STMicroelectronics 74VHC244TTR

Overview

74VHC244TTR from STMicroelectronics is an octal non-inverting 3-state bus buffer IC used for bidirectional data routing and bus isolation in 2V–5.5V digital systems. It features 3.9 ns typical propagation delay at 5V, ±8 mA symmetrical output drive, 2 kV ESD immunity, and input tolerance up to 7V independent of VCC - enabling robust 5V-to-3V level translation in memory address drivers and peripheral interfaces.

For engineers reviewing the 74VHC244TTR datasheet, 74VHC244TTR pinout, 74VHC244TTR application, or 74VHC244TTR equivalent, key selection criteria include guaranteed 3-state timing (tPZL/tPLZ), high-noise-immunity inputs (28% VCC hysteresis), power-down protected I/Os, and TSSOP-20 package compatibility with legacy 74-series footprints.

Technical Context

The device integrates eight CMOS buffer channels split into two independent 4-bit groups, each controlled by a dedicated active-low output enable (1G, 2G). Its C2MOS sub-micron process enables rail-to-rail input tolerance and low quiescent current (4 µA max) across –40°C to +85°C operation.

All inputs and outputs feature integrated protection diodes and latch-up immunity. Propagation delays are balanced (tPLH ≅ tPHL), skew between outputs is ≤1.0 ns at 5V/50 pF, and dynamic noise margins (VOLP = 0.9 V max, VIHD/VILD = 3.5 V/1.5 V) ensure signal integrity in mixed-voltage bus environments.

Key Specifications

Pinout & Package

TSSOP-20 package: 6.5 mm × 4.4 mm body, 0.65 mm pitch, exposed pad not present, RoHS-compliant lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC244APWR and 74HC244D,653, the 74VHC244TTR uniquely balances wide VCC range, 7 V input tolerance, and sub-4 ns speed - making it the only choice for mixed-voltage hot-swap and level-shifting applications requiring both robustness and timing precision.

Availability

74VHC244TTR is available at Aetrix Electronics and suitable for memory subsystems, industrial I/O expansion, USB power management, and automotive body control modules requiring stable component supply across extended temperature and mixed-voltage conditions.

Supply support for 74VHC244TTR 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, specializing in automotive, industrial, and power management solutions with vertical manufacturing capability.

The 74VHC series targets high-speed, low-power CMOS logic replacement for legacy TTL and HC families - designed specifically for mixed-voltage system interfacing and noise-resilient digital infrastructure.

FAQ

Is 74VHC244TTR compatible with 5 V TTL logic inputs?

Yes. Its VIH minimum is 0.7×VCC (3.5 V at 5 V supply), exceeding TTL's 2.0 V high-level threshold. Input hysteresis (28% VCC) further ensures noise rejection. The 7 V absolute max input rating also protects against TTL overshoot transients without clamping diodes.

Can 74VHC244TTR operate with VCC = 2.5 V while interfacing to 3.3 V peripherals?

Yes. At VCC = 2.5 V, VOH is guaranteed ≥2.0 V (IO = –50 µA), sufficient to meet 3.3 V CMOS VIH (≥2.31 V) with margin when driving light loads. For heavier loads, use pull-up resistors or verify actual VOH under target IOL conditions per DC specs.

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

The AC specs guarantee timing up to 50 pF (CL). Driving >50 pF increases propagation delay and skew; for 100 pF loads, expect ~12 ns tPD at 5 V. Maintain trace impedance and minimize stub length to avoid ringing - design review recommended for >75 pF loads.

Does 74VHC244TTR require external pull-up or pull-down resistors on unused inputs?

No. Inputs have internal protection diodes and exhibit <1 µA leakage (II), but floating inputs risk undefined logic states and increased noise susceptibility. STMicroelectronics recommends tying unused inputs to VCC or GND - especially 1G/2G - to prevent unintended 3-state activation and reduce dynamic power.