Part Number: ADS5400
Hello TI team,
I am using two ADS5400IPZP devices in parallel and trying to
synchronize them using the RESET/SYNC feature.
■My configuration is:
- Device: ADS5400IPZP
- Two ADCs operating from the same sampling clock
- Dual Bus Mode
- CLKOUT Divide by 4
- Synchronization mode enabled (Register 0x05, Sync Mode)
- Using RESETP/RESETN as the synchronization input
- Monitoring SYNCOUTB according to Figure 4 "Dual Bus Mode - Aligned, CLKOUT Divide By 4" in the datasheet [ads5400 | PDF]
■Expected behavior:
- Every valid RESET pulse applied to RESETP/RESETN should generate a corresponding SYNCOUTB pulse.
- Both ADS5400 devices should produce SYNCOUTB consistently.
■Observed behavior:
- Sometimes both ADCs generate SYNCOUTB correctly.
- Sometimes neither ADC generates SYNCOUTB.
- Sometimes only one ADC generates SYNCOUTB.
- The behavior is inconsistent even though the hardware configuration appears unchanged.
■Questions:
- Under what conditions can RESETP/RESETN be ignored by the device?
- Is there any minimum pulse width, setup/hold margin, or common-mode requirement beyond those shown in the datasheet?
- Can SYNCOUTB fail to appear if RESET is not aligned to the proper CLKIN edge?
- Are there any known issues regarding synchronization when using:
- Dual Bus Mode
- CLKOUT Divide by 4
- Two ADS5400 devices receiving the same RESET signal?
- Is there a recommended method to verify that the RESET pulse has been successfully captured internally?
■Additional information:
- RESET is provided as a differential LVDS signal.
- Sampling clock is common to both ADS5400 devices.
- Output bus configuration follows Figure 4 in the datasheet.
- RESETP and RESETN timing appears to satisfy tRSU and tRH requirements. [ads5400 | PDF]
Any guidance would be appreciated.
Thank you.
