Datasheet

X XX
CLKOUT
(RFB = L)
BISTEN
(DES)
PASS
DATA
(internal)
PASS
BIST Duration
Prior Result
BIST
Result
Held
PASS
FAIL
X = bit error(s)
BISTEN
(SER)
DO[23:0]
CO1,CO2,CO3
DATA
(internal)
Case 1 - Pass Case 2 - Fail
Prior Result
Normal PRBS
BIST Test
Normal
DES Outputs
SER
Normal
BIST
start
BIST
stop
BIST
Wait
Step 1: SER in BIST
Step 2: Wait, DES in BIST
Step 3: DES in Normal
Mode - check PASS
Step 4: SER in Normal
DS92LV2411, DS92LV2412
SNLS302C –MAY 2010–REVISED APRIL 2013 www.ti.com
Figure 31. BIST Mode Flow Diagram
BER Calculations
It is possible to calculate the approximate Bit Error Rate (BER). The following is required:
• Clock Frequency (MHz)
• BIST Duration (seconds)
• BIST test Result (PASS)
The BER is less than or equal to one over the product of 24 times the CLK rate times the test duration. If we
assume a 50 MHz clock, a 10 minute (600 second) test, and a PASS, the BERT is ≤ 1.39 X 10E-12
The BIST mode runs a check on the data payload bits. The LOCK pin also provides a link status. It the recovery
of the C0 and C1 bits does not reconstruct the expected clock signal, the LOCK pin will switch Low. The
combination of the LOCK and At-Speed BIST PASS pin provides a powerful tool for system evaluation and
performance monitoring.
Figure 32. BIST Waveforms
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