Texas Instruments SN74GTL16622ADGG

Overview

SN74GTL16622ADGG from Texas Instruments is an 18-bit LVTTL-to-GTL/GTL+ registered bus transceiver in a 64-pin TSSOP (DGG) package. It implements two independent 9-bit bidirectional data paths with D-type flip-flop storage, clock-enable controls, and bus-hold on A-port inputs. It enables high-speed interface between 3.3-V LVTTL logic cards and GTL/GTL+ backplanes operating at VTT = 1.2 V / 1.5 V and VREF = 0.8 V / 1.0 V.

For engineers reviewing the SN74GTL16622ADGG datasheet, SN74GTL16622ADGG pinout, SN74GTL16622ADGG application, or SN74GTL16622ADGG equivalent, key selection criteria include its dual 9-bit clocked transceiver architecture, Ioff partial-power-down support, GTL+ noise margin compatibility, and 200-MHz maximum clock frequency under both GTL and GTL+ signaling conditions.

Technical Context

The SN74GTL16622ADGG uses edge-triggered D-type flip-flops per channel for synchronous data latching in both A-to-B and B-to-A directions, controlled by separate CLKAB/CLKBA and CEAB/CEBA signals. Its dual 9-bit partitioning allows independent enable and clock control of each half, supporting asymmetric timing and mixed-mode operation.

It supports true mixed-voltage operation: A-port and control inputs tolerate 5-V logic levels while operating from a 3.3-V VCC supply; B-port operates at GTL (1.2 V) or GTL+ (1.5 V) termination voltages with dedicated VREF input. Ioff circuitry disables outputs during power-down to prevent backflow current, and active bus-hold eliminates external pull resistors on undriven A-port inputs.

Key Specifications

Pinout & Package

The SN74GTL16622ADGG is housed in a 64-pin Plastic Thin Shrink Small-Outline Package (DGG), measuring 12.5 mm × 6.1 mm × 1.2 mm, with 0.5-mm lead pitch and exposed thermal pad. Pin numbering follows standard TSSOP top-view orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LVTTL-to-GTL+ bus transceiver applications.

Compared with SN74GTL16622ADGG, SN74GTL16612DGGR offers reduced channel count and GTL-only operation at lower cost, while SN74GTLPH16612ZQLR provides 2.5-V flexibility and stronger drive but sacrifices bus-hold and GTL+ precision-making SN74GTL16622ADGG optimal for established 3.3-V GTL+ backplane upgrades requiring minimal design change.

Availability

SN74GTL16622ADGG is available at Aetrix Electronics and suitable for backplane interconnect, hot-swappable module interfaces, high-speed memory expansion, and mixed-voltage system bridging requiring stable component supply and long-term industrial lifecycle support.

Supply support for SN74GTL16622ADGG 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 decades of heritage in high-speed interface ICs and Widebus™ technology.

The SN74GTL16622ADGG belongs to TI's Widebus™ family of registered transceivers, engineered specifically for high-reliability, high-speed backplane and motherboard interconnect in telecom, computing, and industrial systems.

FAQ

What is the operating temperature range for the SN74GTL16622ADGG?

The SN74GTL16622ADGG is characterized for operation from –40°C to +85°C, making it suitable for commercial and industrial environments. This range is specified per the SN74GTL16622A designation (as opposed to the military-grade SN54GTL16622A, rated –55°C to +125°C). Thermal performance is supported by a θJA of 55°C/W in the DGG package, and all electrical parameters are guaranteed across this full range.

Does the SN74GTL16622ADGG support both GTL and GTL+ signaling modes?

Yes, the SN74GTL16622ADGG supports both GTL and GTL+ signaling on the B port via configurable VTT and VREF. For GTL: VTT = 1.2 V and VREF = 0.8 V; for GTL+: VTT = 1.5 V and VREF = 1.0 V. The device's input thresholds and output drive strength are fully specified under both conditions, and timing parameters (including 200-MHz max clock) apply to both modes per the datasheet.

How does the bus-hold feature work on the SN74GTL16622ADGG A-port inputs?

The SN74GTL16622ADGG integrates active bus-hold circuitry on all A-port inputs (1A1–1A9, 2A1–2A9), which applies ±75 µA holding current to maintain undriven inputs at their last-valid logic state. This eliminates the need for external pullup/pulldown resistors. Using external resistors with enabled bus-hold is not recommended, as they may conflict with the internal hold current and degrade noise immunity.

Can the SN74GTL16622ADGG be used in partial-power-down systems?

Yes, the SN74GTL16622ADGG includes Ioff circuitry that disables all I/Os when VCC = 0 V, limiting input/output leakage to 100 µA maximum. This prevents damaging current backflow from live GTL+ or LVTTL buses into the unpowered device-a critical requirement for hot-swap and power-gated subsystems. Ioff behavior is guaranteed over the full –40°C to +85°C range.

What is the pin-compatible replacement for SN74GTL16622ADGG if higher drive strength is needed?

There is no pin-compatible replacement for SN74GTL16622ADGG offering higher B-port drive while retaining identical pinout, VREF support, and GTL+ compatibility. The SN74GTLPH16612ZQLR provides higher drive (64 mA vs. 50 mA) but uses a different package (ZQL), lacks bus-hold, and has no VREF pin. For direct functional upgrade within the same DGG footprint, no documented drop-in alternative exists-system-level redesign would be required to adopt higher-drive variants.