Datasheet

Data Sheet AD9148
Rev. B | Page 39 of 72
Register Name
Addr
(Hex) Bit Name Function Default
FTW (LSB) 54 7:0 FTW[7:0] See Register 0x57. 0
FTW 55 7:0 FTW[15:8] See Register 0x57. 0
FTW 56 7:0 FTW [23:16] See Register 0x57. 0
FTW (MSB) 57 7:0 FTW [31:24]
FTW[31:0] is the 32-bit frequency tuning word that
determines the frequency of the complex carrier generated
by the on-chip NCO. The frequency is not updated when the
FTW registers are written. The values are only updated when
Register 0x5A[2] transitions from 0 to 1.
0
Phase Offset MSB 58 7:0
NCO Phase
Offset[15:8]
See Register 0x59. 0
Phase Offset LSB 59 7:0
NCO Phase
Offset[7:0]
NCO Phase Offset[15:0] sets the phase of the complex carrier
signal when the NCO is reset. The phase offset spans between
0º and 360º. Each bit represents an offset of 0.0055°. Value is
in twos complement format.
0
DDS/Mod Control 5A 7 Bypass DDS/MOD 1 = bypass NCO. 1
5 Frame NCO reset ack
1 = indicates that the NCO has been reset due to an
extended FRAMEx_x pulse signal.
0
4
Frame NCO
reset request
0→1 = The NCO is reset on the first extended FRAMEx_x
pulse after this bit transitions from 0 to 1.
0
3 FTW update ack
1 = indicates that the FTW has been updated with the
SPI value.
0
2 FTW update request
0
→
1 = FTW is updated with the SPI value on a 0-to-1
transition of this bit.
0
0 Sideband select 0 = The modulator output high-side image. 0
1 = The modulator output low-side image. The image is
spectrally inverted compared to the input data.
Die Temp Control 0
5C
1
Latch temp data
0
→
1 = latches temp sensor data. This should be completed
before the Die Temp[15:0] is readback.
0
0
Temp sensor
power-down
1 = powers down the aux ADC that converts die temperature. 1
Die Temp Control 1 5D 7:0 00001010
Set these bits to 00001010 for optimal temperature sensor
operation.
100000
Die Temp (LSBs) 5E 7:0 Die Temp[7:0] Die Temp[15:0] indicates the approximate die temperature.
Read-
only
Die Temp (MSBs) 5F 7:0 Die Temp[15:8] Die Temp[15:0] indicates the approximate die temperature.
Read-
only
DCI Delay 72 1:0 DCI delay Programmable delay added DCI. 00
00 = no added delay.
01 = 200 ps delay.
10 = 400 ps delay.
11 = 600 ps delay.