SBAS745B December 2015 – January 2023 ADS54J66
PRODUCTION DATA
The ADS54J66 supports decimation-by-2 and -4 and un-decimated output. The four channels can be configured as pairs (A, B and C, D; however, the same decimation factor must be chosen for all four channels).
Figure 7-2 shows signal processing done in the digital down-conversion (DDC) block of the ADS54J66. Table 7-1 shows available modes of operation for this block.
OPERATING MODE | DESCRIPTION | DIGITAL MIXER | DECIMATION | BANDWIDTH | OUTPUT FORMAT | MAX OUTPUT RATE | |
---|---|---|---|---|---|---|---|
491 MSPS | 368 MSPS | ||||||
0 | Decimation | ±fS / 4 | 2 | 200 MHz | 150 MHz | Complex | 250 MSPS |
2 | – | 2 | 100 MHz | 75 MHz | Real | 250 MSPS | |
4 | N × fS / 16 | 2 | 100 MHz | 75 MHz | Real | 250 MSPS | |
5 | N × fS / 16 | 2 | 200 MHz | 150 MHz | Complex | 250 MSPS | |
6 | N × fS / 16 | 4 | 100 MHz | 75 MHz | Complex | 125 MSPS | |
7 | N × fS / 16 | 2 | 100 MHz | 75 MHz | Real | 500 MSPS | |
8 | No decimation | – | – | 245.76 MHz | 184.32 MHz | Real | 500 MSPS |
Table 7-2 shows characteristics of different blocks of DDC signal processing blocks active in different modes.
MODE | fmix1 | FILTER AND DECIMATION | fmix2 | OUTPUT |
---|---|---|---|---|
0 | fS / 4 | LPF cutoff at fS / 4, decimation-by-2 | Not used | I, Q data at 250 MSPS each are given out |
2 | Not used | LPF or HPF cutoff at fS / 4, decimation-by-2 | Not used | Straight 250 MSPS data are given out |
4 | k fS / 16 | LPF cutoff at fS / 8, decimation-by-2 | fS / 8 | Real data at 250 MSPS are given out |
5 | k fS / 16 | LPF cutoff at fS / 8, decimation-by-2 | Not used | I, Q data at 250 MSPS each are given out |
6 | k fS / 16 | LPF cutoff at fS / 8, decimation-by-4 | Not used | I, Q data at 125 MSPS each are given out |
7 | k fS / 16 | LPF cutoff at fS8, decimation-by-2 | fS / 8 | Real data are up-scaled, zero-padded and given out at 500 MSPS |
Default | Not used | Not used | Not used | Straight 500-MSPS, 14-bit data are given out |