SLASFB2 November 2023 AFE432A3W , AFE532A3W
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
All the DAC output channels remain in a Hi-Z when VDD is off. Figure 6-9 shows a simplified schematic of the AFEx32A3W used in a voltage-margining application. Almost all linear regulators and DC/DC converters have a feedback voltage of ≤ 1.25 V. The low-leakage currents at the outputs are maintained for VFB of ≤ 1.25 V. Thus, for all practical purposes, the DAC outputs appear as Hi-Z when VDD of the DAC is off in voltage margining and scaling applications. This feature allows for seamless integration of the AFEx32A3W into a system without any need for additional power-supply sequencing for the DAC.
The DAC channels power down to Hi-Z at boot up. The outputs can power up with a preprogrammed code that corresponds to the nominal output of the DC/DC converter or the linear regulator. This feature allows for smooth power up and power down of the DAC without impacting the feedback loop of the DC/DC converter or the linear regulator.
Table 6-9 shows how the GPIO/SDO pin of the AFEx32A3W can be configured as a PROTECT function. PROTECT takes the DAC outputs to a predictable state with a slewed or direct transition. This function is useful in systems where a fault condition (such as a brownout), a subsystem failure, or a software crash requires that the DAC outputs reach a predefined state without the involvement of a processor. The detected event can be fed to the GPIO/SDO pin that is configured as the PROTECT input. The PROTECT function can also be triggered using the PROTECT bit in the COMMON-TRIGGER register. Table 6-5 shows how to configure the behavior of the PROTECT function in the PROTECT-CONFIG field in the DEVICE-MODE-CONFIG register.
PROTECT-CONFIG FIELD | FUNCTION |
---|---|
00 | Switch to Hi-Z power-down (no slew). |
01 | Switch to DAC code stored in NVM (no slew) and then switch to Hi-Z power-down. |
10 | Slew to margin-low code and then switch to Hi-Z power-down. |
11 | Slew to margin-high code and then switch to Hi-Z power-down. |