DRV8805_12 Datasheet, PDF (9/19 Pages) Texas Instruments – UNIPOLAR STEPPER MOTOR DRIVER IC

DRV8805
www.ti.com
SLVSAW3C – JULY 2011 – REVISED MARCH 2012
nENBL and RESET Operation
The nENBL pin enables or disables the output drivers. nENBL must be low to enable the outputs. nENBL does
not affect the operation of the serial interface logic. Note that nENBL has an internal pulldown.
The RESET pin, when driven active high, resets the internal logic. The indexer is reset to the home state. All
inputs are ignored while RESET is active. Note that RESET has an internal pulldown. An internal power-up reset
is also provided, so it is not required to drive RESET at power-up.
Protection Circuits
The DRV8805 is fully protected against undervoltage, overcurrent and overtemperature events.
Overcurrent Protection (OCP)
An analog current limit circuit on each FET limits the current through the FET by removing the gate drive. If this
analog current limit persists for longer than the t_OCP deglitch time (approximately 3.5 µs), the driver will be
disabled and the nFAULT pin will be driven low. The driver will remain disabled for the t_RETRY retry time
(approximately 1.2 ms), then the fault will be automatically cleared. The fault will be cleared immediately if either
RESET pin is activated or VM is removed and re-applied.
Thermal Shutdown (TSD)
If the die temperature exceeds safe limits, all output FETs will be disabled and the nFAULT pin will be driven low.
The STEP input will be ignored. Once the die temperature has fallen to a safe level, operation will automatically
resume.
Undervoltage Lockout (UVLO)
If at any time the voltage on the VM pin falls below the undervoltage lockout threshold voltage, all circuitry in the
device will be disabled, and internal logic will be reset. Operation will resume when VM rises above the UVLO
threshold.
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): DRV8805
Submit Documentation Feedback
9