JAJSTM8 April 2024 AFE20408
PRODUCTION DATA
The AFE20408 is capable of monitoring all power supply voltages, including the internal reference. For VSS and VCC power supply pins, after the voltage supply reaches the power-on threshold, the corresponding bits in the Alarm Status registers are set if the magnitude of voltage at the respective supply pin is less than the supply collapse threshold. Table 6-5 shows the voltage thresholds for power-supply alarm activation.
POWER SUPPLY | ALARM THRESHOLD (POWER-ON) | ALARM THRESHOLD (SUPPLY COLLAPSE) |
---|---|---|
VDD | 2.3V | 2.6V |
VCCA/VCCB | 2.2V | 1.7V |
VSSA/VSSB (low-range) | –2.2V | –1.7V |
VSSA/VSSB (mid-range) | –3.7V | –3.2V |
VSSA/VSSB (high-range) | –6.7V | –6.2V |
The alarm depends on voltage magnitude (not polarity); therefore, the VSSA and VSSB alarms are set when the respective pin voltages are less negative than the specified supply collapse thresholds. Additionally, the VSSA and VSSB alarm thresholds are determined based on the range selected for the respective DAC group; see also Section 7.2.1.5.
The device provides out-of-range detection for the high performance internal reference. If the internal reference voltage is less than 1.5V (after initially reaching a power-on threshold of 2.0V), the reference alarm flag is set. Verify that the reference alarm condition has not been issued prior to powering up the DAC output buffers.
By setting the appropriate bits in the DAC_APD_SRC and OUT_APD_SRC registers, both the power supply and internal reference alarms can be configured to trigger the alarm pin, a DAC auto power-down event, or both.