Texas Instruments SN74GTLP21395GQNR

Overview

SN74GTLP21395GQNR from Texas Instruments is a dual 1-bit LVTTL-to-GTLP adjustable-edge-rate bus transceiver with split LVTTL port, feedback path, and selectable polarity. It provides bidirectional level translation between 3.3-V LVTTL logic (5-V tolerant) and GTLP backplane signals (VTT = 1.5 V, VREF = 1 V), supports live insertion via Ioff, power-up 3-state, and BIAS VCC, and delivers high-drive GTLP outputs (100 mA sink) for distributed backplane loads down to 11 Ω.

For engineers reviewing the SN74GTLP21395GQNR datasheet, SN74GTLP21395GQNR pinout, SN74GTLP21395GQNR application, or SN74GTLP21395GQNR equivalent, this device is critical for IEEE 1394 backplane PHY interfacing, high-speed clock distribution in VME/FB+/CPCI systems, diagnostics monitoring with true/complement control, and hot-pluggable card designs requiring ERC-adjusted edge rates and TI-OPC™ ringing suppression.

Technical Context

The SN74GTLP21395GQNR integrates two independent 1-bit transceivers, each with separate A (LVTTL input), B (GTLP I/O), and Y (LVTTL output) ports, enabling transparent or inverted data flow controlled by T/C and dual OE inputs (OEAB for B-port, OEBY for Y-output). Its TI-OPC™ circuitry actively limits overshoot on unevenly terminated backplanes, while OEC™ improves signal integrity and EMI performance.

Variable edge-rate control (ERC) selects fast (ERC = L) or slow (ERC = H) B-port rise/fall times - 1.3 ns/2.6 ns (fast) or 2.5 ns/3.0 ns (slow) - optimizing timing margin versus data rate in distributed RLC loads. The device operates across –40°C to 85°C with VCC = 3.15–3.45 V, supports GTL (VTT = 1.2 V) or GTLP (VTT = 1.5 V) modes, and features built-in 26-Ω series termination on Y outputs.

Key Specifications

Pinout & Package

VFBGA package (GQN), 20-pin, 2.5 mm × 3.5 mm, 0.5-mm pitch, bottom-side ball layout per TI SCES350C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74GTLP2203PW, SN74GTLP21395GQNR adds critical diagnostics capability and live-insertion robustness; compared with SN74GTLP1395DGVR, it offers identical functionality in a smaller, higher-density VFBGA package optimized for space-constrained backplane cards.

Availability

SN74GTLP21395GQNR is available at Aetrix Electronics and suitable for IEEE 1394 backplane PHY interfacing, VME/FB+/CPCI diagnostic bus implementation, and hot-pluggable card control requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for SN74GTLP21395GQNR 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 connectivity technologies, with decades of innovation in high-speed interface solutions.

The SN74GTLP21395GQNR belongs to TI's GTLP family of backplane transceivers, designed specifically to enable robust, high-bandwidth communication between LVTTL controllers and GTLP backplanes in IEEE 1394, VME, and CPCI systems.

FAQ

What is the primary function of the SN74GTLP21395GQNR in a backplane system?

The SN74GTLP21395GQNR serves as a dual 1-bit bidirectional level translator between 3.3-V LVTTL logic and GTLP backplane signals. It enables high-speed data and strobe transmission (e.g., for IEEE 1394 PHYs), provides a dedicated LVTTL feedback path (Y outputs) for diagnostics, and supports live insertion via Ioff, power-up 3-state, and BIAS VCC. Its TI-OPC™ and OEC™ circuits enhance signal integrity on distributed loads.

How does the ERC pin affect timing performance of the SN74GTLP21395GQNR?

The ERC pin on the SN74GTLP21395GQNR selects between two discrete edge rates for the GTLP B-port outputs: ERC = L yields fast edges (1.3 ns rise / 2.6 ns fall), while ERC = H yields slow edges (2.5 ns rise / 3.0 ns fall). This adjustment directly impacts propagation delay (3.4–4.3 ns A→B), jitter tolerance, and reflection control - allowing designers to optimize for either maximum data rate or signal integrity on specific backplane loads.

Can the SN74GTLP21395GQNR operate with GTL (1.2-V) signaling instead of GTLP (1.5-V)?

Yes, the SN74GTLP21395GQNR supports both GTL and GTLP signaling standards. When used in GTL mode, VTT = 1.2 V and VREF = 0.8 V; in GTLP mode, VTT = 1.5 V and VREF = 1.0 V. The device's ac specifications are guaranteed for GTLP, but dc parameters remain valid across both configurations. Designers must adjust VREF accordingly and verify noise margins per TI application reports SCEA019 and SCEA017.

What is the role of the split LVTTL port (A and Y) in the SN74GTLP21395GQNR?

The split LVTTL port in the SN74GTLP21395GQNR separates the LVTTL input (A) from the LVTTL output (Y), creating an independent feedback path. This allows the host controller to monitor backplane activity (e.g., strobe/data from GTLP B-port) without interfering with upstream data flow. The Y outputs include integrated 26-Ω series resistors, eliminating external termination components while maintaining signal fidelity for diagnostics and control loops.

Does the SN74GTLP21395GQNR support hot-plug operation, and what features enable it?

Yes, the SN74GTLP21395GQNR is explicitly designed for live insertion. Key enablers include Ioff circuitry (<10 µA leakage at VCC = 0 V), power-up 3-state (outputs remain high-Z during power ramp), and BIAS VCC precharge (conditions B-port I/O before VCC is applied). These features prevent damaging current backflow, bus contention, and data corruption when cards are inserted or removed from an active backplane - critical for IEEE 1394 and telecom chassis applications.