Texas Instruments 74LVC1G123DCTRE4

Overview

74LVC1G123DCTRE4 from Texas Instruments is a single retriggerable monostable multivibrator with Schmitt-trigger inputs, designed for 1.65 V to 5.5 V operation. It delivers programmable output pulse durations (ns to ms range) via external R/C network, supports mixed-mode voltage translation, and features glitch-free power-up reset and I_off protection. It is used in switch debouncing, timing control, and edge-sensitive event conditioning in consumer digital audio/video systems.

For engineers reviewing the 74LVC1G123DCTRE4 datasheet, 74LVC1G123DCTRE4 pinout, 74LVC1G123DCTRE4 application, or 74LVC1G123DCTRE4 equivalent, key selection criteria include retriggerable pulse width control, Schmitt-trigger input hysteresis for slow transitions, 8 ns max t_pd at 3.3 V, I_off support for live insertion, and compatibility with 1.65–5.5 V logic domains.

Technical Context

The 74LVC1G123DCTRE4 implements a CMOS-based retriggerable monostable architecture where output pulse duration is externally set by R_ext and C_ext, with three valid trigger conditions: A↓/B↑, A↑/B↓, or A↓/B↑/CLR↑. Its dual-edge-sensitive inputs (A active-low, B active-high) are buffered by Schmitt triggers with ≥0.35×V_CC hysteresis, enabling jitter-free triggering on slow-rising/falling signals.

It operates across –40°C to 125°C with full I_off functionality (±10 µA leakage at 5.5 V), supports down-translation from 5.5 V inputs to V_CC, and guarantees 100% duty cycle capability via retriggering. The device uses NanoFree™ packaging - die-as-package - eliminating bond wires and reducing parasitic inductance.

Key Specifications

Pinout & Package

74LVC1G123DCTRE4 is packaged in an 8-pin SSOP (DCT) with nominal body size 2.95 mm × 2.80 mm and 0.65 mm pitch. The package is RoHS-compliant, lead-free, and optimized for automated surface-mount assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar monostable multivibrator applications.

Compared with SN74LVC1G123DCUR and MC74VHC1G123DTT1G, the 74LVC1G123DCTRE4 uniquely combines industrial temperature rating (–40°C to 125°C), I_off protection, and NanoFree™ SSOP packaging - making it optimal for ruggedized, hot-pluggable, and thermally demanding embedded timing tasks.

Availability

74LVC1G123DCTRE4 is available at Aetrix Electronics and suitable for switch debouncing, edge-sensitive event capture, PWM gate control, and power sequencing delay generation requiring stable component supply across industrial, consumer, and computing applications.

Supply support for 74LVC1G123DCTRE4 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies with over 90 years of innovation in precision timing and logic solutions.

The SN74LVC1G123 product line delivers single-channel retriggerable monostables optimized for low-voltage, mixed-signal systems - targeting robust timing control in space-constrained, thermally demanding, and hot-swap-capable applications.

FAQ

What is the minimum external timing capacitor value supported by the 74LVC1G123DCTRE4?

The 74LVC1G123DCTRE4 supports external timing capacitors down to 10 pF, as confirmed in Figure 5-3 through Figure 5-5 of the datasheet. At V_CC = 3.3 V and R_ext = 1 kΩ, a 10 pF C_ext yields a typical output pulse duration of ~225 ns. Lower values may result in unstable timing due to parasitic capacitance dominance, so 10 pF is the validated lower limit for predictable operation.

Can the 74LVC1G123DCTRE4 operate with a 1.65 V supply and still drive a 3.3 V logic input?

Yes, the 74LVC1G123DCTRE4 can operate at V_CC = 1.65 V and interface with 3.3 V logic inputs because its outputs are overvoltage tolerant up to 5.5 V and its inputs accept voltages to 5.5 V. However, the Q output high-level voltage will be limited to ~1.55 V (V_CC – 0.1 V) at 1.65 V supply, which may fall below the VIH threshold of standard 3.3 V CMOS inputs (typically 2.0 V). A pull-up to 3.3 V on Q is recommended for reliable interfacing.

How does the retriggering behavior of the 74LVC1G123DCTRE4 differ from a non-retriggerable monostable?

The 74LVC1G123DCTRE4 extends its output pulse duration upon each valid A or B trigger event while the pulse is active - enabling continuous output assertion as long as triggers occur within the current pulse window. In contrast, a non-retriggerable monostable ignores subsequent triggers until the initial pulse completes. This makes the 74LVC1G123DCTRE4 ideal for applications like switch debounce where multiple bounces must extend, not restart, the output pulse.

Is the Rext/Cext pin bidirectional, and what happens if it's tied directly to VCC or GND?

Yes, the Rext/Cext pin is bidirectional: it connects internally to both the timing capacitor and the timing resistor network. Per Section 5.3 of the datasheet, Rext/Cext must not be connected directly to V_CC or GND - doing so disables timing functionality and may cause excessive current or undefined behavior. It must be connected to the junction of an external resistor (to V_CC) and capacitor (to Cext), forming the RC timing network essential for pulse duration control.

Does the 74LVC1G123DCTRE4 support 5 V-tolerant inputs when powered from 1.8 V?

Yes, the 74LVC1G123DCTRE4 supports 5 V-tolerant inputs across its full operating range (1.65 V to 5.5 V V_CC). When powered from 1.8 V, the A, B, and CLR inputs accept voltages up to 5.5 V without damage or clamping - verified by the Absolute Maximum Ratings table (VI = –0.5 V to 6.5 V) and the "Inputs Accept Voltages to 5.5 V" feature statement. This enables seamless interfacing with higher-voltage control signals in mixed-supply systems.