Texas Instruments CD4055BPW

Overview

CD4055BPW from Texas Instruments is a BCD-to-7-segment latch/decoder/driver IC designed for direct LED display interfacing, featuring 16-pin TSSOP packaging, -55°C to +125°C operating temperature range, TTL-compatible input thresholds, and open-drain segment outputs capable of sinking up to 10 mA per segment. It drives common-anode 7-segment displays in industrial panel meters and legacy instrumentation systems.

For engineers reviewing the CD4055BPW datasheet, CD4055BPW pinout, CD4055BPW application, or CD4055BPW equivalent, key selection criteria include its BCD latching behavior, segment output drive capability, absence of internal current limiting, compatibility with common-anode LED configurations, and qualification for extended temperature operation without derating.

Technical Context

The CD4055BPW implements a synchronous BCD-to-7-segment decoding function with integrated transparent latch, accepting 4-bit binary-coded decimal inputs and producing active-low segment drive signals (a–g) for common-anode displays. Its latch enables stable display hold during BCD updates.

Unlike the CD4056B, the CD4055BPW lacks built-in current-limiting resistors and requires external series resistors for LED current control; it also omits the blanking input found on the CD4056B, offering only latch enable and reset functionality.

Key Specifications

Pinout & Package

TSSOP-16 package (PW suffix), 4.4 mm × 5.0 mm body, 1.2 mm max height, 0.65 mm lead pitch, exposed metal pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar BCD-to-7-segment driver applications.

Compared with CD4056BPW and MC14495P, the CD4055BPW uniquely combines latch functionality, open-drain flexibility, and extended temperature operation - making it the sole option for new designs requiring hold-stable display updates in harsh environments without added latch circuitry.

Availability

CD4055BPW is available at Aetrix Electronics and suitable for industrial panel meters, avionics cabin monitoring units, and energy meter display modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD4055BPW 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 CD4055BPW belongs to TI's legacy CMOS logic family, engineered specifically for robust, low-power digital display interfacing in mission-critical instrumentation where reliability and temperature resilience outweigh modern integration trends.

FAQ

What is the primary function of the CD4055BPW?

The CD4055BPW is a BCD-to-7-segment latch/decoder/driver IC optimized for common-anode LED displays. It accepts 4-bit BCD inputs, latches them on the LE signal, and drives segments a–g with open-drain outputs. Unlike the CD4056B, it lacks internal current-limiting resistors and a blanking input, making external current-setting resistors mandatory. The CD4055BPW operates across -55°C to +125°C and supports supply voltages from 3 V to 18 V.

Does the CD4055BPW support common-cathode LED displays?

No, the CD4055BPW does not support common-cathode LED displays. Its segment outputs are open-drain and designed to sink current from a common-anode configuration, where the LED anodes connect to a positive supply and cathodes connect to the CD4055BPW outputs. Attempting to drive common-cathode displays would require external level-shifting or inversion circuitry, which is not supported by the CD4055BPW's architecture or datasheet specifications.

Is the CD4055BPW pin-compatible with the CD4055BE or CD4055BM?

No, the CD4055BPW is not pin-compatible with the CD4055BE (PDIP-16) or CD4055BM (SOIC-16). While all three share identical logic functionality and pin numbering, their physical packages differ: CD4055BPW uses a 16-pin TSSOP (PW) with 0.65 mm pitch and 4.4 mm × 5.0 mm body, whereas CD4055BE uses PDIP (N) and CD4055BM uses SOIC (D). PCB layout changes are required to substitute CD4055BPW for either variant.

What is the role of Pin 16 (NC) on the CD4055BPW?

Pin 16 on the CD4055BPW is designated NC (No Connect) and is internally unconnected. It must not be used as a ground or supply tie point. TI's packaging documentation confirms no internal bond wire connects to this pin. Best practice is to leave it floating or optionally tie it to V_SS for mechanical stability - but never to V_DD or signal lines. This NC designation applies exclusively to the CD4055BPW and differs from the CD4056BPW, which uses Pin 16 for blanking input.

Can the CD4055BPW drive multiple 7-segment digits without external multiplexing components?

No, the CD4055BPW drives only one 7-segment digit per device. It provides seven segment outputs (a–g) and no digit-select or multiplexing control signals. To drive multi-digit displays, external digit drivers (e.g., high-side PNP transistors or dedicated digit drivers) and time-multiplexed BCD updates are required. The CD4055BPW's latch enables stable per-digit display hold during multiplexing, but it does not integrate digit scanning logic - that function remains external to the CD4055BPW.