SN74GTLPH16612GR

Overview

The SN74GTLPH16612GR is an 18-bit Universal Bus Transceiver (UBT) manufactured by Texas Instruments in a TSSOP-56 package. It provides bidirectional voltage level translation between LVTTL and GTLP signal levels. The device supports transparent, latched, clocked, and clock-enabled data transfer modes using D-type latches and flip-flops. Recommended operating conditions specify VCC(3.3V) at 3.15–3.45 V and VCC(5V) at 4.75–5.25 V. Maximum clock frequency is 85 MHz. Propagation delays range from 1.5 ns to 7.8 ns depending on the path. Operating temperature spans -40°C to +85°C.

Feature Summary

• Combines D-type latches and flip-flops for flexible data transfer modes including transparent, latched, clocked, and clock-enabled operations.
• Features OEC circuitry designed to improve signal integrity and reduce electromagnetic interference in distributed backplane loads.
• Includes active bus-hold circuitry on A-port inputs to maintain valid logic states for unused or undriven lines.
• Supports partial-power-down mode via Ioff circuitry to prevent damaging current backflow during power transitions.

Applications

• High-speed interface between cards operating at LVTTL logic levels and backplanes operating at GTLP signal levels
• Replacement for standard UBT transceivers, registered transceivers, and latched transceivers in system designs
• Bidirectional data buffering and translation in distributed load environments

Procurement Notes

Verify that the specific orderable part number matches the required package style, as the SN74GTLPH16612 series is available in both SSOP and TSSOP configurations. Confirm supply voltage requirements align with the dual VCC architecture (3.3 V and 5 V). Ensure design accounts for the recommended connection sequence of GND first, followed by VCC supplies, to guarantee proper device operation and high-impedance state initialization.

Selection Notes

Select this component when an 18-bit wide bus interface is required between mixed-voltage domains. The device accommodates both GTL and GTLP termination voltages, offering flexibility in noise margin optimization. Designers must ensure control inputs are tied to VCC or GND to prevent floating states. The medium-drive output capability supports specific backplane impedance models without exceeding DC current ratings.

Part Context

This device belongs to the Widebus family of Universal Bus Transceivers. It integrates multiple logic functions into a single package, replacing separate buffers, drivers, latches, and flip-flops. The GTLP standard utilized is a Texas Instruments derivative of the JEDEC Gunning Transceiver Logic specification. The GR suffix specifically denotes the TSSOP-56 tape and reel packaging format.

Replacement Considerations

The datasheet explicitly lists replacements for 8-bit, 9-bit, 10-bit, and 16-bit functions. For 18-bit applications, it replaces the SN74GTL16863 registered transceiver, SN74GTL16843 latch, and SN74GTL16823 flip-flop with clock enable.