Tool/software:
Hello TI Rep,
We’re observing rare, localized data corruption across multiple systems that use the TLK2501 as the high-speed transmit serializer. In a representative run at room temperature, we captured 10 bad frames out of ~4,400 total. Each event is confined to a single horizontal row within the frame, with bit-level anomalies such as words forced to 0x0000 or apparent MSB flips, while adjacent rows remain clean. After replacing the TLK2501 on one affected board, the corruption ceased, and subsequent captures produced no bad frames. Our schematic and layout have been reviewed against TLK2501 documentation and appear compliant. We’re seeking guidance on potential device sensitivities or operating conditions that could explain these intermittent word/bit errors.
Setup (summary)
- TX only (RX unused). AC-coupled CML outputs into 50 Ω.
- VDD = 2.5 V; 49.9 Ω pull-ups to 2.5 V on DOUTTXP/N; RREF = 150 Ω; local decoupling + ferrite bead per datasheet.
- GTX_CLK provided from FPGA; TLK2501 control/test pins in normal (non-test) mode.
- Payload is a deterministic 14-bit test pattern (frame timing identical to operational mode) used to detect single-bit/word errors.
Test Method
- Frames were captured continuously and compared against a known-good reference on a pixel/bit basis to detect single-bit or word errors.
Observed Behavior
- Room temperature run: 10 bad frames out of ~4,400 total
- (frames 4280, 4307, 4327, 4335, 4346, 4366, 4377, 4380, 4382, 4389).
Error Characteristics:
- Corruption is row-localized: each event affects one horizontal row; adjacent rows are clean.
- Bit-level deltas show:
- entire words forced to 0x0000, or
- MSB group toggling (upper bits flip), or
- specific repeated word values.
- No pixel location repeats across events (intermittent, not stuck).
- Additional analysis across the 10 frames shows dropped bits, repeated data patterns, and specific erroneous pixel values consistent with the above behaviors.
What we’ve tried / observed
- Replacing TLK2501 on an affected board removed the failures (no bad frames observed afterward).
- We reviewed our schematic/layout against TLK2501 + PowerPAD app notes; no non-compliance found (details available).
Request for guidance
- Are there known TLK2501 sensitivities that could produce intermittent word-level clears (0x0000) or MSB flips under otherwise nominal conditions?
- e.g., RREF tolerance/drift, VDD ripple, CML load/termination tolerance, GTX_CLK jitter, device aging/ESD/latent damage, PowerPAD solder voiding/thermal excursions.
- Are there errata or field notes related to mid-packet disturbances (e.g., IDLE insertion, TX_EN/TX_ER timing) that might map to our symptoms?
- Recommended bench diagnostics to isolate the device vs. system:
- eye diagram at DOUTTX±, supply ripple at the TLK2501 pins, jitter mask at GTX_CLK, PRBS mode BER targets, temperature sweep guidance.
- Any minimum/typical BER expectations for TLK2501 in AC-coupled 50 Ω links and recommended PRBS pattern/length?
We can share scope captures (TX eye, VDD, GTX_CLK), layout excerpts (PowerPAD, RREF placement), and error logs upon request.
Thanks for any pointers or known pitfalls to investigate.
