AD9251BCPZ-20 Analog Devices Inc, AD9251BCPZ-20 Datasheet - Page 28
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AD9251BCPZ-20
Manufacturer Part Number
AD9251BCPZ-20
Description
14 BIT DUAL 20/ Msps Low Power ADC
Manufacturer
Analog Devices Inc
Datasheet
1.AD9251BCPZRL7-20.pdf
(36 pages)
Specifications of AD9251BCPZ-20
Number Of Bits
14
Sampling Rate (per Second)
20M
Data Interface
Serial, SPI™
Number Of Converters
2
Power Dissipation (max)
77mW
Voltage Supply Source
Analog and Digital
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
64-LFCSP
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
AD9251BCPZ-20
Manufacturer:
MICRON
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AD9251
BUILT-IN SELF-TEST (BIST) AND OUTPUT TEST
The AD9251 includes a built-in test feature designed to enable
verification of the integrity of each channel, as well as to
facilitate board level debugging. A built-in self-test (BIST) feature
that verifies the integrity of the digital datapath of the AD9251
is included. Various output test options are also provided to place
predictable values on the outputs of the AD9251.
BUILT-IN SELF-TEST (BIST)
The BIST is a thorough test of the digital portion of the selected
AD9251 signal path. Perform the BIST test after a reset to ensure
the part is in a known state. During BIST, data from an internal
pseudorandom noise (PN) source is driven through the digital
datapath of both channels, starting at the ADC block output. At
the datapath output, CRC logic calculates a signature from the
data. The BIST sequence runs for 512 cycles and then stops.
Once completed, the BIST compares the signature results with a
pre-determined value. If the signatures match, the BIST sets Bit 0
of Register 0x24, signifying the test passed. If the BIST test fails,
Bit 0 of Register 0x24 is cleared. The outputs are connected
during this test, so the PN sequence can be observed as it runs.
Writing the value 0x05 to Register 0x0E runs the BIST. This enables
the Bit 0 (BIST enable) of Register 0x0E and resets the PN sequence
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generator, Bit 2 (BIST INIT) of Register 0x0E. At the completion of
the BIST, Bit 0 of Register 0x24 is automatically cleared. The PN
sequence can be continued from its last value by writing a 0 in
Bit 2 of Register 0x0E. However, if the PN sequence is not reset,
the signature calculation does not equal the predetermined
value at the end of the test. At that point, the user needs to rely
on verifying the output data.
OUTPUT TEST MODES
The output test options are described in Table 16 at Address
0x0D. When an output test mode is enabled, the analog section
of the ADC is disconnected from the digital back-end blocks
and the test pattern is run through the output formatting block.
Some of the test patterns are subject to output formatting, and
some are not. The PN generators from the PN sequence tests
can be reset by setting Bit 4 or Bit 5 of Register 0x0D. These
tests can be performed with or without an analog signal (if
present, the analog signal is ignored), but they do require an
encode clock. For more information, see the
Application Note, Interfacing to High Speed ADCs via SPI.
AN-877