Texas Instruments SN74GTL16622ADGGR

Overview

SN74GTL16622ADGGR from Texas Instruments is an 18-bit registered LVTTL-to-GTL/GTL+ bus transceiver in a 64-pin TSSOP package, supporting bidirectional signal translation between 3.3 V LVTTL logic (A-port and controls) and GTL (VTT = 1.2 V, VREF = 0.8 V) or GTL+ (VTT = 1.5 V, VREF = 1.0 V) backplane signaling. It features dual 9-bit channels with independent clock-enable (CEAB/CEBA), output-enable (OEAB/OEBA), and clock (CLKAB/CLKBA) controls, enabling precise timing control in high-speed server backplanes.

For engineers reviewing the SN74GTL16622ADGGR datasheet, SN74GTL16622ADGGR pinout, SN74GTL16622ADGGR application, or SN74GTL16622ADGGR equivalent, key selection considerations include its 200 MHz clock frequency support, ±50 mA B-port drive capability, Ioff partial-power-down compliance, bus-hold on A-port inputs, and OEC™ circuitry for enhanced signal integrity in dense PCB layouts.

Technical Context

This device implements two independent 9-bit D-type flip-flop-based transceivers, each with qualified storage enable logic. Data flow direction (A→B or B→A) is controlled by separate OE and CLK inputs per channel, while CEAB/CEBA gates clock propagation to the respective flip-flops-enabling selective latching without affecting the other channel.

It operates with mixed-mode voltage domains: A-port and control inputs tolerate up to 5.5 V and interface with LVTTL systems, while B-port outputs drive GTL/GTL+ loads with VREF-referenced thresholds and VTT-terminated swing. The distributed VCC/GND pin architecture minimizes simultaneous switching noise at >100 MHz operation.

Key Specifications

Pinout & Package

SN74GTL16622ADGGR uses a 64-pin Thin Shrink Small-Outline Package (TSSOP-DGG) with 0.5 mm pitch, 12.6 mm × 6.2 mm body, and JEDEC MO-153 compliance. Pin 1 is located in Quadrant Q1 per tape-and-reel orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74GTL16622DGGR and SN74GTL16612DGGR, SN74GTL16622ADGGR delivers superior GTL+ noise margin, per-channel clock-enable granularity, and updated reliability specs-making it the preferred choice for new high-speed backplane designs demanding deterministic timing and mixed-mode interoperability.

Availability

SN74GTL16622ADGGR is available at Aetrix Electronics and suitable for server backplane interfaces, network switch fabrics, and industrial control backplanes requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for SN74GTL16622ADGGR 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 50 years of innovation in high-speed interface and signal-integrity technologies.

The Widebus™ family-including SN74GTL16622ADGGR-is engineered specifically for high-density, high-speed backplane interconnects in computing and communications infrastructure, emphasizing noise resilience, timing precision, and mixed-voltage interoperability.

FAQ

What voltage levels does SN74GTL16622ADGGR support on its A-port and B-port?

SN74GTL16622ADGGR supports LVTTL logic levels (VIH = 2 V, VIL = 0.8 V) and 5-V-tolerant inputs on its A-port and control signals, while the B-port operates at GTL (VTT = 1.2 V, VREF = 0.8 V) or GTL+ (VTT = 1.5 V, VREF = 1.0 V) signal levels. This dual-domain design allows seamless interfacing between 3.3 V LVTTL subsystems and GTL/GTL+ backplanes without external level shifters. The VREF pin must be externally biased to match the selected mode.

How does the clock-enable (CE) function work in SN74GTL16622ADGGR?

In SN74GTL16622ADGGR, CEAB and CEBA are active-low inputs that gate the respective CLKAB and CLKBA signals to their associated 9-bit D-flip-flop arrays. When CEAB is low, CLKAB transitions propagate to latch A-port data to the B-port; when high, the clock is blocked and data remains latched. This per-channel enable allows independent timing control-e.g., pausing one data lane while continuing transfers on the other-enhancing flexibility in multi-lane backplane architectures.

Does SN74GTL16622ADGGR support partial-power-down operation?

Yes, SN74GTL16622ADGGR supports partial-power-down via its Ioff circuitry. When VCC = 0 V, the Ioff feature limits off-state current to ≤100 µA, preventing damaging current backflow from live B-port or A-port signals into the unpowered device. This enables safe hot-plug operation in modular systems and simplifies power sequencing in complex backplane designs where supply rails may ramp independently.

What is the purpose of the VREF and VTT pins on SN74GTL16622ADGGR?

VREF sets the input threshold voltage for the B-port receivers (0.8 V for GTL, 1.0 V for GTL+), directly determining noise margin and switching point accuracy. VTT supplies the termination voltage for B-port outputs, establishing the 1.2 V or 1.5 V swing amplitude referenced to ground. Both pins must be externally decoupled and stabilized-VREF typically derived from a precision divider of VTT-to ensure consistent GTL/GTL+ signal integrity across temperature and process variation in SN74GTL16622ADGGR applications.

Can SN74GTL16622ADGGR be used in both GTL and GTL+ modes simultaneously?

No, SN74GTL16622ADGGR operates in either GTL or GTL+ mode-not both simultaneously-determined by the external VTT and VREF voltages applied. GTL requires VTT = 1.2 V and VREF = 0.8 V; GTL+ requires VTT = 1.5 V and VREF = 1.0 V. The device's electrical characteristics (e.g., VOL, noise margin, timing) are specified separately for each mode in the datasheet, and mixing values invalidates guaranteed performance. System design must select one standard and configure all backplane terminations accordingly for SN74GTL16622ADGGR.