Figure 1-1 Typical Sync Configuration

The TPS389006 is equipped with a SYNC pin as shown in Figure 2-1. It also has a sequence logging feature to monitor and assign timestamps/log for the power rails turning on and off. It can perform sequence logging on a single device or across multiple devices on a board. When either the ACT or SLEEP pin transitions from low to high or high to low, the sequence logging function becomes active until the expiry of the sequence timeout (SEQ_TOUT). During the sequence timeout, the UV faults can be masked (Automask - AMSK) to allow the power rails to rise without triggering a fault. The TPS389006 is designed to assert active low output signals (NIRQ) when the monitored voltage is outside the safe window.

In this EVM, when ACT is driven high, the first EN signal in the power up sequence is turned on by TPS38700S-Q1. Then, the MON1 voltage rises and triggers TPS389006 to send the first SYNC signal which causes TPS38700S-Q1 to turn on the second EN voltage. This process repeats until all Enable voltages turn on. Note that the TPS389006 defaults to using UV thresholds for sending the SYNC pulse when sequencing up. When ACT is driven low, the first EN signal in the power down sequence is immediately driven low. When the corresponding MON voltage drops below the threshold, TPS389006 sends a SYNC pulse. The SYNC pulse causes TPS38700S-Q1 to turn off the second EN signal. This process also repeats until all voltages have been turned off. By default, SYNC voltage thresholds for TPS389006 are based on the OFF voltage. The voltage thresholds can be changed to UV voltage thresholds for both sequencing up and down. Note that the TPS389006 defaults to using OFF voltage threshold (MONx<140mV) for sending the SYNC pulse when sequencing down.