AD9204 Analog Devices, AD9204 Datasheet - Page 27

• Manufacturer Part Number: AD9204
• Description: 10-Bit, 20 MSPS/40 MSPS/65 MSPS/80 MSPS, 1.8 V Dual Analog-to-Digital Converter
• Manufacturer: Analog Devices

Specifications of AD9204

• Resolution (bits): 10bit
• # Chan: 2
• Sample Rate: 80MSPS
• Interface: Par
• Analog Input Type: Diff-Uni,SE-Uni
• Ain Range: (2Vref) p-p,1 V p-p,2 V p-p
• Adc Architecture: Pipelined
• Pkg Type: CSP

BUILT-IN SELF-TEST (BIST) AND OUTPUT TEST
The AD9204 includes a built-in test feature designed to enable
verification of the integrity of each channel, as well as facilitate
board level debugging. A built-in self-test (BIST) feature that
verifies the integrity of the digital datapath of the AD9204 is
included. Various output test options are also provided to place
predictable values on the outputs of the AD9204.
BUILT-IN SELF-TEST (BIST)
The BIST is a thorough test of the digital portion of the selected
AD9204 signal path. Perform the BIST test after a reset to ensure
that 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
predetermined value. If the signatures match, the BIST sets Bit 0
of Register 0x24, signifying that the test passed. If the BIST test
failed, Bit 0 of Register 0x24 is cleared. The outputs are connected
during this test so that the PN sequence can be observed as it
runs. Writing 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 will not equal the predetermined value
at the end of the test. At that point, the user must rely on
verifying the output data.
OUTPUT TEST MODES
The output test options are described in Table 17 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 AN-877 Appli-
cation Note, Interfacing to High Speed ADCs via SPI.
AD9204