1. Yes, the ADG734 fully supports dual-supply operation. Applying VDD = +2.5 V and VSS = –2.5 V is well within the specified operating range of the device.
According to the datasheet:
- The allowed VDD – VSS difference is up to 5.5 V, so ±2.5 V (i.e., 5.0 V total) is acceptable.
- This supply configuration enables symmetric signal switching around 0 V (i.e., ground-referenced systems with bipolar signals).
2. Under this supply configuration: The analog signal inputs (Sx, Dx) must remain within the range of VSS + 0.3 V to VDD – 0.3 V to avoid forward-biasing internal protection diodes.
So for VSS = –2.5 V and VDD = +2.5 V, the safe signal swing is approximately: –2.2 V ≤ Signal ≤ +2.2 V
Attempting to drive signals fully to ±2.5 V could result in leakage current or device stress. Therefore, it is recommended to limit input/output analog signals to within ±2.2 V for reliable operation.
3. No, the digital control pins (IN1–IN4 and EN) are not tolerant to negative voltages.
These pins are referenced to GND (which must sit between VSS and VDD), and they expect standard CMOS logic levels:
- Logic low: typically 0 V
- Logic high: up to VDD
For your ±2.5 V supply, VDD = +2.5 V and GND = 0 V, so valid logic inputs must be 0 to 2.5 V.