AD6657ABBCZ AD [Analog Devices], AD6657ABBCZ Datasheet - Page 28

• Manufacturer Part Number: AD6657ABBCZ
• Description: Quad IF Receiver
• Manufacturer: AD [Analog Devices]

BUILT-IN SELF TEST (BIST) AND OUTPUT TEST
The
the integrity of each channel and to facilitate board-level debug-
ging. A built-in self test (BIST) feature is included that verifies
the integrity of the digital datapath of the AD6657A. Various
output test options are also provided to place predictable values
on the outputs of the AD6657A.
BIST
The BIST is a thorough test of the digital portion of the selected
AD6657A
internal pseudorandom noise (PN) source through the digital
datapath starting at the ADC block output. The BIST sequence
runs for 512 cycles and stops. The BIST signature value for the
selected channel is written to Register 0x24 and Register 0x25.
If more than one channel is BIST enabled, the channel that
is first according to alphabetical order is written to the BIST
signature registers. For example, if Channel B and Channel C
are BIST enabled, the results from Channel B are written to the
BIST signature registers.
AD6657A
AD6657A
signal path. When enabled, the test runs from an
includes built-in test features designed to verify
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The outputs are not disconnected during this test, so the PN
sequence can be observed as it runs. The PN sequence can be
continued from its last value or reset from the beginning, based
on the value programmed in Register 0x0E, Bit 2. The BIST
signature result varies based on the channel configuration.
OUTPUT TEST MODES
The output test options are shown in Table 13. When an output
test mode is enabled, the analog section of the receiver is dis-
connected 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. The seed value for the
PN sequence tests can be forced if the PN reset bits are used to
hold the generator in reset mode 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
require an encode clock. For more information, see the
Application
Note, Interfacing to High Speed ADCs via SPI.
Data Sheet
AN-877