STMicroelectronics 74VHCT244AMTR

Overview

74VHCT244AMTR from STMicroelectronics is an octal non-inverting 3-state bus buffer IC designed for bidirectional data routing in 5V TTL-compatible digital systems. It features 8 channels split into two independent 4-bit groups, each controlled by a dedicated output-enable input (1G, 2G), propagation delay of 5.4 ns (typ.), ±8 mA output drive, and operation across 4.5–5.5 V with 2 kV ESD protection.

For engineers reviewing the 74VHCT244AMTR datasheet, 74VHCT244AMTR pinout, 74VHCT244AMTR application, or 74VHCT244AMTR equivalent, key selection criteria include 3-state output timing symmetry (tPLH ≅ tPHL), power-down input/output protection (0–7 V tolerant), TTL-compatible input thresholds (VIH ≥ 2 V, VIL ≤ 0.8 V), and SO-20 package compatibility with legacy 74-series layouts.

Technical Context

The device implements two independent 4-bit non-inverting buffers, each gated by a dedicated active-low enable input (1G, 2G). All inputs accept 0–7 V regardless of VCC, enabling robust level-shifting between 5 V and 3 V domains without external circuitry.

Its C2MOS process delivers symmetrical output impedance (|IOH| = IOL = 8 mA min), low dynamic noise (VOLP ≤ 0.9 V), and latch-up immunity. The 3-state outputs exhibit matched disable/enable times (tPLZ/tPHZ ≤ 12.0 ns, tPZL/tPZH ≤ 13.0 ns at CL = 50 pF) critical for bus arbitration timing integrity.

Key Specifications

Pinout & Package

74VHCT244AMTR is supplied in a 20-pin Small Outline Package (SO-20), 0.300-inch body width, with 1.27 mm pitch and gull-wing leads. Pin 1 marked via notch or bevel; pin 10 = GND, pin 20 = VCC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal non-inverting 3-state buffer applications.

Compared with SN74HCT244N and 74VHC244M, the 74VHCT244AMTR uniquely combines TTL input compatibility, SO-20 surface-mount packaging, ultra-low ICC (4 µA), and 5.4 ns speed-making it optimal for space-constrained, mixed-signal industrial control boards requiring direct legacy interface support.

Availability

74VHCT244AMTR is available at Aetrix Electronics and suitable for memory address buffering, microcontroller bus expansion, industrial PLC I/O modules, and legacy system interface adapters requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for 74VHCT244AMTR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The VHCT logic family targets high-speed, low-power 5 V digital interfacing with TTL compatibility and enhanced robustness-specifically engineered for industrial control, instrumentation, and legacy-system modernization applications.

FAQ

Is 74VHCT244AMTR pin-compatible with the original 74LS244?

Yes, it is fully pin- and function-compatible with the 74LS244, including identical pin numbering, truth table, and 3-state behavior. The 74VHCT244AMTR replaces it directly in socketed or soldered designs without layout changes, while offering lower power consumption, higher noise immunity, and improved ESD tolerance.

Can 74VHCT244AMTR safely interface a 3.3 V microcontroller to a 5 V peripheral?

No-it is not a level shifter. Its inputs are TTL-compatible (VIH ≥ 2 V), so 3.3 V logic HIGH is recognized correctly, but its outputs swing rail-to-rail (0 V to VCC), meaning it outputs 5 V when VCC = 5 V. To drive 3.3 V inputs, add series resistors or use a dedicated level translator; do not rely on input tolerance alone for output voltage compliance.

What is the maximum capacitive load this device can drive reliably?

The datasheet specifies timing parameters up to CL = 50 pF. While outputs can physically drive heavier loads, propagation delay increases linearly beyond that point (e.g., tPD rises to 5.9 ns at CL = 50 pF), and VOL/VOLP degrade. For guaranteed timing and noise performance, keep total load ≤ 50 pF per output, including trace capacitance and connected inputs.

Does 74VHCT244AMTR require external pull-up or pull-down resistors on its enable inputs?

No-its enable inputs (1G, 2G) have CMOS-compatible input structure with negligible leakage (<1 µA). When driven actively (e.g., by MCU GPIO or another logic gate), no external resistors are needed. However, if left floating during power-up, undefined output states may occur; best practice is to tie unused enables to VCC via 10 kΩ for default-disabled operation.