| ??? 08/29/06 18:18 Read: times |
#123349 - Problem With AD7862 |
Hi all members Recently i used an AD574 in my Fpga board,It works truly I gave this schematic and pcb to my friend and he redesign his board with only one difference, using AD7862AN-3 (4 Channel ADC) instead of AD574. He called me today for solving his problem, bad treat of ADC ADC-Out: 15DH 150H 152H 158H 15EH 150H .....160H I doubt that this is for timing I check his code and did'nt see any problem then i doubt to pcb , a gnd polygon , agnd and dgnd was apart and joint at one point 0.1uF multilayer decoupling caps near every supply pins even i brought my power supply but the problem didn't solve! Unfortunately my scope isn't calibrate these days and it's ground has 40-50 mv He used a 5k multi turn for ADC analog input, and 0.1uF,1uF multilayer and 10uF tantal for these inputs Then i used software method(100 instances mean),but there are 2 lsb fluctuate yet Can you please say your valuable comment Thanks beforehand Mehdi |
| Topic | Author | Date |
| Problem With AD7862 | 01/01/70 00:00 | |
| Reference generator | 01/01/70 00:00 | |
| Reference generator | 01/01/70 00:00 | |
| Try | 01/01/70 00:00 | |
| Thanks Steve | 01/01/70 00:00 | |
| Is this a problem? | 01/01/70 00:00 | |
| Huge Osc | 01/01/70 00:00 | |
| Picture | 01/01/70 00:00 | |
| Ok | 01/01/70 00:00 | |
| Picture | 01/01/70 00:00 | |
| Picture-Jpeg | 01/01/70 00:00 | |
| ? | 01/01/70 00:00 | |
| ? | 01/01/70 00:00 | |
| AD 7900 | 01/01/70 00:00 | |
| Its there... | 01/01/70 00:00 | |
| Sorry | 01/01/70 00:00 | |
| excuse me | 01/01/70 00:00 | |
| What oscillation without averaging? | 01/01/70 00:00 | |
| Averaging! | 01/01/70 00:00 | |
| Do you mean... | 01/01/70 00:00 | |
| No | 01/01/70 00:00 | |
| How did you measure it? | 01/01/70 00:00 | |
| 10mH chokes | 01/01/70 00:00 | |
| agnd and dgnd | 01/01/70 00:00 | |
| Highly unsuited! | 01/01/70 00:00 | |
| Lcd | 01/01/70 00:00 | |
| What do you mean? | 01/01/70 00:00 | |
| jp4 and jp5 | 01/01/70 00:00 | |
| Please explain | 01/01/70 00:00 | |
| Lcd | 01/01/70 00:00 | |
Use a scope to check it | 01/01/70 00:00 | |
| 5k trimmer is not well suited | 01/01/70 00:00 | |
| 5k trimmer is not well suited | 01/01/70 00:00 | |
| What do you mean by "huge oscillation"? | 01/01/70 00:00 | |
| changed to a new part and it doesn't work | 01/01/70 00:00 |