Nexperia USA Inc. 74HC42D,653

Overview

74HC42D,653 from Nexperia is a CMOS BCD-to-decimal decoder (1-of-10) with four binary-coded decimal inputs (0A–3A) and ten mutually exclusive active-HIGH outputs (0Y–9Y), operating across 2.0 V to 6.0 V supply, specified for -40 °C to +125 °C, and featuring input clamp diodes for overvoltage-tolerant interfacing in industrial control panels and digital instrumentation displays.

For engineers reviewing the 74HC42D,653 datasheet, 74HC42D,653 pinout, 74HC42D,653 application, or 74HC42D,653 equivalent, this device supports BCD-driven 7-segment display decoding, 1-of-8 demultiplexing via 3A as data input, and high-noise-immunity logic-level translation in legacy TTL-compatible systems requiring stable low-power decoding.

Technical Context

The 74HC42 implements combinational logic that asserts exactly one output HIGH for valid BCD inputs (0000–1001), while forcing all ten outputs HIGH for invalid codes (1010–1111). Its architecture includes internal clamping diodes on all inputs, enabling safe interface with signals exceeding VCC when current-limiting resistors are used.

Input 3A serves dual roles: as the MSB of the BCD word and as an enable/inhibit signal-when held LOW, it restricts operation to eight outputs (0Y–7Y), effectively configuring the IC as a 1-of-8 decoder or 8-output demultiplexer with 0A–2A as address lines.

Key Specifications

Pinout & Package

74HC42D,653 is housed in a plastic small outline package (SO16, SOT109-1) with 16 leads, 3.9 mm body width, and gull-wing surface-mount terminals compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar BCD-to-decimal decoding applications.

Compared with 74HC42D,653, the 74HCT42D,653 offers superior TTL input compatibility but reduced noise margin in CMOS systems, while SN74LS42N sacrifices power efficiency, temperature range, and fault detection for legacy board compatibility - making the HC variant optimal for new industrial designs requiring wide VCC, high noise immunity, and diagnostic capability.

Availability

74HC42D,653 is available at Aetrix Electronics and suitable for industrial panel meters, digital multimeter displays, and legacy equipment interface cards requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 74HC42D,653 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 logic, discrete, and MOSFET solutions with focus on efficiency, reliability, and sustainability in industrial and automotive applications.

The 74HC42 belongs to Nexperia's 74HC logic family, designed for low-power, high-noise-immunity digital interfacing in industrial control, instrumentation, and legacy system upgrades where robust BCD decoding is essential.

FAQ

What is the maximum clock frequency supported by the 74HC42D,653?

The 74HC42D,653 is a combinational logic device with no internal clock; its speed is defined by propagation delay. At VCC = 6.0 V and CL = 50 pF, tpd is 14 ns (typ.), supporting reliable operation in systems with signal transitions up to ~35 MHz. Actual timing depends on load capacitance and PCB routing.

Can the 74HC42D,653 drive LEDs directly?

Yes - each output can sink or source up to ±4.0 mA at VCC = 4.5 V, sufficient to drive low-current LEDs (e.g., 2 mA @ 1.8 V forward voltage) with appropriate series resistors. For higher-brightness LEDs, external transistors or drivers are recommended to avoid exceeding output current limits.

Why do all outputs go HIGH for BCD codes above 9?

This behavior is intentional logic design: invalid inputs (1010–1111) force all ten outputs HIGH to provide unambiguous fault indication. It enables hardware-level error detection - for example, lighting all ten indicator LEDs simultaneously signals corrupted BCD data to operators or monitoring firmware.

Is the 74HC42D,653 pin-compatible with the 74LS42?

Yes - both devices use identical SO16 pinouts and share the same 0A–3A input and 0Y–9Y output assignments. However, electrical differences exist: 74HC42D,653 has CMOS input thresholds and clamp diodes, while 74LS42 uses TTL thresholds and lacks overvoltage protection - direct substitution requires verifying input drive strength and voltage levels.