ADS54J69 Datasheet, PDF (48/75 Pages) Texas Instruments – Dual-Channel, 16-Bit, 500-MSPS, Analog-to-Digital Converter

ADS54J69
SBAS713B – MAY 2015 – REVISED FEBRUARY 2016
7.5.3.4.3 Register 42h (address = 42h), Main Digital Page (6800h)
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Figure 101. Register 42h
7
6
5
4
0
0
0
0
W-0h
W-0h
W-0h
W-0h
LEGEND: R/W = Read/Write; W = Write only; -n = value after reset
3
0
W-0h
2
1
0
NYQUIST ZONE
R/W-0h
Table 34. Register 42h Field Descriptions
Bit Field
7-3 0
2-0 NYQUIST ZONE
Type
W
R/W
Reset
0h
0h
Description
Must write 0
The Nyquist zone must be selected for proper interleaving
correction. Here Nyquist refers to Device Clock/2. For 1 GSPS
Device clock, Nyquist frequency is 500 MHz. Also set register bit
CTRL NYQUIST (4Eh, bit 7).
000 = 1st Nyquist zone (0 MHz to 500 MHz)
001 = 2nd Nyquist zone (500 MHz to 1000 MHz)
010 = 3rd Nyquist zone (1000 MHz to 1500 MHz)
All others = Not used
7.5.3.4.4 Register 43h (address = 43h), Main Digital Page (6800h)
Figure 102. Register 43h
7
6
5
4
0
0
0
0
W-0h
W-0h
W-0h
W-0h
LEGEND: R/W = Read/Write; W = Write only; -n = value after reset
3
0
W-0h
2
0
W-0h
1
0
W-0h
0
FORMAT SEL
R/W-0h
Bit Field
7-1 0
0
FORMAT SEL
Table 35. Register 43h Field Descriptions
Type
W
R/W
Reset
0h
0h
Description
Must write 0
Changes the output format. Set the FORMAT EN bit (register
4Bh, bit 5) to enable control using this bit.
0 = Twos complement
1 = Offset binary
7.5.3.4.5 Register 44h (address = 44h), Main Digital Page (6800h)
Figure 103. Register 44h
7
6
5
4
3
2
1
0
0
DIGITAL GAIN
R/W-0h
R/W-0h
LEGEND: R/W = Read/Write; -n = value after reset
Bit Field
7
0
6-0 DIGITAL GAIN
Table 36. Register 44h Field Descriptions
Type
R/W
R/W
Reset
0h
0h
Description
Must write 0
Digital gain setting. Digital gain must be enabled (register 52h,
bit 0).
Gain in dB = 20log (digital gain / 32).
7Fh = 127, equals digital gain of 9.5 dB.
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