AIT1042 Datasheet, PDF (12/19 Pages) ANADIGICS, Inc – Integrated Digital Tuner with RF and IF Gain Control

AIT1042
PROGRAMMING THE AIT1042
This section describes how to program the registers of the AIT1042 to control its operation.The 24-bit registers
that control the dividers and other functions are each segmented into three 8-bit data words. Some bits have
required fixed values (reserved bits and addressing), while others are used for control and synthesizer operation.
The grayed areas of the addresses and control registers are fixed values and must be set as indicated in Table
8.
Control Register I
Control register I has two user programmable functions:
• Wake-up (Bit 19)
• Charge pump current settings (Bits 8-10 and bits 12-14) in the synthesizers
Table 9 shows how the Wake-up bit is used to control power up of the AIT1042. When the device is initially
powered up the wake up bit (19) is set to 0 and the device will draw minimum current. Setting bit 19 to 1 will
turn the device on for normal operation.
The charge pump current settings for the upconverter (CPI1) and downconverter (CPI2) synthesizers are
set by Bits 8-10 and Bits 12-14, respectively. Refer to Table 10.
MSB
Table 8: Control Register I
PLL_CtrlI (Control Register I)
LSB
First data byte
Second data byte
Third data byte
23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 1 0 0W 0 0 0 0
CPI2
0
CPI1
10 0000 0 1
Table 9: Wake-up Mode Bit
Bit 19
Wake-up mode
0
Power down (default)
1
Normal operation
Table 10: Charge Pump Current Bits
CPIx Bits Charge Pump Current
0000
(reserved)
0001
0.7 mA
0010
1.3 mA
0011
1.9 mA
0100
2.5 mA
0101
3.1 mA
0110
3.6 mA
0111
4.1 mA
Note: 1000 thru 1111 are Reserved.
12
PRELIMINARY DATA SHEET - Rev 1.0
02/2009