Texas Instruments CD4515BM

Overview

CD4515BM from Texas Instruments is a 4-bit latched binary-to-1-of-16 decoder/demultiplexer in a 24-pin SOIC package, featuring CMOS logic compatibility, 20 V max supply voltage, and operation across –55°C to +125°C. It enables precise address selection in memory expansion and I/O port decoding for industrial control systems.

For engineers reviewing the CD4515BM datasheet, CD4515BM pinout, CD4515BM application, or CD4515BM equivalent, key selection criteria include its active-low output enable (OE), latch-enable (LE) control, 1-of-16 decoded output architecture, and compatibility with CD4000-series logic families in high-reliability embedded designs.

Technical Context

The CD4515BM implements dual-stage decoding: first latching 4-bit binary inputs via LE, then decoding to one of sixteen active-low outputs when OE is asserted. Its CMOS structure ensures low static power consumption and high noise immunity.

Input thresholds are referenced to V_DD/2, supporting direct interfacing with TTL and other CMOS devices. All outputs drive loads up to ±4.2 mA at V_DD = 15 V, with propagation delays under 120 ns (typ.) at 10 V supply.

Key Specifications

Pinout & Package

CD4515BM is supplied in a 24-pin SOIC (DW) package, 7.5 mm wide, with 0.65 mm lead pitch and RoHS-compliant NiPdAu plating. The package meets JEDEC MO-153 and is rated MSL Level-1 (unlimited floor life).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-bit latched decoder applications.

Compared with CD4515BF3A, CD4515BM offers surface-mount compatibility and RoHS compliance at identical electrical performance; compared with CD4514BM, it adds critical input latching for robust operation in asynchronous bus environments.

Availability

CD4515BM is available at Aetrix Electronics and suitable for memory address decoding, I/O port expansion, industrial display multiplexing, and test equipment signal routing requiring stable component supply across extended temperature ranges.

Supply support for CD4515BM 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 for industrial, automotive, and communications markets.

The CD4515BM belongs to TI's legacy CD4000B series of radiation-tolerant, high-voltage CMOS logic ICs designed for reliability-critical applications in harsh environments.

FAQ

What is the maximum supply voltage rating for CD4515BM?

The CD4515BM supports a maximum supply voltage of 20 V DC. This rating is absolute maximum and applies across the full operating temperature range (–55°C to +125°C). Operation above 20 V risks permanent damage to the internal oxide layers. For long-term reliability at elevated temperatures, TI recommends limiting V_DD to ≤18 V when operating above +85°C. The CD4515BM maintains specified timing and drive performance up to 15 V.

Does CD4515BM require external pull-up resistors on its outputs?

No, CD4515BM does not require external pull-up resistors on its outputs. Its outputs are buffered CMOS totem-pole drivers capable of actively sourcing and sinking current. Each Y0–Y15 output can sink up to 4.2 mA and source up to 0.36 mA at V_DD = 15 V. Pull-ups are only needed if interfacing with open-drain or high-impedance inputs not compatible with active-drive logic levels - a scenario not typical for standard CD4515BM applications.

How does the latch enable (LE) function differ from output enable (OE) in CD4515BM?

In CD4515BM, LE (pin 5) controls input capture: a high-to-low transition latches the current A0–A3 values into the internal register, freezing them regardless of subsequent input changes. OE (pin 6) independently gates the decoded outputs: only when OE is low do Y0–Y15 reflect the latched address. This separation allows asynchronous address updates (via LE) and synchronous output activation (via OE), preventing glitches during bus arbitration - a key distinction from non-latched decoders like CD4514BM.

Is CD4515BM pin-compatible with CD4514BM?

No, CD4515BM is not pin-compatible with CD4514BM. Although both are 24-pin SOIC devices with identical package outline (DW), their pin functions differ significantly: CD4515BM uses pins 1–4 for A0–A3 and pin 5 for LE, whereas CD4514BM assigns pins 1–4 to Y0–Y3 and uses different control pin allocations. Substituting one for the other without PCB revision will result in incorrect logic behavior or non-functional outputs. Always verify pin mapping against the respective datasheets before replacement.

What is the recommended reflow profile for CD4515BM96.A?

The CD4515BM96.A is rated MSL Level-1 with unlimited floor life and a peak reflow temperature of 260°C. TI specifies a standard lead-free reflow profile: preheat (150–200°C, 60–120 s), soak (200–220°C, 60–120 s), reflow (peak 235–260°C, time above liquidus 40–80 s), and cooling. The part marking "CD4515BM" appears on the top surface, and the tape-and-reel orientation follows quadrant Q1 per TI's DW package specification. No special baking is required prior to assembly.