Circuit Details-
- VCC = +5V, VEE = -5 V, Analog ground is represented as AGND, VA = +5 V same as VCC with respect to AGND, VBD = 5V_B=5 V with respect to BGND (digital ground)
2. AGND and DGND shorted on one point using Jumper J10 in schematic.
3. REFOUT connected to REFIN and BUSY connected to MXCLK.
4. BUS18_16 and BYTE are permanently grounded (logic low level)to get 18 bit output, we are reading upper 16 bits leaving lower two LSB’s using DSP. Buffer is connected at the outputs of the ADC.
5. C1 is permanently high (logic high), C2 and C3 are permanently low (logic low) and AUTO is permanently high for auto mode. With this connection we would like to read from channel 0 and channel1 two channels in auto mode.
6. CS and RD are toggled using DSP.
7. Start of conversion (Active low) is generated (a pulse) using DSP.
We are getting
3.76 Volt on internal reference output pin 11,
3.76 Volt on BUF-REF pin15
and 1.88 Volt on VCMO pin 14
but as per datasheet these should be 4 volt , 4 volt and 2 volt respectively.
Please clarify????
When we give start of conversion on pin 2 we get busy signal after giving start of conversion but we get fixed digital data either 0 or 5AD2 on giving read signal for all the inputs (-4 volt to +4 volt).
We do not understand where is problem. Pl provide technical support for getting correct digital outputs.