Texas Instruments CD40147BM96

Overview

CD40147BM96 from Texas Instruments is a CMOS 10-line-to-4-line priority encoder IC that converts active-high decimal inputs (0–9) into active-low BCD outputs (8, 4, 2, 1), with highest priority assigned to input line 9. It operates over –55°C to +125°C, features buffered TTL-compatible outputs (driving one LSTTL load), and exhibits active-low output logic (all outputs high when all inputs inactive). It is used in keyboard encoding, interrupt prioritization, and digital control panels requiring deterministic highest-priority resolution.

For engineers reviewing the CD40147BM96 datasheet, CD40147BM96 pinout, CD40147BM96 application, or CD40147BM96 equivalent, key selection considerations include its priority encoding behavior, active-low BCD output polarity, SOIC-16 package footprint, –55°C to +125°C operating range, and functional equivalence to TTL 74147 with pin 15 grounded.

Technical Context

The CD40147BM96 implements a fixed-priority combinational logic encoder with hardwired priority order (9 > 8 > … > 0), where only the highest asserted input determines the BCD output. Its internal architecture uses NAND/NOR-based gate arrays without latching or clocking - it is purely asynchronous and level-sensitive.

All ten inputs are active-high; all four outputs are active-low open-drain compatible (with internal pull-up to VDD not present - outputs sink current only). Output states are fully defined: when no input is active, all outputs go high (logic 1), satisfying IEEE Std 91-1984 truth table requirements for priority encoders.

Key Specifications

Pinout & Package

CD40147BM96 is supplied in a 16-pin SOIC (Small-Outline Integrated Circuit) package, body width 3.9 mm, standard JEDEC MS-012AC, moisture sensitivity level 1 (unlimited floor life at ≤30°C/60% RH).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar priority encoding applications.

Compared with CD40147BE and 74HC147, the CD40147BM96 uniquely combines wide VDD (3–18 V), extended temperature (–55°C to +125°C), and SOIC-16 packaging - making it the sole option for ruggedized, multi-voltage, surface-mount priority encoding.

Availability

CD40147BM96 is available at Aetrix Electronics and suitable for industrial control panels, legacy system upgrades, and ruggedized keyboard interfaces requiring stable component supply, long-term lifecycle assurance, and guaranteed SOIC-16 sourcing.

Supply support for CD40147BM96 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The CD40147BM96 belongs to TI's CD4000B series of radiation-tolerant, high-voltage CMOS logic devices designed for reliability-critical applications including aerospace subsystems, energy infrastructure controls, and military communications equipment.

FAQ

What is the function of pin 15 on the CD40147BM96?

Pin 15 is the O8 (MSB BCD) output, active-low. When tied low externally, the CD40147BM96 matches the output behavior of the TTL 74147 encoder. Leaving it unconnected or floating is invalid - it must be either used as an output or actively pulled low for compatibility mode. The CD40147BM96 datasheet specifies this connection for functional equivalence with 74147-based designs.

Does the CD40147BM96 include internal pull-up or pull-down resistors on its inputs?

No, the CD40147BM96 has no internal pull-up or pull-down resistors on any input. All ten inputs (I0–I9) are high-impedance CMOS gates and must be externally biased - typically with 10 kΩ pull-down resistors to VSS when unused or in open-keyboard configurations. Floating inputs cause undefined output states and increased static power consumption in the CD40147BM96.

Can the CD40147BM96 operate from a 3.3 V supply?

Yes, the CD40147BM96 is fully specified to operate from 3 V to 18 V DC. At 3.3 V, it meets all AC and DC parametric limits in the datasheet, including propagation delay (≤120 ns max), output drive (≥2.5 mA sink per output), and noise margin (≥0.8 V). This makes the CD40147BM96 suitable for mixed-voltage systems interfacing with 3.3 V microcontrollers while retaining compatibility with legacy 5 V or 12 V peripherals.

How does the CD40147BM96 handle simultaneous input assertions?

The CD40147BM96 resolves simultaneous input assertions using fixed hardware priority: only the highest-numbered active input (I9 > I8 > … > I0) determines the BCD output. There is no arbitration delay or metastability - the output settles to the correct code within 60 ns (typical) at 5 V. This deterministic behavior is intrinsic to the CD40147BM96's gate-level design and requires no external clock or enable signal.

Is the CD40147BM96 RoHS compliant and lead-free?

Yes, the CD40147BM96 is RoHS compliant and features a NIPDAU (nickel/palladium/gold) lead finish, as confirmed in TI's official packaging addendum. It meets JEDEC J-STD-020 moisture sensitivity level 1 (unlimited floor life) and is rated for peak reflow temperatures up to 260°C. All CD40147BM96 units shipped by Aetrix Electronics carry full RoHS documentation and material declarations traceable to TI's manufacturing lot data.