Texas Instruments SN74LV123APWRG4

Overview

SN74LV123APWRG4 from Texas Instruments is a dual retriggerable monostable multivibrator IC with Schmitt-trigger inputs, operating from 2 V to 5.5 V supply, delivering ≤11 ns propagation delay at 5 V, ±1% pulse-duration matching between channels, and programmable output pulse width up to 100% duty cycle via external R/C network - used for edge-sensitive timing control in digital interrupt conditioning and signal debouncing circuits.

For engineers reviewing the SN74LV123APWRG4 datasheet, SN74LV123APWRG4 pinout, SN74LV123APWRG4 application, or SN74LV123APWRG4 equivalent, key selection criteria include its dual-channel retriggerability, Ioff partial-power-down support, mixed-mode voltage tolerance on all I/Os, and guaranteed glitch-free power-up reset - critical for embedded microcontroller interface timing integrity.

Technical Context

The SN74LV123APWRG4 implements two independent monostable multivibrators, each triggered by rising- or falling-edge logic on A/B inputs with Schmitt-trigger hysteresis (≥0.3×VCC), enabling robust operation with slow or noisy signals. Pulse duration is set externally via Rext/Cext network, with tw = K × RT × CT where K ≈ 1.0 for CT ≥ 1000 pF.

Each channel supports three trigger modes: (1) 1A↓ with 1B = L, (2) 1B↑ with 1A = H, or (3) 1CLR↑ while 1A = L and 1B = H. The active-low clear input overrides ongoing pulses, and Ioff circuitry disables outputs during power-down to prevent backflow current.

Key Specifications

Pinout & Package

TSSOP-16 package (6.40 mm × 5.00 mm), lead pitch 0.65 mm, exposed pad not electrically connected - compatible with standard surface-mount reflow profiles and automated optical inspection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LV123APW and 74LVC123AD, SN74LV123APWRG4 uniquely combines automotive-grade reliability (AEC-Q100), Ioff-enabled power-down safety, and wide-input-hysteresis noise immunity - making it the sole choice for industrial control and automotive body electronics requiring fail-operational timing integrity.

Availability

SN74LV123APWRG4 is available at Aetrix Electronics and suitable for keyboard debounce, microcontroller interrupt conditioning, dual-channel timing synchronization, and power sequencing timeout applications requiring stable component supply across automotive, industrial, and medical device production cycles.

Supply support for SN74LV123APWRG4 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 logic solutions, with over 50 years of innovation in high-reliability timing and interface ICs.

The SN74LV123A product line delivers retriggerable monostable multivibrators optimized for noise-immune digital timing in automotive body control, industrial PLC I/O modules, and medical diagnostic equipment requiring AEC-Q100 compliance and long-term supply stability.

FAQ

What is the minimum external timing capacitance supported by SN74LV123APWRG4?

The SN74LV123APWRG4 supports external timing capacitance down to 1 pF, though for accurate pulse width calculation (tw = K × RT × CT), CT ≥ 1000 pF is recommended to maintain K ≈ 1.0. At lower values, K deviates from unity and must be interpolated from Figure 3 in the datasheet. Operation below 1 pF is not characterized and may yield inconsistent timing.

Does SN74LV123APWRG4 support both rising- and falling-edge triggering on the same input pin?

Yes - SN74LV123APWRG4 supports configurable edge sensitivity per channel: 1A and 2A accept falling-edge triggers when the corresponding B input is held low, while 1B and 2B accept rising-edge triggers when the corresponding A input is held high. This dual-mode capability is inherent to the internal gated logic and requires no external configuration.

Can SN74LV123APWRG4 operate with VCC = 2.0 V and still meet its specified propagation delay?

Yes - SN74LV123APWRG4 is fully specified down to VCC = 2.0 V, with maximum tpd of 37 ns (CL = 50 pF) at that voltage. While propagation delay increases as VCC decreases, all timing parameters including tpd, tw, and trr remain guaranteed across the full 2 V to 5.5 V range per the Recommended Operating Conditions table.

How does the Ioff feature of SN74LV123APWRG4 protect downstream circuitry during power-down?

The Ioff feature in SN74LV123APWRG4 disables all output drivers when VCC = 0 V, presenting high-impedance outputs that prevent current backflow from powered I/O lines into the unpowered IC. This protects against latch-up and damage in mixed-voltage systems where other devices remain active during partial power-down sequences.

Is the pulse duration matching between the two channels of SN74LV123APWRG4 specified over temperature?

Yes - SN74LV123APWRG4 guarantees ±1% pulse-duration matching (Δtw) between Channel 1 and Channel 2 over the full operating temperature range (–40°C to 125°C) and supply voltage range (2 V to 5.5 V), as confirmed in Section 7.9 Switching Characteristics under CL = 50 pF test conditions.