Texas Instruments SN74LVC1G123YEPR

Overview

SN74LVC1G123YEPR 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 timing network, supports mixed-mode voltage translation, and features glitch-free power-up reset and Ioff for live insertion. It is used in switch debouncing, timing control, and pulse shaping in consumer electronics interfaces.

For engineers reviewing the SN74LVC1G123YEPR datasheet, SN74LVC1G123YEPR pinout, SN74LVC1G123YEPR application, or SN74LVC1G123YEPR 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 partial-power-down support, and NanoFree™ DSBGA-8 package compatibility with high-density PCB layouts.

Technical Context

The SN74LVC1G123YEPR implements a CMOS-based retriggerable monostable architecture where output pulse width is determined by external Rext and Cext components connected to dedicated Rext/Cext and Cext pins. Triggering occurs on edge transitions of A (falling) or B (rising), with optional override via active-low CLR - enabling early termination or synchronous reset.

Schmitt-trigger inputs on A and B provide ≥0.3 V hysteresis at 3.3 V, ensuring jitter-free response to slow-rising/falling signals. The device operates across –40°C to 125°C with full Ioff functionality, allowing safe back-drive protection during partial power-down states without latch-up risk (>100 mA per JESD 78 Class II).

Key Specifications

Pinout & Package

The SN74LVC1G123YEPR is packaged in an 8-pin DSBGA (YZP) measuring 1.91 mm × 0.91 mm, optimized for space-constrained portable and wearable designs. Its NanoFree™ construction eliminates traditional packaging layers, using the silicon die directly as the package body.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC1G123DBVR and MC74VHC1G123DTT1G, the SN74LVC1G123YEPR uniquely combines 125°C operation, Ioff-enabled hot-swap safety, and NanoFree™ package size - making it the sole option for thermally demanding, high-reliability, or miniaturized embedded timing functions.

Availability

SN74LVC1G123YEPR is available at Aetrix Electronics and suitable for switch debouncing, power sequencing control, LED flash timing, and interrupt signal conditioning requiring stable component supply across automotive, industrial, and portable electronics programs.

Supply support for SN74LVC1G123YEPR 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 decades of expertise in logic IC design and high-volume manufacturing.

The SN74LVC1G123YEPR belongs to TI's LVC low-voltage CMOS logic family, engineered for robust mixed-signal timing applications in space-constrained, thermally aggressive, and power-sensitive systems.

FAQ

What is the minimum external timing capacitor value supported by the SN74LVC1G123YEPR?

The SN74LVC1G123YEPR supports external timing capacitors down to 10 pF, as verified in Figure 5-7 of the datasheet showing minimum retrigger time vs. supply voltage. At VCC = 3.3 V, a 10 pF Cext yields ~1.4 µs minimum retrigger interval. Smaller values risk timing instability due to parasitic capacitance dominance, so 10 pF is the practical lower limit for reliable operation.

Can the SN74LVC1G123YEPR operate with a 1.65 V supply and still meet its specified propagation delay?

Yes - the SN74LVC1G123YEPR is fully characterized down to 1.65 V VCC. At this voltage, typical tpd is 18.5 ns (CL = 15 pF, –40°C to 85°C), per Table 5.7. While slower than the 8 ns maximum at 3.3 V, this delay remains stable and guaranteed across temperature, enabling low-power operation in battery-powered devices without sacrificing timing predictability.

How does the SN74LVC1G123YEPR handle simultaneous assertion of A and B inputs?

Per Table 7-1 (Function Table), when both A and B are asserted (A = low, B = high), the SN74LVC1G123YEPR enters a stable triggered state - Q goes high and remains high until cleared by CLR or timed out. Simultaneous assertion does not cause metastability or undefined behavior; it simply initiates the monostable output pulse as intended in the third trigger method described in Section 3.

Is the SN74LVC1G123YEPR compatible with 5 V-tolerant microcontroller GPIOs driving its A and B inputs?

Yes - the SN74LVC1G123YEPR inputs accept voltages up to 5.5 V regardless of VCC level, as stated in Section 5.1 Absolute Maximum Ratings and Section 1 Features. When VCC = 3.3 V, a 5 V GPIO can safely drive A or B without level shifters, enabling direct interface with legacy 5 V controllers while maintaining full logic-level compatibility and timing performance.

Does the SN74LVC1G123YEPR require external pull-up or pull-down resistors on unused inputs?

Yes - per Section 5.3 Recommended Operating Conditions, all unused inputs (A, B, CLR) must be held at VCC or GND to ensure proper device operation and prevent floating-node-induced current leakage or erratic triggering. TI recommends tying unused inputs directly to VCC or GND with short PCB traces; no pull-up/pull-down resistors are needed unless routing constraints necessitate them.