onsemi GTLP1B151K8X

Overview

GTLP1B151K8X from Fairchild Semiconductor is a 1-bit bidirectional LVTTL-to-GTLP transceiver with separate LVTTL input (A), GTLP I/O (B), and LVTTL output (C) ports, individual OEB/OEC enables, VREF-adjustable receiver threshold, and flow-through pinout in an 8-lead US8 package. It supports high-speed backplane interfaces requiring <1V GTLP swing, 1.5V VOH, 0.5V VOL, and 2.8–7.5ns propagation delays.

For engineers reviewing the GTLP1B151K8X datasheet, pinout, applications, or equivalent options, key selection criteria include GTLP/LVTTL level translation capability, VREF-based threshold tuning, open-drain B-port support for wired-OR, bushold A-port inputs eliminating pull-ups, and live-insertion compatibility via power-up/down high-Z states.

Technical Context

The GTLP1B151K8X implements a non-inverting bidirectional signal path between LVTTL logic (A/C ports) and GTLP backplane logic (B port), with independent enable controls OEB (active-high, B port) and OEC (active-low, C port). Its internal edge-rate control minimizes GTLP bus settling time while maintaining JEDEC JESD8-3 GTL compatibility.

VREF (0.98–1.02V) sets the B-port input threshold; VTT (1.47–1.53V) supplies GTLP termination; and the device uses Fairchild's BiCMOS process with PVT compensation to stabilize timing and drive strength across −40°C to +85°C. The A port features bushold to retain state on floating inputs.

Key Specifications

Pinout & Package

GTLP1B151K8X is housed in an 8-lead US8 package (JEDEC MO-187, Variation CA, 3.1mm wide), with gull-wing leads and 0.5mm pitch. This compact surface-mount outline supports high-density PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LVTTL/GTLP level translation applications.

Compared with SN74GTL16622DGGR and 74ALVC164245PAG, GTLP1B151K8X uniquely delivers single-bit GTLP backplane interface with VREF-adjustable threshold, open-drain B port for wired-OR, and bushold A inputs-making it optimal for space-constrained, high-integrity control and diagnostics paths where precision GTLP timing and live-insertion safety are required.

Availability

GTLP1B151K8X is available at Aetrix Electronics and suitable for backplane data bus interfaces, hot-swappable module control, shared status monitoring buses, and high-density rack management systems requiring stable component supply and long-term industrial availability.

Supply support for GTLP1B151K8X 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

Fairchild Semiconductor was a leading analog and discrete semiconductor manufacturer, acquired by ON Semiconductor in 2016; its legacy GTLP product line remains widely deployed in industrial and telecom infrastructure.

The GTLP1B151K8X belongs to Fairchild's GTLP family, engineered specifically for high-speed, noise-resilient backplane interconnects in telecom switches, modular servers, and carrier-grade equipment operating under stringent EMI and thermal constraints.

FAQ

What is the function of the VREF pin on the GTLP1B151K8X?

The VREF pin on the GTLP1B151K8X provides an external reference voltage (typically 1.0V ±20mV) that sets the input threshold for the GTLP B port. This allows system designers to fine-tune noise margin on lossy or impedance-mismatched backplanes. Unlike fixed-threshold devices, GTLP1B151K8X uses VREF to maintain consistent switching points across voltage and temperature variations, directly supporting JEDEC JESD8-3 GTL compliance.

Does the GTLP1B151K8X support hot-swap insertion?

Yes, the GTLP1B151K8X supports hot-swap insertion through inherent power-up/power-down high-impedance behavior: both B and C ports enter high-Z states when VCC is below ~1.5V, preventing bus contention during live insertion. This feature is verified in the Absolute Maximum Ratings and DC Electrical Characteristics tables, and requires no external circuitry-making GTLP1B151K8X suitable for modular telecom and server backplane applications where field-replaceable units are standard.

What is the purpose of bushold on the A port of the GTLP1B151K8X?

Bushold on the A port of the GTLP1B151K8X maintains the last valid logic state on unused or floating inputs without requiring external pull-up resistors. This reduces BOM cost and PCB area while preventing undefined states that could cause downstream logic errors. Measured II(HOLD) values (±75µA at VCC = 3.15V) confirm robust state retention across temperature, making GTLP1B151K8X ideal for systems with partially populated control interfaces.

Can the GTLP1B151K8X be used for wired-OR bus configurations?

Yes, the GTLP1B151K8X supports wired-OR configurations exclusively on its B port, which is open-drain. When multiple GTLP1B151K8X devices share a common B-bus, their outputs can be tied together with a single pull-up resistor to VTT (1.5V), enabling logical OR functionality for status aggregation or interrupt sharing. This capability is explicitly documented in the Features list and functional tables, distinguishing it from push-pull alternatives.

How does the GTLP1B151K8X differ from standard GTL or BTL transceivers?

The GTLP1B151K8X differs from standard GTL/BTL transceivers by integrating edge-rate control, PVT compensation, and a dedicated VREF pin for threshold adjustment-features absent in basic GTL implementations. Its output levels (VOH = 1.5V, VOL = 0.5V) and receiver thresholds are optimized for 3.3V LVTTL compatibility, whereas GTL typically operates at 1.2V and BTL at 2.0V. These distinctions make GTLP1B151K8X uniquely suited for modern 3.3V backplane designs requiring tighter noise margins and thermal stability.