The AD7655 data sheet (Rev. D) states that the ADC is capable of 1 MSPS (normal mode). That's in the features caption and in Table 1 on page 1. However, table 3 on page 6 specifies the "time between conversions" t_2 to be greater than 2 us. How come this converter can sample at 1 us, then? I reckon, either must be true: which one?
I'd like to know because we would like to replace an AD7654 (specified at 500kSPS) with a faster dual-channel ADC. The AD7655 would be an ideal candidate because it is pin-compatible and it'd allow us to test the behaviour on the same board.
If the AD7655 cannot sample (or cannot be made to sample) at 1 MSPS after all and the datasheet proves to be wrong, could anybody suggest a replacement for it that meets the critera:
- pin-compatibility with AD7654
- two-channel simulatneous
- sample rate > 1 MSPS