Texas Instruments SCAN921025HSM

Overview

SCAN921025H from Texas Instruments is a high-temperature 10-bit parallel-to-serial LVDS Serializer IC designed for backplane and cable interconnects. It converts 10-bit LVCMOS/LVTTL data plus 2 control bits into an 800 Mbps Bus LVDS serial stream with embedded clock, supports 20–80 MHz input clocks, operates up to +125°C, and features IEEE 1149.1 JTAG compliance and at-speed BIST for automotive and aerospace data links.

For engineers reviewing the SCAN921025H datasheet, SCAN921025H pinout, SCAN921025H application, or SCAN921025H equivalent, this page delivers verified electrical specs, synchronization behavior, powerdown timing, tri-state control logic, and real-world lock recovery characteristics - all confirmed from TI's SNLS185C datasheet (Rev. May 2013).

Technical Context

The SCAN921025H implements a PLL-based serialization architecture that embeds start/stop bits as clock markers within each 12-bit frame (10 data + 2 control), enabling deterministic clock recovery without a separate clock line. Its Bus LVDS output drives a single 27Ω differential load with 200–290 mV differential voltage and ±35 mV unbalance.

It supports programmable edge-triggered latching (TCLK_R/F), synchronous initialization via SYNC1/SYNC2, and three operational states: Data Transfer, Resynchronization, and Powerdown. The LOCK indicator and tri-state enable (DEN) provide system-level control over link integrity and bus contention.

Key Specifications

Pinout & Package

SCAN921025H uses a 49-lead NFBGA package (7 mm × 7 mm, 0.8 mm pitch) with exposed thermal pad. Pin functions are defined per TI SNLS185C Figure 19 (Pin Assignments) and Table 2.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar serializer applications.

Compared with MAX9205 and DS90CR285, SCAN921025H uniquely combines embedded-clock serialization, IEEE 1149.1 JTAG, at-speed BIST, and +125°C operation - making it the only option qualified for safety-critical, high-reliability backplane links requiring deterministic lock recovery and production test coverage.

Availability

SCAN921025H is available at Aetrix Electronics and suitable for automotive ADAS backhaul, avionics sensor aggregation, and industrial PLC I/O expansion requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for SCAN921025H includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader focused on analog, embedded processing, and connectivity technologies, with deep expertise in high-reliability interface solutions.

The SCAN921025H belongs to TI's high-temperature Bus LVDS SerDes chipset family, engineered specifically for deterministic, low-skew, high-integrity data transport in harsh-environment backplanes and cable systems.

FAQ

What is the maximum serial data rate supported by SCAN921025H?

The SCAN921025H achieves a payload data rate of 800 Mbps (10 bits × 80 MHz TCLK) and a gross serial rate of 960 Mbps (12 bits × 80 MHz). This is achieved by embedding start/stop bits as clock markers in every frame. The device is specified for TCLK frequencies from 20 MHz to 80 MHz, with timing parameters validated across that range per SNLS185C.

Does SCAN921025H require an external clock for the deserializer partner?

Yes - the SCAN921025H itself does not require an external clock for its own operation, but its companion deserializer SCAN921226H requires a stable REFCLK input to recover the embedded clock. The SCAN921025H transmits clock information within the serial stream, but the deserializer uses REFCLK to initialize and stabilize its PLL before locking to the incoming data. This dual-clock architecture ensures robust lock acquisition under varying jitter conditions.

How does SCAN921025H handle loss of synchronization during operation?

SCAN921025H does not directly detect loss of sync - that function resides in the SCAN921226H deserializer, which asserts LOCK high upon losing lock. However, SCAN921025H supports resynchronization via SYNC1/SYNC2: when driven high for ≥5 TCLK cycles, it transmits dedicated SYNC patterns to accelerate relock. This enables closed-loop recovery when LOCK is fed back to SYNC1, ensuring minimal data interruption (<3 invalid cycles) after transient link faults.

Can SCAN921025H drive multiple receivers on a single Bus LVDS line?

No - the SCAN921025H Bus LVDS output is designed for point-to-point connections or limited multi-drop topologies only. Its driver is rated for a 27Ω differential load and lacks the current drive capability for true multi-point termination. TI explicitly states in SNLS185C that "outputs can drive a point-to-point connection or in limited multi-point or multi-drop backplanes," and recommends verifying signal integrity with IBIS models for any multi-drop use case.

What is the purpose of the TCLK_R/F pin on SCAN921025H?

The TCLK_R/F pin selects the clock edge used to sample the DIN0–DIN9 parallel inputs: high configures rising-edge capture, low configures falling-edge capture. This allows alignment with source ASIC timing domains without requiring external inverters or layout adjustments. The feature is fully characterized in the timing tables (e.g., tDIS/tDIH hold/setup times differ slightly based on edge selection), and is essential for interfacing with legacy controllers using non-standard clock phase relationships.