AD9253-125EBZ AD [Analog Devices], AD9253-125EBZ Datasheet - Page 29

• Manufacturer Part Number: AD9253-125EBZ
• Description: Quad, 14-Bit, 80 MSPS/105 MSPS/125 MSPS
• Manufacturer: AD [Analog Devices]

Data Sheet
Table 11. Flexible Output Test Modes
Output Test
Mode
Bit Sequence
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1
When the SPI is used, the DCO phase can be adjusted in 60°
increments relative to the data edge. This enables the user to
refine system timing margins if required. The default DCO+
and DCO− timing, as shown in Figure 2, is 90° relative to the
output data edge.
A 12-bit serial stream can also be initiated from the SPI. This
allows the user to implement and test compatibility to lower
resolution systems. When changing the resolution to a 12-bit
serial stream, the data stream is shortened. See Figure 3 for the
12-bit example. However, in the default option with the serial
output number of bits at 16, the data stream stuffs two 0s at the
end of the 14-bit serial data.
In default mode, as shown in Figure 2, the MSB is first in the
data output serial stream. This can be inverted so that the LSB is
first in the data output serial stream by using the SPI.
There are 12 digital output test pattern options available that
can be initiated through the SPI. This is a useful feature when
validating receiver capture and timing. Refer to Table 11 for the
output bit sequencing options available. Some test patterns have
two serial sequential words and can be alternated in various
ways, depending on the test pattern chosen. Note that some
All test mode options except PN sequence short and PN sequence long can support 12-bit to 16-bit word lengths to verify data capture to the receiver.
Pattern Name
Off (default)
Midscale short
+Full-scale short
−Full-scale short
Checkerboard
PN sequence long
PN sequence short
One-/zero-word
toggle
User input
1-/0-bit toggle
1× sync
One bit high
Mixed frequency
1
1
Digital Output Word 1
N/A
1000 0000 0000 (12-bit)
1000 0000 0000 0000 (16-bit)
1111 1111 1111 (12-bit)
0000 0000 0000 0000 (16-bit)
0000 0000 0000 (12-bit)
0000 0000 0000 0000 (16-bit)
1010 1010 1010 (12-bit)
1010 1010 1010 1010 (16-bit)
N/A
N/A
1111 1111 1111 (12-bit)
111 1111 1111 1100 (16-bit)
Register 0x19 to Register 0x1A
1010 1010 1010 (12-bit)
1010 1010 1010 1000 (16-bit)
0000 0011 1111 (12-bit)
0000 0001 1111 1100 (16-bit)
1000 0000 0000 (12-bit)
1000 0000 0000 0000 (16-bit)
1010 0011 0011 (12-bit)
1010 0001 1001 1100 (16-bit)
Rev. 0 | Page 29 of 40
patterns do not adhere to the data format select option. In
addition, custom user-defined test patterns can be assigned in
the 0x19, 0x1A, 0x1B, and 0x1C register addresses.
The PN sequence short pattern produces a pseudorandom bit
sequence that repeats itself every 2
description of the PN sequence and how it is generated can be
found in Section 5.1 of the ITU-T 0.150 (05/96) standard. The
seed value is all 1s (see Table 12 for the initial values). The
output is a parallel representation of the serial PN9 sequence in
MSB-first format. The first output word is the first 14 bits of the
PN9 sequence in MSB aligned form.
The PN sequence long pattern produces a pseudorandom bit
sequence that repeats itself every 2
description of the PN sequence and how it is generated can be
found in Section 5.6 of the ITU-T 0.150 (05/96) standard. The
seed value is all 1s (see Table 12 for the initial values) and the
AD9253
The output is a parallel representation of the serial PN23 sequence
in MSB-first format. The first output word is the first 14 bits of the
PN23 sequence in MSB aligned form
Digital Output Word 2
N/A
N/A
N/A
N/A
0101 0101 0101 (12-bit)
0101 0101 0101 0100 (16-bit)
N/A
N/A
0000 0000 0000 (12-bit)
0000 0000 0000 0000 (16-bit)
Register 0x1B to Register 0x1C
N/A
N/A
N/A
N/A
inverts the bit stream with relation to the ITU standard.
Subject to
Data Format
Select
N/A
Yes
Yes
Yes
No
Yes
Yes
No
No
No
No
No
No
9
23
− 1 or 511 bits. A
− 1 or 8,388,607 bits. A
Notes
Offset binary
code shown
Offset binary
code shown
Offset binary
code shown
PN23
ITU 0.150
X
PN9
ITU 0.150
X
Pattern
associated
with the
external pin
AD9253
23
9
+ X
+ X
5
18
+ 1
+ 1