Datasheet

MAX2121
Complete Direct-Conversion L-Band Tuner
12
Table 8. PLL Register (Address: 0x06)
BIT NAME BIT LOCATION (0 = LSB) DEFAULT FUNCTION
D24 7 1
VCO divider setting.
0 = Divide by 2. Use for LO frequencies  1125MHz.
1 = Divide by 4. Use for LO frequencies < 1125MHz.
CPS 6 1
Charge-pump current mode.
0 = Charge-pump current controlled by ICP bit.
1 = Charge-pump current controlled by VCO autoselect (VAS).
ICP 5 0
Charge-pump current.
0 = 600µA typical.
1 = 1200µA typical.
X 4–0 X Don’t care.
Table 9. VCO Register (Address: 0x07)
BIT NAME BIT LOCATION (0 = LSB) DEFAULT FUNCTION
VCO[4:0] 7–3 11001
Controls which VCO is activated when using manual VCO programming mode.
This also serves as the starting point for the VCO autoselection (VAS) mode.
VAS 2 1
VCO autoselection (VAS) circuit.
0 = Disable VCO selection must be programmed through I
2
C.
1 = Enable VCO selection controlled by autoselection circuit.
ADL 1 0
Enables or disables the VCO tuning voltage ADC latch when the VCO
autoselect mode (VAS) is disabled.
0 = Disables the ADC latch.
1 = Latches the ADC value.
ADE 0 0
Enables or disables VCO tuning voltage ADC read when the VCO
autoselect mode (VAS) is disabled.
0 = Disables ADC read.
1 = Enables ADC read.
Table 10. Lowpass Filter Register (Address: 0x08)
BIT NAME BIT LOCATION (0 = LSB) DEFAULT FUNCTION
Reserved 7–0 01001011 User must program to 10010111 (97h) upon powering up the device.