SLASF96 April 2024 AFE20408
PRODUCTION DATA
In the AFE20408 all-negative DAC range mode, the two DAC groups are set to a negative-voltage output range (–10V to 0V).
The maximum DAC output for each group cannot be less than the corresponding VCC voltage. In all-negative DAC range mode, the maximum DAC output for both groups is 0V, and consequently, the VCCA and VCCB pins must be connected to GND.
The minimum DAC output for each group cannot be less than the corresponding VSS voltage. In all-negative DAC range mode, the VSSA and VSSB pins must be connected to a negative supply voltage; however, these pins are not required to be tied to the same potential. Specifically, the voltage at the VSSA pin must always be less than (more negative) or equal to the VSSB voltage. Typically, the negative voltage at each VSS pin is dictated by the desired negative-voltage output range, but this configuration is not required. In the case where the VSS supply voltage for a group is less than the negative full-scale range configuration, the minimum DAC voltage is limited to VSS[A,B]. Table 6-7 lists the typical configurations for this mode.
PIN | TEST CONDITIONS | TYPICAL CONNECTION |
---|---|---|
VDD | 4.5V to 5.5V | |
VIO | VIO ≤ VDD | 1.65V to 5.5V |
VCCA | GND | |
VCCB | GND | |
VSSA | VDACA ≥ VSSA | –11V ≤ VSSA ≤ –3V |
VSSB | VDACB ≥ VSSB | –11V ≤ VSSB ≤ –3V |
Thermal Pad | GND |
After a reset event, the output range for each DAC group is automatically set by the autorange detector.
The VSS[A,B] pins set the clamp voltage for each DAC group. The clamp voltage depends only on the voltage in the VSS[A,B] pins; therefore, changes to the DAC range registers do not affect the clamp setting. With both VSSA and VSSB pins connected to negative supply voltages, the clamp voltage for DAC group A is equal to VSSA, and the clamp voltage for DAC group B is equal to VSSB.