Texas Instruments SN74AVCH20T245GR

Overview

SN74AVCH20T245GR from Texas Instruments is a 20-bit dual-supply noninverting bus transceiver enabling bidirectional voltage-level translation between 1.2-V to 3.6-V domains. It features independent A and B ports tracking VCCA and VCCB, respectively, with 4.6-V tolerant I/Os, bus-hold on all data inputs, and VCC isolation that forces high-impedance outputs when either supply is grounded. It supports mixed-voltage interconnect in FPGA-to-ASIC, SoC-to-memory, and multi-rail processor subsystems.

For engineers reviewing the SN74AVCH20T245GR datasheet, SN74AVCH20T245GR pinout, SN74AVCH20T245GR application, or SN74AVCH20T245GR equivalent, key selection criteria include its 1.2–3.6-V dual-rail flexibility, 380-Mbps max data rate (1.8V↔3.3V), Ioff partial-power-down support, and TSSOP-56 package compatibility with industrial temperature range (−40°C to 85°C).

Technical Context

The SN74AVCH20T245GR implements two independent 10-bit transceiver sections, each with dedicated DIR and OE controls referenced to VCCA. Its control inputs (1DIR/2DIR/1OE/2OE) are VCCA-referenced, while data I/Os tolerate up to 4.6 V regardless of rail voltage. The device uses active bus-hold circuitry-eliminating external pull resistors-and incorporates VCC isolation logic that disables both ports if either VCCA or VCCB drops to GND.

It supports asynchronous bidirectional data flow: low DIR enables A→B transmission; high DIR enables B→A. OE asserts high-impedance state on both ports. Ioff functionality prevents backflow current during partial power-down, meeting JESD78 Class II latch-up immunity (>100 mA) and JESD22 ESD ratings (8 kV HBM, 200 V MM, 1 kV CDM).

Key Specifications

Pinout & Package

TSSOP-56 (DGG) package, 12.5 mm × 6.1 mm × 1.2 mm body height, lead pitch 0.5 mm, RoHS-compliant NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AVCH16T245DGGR, the SN74AVCH20T245GR provides four additional bidirectional channels in the same pin-compatible TSSOP footprint-enabling full 20-bit bus coverage without redesign. Against SN74LVC245APWR, it delivers true dual-rail translation, VCC isolation, and Ioff-making it essential for heterogeneous voltage systems requiring robustness and interoperability.

Availability

SN74AVCH20T245GR is available at Aetrix Electronics and suitable for FPGA-to-ASIC interconnect, multi-rail embedded controllers, and industrial I/O modules requiring stable component supply across extended temperature ranges.

Supply support for SN74AVCH20T245GR 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.

The SN74AVCH20T245GR belongs to TI's AVCH advanced CMOS logic family, engineered specifically for low-voltage, high-speed bidirectional bus translation in power-constrained, multi-supply systems.

FAQ

What voltage ranges does the SN74AVCH20T245GR support on its A and B ports?

The SN74AVCH20T245GR supports independent supply voltages from 1.2 V to 3.6 V on both VCCA (A port) and VCCB (B port). This allows translation between any pair within the 1.2-V, 1.5-V, 1.8-V, 2.5-V, and 3.3-V logic families. Operation down to 1.2 V is fully specified-not just functional-ensuring reliable timing and drive strength across the entire range.

Does the SN74AVCH20T245GR require external pullup or pulldown resistors on its data lines?

No, the SN74AVCH20T245GR includes active bus-hold circuitry on all 20 data inputs (A and B ports), which maintains valid logic states without external resistors. Using external pullups or pulldowns is explicitly discouraged in the datasheet, as they may interfere with bus-hold operation and increase power consumption or signal distortion.

How does the VCC isolation feature work in the SN74AVCH20T245GR?

The VCC isolation feature in the SN74AVCH20T245GR monitors both VCCA and VCCB. If either supply drops to GND, the device automatically places both A and B ports into a high-impedance state-regardless of DIR or OE logic levels. This prevents bus contention and backdrive damage during power sequencing, hot-swap events, or supply faults.

What is the maximum data rate supported by the SN74AVCH20T245GR, and under what conditions?

The SN74AVCH20T245GR achieves a maximum data rate of 380 Mbps when translating between 1.8-V and 3.3-V domains. Lower rates apply for other combinations: 260 Mbps for <1.8-V ↔ 3.3-V or ↔2.5-V, 210 Mbps for ↔1.8-V, 120 Mbps for ↔1.5-V, and 100 Mbps for ↔1.2-V. These values reflect guaranteed timing under recommended operating conditions.

Is the SN74AVCH20T245GR compatible with partial-power-down modes?

Yes-the SN74AVCH20T245GR fully supports partial-power-down via its Ioff specification. When either VCCA or VCCB is at 0 V, the Ioff leakage remains ≤ ±5 µA per port, preventing damaging current backflow through powered I/Os. This enables safe power sequencing in complex multi-rail systems without requiring external isolation switches.