Nexperia USA Inc. 74AHCT245APWJ

Overview

74AHCT245APWJ from Nexperia is an octal 3-state bus transceiver with bidirectional data flow control via DIR and output enable (OE) inputs. It operates from 4.5 V to 5.5 V, delivers typical propagation delay of 3.0 ns at 5 V, supports mixed-voltage translation with overvoltage-tolerant TTL-compatible inputs up to 5.5 V, and features IOFF partial power-down protection. It is used in industrial backplane interfaces requiring level-shifting and bus isolation.

For engineers reviewing the 74AHCT245APWJ datasheet, 74AHCT245APWJ pinout, 74AHCT245APWJ application, or 74AHCT245APWJ equivalent, key selection criteria include direction control logic, 3-state timing (enable/disable), IOFF leakage specs (<0.5 μA at VCC = 0 V), Schmitt-trigger noise immunity, and TSSOP20 thermal derating (10 mW/K above 100 °C).

Technical Context

This device implements dual-bus bidirectional translation using a single DIR signal to determine data flow direction between two 8-bit ports (A0–A7 and B0–B7). OE is active-low and independently disables all outputs into high-impedance state regardless of DIR state.

The IOFF circuit ensures <0.5 μA power-off leakage when VCC = 0 V, enabling safe hot-insertion in partially powered systems. Schmitt-trigger inputs provide ≥1.0 V hysteresis, tolerating slow edge rates (≤20 ns/V) and improving noise margin in electrically noisy environments.

Key Specifications

Pinout & Package

TSSOP20 package (SOT360-1): 20-pin thin shrink small outline, 4.4 mm body width, 0.65 mm pitch, 1.1 mm max height - optimized for high-density PCB layouts and automated optical inspection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AHCT245PW and 74LVC245AT20, the 74AHCT245APWJ uniquely combines +125 °C qualification, sub-0.5 μA IOFF leakage, and 5.5 V input tolerance - making it the sole option for automotive-grade hot-swap-capable bus isolation.

Availability

74AHCT245APWJ is available at Aetrix Electronics and suitable for industrial backplane interfaces, microcontroller bus expansion, automotive diagnostic gateways, and test equipment signal routing requiring stable component supply across extended temperature and mixed-voltage conditions.

Supply support for 74AHCT245APWJ 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

Nexperia is a global semiconductor expert delivering high-performance, reliable logic, analog, and MOSFET solutions with focus on efficiency, reliability, and miniaturization for industrial and automotive markets.

The 74AHCT series targets robust 5 V logic interfacing in harsh environments, emphasizing IOFF protection, wide temperature operation, and noise-immune Schmitt-trigger inputs for mission-critical embedded control.

FAQ

What is the maximum allowable input voltage on A/B pins when VCC = 5.0 V?

The absolute maximum input voltage is +7.0 V per IEC 60134 limiting values, but recommended operating conditions specify 0 V to 5.5 V. Inputs remain overvoltage tolerant up to 5.5 V while powered - enabling safe interfacing with 5 V peripherals even if VCC sags to 4.5 V. Exceeding 5.5 V risks permanent damage despite clamping current limits.

Does 74AHCT245APWJ support hot-swap in live backplane systems?

Yes - its IOFF circuit actively disables outputs and limits leakage to ≤0.5 μA when VCC = 0 V, preventing damaging backflow current during insertion or removal. This meets JESD78 Class II latch-up immunity (>250 mA), making it suitable for modular PLC and telecom line card applications requiring live maintenance.

How does the Schmitt-trigger input improve noise immunity compared to standard CMOS inputs?

Schmitt-trigger inputs provide ≥1.0 V hysteresis (VIH − VIL), rejecting noise spikes up to 1.5 ns duration and tolerating slow edge rates down to 20 ns/V. This prevents false triggering from EMI in motor drives or relay-switching environments - unlike standard CMOS inputs which have near-zero hysteresis and require clean, fast edges.

Can OE and DIR be driven directly from a 3.3 V microcontroller GPIO?

No - OE and DIR require VIH ≥2.0 V and VIL ≤0.8 V per static characteristics, but 3.3 V GPIO may not guarantee sufficient noise margin at VCC = 5 V. A level-shifter or resistor divider is recommended to ensure VIH ≥2.4 V (min 70% of VCC) and avoid marginal switching, especially over temperature and process variation.