Texas Instruments SN74AVC20T245GQLR

Overview

SN74AVC20T245GQLR from Texas Instruments is a 20-bit dual-rail noninverting bus transceiver enabling bidirectional voltage-level translation between 1.2-V to 3.6-V domains. It features independent VCCA and VCCB rails, 4.6-V tolerant I/Os, I_off partial-power-down support, and VCC isolation - used in FPGA-to-ASIC interconnects, multi-voltage SoC subsystem bridging, and DDR memory interface level-shifting.

For engineers reviewing the SN74AVC20T245GQLR datasheet, SN74AVC20T245GQLR pinout, SN74AVC20T245GQLR application, or SN74AVC20T245GQLR equivalent, key selection criteria include mixed-voltage translation capability, 20-bit channel count, VFBGA-56 package footprint, 380 Mbps max data rate (1.8V↔3.3V), and guaranteed operation down to 1.2 V on both rails.

Technical Context

The SN74AVC20T245GQLR implements two independent 10-bit transceiver sections (1A/1B and 2A/2B), each with dedicated DIR and OE controls referenced to VCCA. Its dual-rail architecture allows simultaneous operation at different supply voltages - e.g., A port at 1.5 V and B port at 3.3 V - with VIH/VIL thresholds dynamically scaled to VCCA.

VCC isolation ensures both ports enter high-impedance when either VCCA or VCCB is at GND, while I_off protection prevents back-current during power sequencing. The device supports asynchronous bidirectional data flow without internal latching or clocking logic.

Key Specifications

Pinout & Package

VFBGA-56 (GQL) package, 3.5 mm × 5.5 mm, 0.5-mm pitch, bottom-side ball array with exposed thermal pad. Pin 1 located at corner marked by chamfered edge per JEDEC MO-220.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AVC20T245GQLR, SN74AVCH20T245GQLR delivers superior timing at sub-1.4-V rails but adds no new functionality, while SN74LVC20T245GQLR sacrifices VCC isolation and I_off to reduce cost - making SN74AVC20T245GQLR the optimal choice for mixed-voltage, hot-pluggable, or power-gated systems.

Availability

SN74AVC20T245GQLR is available at Aetrix Electronics and suitable for FPGA-to-ASIC bridging, multi-rail SoC subsystems, and high-speed memory interface designs requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for SN74AVC20T245GQLR 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 solutions with over 90 years of innovation in high-reliability components.

The AVC family targets low-voltage, high-speed digital interface applications - specifically engineered for seamless voltage translation across heterogeneous voltage domains in portable, industrial, and communications equipment.

FAQ

What is the minimum operating voltage for SN74AVC20T245GQLR on both VCCA and VCCB rails?

The SN74AVC20T245GQLR is fully specified to operate with VCCA and VCCB as low as 1.2 V each. Datasheet Section 4 confirms recommended operating conditions from 1.2 V to 3.6 V per rail, and electrical characteristics (Section 5) validate VOH/VOL performance at 1.2 V with IOH/IOL = ±3 mA. Operation below 1.2 V is not guaranteed.

Does SN74AVC20T245GQLR support true bidirectional data flow without external logic?

Yes. The SN74AVC20T245GQLR supports true bidirectional operation through its dedicated DIR inputs (1DIR and 2DIR). When DIR = low, data flows from B port to A port; when DIR = high, data flows from A port to B port - all under control of a single logic signal per 10-bit section, with no clock or handshake required.

How does the VCC isolation feature behave during power-up sequencing of SN74AVC20T245GQLR?

Per datasheet Section 1, if either VCCA or VCCB is at GND during power-up, both A and B ports automatically enter high-impedance state - preventing bus contention or back-driving. This occurs regardless of DIR/OE states. To ensure clean enablement, tie OE to VCCA via pullup resistor (min value per driver sink capability) before applying VCCB.

Can SN74AVC20T245GQLR safely interface a 3.3-V microcontroller with a 1.2-V FPGA I/O bank?

Yes. The SN74AVC20T245GQLR's overvoltage-tolerant I/Os accept up to 4.6 V regardless of VCCA or VCCB voltage. With VCCA = 3.3 V and VCCB = 1.2 V, the A-port pins tolerate 3.3 V + 0.5 V = 3.8 V (well within 4.6 V limit), and B-port pins tolerate 1.2 V + 0.5 V = 1.7 V - sufficient for 3.3-V signals driven onto B port when OE is asserted and DIR configured appropriately.

What is the thermal resistance (θ_JA) of the SN74AVC20T245GQLR VFBGA package?

The SN74AVC20T245GQLR in VFBGA-56 (GQL) package has a junction-to-ambient thermal resistance (θ_JA) of 42°C/W, as specified in Absolute Maximum Ratings (Section 3). This value assumes standard JEDEC 2-layer board conditions and is critical for calculating maximum allowable power dissipation in thermally constrained layouts.