AD9874BST AD [Analog Devices], AD9874BST Datasheet - Page 12

• Manufacturer Part Number: AD9874BST
• Description: IF Digitizing Subsystem
• Manufacturer: AD [Analog Devices]

AD9874
SERIAL PERIPHERAL INTERFACE (SPI)
The serial peripheral interface (SPI) is a bidirectional serial port. It is used to load configuration information into the registers listed
below as well as to read back their contents. Table I provides a list of the registers that may be programmed through the SPI port.
Addresses and default values are given in hexadecimal form.
Address Bit
(Hex)
POWER CONTROL REGISTERS
0x00
0x01
0x02
AGC
0x03
0x04
0x05
0x06
DECIMATION FACTOR
0x07
LO SYNTHESIZER
0x08
0x09
0x0A
0x0B
0x0C
0x0D
0x0E
Breakdown
(7:0)
(7:6)
(5:4)
(3:2)
(1:0)
(7:0)
(7)
(6:0)
(7:0)
(7:4)
(3:0)
(7)
(6:4)
(3)
(2:0)
(7:5)
(4)
(3:0)
(5:0)
(7:0)
(7:5)
(4:0)
(7:0)
(6)
(5)
(4:2)
(1:0)
(5:0)
(7:0)
Width
8
2
2
2
2
8
1
7
8
4
4
1
3
1
3
3
1
4
6
8
3
5
8
1
1
3
2
4
8
0x0
Default Value
0xFF
0
0
0
0
0x00
0
0x00
0x00
0
0
0
0
0
0
0
4
0x00
0x38
0x5
0x00
0x1D
0
0
0
3
0x04
Name
STBY
LNAB
MIXB
CKOB
ADCB
TEST
ATTEN
AGCG(14:8) AGC Attenuation Setting (7 MSBs of a 15-Bit Unsigned Word)
AGCG(7:0)
AGCA
AGCD
AGCV
AGCO
AGCF
AGCR
Unused
K
M
LOR(13:8)
LOR(7:0)
LOA
LOB(12:8)
LOB(7:0)
LOF
LOINV
LOI
LOTM
LOFA(13:8)
LOFA(7:0)
Table I. SPI Address Map
Description
Standby Control Bits (REF, LO, CKO, CK, GC, LNAMX, Unused, and ADC)
LNA Bias Current (0 = 0.5 mA, 1 = 1 mA, 2 = 2 mA, 3 = 3 mA)
Mixer Bias Current (0 = 0.5 mA, 1 = 1.5 mA, 2 = 2.7 mA, 3 = 4 mA)
CK Oscillator Bias (0 = 0.25 mA, 1 = 0.35 mA, 2 = 0.40 mA, 3 = 0.65 mA)
Do Not Use
Factory Test Mode. Do not use.
Apply 16 dB Attenuation in the Front End
AGC Attenuation Setting (8 LSBs of a 15-Bit Unsigned Word)
Default corresponds to maximum gain
AGC Attack Bandwidth Setting. Default yields 50 Hz raw loop bandwidth.
AGC Decay Time Setting. Default is decay time = attack time.
Enable Digital VGA to increase AGC Range by 12 dB
AGC Overload Update Setting. Default is slowest update
Fast AGC (Minimizes resistance seen between GCP and GCN)
AGC Enable/Reference Level (Disabled, 3 dB, 6 dB, 9 dB, 12 dB, 15 dB below Clip)
Decimation Factor = 60 × (M + 1), if K = 0; 48 × (M + 1), if K = 1
Default is Decimate-by-300
Reference Frequency Divisor (6 MSBs of a 14-Bit Word)
Reference Frequency Divisor (8 LSBs of a 14-Bit Word)
Default (56) Yields 300 kHz from f
“A” Counter (Prescaler Control Counter)
“B” Counter MSBs (5 MSBs of a 13-Bit Word)
Default LOA and LOB values yield 300 kHz from 73.35 MHz–2.25 MHz
“B” Counter LSBs (8 LSBs of a 13-Bit Word)
Enable Fast Acquire
Invert Charge Pump (0 = Source Current to Increase VCO Frequency)
Charge Pump Current in Normal Operation. I
Manual Control of LO Charge Pump (0 = Off, 1 = Up, 2 = Down, 3 = Normal)
LO Fast Acquire Time Unit (6 MSBs of a 14-Bit Word)
LO Fast Acquire Time Unit (8 LSBs of a 14-Bit Word)
–12–
REF
= 16.8 MHz
PUMP
= (LOI + 1) × 0.625 mA
REV. 0