The DRV8846 provides a highly-integrated stepper motor driver for cameras, printers, projectors, and other automated equipment applications. The device has two H-bridges and a microstepping indexer and is intended to drive a bipolar stepper motor. The output block of each H-bridge driver consists of N-channel and P-channel power MOSFETs configured as full H-bridges to drive the motor windings. The DRV8846 is capable of driving up to 1.4-A full-scale output current (with proper heatsinking and TA = 25°C).
A simple STEP/DIR interface allows easy interfacing to controller circuits. Pins allow configuration of the motor in full-step up to 1/32-step modes. Decay mode is configurable so that smart tune, slow decay, fast decay, and mixed decay can be used. The PWM current chopping off-time can also be selected. A low-power sleep mode is provided which shuts down internal circuitry to achieve very-low quiescent current draw. This sleep mode can be set using a dedicated nSLEEP pin.
Internal protection functions are provided for UVLO, overcurrent protection, short circuit protection, and overtemperature. Fault conditions are indicated via a nFAULT pin.
PART NUMBER | PACKAGE | BODY SIZE (NOM) |
---|---|---|
DRV8846 | VQFN (24) | 4.00 × 4.00 mm |
Changes from * Revision (June 2014) to A Revision
PIN | I/O | DESCRIPTION | ||
---|---|---|---|---|
NAME | NO. | |||
ADEC | 19 | I | Smart tune enable | Logic low sets decay modes by DEC0 and DEC1 pins; logic high – smart tune operation is enabled; must be set prior to coming out of sleep; internal pulldown |
AISEN | 2 | O | Winding A sense | Connect to current sense resistor for bridge A, or GND if current regulation is not required |
AOUT1 | 1 | O | Winding A output | |
AOUT2 | 3 | |||
BISEN | 5 | O | Winding B sense | Connect to current sense resistor for bridge B, or GND if current regulation is not required |
BOUT1 | 6 | O | Winding B output | |
BOUT2 | 4 | |||
DEC0 | 22 | I | Decay mode setting pins | Sets the decay mode; see description section; tri-level pin |
DEC1 | 24 | I | ||
DIR | 13 | I | Direction input | Logic level sets the direction of stepping; internal pulldown |
GND | 18, PPAD | PWR | Device ground | Both the GND pin and device thermal pad must be connected to ground |
I0 | 20 | I | Torque DAC current scalar | Scales the current from 100% to 12.5% in 12.5% steps; tri-level pin |
I1 | 21 | I | ||
MO | 8 | I | Microstepping mode setting pins | Controls step mode (full, half, up to 1/32-step) and single- or dual-edge clocking; tri-level pin |
M1 | 9 | I | ||
NC | 16 | — | No connect | Unused pin not connected internally |
nENBL | 11 | I | Enable driver output | Logic low to enable device outputs and internal indexer; logic high to disable; internal pulldown |
nFAULT | 7 | OD | Fault indication pin | Pulled logic low with fault condition; open-drain output requires external pullup |
nSLEEP | 23 | I | Sleep mode input | Logic high to enable device; logic low to enter low-power sleep mode; internal pulldown |
STEP | 12 | I | Step input | A rising edge (or rising and falling depending on step mode) advances the indexer one step; internal pulldown |
TOFF_SEL | 10 | I | Decay mode off time set | Sets the off-time during current chopping; tri-level pin |
VINT | 17 | — | Internal regulator | Internal supply voltage; bypass to GND with 2.2-μF, 6.3-V capacitor |
VM | 15 | PWR | Power supply | Connect to motor power supply; bypass to GND with a 0.1- and 10-μF (minimum) ceramic capacitor rated for VM |
VREF | 14 | I | Full-scale current reference input | Voltage on this pin sets the full scale chopping current; short to VINT if not supplying an external reference voltage |