Texas Instruments CD74HC4515E

Overview

CD74HC4515E from Texas Instruments is a high-speed CMOS 4-to-16 line decoder/demultiplexer with input latches, functioning as a binary-to-1-of-16 decoder or 1-to-16 demultiplexer depending on E-input usage. It features latch enable (LE), active-low enable (E), 4-bit address inputs (A0–A3), and 16 active-low outputs (Y0–Y15). Designed for industrial control logic and address decoding in microprocessor systems operating from -55°C to 125°C.

For engineers reviewing the CD74HC4515E datasheet, CD74HC4515E pinout, CD74HC4515E application, or CD74HC4515E equivalent, key selection criteria include its active-low output polarity, latch-controlled input sampling, wide VCC range (2V–6V), LSTTL fanout capability (10 loads), and guaranteed operation across extended temperature extremes.

Technical Context

The CD74HC4515E integrates a 4-bit strobed latch and a 4-to-16 decoder in a single monolithic silicon gate CMOS device. Its latch enable (LE) controls transparent vs. latched behavior: when LE is high, outputs follow A0–A3 changes; when LE is low, outputs hold their prior state at logic low (unlike CD74HC4514's high-hold behavior).

Demultiplexing is implemented by routing data to the E input while using A0–A3 as address lines; cascading is supported via E as chip select. Output polarity is active-low - all 16 outputs go low on decode match, and all go high when E is high (inhibit mode), enabling direct interface with LED drivers or low-side logic loads.

Key Specifications

Pinout & Package

CD74HC4515E is supplied in a 24-pin plastic dual in-line package (PDIP) with 0.600-inch body width and through-hole mounting. Pin 1 is located at the top-left corner adjacent to the notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD74HC4515E, CD74HC4514E offers identical timing and drive but opposite output polarity, while SN74HC154N reduces cost and complexity at the expense of missing latch and demux capabilities - making CD74HC4515E the optimal choice for systems requiring both address decoding and data routing with state retention.

Availability

CD74HC4515E is available at Aetrix Electronics and suitable for industrial PLC expansion, avionics subsystem addressing, and automotive ECU diagnostics requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HC4515E 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 delivering analog, embedded processing, and logic solutions with emphasis on reliability, longevity, and industrial-grade qualification.

The CD74HC4515E belongs to TI's HC-series high-speed CMOS logic family, engineered specifically for robust digital control functions in harsh environments including aerospace, defense, and heavy industrial automation.

FAQ

What is the output behavior of CD74HC4515E when the enable (E) input is high?

When E is high, all 16 outputs (Y0–Y15) are forced high regardless of address inputs (A0–A3) or latch enable (LE) state. This inhibit mode ensures safe default state during reset or bus contention. The CD74HC4515E maintains this behavior across its full -55°C to +125°C operating range and 2V–6V supply voltage window.

How does CD74HC4515E differ from CD74HC4514E in functional operation?

The CD74HC4515E produces active-low outputs (Yx = LOW on decode match), whereas CD74HC4514E produces active-high outputs (Yx = HIGH on decode match). Both share identical pinout, timing, latch behavior, and electrical specs. The CD74HC4515E is selected when interfacing with NMOS loads, LED cathodes, or systems requiring low-true assertion logic.

Can CD74HC4515E operate reliably at 2V supply voltage?

Yes, CD74HC4515E is fully specified down to 2V VCC, with propagation delays up to 415ns and guaranteed noise margins (NIL/NIH = 30% of VCC) at that level. At 2V, it delivers 10 LSTTL loads of fanout and draws ≤8µA quiescent current - making it suitable for ultra-low-power portable instrumentation where CD74HC4515E replaces higher-voltage logic families.

What is the purpose of the latch enable (LE) pin on CD74HC4515E?

The LE pin controls whether the CD74HC4515E operates in transparent or latched mode: when LE is high, outputs respond immediately to changes on A0–A3; when LE is low, outputs freeze at their last decoded low state. This allows synchronization of address sampling with system clocks or control signals, preventing metastability in real-time control applications using CD74HC4515E.

Is CD74HC4515E compatible with 5V TTL logic inputs?

Yes, CD74HC4515E accepts TTL-level inputs across its full VCC range: at VCC = 5V, VIH(min) = 3.15V and VIL(max) = 1.35V - comfortably exceeding standard TTL thresholds (2.0V/0.8V). Its high noise immunity (30% VCC) and 10 LSTTL load drive capability ensure robust interoperability with legacy 5V TTL systems when using CD74HC4515E in mixed-signal designs.