Texas Instruments CD74HCT4514E

Overview

CD74HCT4514E from Texas Instruments is a 4-line to 16-line decoder/demultiplexer with input latches, operating at 4.5 V to 5.5 V VCC, featuring ±25 mA output drive, balanced propagation delays (max 83 ns), and wide temperature range (–55°C to 125°C). It serves as address decoder in memory-mapped I/O systems and enables channel selection in industrial multiplexed sensor arrays.

For engineers reviewing the CD74HCT4514E datasheet, CD74HCT4514E pinout, CD74HCT4514E application, or CD74HCT4514E equivalent, key selection criteria include latch-enable timing (tsu = 30 ns min), TTL/CMOS input compatibility (VIL ≤ 0.8 V, VIH ≥ 2 V), output polarity (active-high Y0–Y15), and PDIP-24 thermal performance (θJA = 67°C/W).

Technical Context

The CD74HCT4514E integrates a 4-bit strobed latch and a binary-to-1-of-16 decoder in a single silicon-gate CMOS device. Its latch enable (LE) controls data capture timing, while enable (E) serves dual roles: output enable for decoding and data input for demultiplexing.

Logic operation follows positive-logic decode tables where LE high allows real-time input tracking, and LE low freezes latched state. Output behavior is defined strictly by E and A0–A3 inputs, with no internal feedback or state retention beyond latch hold.

Key Specifications

Pinout & Package

CD74HCT4514E is housed in a 24-pin plastic dual-in-line package (PDIP) compliant with JEDEC MS-010, with 0.300-inch body width, 0.100-inch lead pitch, and 67°C/W junction-to-ambient thermal resistance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-to-16 decoder applications.

Compared with CD74HCT4514E, SN74HCT154N lacks latch synchronization for volatile address buses, while CD74HC4514E sacrifices LSTTL compatibility for lower static power - both require redesign of input drive and timing validation.

Availability

CD74HCT4514E is available at Aetrix Electronics and suitable for memory-mapped I/O decoding, industrial sensor multiplexing, and LED matrix row selection requiring stable component supply across extended temperature ranges.

Supply support for CD74HCT4514E 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 decades of experience in high-reliability industrial and automotive IC design.

The CD74HCT4514E belongs to TI's legacy HCT logic family, engineered for seamless integration with legacy TTL systems while delivering CMOS power efficiency and extended temperature operation.

FAQ

What is the maximum clock frequency supported by CD74HCT4514E for reliable decoding?

The CD74HCT4514E does not operate on a clock signal; it is asynchronous. Its usable maximum address transition rate is determined by propagation delay (tpd ≤ 83 ns) and setup/hold timing. For stable operation with LE-controlled latching, input addresses must be stable ≥30 ns before LE falls and held ≥5 ns after, supporting effective address update rates up to ~10 MHz in buffered bus systems. The CD74HCT4514E itself imposes no internal clock limit.

Can CD74HCT4514E drive LEDs directly without current-limiting resistors?

No - CD74HCT4514E outputs are rated for ±25 mA continuous sink/source, but internal output impedance and VOL/VOL specifications assume external current limiting. Driving LEDs directly risks exceeding absolute maximum ratings under VCC variation or temperature extremes. Each Yx output requires a series resistor calculated using (VCC – VF_LED)/I_LED, where I_LED ≤ 20 mA ensures long-term reliability. The CD74HCT4514E provides drive capability, not current regulation.

How does the latch enable (LE) pin affect timing behavior in CD74HCT4514E?

When LE is high, Y outputs follow A0–A3 changes with propagation delay (tpd). When LE falls, the current A0–A3 state is captured and held; subsequent input changes have no effect until LE rises again. This creates a clean break between address sampling and output assertion, eliminating glitches during bus contention. The CD74HCT4514E requires minimum LE pulse width (tw ≥ 30 ns) and respects tsu/th timing relative to LE↓ - critical for synchronizing with microcontroller write strobes.

Is CD74HCT4514E pin-compatible with CD74HCT4515E?

Yes - CD74HCT4514E and CD74HCT4515E share identical pinout, package (PDIP-24), electrical specifications, and functional block diagram. The sole difference is output polarity: CD74HCT4514E asserts Yx high for selected address, while CD74HCT4515E asserts Yx low. Swapping them requires inverting downstream logic or adjusting enable polarity; no PCB change is needed, but firmware or schematic logic must accommodate active-high vs. active-low outputs.

What thermal considerations apply to CD74HCT4514E in high-density PCB layouts?

CD74HCT4514E has θJA = 67°C/W in PDIP-24. At 5 V and full 16-output toggle (worst-case Cpd = 75 pF), dynamic power is ~18.75 mW - negligible heating. However, sustained 25 mA per output into low-impedance loads increases junction temperature. Maintain ≥2 mm clearance from adjacent heat sources, use 2+ thermal vias under GND/VCC pads if layer stack permits, and avoid placing CD74HCT4514E near power inductors or regulators. Derate maximum ambient temperature by 10°C per additional 100 mW dissipated beyond datasheet typicals.