STMicroelectronics 74AC373TTR

Overview

74AC373TTR from STMicroelectronics is a high-speed CMOS octal D-type transparent latch with 3-state non-inverting outputs, designed for bus interface and data latching in TTL/CMOS mixed-signal systems. It features 5 ns typical propagation delay at 5 V, ±24 mA output drive, 2 V to 6 V operating voltage, latch enable (LE) and output enable (OE) control, and 2 kV ESD immunity.

For engineers reviewing the 74AC373TTR datasheet, 74AC373TTR pinout, 74AC373TTR application, or 74AC373TTR equivalent, key selection criteria include 3-state bus driving capability, latch timing symmetry (tPLH ≅ tPHL), 50 Ω transmission line compatibility, low quiescent current (4 µA max), and TSSOP-20 package suitability for high-density PCB layouts.

Technical Context

The 74AC373TTR implements an 8-bit transparent latch architecture where Q outputs follow D inputs when LE is high, and hold state when LE transitions low. Its dual enable structure-LE for data capture and OE for output tri-state control-enables precise bus arbitration in shared-data-path systems.

Designed using sub-micron C2MOS technology, it delivers symmetrical output impedance (|IOH| = IOL ≥ 24 mA), balanced propagation delays, and high noise immunity (VNIH/VNIL ≥ 28% VCC). It operates across industrial temperature range (–55°C to +125°C) with guaranteed AC performance at CL = 50 pF and RL = 500 Ω.

Key Specifications

Pinout & Package

TSSOP-20 package: 6.5 mm × 4.4 mm body, 0.65 mm pitch, exposed pad optional, JEDEC MO-153 compliant. RoHS-compliant, lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AC373PWR and 74VHC373FT, the 74AC373TTR offers optimal balance of speed (5 ns), drive (±24 mA), and quiescent current (4 µA), making it preferred for high-fidelity bus buffering in industrial and automotive real-time control systems.

Availability

74AC373TTR is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, automated test equipment, and medical imaging front-ends requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 74AC373TTR 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 ICs with vertical manufacturing capabilities and broad IP portfolio.

The 74AC logic family targets high-speed, low-power interface and data-path applications in mixed-signal systems, emphasizing interoperability with legacy TTL and robustness in harsh electrical environments.

FAQ

What is the maximum clock frequency supported by the 74AC373TTR?

The 74AC373TTR does not use a clock signal-it is a transparent latch controlled by level-sensitive LE and OE inputs. Its usable data rate depends on propagation delay (5 ns typical) and setup/hold timing (ts = 4.5 ns, th = 5.0 ns at 5 V), supporting reliable operation up to approximately 80 MHz in well-designed bus systems with proper signal integrity.

Can the 74AC373TTR drive a 50 Ω transmission line directly?

Yes-the device guarantees ±24 mA output drive capability at VCC = 5 V, enabling direct 50 Ω line driving without external series termination. This is confirmed by the "50Ω TRANSMISSION LINE DRIVING CAPABILITY" specification and verified under AC test conditions with CL = 50 pF and RL = 500 Ω.

Is the 74AC373TTR compatible with 3.3 V logic systems?

Yes-it operates across 2 V to 6 V, with full DC and AC specifications guaranteed at 3.3 V (±0.3 V). Input thresholds scale with VCC (VIH = 2.25 V min, VIL = 1.35 V max at 3.3 V), and output VOH/VOL meet 3.3 V LVTTL requirements, enabling seamless integration with 3.3 V microcontrollers and FPGAs.

Does the 74AC373TTR require external pull-up or pull-down resistors on OE or LE?

No-OE and LE are standard CMOS inputs with ±0.1 µA leakage current at 5.5 V. They may float to indeterminate states if unconnected; however, system design should actively drive these controls. No pull resistors are specified or required in the datasheet, and adding them risks violating VIH/VIL thresholds or increasing dynamic power.