Nexperia USA Inc. 74HC161D-Q100J

Overview

74HC161D-Q100 from Nexperia is an AEC-Q100 Grade 1 qualified, synchronous presettable 4-bit binary counter with asynchronous master reset (MR), look-ahead carry (TC), and dual count-enable inputs (CEP/CET). It operates from 2.0 V to 6.0 V, delivers ≤38 ns CP-to-Q propagation delay at VCC = 4.5 V, and supports automotive ambient temperatures up to +125 °C. It is used in engine control unit (ECU) timing sequencers for gear position counting and diagnostic pulse generation.

For engineers reviewing the 74HC161D-Q100 datasheet, 74HC161D-Q100 pinout, 74HC161D-Q100 application, or 74HC161D-Q100 equivalent, this page provides verified functional role, SO16 pin mapping, automotive-grade thermal and timing specifications, cascade enable logic behavior, and validated alternatives for multi-stage counter designs.

Technical Context

The device implements four edge-triggered D-type flip-flops synchronized to the rising edge of CP, with parallel load enabled by active-LOW PE and asynchronous clear via active-LOW MR. Its internal look-ahead carry architecture uses CET to gate TC output, ensuring deterministic terminal count pulse width (~Q0 HIGH duration) for reliable cascading without external logic.

Counting requires both CEP and CET HIGH; TC asserts only when CET = HIGH and Q3–Q0 = HHHH. Input clamping diodes allow interfacing to voltages exceeding VCC using current-limiting resistors, and CMOS input thresholds (VIH ≥ 3.15 V @ VCC = 4.5 V) ensure robust noise immunity in noisy automotive environments.

Key Specifications

Pinout & Package

74HC161D-Q100 is housed in a plastic small outline package (SO16), SOT109-1, with 16 leads and 3.9 mm body width. Pin 1 is MR (asynchronous reset), pin 2 is CP (clock), pins 3–6 are D0–D3 (parallel data inputs), pin 7 is CEP (count enable parallel), pin 8 is GND, pin 9 is PE (parallel enable), pin 10 is CET (count enable carry), pins 11–14 are Q3–Q0 (outputs, LSB-first order), pin 15 is TC (terminal count), and pin 16 is VCC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-bit synchronous counter applications.

Compared with SN74HC161QPWRQ1, the 74HC161D-Q100 offers tighter timing for high-density diagnostic pulsing; versus 74HCT161D-Q100, it provides lower input leakage and superior noise immunity in modern 3.3 V domains, making it optimal for new automotive designs prioritizing EMI robustness and speed.

Availability

74HC161D-Q100 is available at Aetrix Electronics and suitable for engine control units, body control modules, and ADAS camera synchronization systems requiring stable component supply across automotive production lifecycles.

Supply support for 74HC161D-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 leading semiconductor manufacturer specializing in high-performance, high-reliability logic, analog, and discrete components for automotive, industrial, and consumer markets.

The 74HC161-Q100 belongs to Nexperia's automotive-qualified HC logic family, designed specifically for timing-critical functions in harsh-environment vehicle subsystems where AEC-Q100 compliance and parametric stability are mandatory.

FAQ

What is the maximum operating frequency when cascading two 74HC161D-Q100 counters?

The maximum cascaded clock frequency is determined by CP-to-TC propagation delay (43 ns max @ VCC = 4.5 V) plus CEP-to-CP setup time (43 ns max), yielding 11.6 MHz. This assumes worst-case conditions and no additional board-level routing delay; actual system frequency may reach 15 MHz with optimized layout and 3.3 V operation.

Can the 74HC161D-Q100 be used with a 3.3 V supply while interfacing to 5 V sensors?

Yes - its integrated input clamping diodes allow safe interface to 5 V signals using a 10 kΩ series resistor. At VCC = 3.3 V, VIH = 2.31 V min and VIL = 1.0 V max ensure reliable recognition of 5 V logic levels, and output VOH = 3.15 V min drives standard 3.3 V CMOS inputs.

How does the TC output behave when CET is held LOW during counting?

When CET = LOW, TC remains LOW regardless of counter state - it only goes HIGH for one clock cycle when both CET = HIGH and Q3–Q0 = HHHH. This behavior prevents false carry assertions during partial-count operations and enables selective stage enablement in multi-counter configurations.

Is the parallel load function affected by the count enable inputs (CEP/CET)?

No - parallel load occurs unconditionally on the rising edge of CP when PE = LOW, irrespective of CEP or CET logic levels. This allows immediate reinitialization even when counting is disabled, supporting fail-safe reset sequences in safety-critical automotive firmware.