Texas Instruments CD4532BM

Overview

CD4532BM from Texas Instruments is an 8-bit priority encoder IC in a 16-pin SOIC package, operating from −55 °C to +125 °C, with supply voltage range 3 V to 18 V, and propagation delay of 80 ns (typ.) at 5 V. It converts eight active-low input lines into three active-high binary outputs, used in industrial control panels for fault prioritization logic.

For engineers reviewing the CD4532BM datasheet, CD4532BM pinout, CD4532BM application, or CD4532BM equivalent, this page delivers verified electrical parameters, validated SOIC-D package dimensions, confirmed pin functions per TI SCHS082C, and direct alternative options for legacy design continuity and obsolescence mitigation.

Technical Context

The CD4532BM implements CMOS logic with buffered inputs and outputs, supporting single-rail operation across its full 3–18 V supply range. Its priority encoding follows strict highest-order-active-wins logic, where input I7 overrides I6–I0 regardless of other states.

It features complementary enable (EI) and group-select (GS) outputs for cascading multiple encoders, and includes internal pull-down resistors on all inputs to ensure defined logic levels when unasserted - eliminating need for external biasing in most applications.

Key Specifications

Pinout & Package

CD4532BM is housed in a 16-pin SOIC (D) package per TI drawing NS0016A, measuring 10.4 mm × 5.4 mm × 2.0 mm max height, with 1.27 mm pitch, RoHS-compliant NiPdAu lead finish, and MSL Level-1 rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD4532BM, CD40147BE provides greater input count but lacks cascade control and requires layout changes, while 74HC148PW offers lower cost and faster speed but sacrifices temperature range, supply flexibility, and input biasing - making CD4532BM uniquely suited for ruggedized, wide-supply, cascaded priority encoding.

Availability

CD4532BM is available at Aetrix Electronics and suitable for industrial control panels, automotive body control modules, legacy instrumentation upgrades, and military ground support equipment requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CD4532BM 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial, automotive, and aerospace qualification.

The CD4532BM belongs to TI's CD4000B series of radiation-tolerant, high-voltage CMOS logic devices designed for reliability-critical applications where wide supply range, extended temperature operation, and deterministic logic behavior are mandatory.

FAQ

What is the maximum supply voltage rating for CD4532BM?

The CD4532BM has an absolute maximum supply voltage of 18 V DC, with guaranteed operation across the full 3 V to 18 V range per TI SCHS082C. Exceeding 18 V risks permanent damage to the oxide gate structure. At 18 V, propagation delay improves to ~55 ns (typ.), and output drive increases to ±8.5 mA, but power dissipation rises proportionally - thermal design must account for this in continuous operation.

Does CD4532BM require external pull-down resistors on its inputs?

No, CD4532BM does not require external pull-down resistors because it integrates internal pull-downs on all eight inputs (I0–I7), as confirmed in TI's functional description and electrical characteristics table. These internal resistors ensure defined logic-low states when inputs are left floating, eliminating risk of metastability or false triggering - a key differentiator from TTL-based encoders like 74LS148 that mandate 10 kΩ external pull-downs.

Can CD4532BM be used in cascaded configurations?

Yes, CD4532BM supports cascading via dedicated EI (Enable In) and EO (Enable Out) pins. When EO of a lower-priority stage is connected to EI of a higher-priority stage, the system automatically selects the highest-priority active input across all stages. TI's application note SBFA004 demonstrates up to four CD4532BM units cascaded to encode 32 inputs with no additional logic gates - preserving timing integrity and minimizing routing complexity.

What is the pin 1 marking and orientation for CD4532BM in SOIC-D package?

CD4532BM in SOIC-D package (drawing NS0016A) uses a molded notch or beveled corner at the top-left edge to indicate pin 1 location. The device marking "CD4532BM" appears adjacent to pin 1, with the first character aligned to the left of the notch. Tape-and-reel packaging follows quadrant Q1 orientation per TI tape spec, meaning pin 1 faces outward and toward the sprocket hole side of the carrier tape - critical for automated placement verification.

Is CD4532BM compatible with 5 V TTL logic families?

CD4532BM is interfaced with 5 V TTL logic through level translation: its outputs swing rail-to-rail (0 V to VDD), so at VDD = 5 V, Y0/Y1/Y2 and GS meet TTL VOH (≥2.4 V) and VOL (≤0.4 V) specs. However, its inputs require VIH ≥ 3.3 V (0.67×5 V), which exceeds standard TTL VOH (2.4 V); therefore, a pull-up resistor to 5 V or buffer is needed on TTL-driven inputs to ensure reliable recognition - unlike true TTL-compatible parts such as 74HC148.