SBAS840C July 2020 – December 2022 ADC3541 , ADC3542 , ADC3543
PRODUCTION DATA
The following sequence summarizes all the relevant registers for changing the output interface and/or enabling the decimation filter. Steps 1 and 2 must come first since the E-Fuse load reset the SPI writes, the remaining steps can come in any order.
STEP | FEATURE | ADDRESS | DESCRIPTION | ||||
---|---|---|---|---|---|---|---|
1 | Output Interface | 0x07 | Select the output interface bit mapping depending on resolution and output interface. | ||||
Output Resolution | SDR | DDR | 2-wire | 1-wire | |||
14-bit | 0xC8 | 0xA9 | 0x2B | 0x6C | |||
16-bit | 0x4B | ||||||
18-bit | N/A | N/A | 0x2B | ||||
20-bit | N/A | N/A | 0x4B | ||||
2 | 0x13 | Load the output interface bit mapping using the E-fuse loader (0x13, D0). Program register 0x13 to 0x01, wait ~ 1ms so that bit mapping is loaded properly followed by 0x13 0x00 | |||||
3 | 0x0A/B/C | Power down relevant CMOS output buffers to avoid contention. | |||||
4 | 0x18 | For serial CMOS modes, DCLKIN EN (D4) needs to be enabled. | |||||
5 | 0x19 | In serial CMOS, configure the FCLK registers based on bypass/decimation and # of lanes used. | |||||
Bypass/Decimation | SCMOS | FCLK
SRC (D7) | FCLK
DIV (D4) | ||||
Bypass/ Real Decimation | 2-wire | 0 | 1 | ||||
1-wire | 0 | 0 | |||||
Complex Decimation | 2-wire | 1 | 0 | ||||
1-wire | 1 | 0 | |||||
6 | 0x1B | Select the output interface resolution using the bit mapper (D5-D3). | |||||
7 | 0x1F | For serial CMOS modes, DCLKIN EN (D6) and DCLK OB EN (D4) need to be enabled. | |||||
8 | 0x20 0x21 0x22 | In serial CMOS, select the FCLK pattern for decimation for proper duty cycle output of the FCLK. | |||||
Decimation | Output Resolution | 2-wire | 1-wire | ||||
Real Decimation | 14-bit | use default | 0xFE000 | ||||
16-bit | 0xFF000 | ||||||
18-bit | 0xFF800 | ||||||
20-bit | 0xFFC00 | ||||||
Complex Decimation | 14-bit | 0xFFFFF | |||||
16-bit | |||||||
18-bit | |||||||
20-bit | |||||||
9 | 0x39..0x72 | Change output bit mapping if desired. This also works with the default interface selection. | |||||
10 | Decimation Filter | 0x24 | Enable the decimation filter | ||||
11 | 0x25 | Configure the decimation filter | |||||
12 | 0x2A/B/C/D | Program the NCO frequency for complex decimation (can be skipped for real decimation) | |||||
13 | 0x27 | Configure the complex output data stream (set both bits to 0 for real decimation) | |||||
Serial CMOS | OP-Order (D4) | Q-Delay (D3) | |||||
2-wire | 1 | 0 | |||||
1-wire | 0 | 1 | |||||
14 | 0x26 | Set the mixer gain and toggle the mixer reset bit to update the NCO frequency. |