DRV8860
SLRS065A –SEPTEMBER 2013–REVISED NOVEMBER 2013
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Protection Circuits
The DRV8860 is fully protected against undervoltage, overcurrent and overtemperature events.
Overcurrent Protection (OCP)
When output current exceeds OCP trigger level, corresponding channel will be automatically turned off. nFault
pin will be set low and corresponding OCP flag in fault register will be set to 1.
Over current faults are automatically cleared whenever the corresponding output is turned off by setting the Data
register bit to ‘0’. Alternatively, a Fault Reset special command will also clear this value. In either case, once all
bits in the Fault register are clear, nFAULT is released.
Open Load Detection (OL)
When any output is in off status (the corresponding Data Register bit is set to ‘0’), a current sink pulls the node
down with approximately 30 µA. If the voltage on the pin is sensed to be less than 1.2 V, then an open load
condition is reported. nFAULT is driven low and the OL bit of the fault register (F8:F1) corresponding to the
specific channel is set.
Open load faults are automatically cleared whenever the corresponding output is turned on by setting the Data
register bit to ‘1’. Alternatively, a Fault Reset special command will also clear this value. In either case, once all
bits in the Fault register are clear, nFAULT is released.
Thermal Shutdown (TSD)
If the die temperature exceeds safe limits, all outputs will be disabled, and the nFAULT pin will be driven low.
Once the die temperature has fallen to a safe level, operation will automatically resume. The nFAULT pin will be
released after operation has resumed.
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. nFAULT will not be asserted in this condition.
Digital Noise Filter
The DRV8860 features an internal noise filter on all digital inputs. In a noisy system, noise may disturb the serial
daisy-chain interface. Without an input filter, this noise may result in an unexpected behavior or output state. The
digital input filter is capable of removing unwanted noise frequencies while allowing fast communication over the
serial interface.
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