STMicroelectronics 74VHC27TTR

Overview

74VHC27TTR from STMicroelectronics is a triple 3-input NOR gate in TSSOP-14 package, operating from 2V to 5.5V, with 4.1 ns typical propagation delay at 5V, ±8 mA symmetrical output drive, and 2 µA max quiescent ICC at 25°C. It enables logic-level translation between 5V and 3V systems in industrial control panels.

For engineers reviewing the 74VHC27TTR datasheet, 74VHC27TTR pinout, 74VHC27TTR application, or 74VHC27TTR equivalent, key selection criteria include input voltage tolerance (0–7V independent of VCC), ESD immunity (2 kV HBM), power-down input protection, balanced tPLH/tPHL delays, and compatibility with legacy 74-series logic footprints.

Technical Context

The device implements three independent NOR gates using sub-micron C2MOS technology with buffered outputs, delivering high noise immunity (VNIH/VNIL ≥ 28% VCC) and latch-up robustness. Input structure accepts 0–7V regardless of VCC, enabling safe hot-swap and mixed-voltage interfacing.

All inputs feature diode-clamp protection and power-down isolation; outputs provide symmetrical sourcing/sinking (≥8 mA) with rail-to-rail VOH/VOL performance across –55°C to +125°C operating range and 2–5.5V supply.

Key Specifications

Pinout & Package

TSSOP-14 package (4.9 × 6.4 mm body, 0.65 mm pitch), thin shrink small outline with exposed pad not present; JEDEC MO-153 compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple 3-input NOR gate applications.

Compared with SN74LVC27PWR and 74HC27PW,118, the 74VHC27TTR uniquely supports 0–7V input tolerance and power-down protection-critical for hot-swap interfaces-while maintaining superior speed/power trade-off across 2–5.5V operation.

Availability

74VHC27TTR is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, and medical diagnostic equipment requiring stable component supply and long-term lifecycle support.

Supply support for 74VHC27TTR 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, designing and manufacturing analog, digital, and mixed-signal ICs for industrial, automotive, and consumer markets.

The 74VHC logic family targets high-speed, low-power, mixed-voltage interface applications where robustness, timing predictability, and legacy compatibility are essential.

FAQ

Is 74VHC27TTR pin-compatible with standard 74LS27?

Yes - it uses the same TSSOP-14 footprint and identical pin assignment as 74LS27 and 74HC27. All 14 pins match functionally: inputs (1A–3C), outputs (1Y–3Y), VCC (pin 14), and GND (pin 7). No PCB redesign is needed for drop-in replacement.

Can 74VHC27TTR operate with VCC = 0V while inputs are driven?

Yes - its power-down protection allows inputs to be driven from 0–7V even when VCC = 0V, with no reverse current or latch-up risk. This enables safe hot-plug operation in backplane or modular systems where supply sequencing is uncontrolled.

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

It reliably drives up to 50 pF (including trace and probe capacitance) while maintaining specified tPLH/tPHL ≤ 9.0 ns at 5V. For loads >50 pF, propagation delay increases linearly; derating curves in Figure 3 of the datasheet confirm stable operation up to 100 pF with <15% delay growth.

Does 74VHC27TTR require external pull-up or pull-down resistors on unused inputs?

No - unused inputs may be left floating without risk of oscillation or excess current, thanks to internal input hysteresis and high-impedance state under all VCC conditions. However, tying them to VCC or GND is recommended for deterministic logic states in noise-prone environments.