Nexperia USA Inc. 74HC123BQ-Q100,115

Overview

74HC123BQ-Q100 from Nexperia is a dual retriggerable monostable multivibrator with independent reset inputs, designed for precise pulse generation and timing extension in automotive-grade systems. It operates from 2.0 V to 6.0 V, supports -40 °C to +125 °C ambient range, delivers programmable pulse widths via external R_EXT/C_EXT, and features Schmitt-trigger inputs for noise immunity. Used in engine control unit (ECU) fault pulse stretching and ADAS sensor debounce circuits.

For engineers reviewing the 74HC123BQ-Q100 datasheet, 74HC123BQ-Q100 pinout, 74HC123BQ-Q100 application, or 74HC123BQ-Q100 equivalent, this device offers AEC-Q100 Grade 1 qualification, dual independent monostable channels with retriggering and direct reset, TTL- or CMOS-compatible variants, and DHVQFN16 packaging optimized for AOI and thermal performance in space-constrained automotive modules.

Technical Context

The 74HC123BQ-Q100 implements two independent edge-triggered monostable circuits, each with separate negative-edge (nA) and positive-edge (nB) trigger inputs, active-low reset (nRD), and complementary outputs (nQ/nQ). Pulse width is externally set by R_EXT and C_EXT on pins 15/14 (Channel 1) and 7/6 (Channel 2), with typical t_W ranging from 75 ns (REXT = 5 kΩ, CEXT = 0 pF) to 450 μs (REXT = 10 kΩ, CEXT = 100 nF).

Schmitt-trigger action on nA/nB inputs ensures robust operation with slow-rising signals; nRD accepts both LOW-going edges and static LOW for immediate output termination. Input clamping diodes allow interfacing to voltages exceeding V_CC using current-limiting resistors, and latch-up immunity exceeds 100 mA per JESD78 Class II Level B.

Key Specifications

Pinout & Package

DHVQFN16 (SOT763-1) package: 2.5 × 3.5 × 0.85 mm body, side-wettable flanks for automated optical inspection (AOI), no leads, 16 terminals, thermal-enhanced construction. Exposed die pad (terminal 1 index area) is electrically isolated; if soldered, must remain floating or connect to V_CC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HC123BQ-Q100, the 74HCT123BQ-Q100 offers TTL input thresholds for legacy compatibility but sacrifices 3.3 V CMOS interoperability, while SN74LV123AQPWRQ1 enables lower-voltage operation and faster timing but demands layout revision - making the HC variant optimal for cost-sensitive 5 V automotive modules with existing DHVQFN16 layouts.

Availability

74HC123BQ-Q100 is available at Aetrix Electronics and suitable for engine control units, ADAS sensor interfaces, and infotainment power sequencing requiring stable component supply across automotive production lifecycles.

Supply support for 74HC123BQ-Q100 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

Nexperia is a global semiconductor expert delivering high-performance, reliable discrete, logic, and MOSFET devices with focus on automotive, industrial, and mobile applications.

The 74HC123BQ-Q100 belongs to Nexperia's automotive-qualified logic portfolio, engineered specifically for robust timing functions in harsh environments where AEC-Q100 compliance, wide temperature operation, and noise immunity are mandatory.

FAQ

What is the minimum external timing capacitor value supported for stable operation?

The datasheet specifies stable operation down to C_EXT = 0 pF (with R_EXT = 5 kΩ), yielding t_W ≥ 75 ns. For C_EXT < 50 pF, a power-up reset pulse is required to prevent spurious output. Pin capacitance at nREXT/CEXT is ~7 pF, so practical minimum C_EXT is 10–22 pF for predictable sub-microsecond timing.

Can both monostable channels share the same R_EXT/C_EXT network?

No - each channel requires independent R_EXT/C_EXT networks. Pins 15/14 serve Channel 1; pins 7/6 serve Channel 2. Sharing would cause crosstalk and unpredictable pulse width interaction. The functional diagram and pin description explicitly assign dedicated timing nodes per channel.

How does the Schmitt-trigger input affect timing accuracy with slow-rising signals?

Schmitt-trigger action introduces hysteresis (~0.4 V at V_CC = 5 V), eliminating multiple triggering from noisy or slowly ramping inputs. This improves timing repeatability but adds deterministic input delay (t_in ≈ 10–30 ns depending on slew rate), which is included in total t_pd specs and does not degrade pulse width accuracy.

Is the exposed thermal pad (terminal 1 index area) electrically connected internally?

No - the exposed pad is not electrically connected to any internal node. Per datasheet Section 5.1, it has no electrical or mechanical requirement to be soldered. If soldered, it must remain electrically floating or be tied to V_CC; grounding it may compromise ESD performance or cause latch-up risk.