AnsweredAssumed Answered

Query about AD8218 Design

Question asked by WayneQ on Oct 22, 2013
Latest reply on Oct 22, 2013 by prb

Dear Supporter,

The schematic of AD8218 is attached for your reference. My testing results are listed as below.

 

Modifications / Circuit Status:

  1. The resistor at the input of AD8218 opamp (R2) is now 47 ohms.
  2. Pin 1 is connected to +48V and Pin 8 is pulled down via a 470kohm resistor.
  3. C3 and C11 caps on o/p of AD are not installed.
  4. C5 100n on Vref is present.
  5. C4 100n on Vcc is present.

  Results / Voltages on all pins of AD: 

  1. Unit powered up via 48V.
  2. Pin 1 and 8: The Voltage across the AD input is 6.1mV. The voltage wrt to ground on pin 1 is 47.9V.
  3. Pin 2: Vcc 4.98V
  4. Pin 3: Enb 4.98V
  5. Pin 4: Gnd 0.00V
  6. Pin 5: O/P 3.446V
  7. Pin 7: Ref 3.313V
  8. Unit powered via 5V. The SMPS not working - PSU connected to SMPS's o/p directly.
  9. Pin 1 and 8: The Voltage across the AD input is 0.1mV. The voltage wrt to ground on pin 1 is 0.732V (slowly dying out).
  10. Pin 2: Vcc 5.00V
  11. Pin 3: Enb 5.00V
  12. Pin 4: Gnd 0.00V
  13. Pin 5:  O/P 0.755V. Also slowly dying out.
  14. Pin 7:  Ref 1.986V

could you please help check with my schematic and testing results?

Thanks so much for you kindly help and support!

 

Br,

Wayne

Attachments

Outcomes