SLOSE70 December 2020 DRV8434S
PRODUCTION DATA
If at any time the voltage on the VM pin falls below the UVLO falling threshold voltage, all the outputs are disabled (High-Z) and the charge pump (CP) is disabled. Normal operation resumes (motor driver and charge pump) when the VM voltage recovers above the UVLO rising threshold voltage.
When the voltage on the VM pin falls below the UVLO falling threshold voltage (4.25 V typical), but is above the VM UVLO reset voltage (VRST, 3.9 V maximum), SPI communication is available, the digital core of the device is active, the FAULT and UVLO bits are made high in the SPI registers and the nFAULT pin is driven low, as shown in Figure 7-19. From this condition, if the VM voltage recovers above the UVLO rising threshold voltage (4.35 V typical), nFAULT pin is released (is pulled-up to the external voltage), and the FAULT bit is reset, but the UVLO bit remains latched high until cleared through the CLR_FLT bit or an nSLEEP reset pulse.
When the voltage on the VM pin falls below the VM UVLO reset voltage (VRST, 3.9 V maximum), SPI communication is unavailable, the digital core is shutdown, the FAULT and UVLO bits are low and the nFAULT pin is high. During a subsequent power-up, when the VM voltage exceeds the VRST voltage, the digital core comes alive, UVLO bit stays low but the FAULT bit is made high; and the nFAULT pin is pulled low, as shown in Figure 7-20. When the VM voltage exceeds the VM UVLO rising threshold, FAULT bit is reset, UVLO bit stays low and the nFAULT pin is pulled high.