SBAS500B june 2022 – august 2023 ADC32RF54 , ADC32RF55
PRODUCTION DATA
The ADC32RF5x supports a dynamic switch mode between two decimation filter configurations without the need to resynchronize the JESD204B interface. This enables support for single, wideband DDC and 4 narrow band DDCs that can be switched in between with minimum impact on latency.
Two different configurations are supported in the dynamic switching mode. Each configuration maintains the # of serdes lanes and serdes output rate during the switch. Table 7-19 shows the specific supported configurations for LMFS and decimation settings for a 2 lane and a 1 lane setup. Since the amount of output data in quad band mode is four times larger compared to single band, the decimation factor in quad band mode needs to be reduced by a factor of four compared to the single band case.
Single Band DDC | Quad Band DDC | |||
---|---|---|---|---|
LMFS | Complex Decimation | LMFS | Complex Decimation | |
2 lanes | 2-4-16-4 | /16 | 2-16-16-1 | /64 |
1 lane | 1-4-32-4 | /32 | 1-16-32-1 | /128 |
There is no information in the JESD204B output data stream indicating if the output data is quad band or single band. The JESD204B receiving device controls the switching and thus needs to decode the incoming data for quad band or single band mode. The LMFS value transmitted ILA when the JESD204B link is established is always from the quad band mode in order to avoid ILA errors at the start of the link.
The dynamic switch is configured with these register writes:
2 Lanes: 2-4-16-4 to 2-16-16-1 | 1 Lane: 1-4-32-4 to 1-16-32-1 | |||
---|---|---|---|---|
Configure ADC 2-16-16-1, Decimation by 64 | Configure ADC to 1-16-32-1, Decimation by 128 | |||
0x05, 0x02 | Select DIGITAL page | 0x05, 0x02 | Select DIGITAL page | |
0x373, 0x04 | Configures internal clockings | 0x373, 0x05 | Configures internal clockings | |
0x388, 0x12 | 0x388, 0x16 | |||
0x388, 0x32 | Bit D5 enables dynamic switch: 0x32: LMFS = 2-4-16-4, /16 0x12: LMFS = 2-16-16-1, /64 | 0x388, 0x36 | Bit D5 enables dynamic switch: 0x36: LMFS = 1-4-32-4, /32 0x16: LMFS = 1-16-32-1, /128 |