4.5.1 Power-On Reset (POR)

A Power-On Reset occurs whenever power is initially applied to the device, or if power is removed and reapplied to the device. A timer within the device will assert the internal reset for approximately 2 ms. Configuration straps are loaded by this reset and must adhere to the timing requirements specified in Power-On Configuration Strap Timing when not using the external pin reset (RESET_N).

After power-on, the POR initially negates after the rising threshold is passed. In the event that the supply drops below the falling threshold, the POR asserts. The POR stays asserted until the rising threshold is once again crossed. The rising and falling thresholds are listed in Table 4-1.

Table 4-1. POR Supply Thresholds
PORRising Threshold1Falling Threshold1
VDDA2.5V2.4V
VDDAU2.5V2.4V
1.8V21.6V1.3V
Note:
  1. Rising and falling threshold voltages are design parameters and are neither tested nor characterized.
  2. The internal 1.8V supply cannot be monitored externally.