Dear Sir,
May I ask a question if AVSS-SW can be used for external application circuit as an analog switch connect to ground or open?
(AVSS is always connected to ground.)
I read datasheet and it looks simple switch which changing PSW will not affect inside function of the ADC besides the switch, correct?
And may I ask what is a typical application schematics usage of AVSS-SW for resistive bridge sensor?
Best regards,
Masa
Hi Masa-san,
The low-side switch of the ADS124S06 was added for bridge sensors in particular. As bridge sensors can draw a considerable current there is often a need to break the flow of current to conserve power.
Take a look at the Functional Block Diagram on page 30 of the datasheet. The switch is connected to AVSS-SW on one side and REFN0 on the other side. Externally the AVSS-SW pin would connect to AVSS.
The bridge input would be configured similar to as shown below, where REF0 is used as the ratiometric reference input, and the sensor current would flow through the low-side switch at the REFN0 connection.
Other types of sensors could be used as well, but the current is an absolute maximum of 100mA through the pins and switch. The connection would need to be similar through REFN0 with AVSS-SW tied to AVSS.
Best regards,
Bob B
