Datasheet

Complete, Direct-Conversion
Tuner for DVB-S2 Applications
Table 8. PLL Register
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
BIT NAME BIT LOCATION (0 = LSB) DEFAULT FUNCTION
VCO[4:0] 7–3 11001
C ontr ol s w hi ch V C O i s acti vated w hen usi ng m anual V C O p r og r am m i ng m od e.
Thi s al so ser ves as the star ti ng p oi nt for the V C O autosel ecti on ( V AS ) m od e.
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
BIT NAME BIT LOCATION (0 = LSB) DEFAULT FUNCTION
LPF[7:0] 7–0 01001011
Sets the baseband lowpass filter 3dB corner frequency.
f
-3dB
= 4MHz + (LPF[7:0]
dec
- 12) x 290kHz.
Default value equates to f
-3dB
= 22.27MHz typical.
MAX2112
Maxim Integrated
11