55
OSD3358-SM-RED
– User Guide
Rev. 1.0 9/19/2017
Octavo Systems LLC
Copyright 2017
4.12
ADC
Figure 52: OSD3358-SM-RED ADC circuit
Figure 52 shows ADC circuit on the OSD3358-SM-RED platform schematics. On the RED
Board, the positive reference voltage VREFP of the ADC is connected to SYS_ADC_1P8V and
the negative reference voltage VREFN of the ADC is connected to AGND (Analog GND). This
provides a 1.8V range for the 12-bit ADC module in the OSD335x-SM. The external resistors
and capacitors are used to filter the noise on the reference voltages.
Of the total 8 analog inputs (AIN0
– AIN7), seven (AIN0 – AIN6) are brought out to expansion
headers on the board and can be used. AIN7 is connected to PMIC_MUX_OUT to monitor the
internal voltages of the PMIC. The PMIC has an analog multiplexer that allows critical voltages
of the system to be monitored. An additional PMIC_MUX_IN input can be used to input any
critical system level voltage that needs to be monitored. The
PMIC’s I2C interface can be used
to select the voltage that needs to be monitored and AIN7 can be used to read the voltage.
More information on the analog multiplexer can be sound in the PMIC datasheet
(
