Texas Instruments SN74LVCH245ANSR

Overview

SN74LVCH245ANSR from Texas Instruments is an octal bus transceiver with tri-state outputs, designed for bidirectional data translation between 1.65-V and 3.6-V logic domains while accepting 5-V-tolerant inputs. It features 20-pin SO package, 6.3 ns max propagation delay at 3.3 V, Ioff support for live insertion, and bus-hold on all data inputs-enabling robust operation in mixed-voltage server backplanes and industrial I/O modules.

For engineers reviewing the SN74LVCH245ANSR datasheet, SN74LVCH245ANSR pinout, SN74LVCH245ANSR application, or SN74LVCH245ANSR equivalent, key selection criteria include its 1.65–3.6-V supply range, 5.5-V input tolerance, tri-state control via active-low OE and DIR pins, and verified performance across –40°C to 125°C ambient temperature.

Technical Context

This device implements a dual-bus, direction-controllable transceiver architecture with independent A and B port I/Os. Its CMOS input structure supports 5-V-tolerant signaling without external level shifters, while the Ioff circuitry ensures isolation during partial power-down by limiting current flow when VCC = 0 V.

The integrated bus-hold circuit maintains valid logic states on floating A/B port inputs without external resistors, and output drive strength is balanced (±24 mA at 3 V) to support fast edge rates into light capacitive loads-critical for maintaining signal integrity in high-speed parallel bus interfaces.

Key Specifications

Pinout & Package

SN74LVCH245ANSR uses a 20-pin SO (Small Outline) package with 12.60 mm × 5.30 mm body size and standard 1.27-mm lead pitch. The package is RoHS-compliant and optimized for reflow soldering in high-volume PCB assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC245APWR and 74AVC16245DGG, the SN74LVCH245ANSR uniquely combines 5-V input tolerance, bus-hold, and Ioff in a single 20-pin SO package-making it the only drop-in solution for legacy-to-modern voltage bridging in space-constrained industrial and automotive designs.

Availability

SN74LVCH245ANSR is available at Aetrix Electronics and suitable for server backplanes, industrial PLC I/O expansion, automotive body control modules, and wearable health sensor hubs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74LVCH245ANSR 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 and embedded processing solutions for industrial, automotive, and communications markets, with over 50 years of innovation in logic and interface ICs.

The SN74LVCH245A product line was engineered specifically for voltage-level translation and bus isolation in mixed-signal systems-targeting applications where interoperability between legacy 5-V and modern low-voltage logic is essential.

FAQ

What is the maximum operating temperature for SN74LVCH245ANSR?

The SN74LVCH245ANSR is fully specified from –40°C to +125°C ambient temperature. This extended range is validated per JEDEC JESD22-A108 and supports deployment in under-hood automotive ECUs, industrial motor drives, and outdoor telecom infrastructure where thermal stress is critical. All electrical parameters-including propagation delay and output drive-are guaranteed across this full range.

Does SN74LVCH245ANSR require external pull-up resistors on its A/B port inputs?

No. The SN74LVCH245ANSR integrates active bus-hold circuitry on all A1–A8 and B1–B8 inputs, which maintains valid logic states without external components. Using pull-up or pull-down resistors with enabled bus-hold is explicitly discouraged in the TI datasheet, as it creates conflicting current paths and may degrade noise margins or increase power consumption.

Can SN74LVCH245ANSR safely interface a 5-V microcontroller with a 1.8-V FPGA?

Yes. The SN74LVCH245ANSR accepts input voltages up to 5.5 V regardless of VCC setting, allowing direct connection to 5-V outputs. When powered at 1.8 V, its outputs swing rail-to-rail (0 V to 1.8 V), making it compatible with 1.8-V FPGA I/O banks. Direction control (DIR) and tri-state (OE) remain functional across the full 1.65–3.6-V supply range.

What is the purpose of the Ioff feature in SN74LVCH245ANSR?

The Ioff feature disables all outputs and blocks current flow when VCC = 0 V, preventing damaging back-current from live buses into a powered-down device. This enables safe hot-plug operation in modular systems like server blade chassis or industrial I/O racks-where individual modules may be inserted or removed while the backplane remains energized.

How does the SN74LVCH245ANSR differ from the SN74LVC245A family?

The SN74LVCH245ANSR adds three key enhancements over SN74LVC245A: (1) 5-V-tolerant inputs without external clamping, (2) integrated bus-hold on all data pins, and (3) Ioff protection for partial-power-down. These features make SN74LVCH245ANSR suitable for mixed-voltage translation where SN74LVC245A requires additional discrete components and careful power sequencing.