onsemi 74VCXH245MTC

Overview

74VCXH245MTC from Fairchild Semiconductor is a low-voltage, bidirectional 8-bit transceiver with bushold inputs and 3-STATE outputs, designed for bus interface applications between mixed-voltage domains. It operates from 1.2V to 3.6V V_CC, delivers 24 mA drive strength at 3.0V, achieves 3.5 ns max propagation delay (3.0–3.6V), and eliminates external pull-up resistors via integrated bushold circuitry - used in portable memory expansion and low-power microcontroller I/O bridging.

For engineers reviewing the 74VCXH245MTC datasheet, pinout, applications, or equivalent options, key selection criteria include voltage-range compatibility (1.2–3.6V), bushold-enabled floating-input robustness, 20-pin TSSOP package footprint, and 3-STATE direction control via OE/T/R signals.

Technical Context

The 74VCXH245MTC implements dual-bus bidirectional data transfer using a single active-low Output Enable (OE) and Transmit/Receive (T/R) control logic. Its bushold circuitry actively maintains valid logic states on A0–A7 and B0–B7 inputs without external biasing, supporting hot-swap and partial-power-down scenarios.

It uses advanced CMOS fabrication for high-speed operation with low static power: ICC ≤ 20 µA typical, CPD = 20 pF, and Quiet Series™ EMI suppression. Propagation delay varies with V_CC and load - 3.5 ns max at 3.3V/30 pF, up to 42.0 ns at 1.2V/30 pF.

Key Specifications

Pinout & Package

74VCXH245MTC is housed in a 20-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, 4.4 mm body width, 0.65 mm lead pitch, with exposed pad not present. Pinout follows standard 74-series transceiver layout with symmetrical A/B port assignment and dedicated control pins.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC245APWR and 74ALVC245MTCX, the 74VCXH245MTC uniquely supports 1.2V operation and eliminates external biasing - critical for ultra-low-power and mixed-voltage embedded designs where input float conditions are unavoidable.

Availability

74VCXH245MTC is available at Aetrix Electronics and suitable for portable medical monitors, battery-powered IoT gateways, and industrial PLC I/O expansion requiring stable component supply across extended temperature and voltage ranges.

Supply support for 74VCXH245MTC 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, signal conditioning, and logic ICs before its acquisition by ON Semiconductor in 2016.

The VCXH logic family was engineered for low-voltage, high-speed bus interfacing in portable and mixed-supply systems - emphasizing bushold robustness, EMI control, and wide V_CC tolerance.

FAQ

What voltage range does the 74VCXH245MTC support, and why is that important?

The 74VCXH245MTC supports 1.2V to 3.6V V_CC, enabling direct interface between disparate logic families - such as 1.2V ASIC cores, 1.8V FPGAs, and 3.3V microcontrollers - without external level shifters. This simplifies power architecture and reduces component count in multi-rail systems, making the 74VCXH245MTC especially valuable in space-constrained portable electronics where voltage domain bridging is routine.

How does bushold functionality work in the 74VCXH245MTC, and what problem does it solve?

The 74VCXH245MTC integrates active bushold circuitry on all A0–A7 and B0–B7 inputs, which detects and reinforces the last-valid logic state when inputs float - eliminating the need for 16 discrete pull-up resistors. This prevents undefined logic levels during power sequencing, hot-swap events, or unconnected test points, thereby improving system reliability and reducing PCB real estate and BOM cost in the 74VCXH245MTC implementation.

Can the 74VCXH245MTC be used in hot-swap applications, and what features support that?

Yes - the 74VCXH245MTC is well-suited for hot-swap interfaces due to its bushold inputs, which maintain defined logic states during connector mating/unmating, and its latchup immunity (>300 mA), which protects against transient current surges. Its 20 µA quiescent current and 1.2V minimum V_CC also allow graceful partial-power-down behavior. These traits make the 74VCXH245MTC a robust choice for modular backplanes and field-replaceable units.

What is the maximum propagation delay of the 74VCXH245MTC, and under what conditions is it specified?

The 74VCXH245MTC has a maximum propagation delay (t_PHL/t_PLH) of 3.5 ns, specified at V_CC = 3.0–3.6V, T_A = –40°C to +85°C, and C_L = 30 pF. Delay increases predictably at lower voltages - e.g., 42.0 ns at 1.2V/30 pF - allowing designers to validate timing margins across the full operating range of the 74VCXH245MTC in their specific application.

Does the 74VCXH245MTC require decoupling capacitors, and if so, what value and placement is recommended?

Yes - a minimum 100 nF ceramic decoupling capacitor is required between V_CC (Pin 20) and GND (Pin 11), placed within 1 cm of the 74VCXH245MTC package. For high-speed or noise-sensitive applications, adding a 10 nF capacitor in parallel improves high-frequency transient response. Proper decoupling ensures stable V_CC during output switching and is essential to achieving the specified 3.5 ns propagation delay and EMI performance of the 74VCXH245MTC.