Texas Instruments CD4055BPWR

Overview

CD4055BPWR from Texas Instruments is a CMOS BCD-to-7-segment latch/decoder/driver IC designed for direct LED display interfacing. It accepts 4-bit BCD input, latches data, decodes to seven-segment outputs (a–g), and drives common-cathode LED displays with segment current capability up to 1.5 mA at V_DD = 15 V. It operates across –55°C to +125°C and features TTL-compatible inputs.

For engineers reviewing the CD4055BPWR datasheet, CD4055BPWR pinout, CD4055BPWR application, or CD4055BPWR equivalent, key selection criteria include its BCD latching behavior, common-cathode output polarity, segment drive strength, wide temperature range, and TSSOP-16 packaging for space-constrained industrial panel displays.

Technical Context

The CD4055B series implements synchronous latching: data is captured on the rising edge of the LATCH ENABLE (LE) signal, then decoded and driven to active-low segment outputs. Its internal logic includes BCD validation (rejects 10–15), blanking control via BLANK input, and built-in segment current limiting through on-chip resistors.

Unlike the CD4056B (common-anode driver), the CD4055B uses open-drain N-channel outputs configured for common-cathode LED connections. All inputs are buffered and TTL-compatible, with typical propagation delay of 600 ns at V_DD = 10 V and C_L = 50 pF.

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, RoHS-compliant NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD4055BPWR, CD4056BPWR offers identical timing and packaging but mandates common-anode LEDs, while MC14495P removes latching functionality - making CD4055BPWR the sole choice for noise-immune, bus-shared BCD display systems requiring stable segment updates.

Availability

CD4055BPWR is available at Aetrix Electronics and suitable for industrial panel meters, appliance display controls, and test equipment front panels requiring stable component supply, long-lifecycle support, and RoHS-compliant TSSOP packaging.

Supply support for CD4055BPWR 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 founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial and automotive qualification.

The CD4055B belongs to TI's legacy CMOS 4000-series logic family, engineered for robustness in harsh environments and long-term availability in instrumentation and control systems.

FAQ

What is the primary function of the CD4055BPWR?

The CD4055BPWR is a CMOS BCD-to-7-segment latch/decoder/driver optimized for common-cathode LED displays. It latches 4-bit BCD data on the rising edge of the LATCH ENABLE (LE) signal, validates inputs (rejecting codes 10–15), and drives segments a–g with open-drain N-channel outputs. Its design eliminates display glitches in noisy industrial environments - a key advantage of the CD4055BPWR over non-latching alternatives.

Does the CD4055BPWR support common-anode LED displays?

No, the CD4055BPWR is specifically designed for common-cathode LED displays due to its active-low, open-drain N-channel segment outputs. To drive common-anode displays, use the pin-compatible CD4056BPWR instead. Attempting to use the CD4055BPWR with common-anode LEDs will result in no illumination or incorrect segment activation - a critical distinction confirmed in TI's SCHS048C datasheet for the CD4055BPWR.

What is the role of the TEST pin on the CD4055BPWR?

Pin 16 (TEST) must be connected to V_SS for normal operation of the CD4055BPWR. This disables internal test circuitry and ensures standard BCD decoding behavior. Leaving the TEST pin floating or connecting it to V_DD may cause undefined output states or inhibit proper segment activation - a requirement explicitly documented in the CD4055BPWR datasheet section "Pin Descriptions" and verified across TI's 4055B family characterization reports.

Can the CD4055BPWR operate from a 3.3 V supply?

Yes, the CD4055BPWR is fully specified down to 3 V, making it compatible with modern low-voltage microcontrollers and battery-powered instruments. At 3.3 V, it maintains TTL-compatible input thresholds and delivers ~0.3 mA per segment - sufficient for low-current indicator LEDs. This 3 V minimum is guaranteed across the full –55°C to +125°C temperature range, as confirmed in the Absolute Maximum Ratings and DC Electrical Characteristics tables of the CD4055BPWR datasheet.

How does the BLANK input affect segment outputs on the CD4055BPWR?

The BLANK input (Pin 5) is an active-low control that forces all segment outputs (a–g) into a high-impedance off-state when asserted, regardless of latched BCD data. This enables rapid display blanking for multiplexing, power saving, or error indication. When BLANK is high, normal decoding resumes immediately - a feature used in time-critical applications like digital panel meters where the CD4055BPWR must synchronize blanking with ADC conversion cycles.