step rate is therefore determined by the timing of the rising edge of the STRn input. The clock rate of the serial interface, defined by the fre- quency of the ...

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A3981 (forwards) 23 (DAC value (reverse) 40 (DAC value ...

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A3981 reference value. Although the current in Q3 and Q4 for phase A is effectively negative, the negation is provided by controlling the direction of the current. The current control scheme still operates using positive values. As shown below, the ...

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A3981 Each of the 16 values written to the phase table is a 6-bit num- ber that determines the current trip point for the associated step. The highest value, 63, represents the maximum phase current defined in the ...

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A3981 32/63=50.8% and so on. The value at each Step Angle Number is then assigned to its corresponding phase table values as follows:   1  where DI represents the digitized value of the current at ...

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A3981 Power Dissipation The A3981 is a power circuit, therefore careful consideration must be given to power dissipation and the effects of high cur- rents on interconnect and supply wiring. A first order approximation of the power dissipation in the ...

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A3981 The total power dissipation for each of the four decay modes the average power for the drive current ramp por- D(TOT) XX tion and the drive current decay portion cycle. For slow ...

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A3981 Layout Traces PCB The printed circuit board (PCB, or printed wiring board) should use a higher weight copper thickness than a standard small signal or digital circuit board. This helps to reduce the impedance of the printed traces when ...

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A3981 Terminal List Table Name Number Description AGND 7 Analog reference ground CP1 24 Charge pump capacitor terminal CP2 23 Charge pump capacitor terminal DIAG 16 Diagnostic output DIR 3 Direction select input ENABLE 26 Bridge enable input MS0 13 ...

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A3981 9.70±0. 5.08 NOM 28X 0.10 C 0.30 0.65 BSC 0.19 Automotive, Programmable Stepper Driver Package LP, 28-Pin TSSOP with Exposed Thermal Pad 8º 0º 0.20 0.09 3 NOM 4.40±0.10 6.40±0.20 0.60 ±0.15 1.00 REF ...

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A3981 A stepper motor is a particular form of brushless DC motor. As for any electric motor, motion is created by magnetic interaction between the stationary part of the motor, known as the stator, and the moving part of the ...

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A3981 Stator Rotor Stator Rotor Stator ...

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A3981 In the next panel, panel (b), the current is flowing down through the phase B winding from top to bottom and there is no current in phase A. The result pole on the B electromagnets and ...

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A3981 in the first instance, by the resistance of the winding and the applied voltage. From figure A2( also apparent that varying the relative current in each phase will make it possible to move the rotor to any ...

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A3981 Improved Half Step Figure A5 shows a circle superimposed on the phase diagram. This circle represents the required locus of the resultant phase cur- rent vectors to maintain 100% current magnitude. At the full-step positions and ...

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A3981 opposite direction. In addition the phase B current at quarter- step positions 3, 5, 11, and 13 also have the same magnitude as that of phase A at quarter-step position 7, with a positive current direction for steps 3 ...

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A3981 Practical limitations The information presented here assumes ideal stepper motors being stepped slowly, with accurate, efficient current control circuits. In practice the stepper motor phase windings are repre- sented by two non-ideal inductors and the motor may be driven ...

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A3981 100% 99% 98% 96% 92% 88% 83% 77% 70% 63% 56% 47% 38% 29% 19% 10 10% 19% 29% 38% 47% 56% 63% 70% 77% 83% 88% 92% 96% 98% 99% 100% 100% 99% 98% 96% 92% ...

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A3981 Copyright ©2010-2011, Allegro MicroSystems, Inc. Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de par tures from the detail spec tions as may be required to per- mit improvements in the ...