Use the following steps to program the WDCO Holdover offset. Instructions for PLL0 and PLL1 are included. Program only the
applicable PLL.
 
1) Lock the device to the XTAL input.
 
2) Make sure that the DPLL settings are set as follows:
DPLL0 Powered up: Register 0xB8 bit2=1
DPLL1 Powered up: Register 0xB8 bit3=1
REVISION A 10/14/14 7 UFT3G FREQUENCY TUNING
DSM_ORD0=3 (Register 0x3A, bits 6 and 7, for PLL0)
DSM_ORD1=3(Register 0x6D, bits 6 and 7, for PLL1, if applicable).
STATEx=11 (Holdover)
 
3) Program the “WDCO HLDOFF” registers. The ppm offset on the output will remain at 0.
 
4) Set WDCOx=1. The WDCO offset will now be observed as the opposite ppm offset on the output.
 
Refer to application note AN-870 for more details. For other questions not addressed by the knowledge base, please submit a technical support request.

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AN-870 UFT3G Frequency Tuning Application Note PDF 926 KB