SNAS736C June 2017 – April 2019 LMX2595
The MUXout pin can be configured for lock detect done in by reading back the rb_LD_VTUNE field or using the pin as shown in the Table 4.
|LD_TYPE||0 = VCO Calibration Status
1 = Indirect Vtune
|Select Lock Detect Type.|
|LD_DLY||0 to 65535||Only valid for Vtune lock detect. This is a delay in state machine cycles.|
|OUT_MUTE||0 = Disabled
1 = Enabled
|Turns off outputs when lock detect is low.|
VCO calibration status lock detect works by indicating a low signal on the MUXout pin whenever the VCO is calibrating or the LD_DLY counter is running. The delay from the LD_DLY is added to the true VCO calibration time (tVCOCAL), so it can be used to account for the analog lock time of the PLL.
Indirect Vtune lock detect is based on internally generated voltage that is related to (but not the same as) the Vtune voltage of the charge pump. It indicates a high signal on MUXout pin or reads back state 2 of rb_LD_VTUNE when the device is locked.