Texas Instruments 74LVC1G123DCUTG4

Overview

74LVC1G123DCUTG4 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 pulse widths up to milliseconds via external R/C network, supports mixed-mode voltage translation, and features glitch-free power-up reset and Ioff for partial-power-down protection. It is used in switch debouncing, timing control, and edge-sensitive event conditioning in consumer digital systems.

For engineers reviewing the 74LVC1G123DCUTG4 datasheet, 74LVC1G123DCUTG4 pinout, 74LVC1G123DCUTG4 application, or 74LVC1G123DCUTG4 equivalent, key selection criteria include retriggerable pulse duration control, Schmitt-trigger input hysteresis for slow-edge immunity, 8 ns max tpd at 3.3 V, Ioff-enabled live insertion support, and NanoFree™ VSSOP-8 packaging compatibility.

Technical Context

The 74LVC1G123DCUTG4 implements a retriggerable monostable architecture where output pulse width is determined by external Rext and Cext components connected to dedicated pins (Rext/Cext and Cext). Triggering occurs on either rising edge at B (with A low), falling edge at A (with B high), or rising edge at CLR (with A low and B high).

Schmitt-trigger inputs on A and B provide ≥0.3 V hysteresis at 3.3 V, enabling jitter-free response to slow-rising/falling signals. The device supports down-translation from 5.5 V inputs to VCC-level outputs and maintains functional integrity across –40°C to 125°C with Ioff active during power-down.

Key Specifications

Pinout & Package

The 74LVC1G123DCUTG4 is packaged in an 8-pin VSSOP (DCU) package measuring 2.30 mm × 2.00 mm, part of Texas Instruments' NanoFree™ family. This ultra-compact leaded package enables high-density PCB layouts while maintaining standard surface-mount assembly compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC1G123DCKT (identical function, reel variant) and MC74VHC1G123DTT1G (slower, no Ioff), the 74LVC1G123DCUTG4 delivers superior timing precision, full hot-swap readiness, and tighter hysteresis-making it optimal for compact, power-aware consumer electronics.

Availability

74LVC1G123DCUTG4 is available at Aetrix Electronics and suitable for switch debouncing, edge-triggered timing control, pulse width conditioning, and system power sequencing requiring stable component supply across industrial temperature ranges and high-volume manufacturing cycles.

Supply support for 74LVC1G123DCUTG4 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, longevity, and design-in support.

The SN74LVC1G123 product line targets space-constrained, low-power digital timing applications-including consumer audio/video, portable computing, and industrial control-where retriggerable pulse generation and robust input conditioning are essential.

FAQ

What is the maximum output pulse duration achievable with the 74LVC1G123DCUTG4?

The 74LVC1G123DCUTG4 does not specify an absolute maximum pulse duration in its datasheet; instead, pulse width is fully programmable via external Rext and Cext components. With Rext = 10 MΩ and Cext = 100 µF, pulse durations exceeding 100 seconds are theoretically possible. However, practical limits arise from capacitor leakage, resistor tolerance, and timing accuracy degradation-TI recommends staying within 10 s for ≤5% error. The 74LVC1G123DCUTG4 achieves this through its retriggerable architecture and stable internal timing reference.

Does the 74LVC1G123DCUTG4 support 1.8 V operation?

Yes, the 74LVC1G123DCUTG4 is fully specified for 1.65 V to 5.5 V VCC operation, including reliable functionality at 1.8 V. At this supply, propagation delay is typically 18.5 ns (CL = 15 pF), input thresholds scale proportionally (VIH ≈ 1.2 V, VIL ≈ 0.6 V), and output drive remains sufficient (IOH/IOL = ±4 mA). All timing curves-including pulse duration vs. R/C and retrigger time-are validated down to 1.65 V. The 74LVC1G123DCUTG4 thus interoperates seamlessly with modern low-voltage microcontrollers and FPGAs.

Can the 74LVC1G123DCUTG4 be used without external timing components?

No-the 74LVC1G123DCUTG4 requires external Rext and Cext components to define output pulse duration; it contains no internal timing elements. Leaving Rext/Cext or Cext unconnected results in undefined behavior or failure to trigger. A minimal configuration uses Rext = 1 kΩ and Cext = 100 pF for ~100 ns pulses at 3.3 V. TI's application note (SCES586E) provides detailed guidance on selecting R/C values for target pulse widths across VCC and temperature. The 74LVC1G123DCUTG4 relies entirely on this external network for timing accuracy.

How does the Schmitt-trigger input on the 74LVC1G123DCUTG4 improve noise immunity?

The Schmitt-trigger inputs on A and B provide ≥0.3 V hysteresis at 3.3 V, meaning the rising and falling input thresholds differ by that amount-e.g., VIH ≈ 1.9 V and VIL ≈ 1.6 V. This prevents multiple output transitions when input signals cross the threshold slowly or with noise, such as from mechanical switches or long PCB traces. Unlike standard CMOS inputs, the 74LVC1G123DCUTG4 ignores sub-threshold fluctuations, ensuring one clean output pulse per valid edge. This eliminates need for external RC filters and improves system-level reliability in electrically noisy environments.

Is the 74LVC1G123DCUTG4 pin-compatible with other members of the SN74LVC1Gxx family?

No-the 74LVC1G123DCUTG4 has a unique pinout optimized for its monostable function, including dedicated Cext and Rext/Cext terminals. It is not pin-compatible with other SN74LVC1Gxx devices (e.g., SN74LVC1G00, SN74LVC1G14), which have different I/O configurations and internal logic. Pin mapping is defined exclusively in Figure 4-2 (DCU package) of the SCES586E datasheet. Substituting another 1Gxx device without verifying pin function alignment will result in incorrect operation or damage. Always validate against the 74LVC1G123DCUTG4-specific pin diagram.