SNAS605AS March 2013 – May 2020 LMK04821 , LMK04826 , LMK04828
PRODUCTION DATA.
This register controls the PLL2 phase detector.
BIT | NAME | POR DEFAULT | DESCRIPTION | |
---|---|---|---|---|
7 | NA | 0 | Reserved | |
6:5 | PLL2_WND_SIZE | 2 | PLL2_WND_SIZE sets the window size used for digital lock detect for PLL2. If the phase error between the reference and feedback of PLL2 is less than the specified time, then the PLL2 lock counter increments. This value must be programmed to 2 (3.7 ns). | |
Field Value | Definition | |||
0 (0x00) | Reserved | |||
1 (0x01) | Reserved | |||
2 (0x02) | 3.7 ns | |||
3 (0x03) | Reserved | |||
4:3 | PLL2_CP_GAIN | 3 | This bit programs the PLL2 charge pump output current level. The table below also illustrates the impact of the PLL2 TRISTATE bit in conjunction with PLL2_CP_GAIN. | |
Field Value | Definition | |||
0 (0x00) | 100 µA | |||
1 (0x01) | 400 µA | |||
2 (0x02) | 1600 µA | |||
3 (0x03) | 3200 µA | |||
2 | PLL2_CP_POL | 0 | PLL2_CP_POL sets the charge pump polarity for PLL2. The internal VCO requires the negative charge pump polarity to be selected. Many VCOs use positive slope.
A positive-slope VCO increases output frequency with increasing voltage. A negative-slope VCO decreases output frequency with increasing voltage. |
|
Field Value | Description | |||
0 | Negative-slope VCO/VCXO | |||
1 | Positive-slope VCO/VCXO | |||
1 | PLL2_CP_TRI | 0 | PLL2_CP_TRI TRI-STATEs the output of the PLL2 charge pump.
0: Disabled 1: TRI-STATE |
|
0 | Fixed Value | 1 | When programming register 0x169, this field must be set to 1. |