Texas Instruments SN74GTLP1394PW

Overview

SN74GTLP1394PW from Texas Instruments is a 2-bit LVTTL-to-GTLP adjustable-edge-rate bus transceiver with split LVTTL port, feedback path, and selectable polarity. It provides bidirectional signal-level translation between 3.3-V LVTTL logic (A/Y ports) and GTLP backplane signals (B port), supports live insertion via Ioff, power-up 3-state, and BIAS VCC, and operates across –40°C to 85°C. It is used in IEEE 1394 backplane systems interfacing with TI TSB14AA1 PHY controllers.

For engineers reviewing the SN74GTLP1394PW datasheet, SN74GTLP1394PW pinout, SN74GTLP1394PW application, or SN74GTLP1394PW equivalent, key selection considerations include GTLP output drive (100 mA), ERC-controlled edge rates (1.2–2.5 ns rise/fall), 5-V-tolerant LVTTL inputs, split-port feedback capability, and TSSOP-16 packaging for high-density backplane card designs.

Technical Context

The SN74GTLP1394PW implements TI-OPC™ circuitry to suppress overshoot on unevenly loaded backplanes and OEC™ circuitry to reduce EMI and improve signal integrity. Its dual-directional architecture supports true or complementary data transfer via the T/C input, while separate A-input and Y-output pins enable real-time control-path feedback without interrupting B-port data flow.

It features adjustable edge-rate control (ERC) that selects fast (ERC = VCC) or slow (ERC = GND) B-port rise/fall times - critical for optimizing noise margin vs. timing in distributed GTLP backplanes. The device is fully specified for hot-plug operation: Ioff disables outputs during power-down, power-up 3-state prevents bus contention, and BIAS VCC preconditions B-port I/O to avoid disturbance during card insertion.

Key Specifications

Pinout & Package

TSSOP-16 package (PW), 4.4 mm × 5.0 mm body, 0.65 mm pitch, exposed thermal pad (not electrically connected). Pin 1 marked by beveled corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74GTLP1394PW, SN74GTLP1395PW doubles channel count at identical per-channel performance, while SN74GTLP1394D trades thermal efficiency and board area for simplified assembly and legacy footprint compatibility - neither offers pin-to-pin replacement without layout revision.

Availability

SN74GTLP1394PW is available at Aetrix Electronics and suitable for IEEE 1394 backplane diagnostics, hot-swappable VME64 module interfaces, and GTLP-based CPCI system management buses requiring stable component supply across extended product lifecycles.

Supply support for SN74GTLP1394PW 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 specializing in analog, embedded processing, and logic solutions, with over 90 years of innovation in high-performance interface and signal-integrity technologies.

The SN74GTLP1394PW belongs to TI's GTLP transceiver family, engineered specifically for robust, high-speed communication between LVTTL host controllers and GTLP backplanes in IEEE 1394, VME64, CPCI, and FB+ systems.

FAQ

What is the primary function of the SN74GTLP1394PW in a 1394 backplane system?

The SN74GTLP1394PW serves as a bidirectional LVTTL-to-GTLP bus transceiver that bridges the 3.3-V LVTTL logic domain of the link-layer controller (e.g., TSB14AA1) with the 1.5-V GTLP signaling domain of the backplane. It handles both DATA and STROBE lines, supports polarity selection, and provides isolated feedback via its split Y-output port - enabling real-time diagnostics without disrupting active backplane traffic. Its TI-OPC and OEC circuitry ensure signal integrity across multi-slot distributed loads.

How does the ERC pin affect timing and signal integrity in the SN74GTLP1394PW?

The ERC pin on the SN74GTLP1394PW selects between two discrete edge-rate modes: ERC = GND yields slow edges (2.0 ns rise / 2.5 ns fall), reducing EMI and improving noise margin on long or poorly terminated backplanes; ERC = VCC enables fast edges (1.2 ns rise / 1.8 ns fall), maximizing data rate in well-characterized, short-trace environments. This hardware-selectable control eliminates external RC tuning components and allows system-level optimization without firmware changes.

Can the SN74GTLP1394PW be used in hot-swap applications, and what features enable this?

Yes, the SN74GTLP1394PW is explicitly designed for live insertion. It incorporates three key features: Ioff circuitry limits current backflow when VCC = 0; power-up 3-state holds outputs high-impedance during power ramping; and BIAS VCC precharges B-port I/O lines before VCC is applied - preventing glitches on active backplanes during card insertion. These capabilities are validated per JESD78 Class II latch-up and JESD22 ESD standards, making SN74GTLP1394PW suitable for IEEE 1394-compliant hot-plug systems.

What is the role of the split LVTTL port (A-inputs and Y-outputs) in the SN74GTLP1394PW?

The split LVTTL port in the SN74GTLP1394PW separates data input (A1/A2) from feedback output (Y1/Y2), enabling non-intrusive monitoring of backplane signals. While A1/A2 drive the B-port onto the GTLP bus, Y1/Y2 simultaneously reflect received B1/B2 signals back to the host controller - allowing real-time diagnostics, loopback testing, or protocol analysis without disabling the primary data path. This architecture is essential for fault-tolerant backplane systems requiring continuous observability.

Is the SN74GTLP1394PW compatible with both GTL and GTLP signaling standards?

Yes, the SN74GTLP1394PW supports both GTL (VTT = 1.2 V, VREF = 0.8 V) and GTLP (VTT = 1.5 V, VREF = 1.0 V) signaling levels. Its AC specifications are guaranteed for GTLP, but the device's flexible input thresholds and output drive allow operation at GTL levels - verified by TI's characterization across recommended operating conditions. Designers may adjust VREF to optimize noise margin, though TI recommends setting VREF ≈ 2/3 × VTT for best performance in either mode.