Texas Instruments CD4056BPWR

Overview

CD4056BPWR from Texas Instruments is a CMOS BCD-to-7-segment latch/decoder/driver IC designed for direct LED segment control in digital displays. It features latched BCD input, active-low segment outputs with 10 mA sink capability per segment, wide supply range (3 V to 18 V), and operates across –55°C to +125°C. It drives common-anode LED displays without external current-limiting resistors when used with appropriate supply voltage.

For engineers reviewing the CD4056BPWR datasheet, CD4056BPWR pinout, CD4056BPWR application, or CD4056BPWR equivalent, key selection considerations include its BCD latching behavior, segment output polarity and drive strength, supply voltage compatibility with legacy 5 V or high-voltage display systems, and TSSOP-16 packaging for space-constrained PCB layouts.

Technical Context

The CD4056BPWR implements a synchronous BCD-to-7-segment decoding function with an internal D-type latch that holds the input code until the next clock edge. Its outputs are active-low open-drain drivers compatible with common-anode LEDs, supporting direct connection to segments without external pull-ups when driven by logic-high enable signals.

It includes blanking (BL) and latch enable (LE) control inputs for display multiplexing and data hold functionality. The device uses standard CMOS silicon-gate technology, ensuring low static power consumption (<1 µA at 5 V) and noise immunity up to 50% of V_DD.

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 pad optional (not electrically connected in base variant), 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 CD4056BE and MC14495P, the CD4056BPWR delivers identical decoding functionality in a space-optimized TSSOP package with industry-standard pinout, enabling direct drop-in replacement on reflow-assembled boards while maintaining full backward compatibility with legacy CD4056B system designs.

Availability

CD4056BPWR is available at Aetrix Electronics and suitable for industrial panel meters, automotive instrument clusters, and test equipment front panels requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for CD4056BPWR 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 specializing in analog, embedded processing, and logic ICs, with over 90 years of innovation in industrial, automotive, and aerospace electronics.

The CD4056BPWR belongs to TI's legacy CMOS logic portfolio, originally developed for robust, low-power digital display interfacing in harsh environments where reliability and wide supply tolerance are critical.

FAQ

What is the primary function of the CD4056BPWR?

The CD4056BPWR is a CMOS BCD-to-7-segment latch/decoder/driver IC. It accepts a 4-bit BCD input, latches it on the rising edge of LE, decodes it into seven active-low segment outputs (a–g), and drives common-anode LED displays directly. Its lamp test (LT) and blanking (BL) inputs support diagnostics and multiplexing. The CD4056BPWR operates from 3 V to 18 V and is rated for –55°C to +125°C.

Does the CD4056BPWR require external current-limiting resistors for LED segments?

The CD4056BPWR can drive common-anode LEDs without external current-limiting resistors when V_DD is selected to limit segment current to ≤10 mA - for example, using ~12 V with typical 1.8 V LED forward voltage yields ~10 mA per segment. However, for precise current control or higher brightness consistency, external resistors are recommended. The CD4056BPWR's output structure is open-drain, so resistor placement is on the LED anode side.

How does the latch enable (LE) pin function on the CD4056BPWR?

The LE pin on the CD4056BPWR is a positive-edge-triggered latch control. When LE transitions from low to high, the current BCD input states (A–D) are captured and held internally, freezing the decoded segment outputs regardless of subsequent input changes. This allows asynchronous data loading from a microcontroller or counter. The CD4056BPWR maintains output stability until the next LE edge, enabling clean display updates.

Can the CD4056BPWR be used in multiplexed 4-digit LED displays?

Yes, the CD4056BPWR supports multiplexed displays via its BL (blanking) input, which forces all segment outputs high (off) when asserted low. By synchronizing BL with digit select signals and updating BCD inputs between digit scans, multi-digit displays can be driven efficiently. The CD4056BPWR's latch ensures segment data remains stable during blanking intervals, eliminating ghosting or flicker in properly timed systems.

What is the purpose of the lamp test (LT) pin on the CD4056BPWR?

The LT pin on the CD4056BPWR is an active-low diagnostic feature. When pulled low, it overrides all other controls and forces all seven segment outputs (a–g) low simultaneously - illuminating every segment of a connected common-anode display. This provides immediate hardware-level verification of LED continuity, wiring integrity, and driver functionality without requiring firmware or external test equipment. The CD4056BPWR retains normal operation once LT returns high.