Texas Instruments CD4028BE

Overview

CD4028BE from Texas Instruments is a BCD-to-decimal decoder/demultiplexer IC in the CD4000B CMOS logic family, performing 4-bit binary-coded decimal (BCD) input decoding into ten active-high decimal outputs (Y0–Y9), with supply voltage range of 3 V to 18 V, propagation delay of 120 ns at 5 V, and operating temperature from –55 °C to +125 °C - used in digital panel meters, address decoders, and industrial control displays.

For engineers reviewing the CD4028BE datasheet, CD4028BE pinout, CD4028BE application, or CD4028BE equivalent, key selection considerations include BCD input compatibility, active-high output drive capability, wide V_DD tolerance, and legacy-compatible PDIP-16 packaging for through-hole prototyping and industrial retrofits.

Technical Context

The CD4028BE implements combinational logic using standard CMOS gate arrays to decode four BCD inputs (A, B, C, D) into ten mutually exclusive high-asserted outputs, with no internal latching or clocking - all outputs are static and level-sensitive. Input thresholds are V_DD-dependent, ensuring noise immunity across the full supply range.

It features TTL- and CMOS-compatible input logic levels, supports fan-out of up to 50 CMOS loads or 10 TTL loads, and exhibits low quiescent current (≤1 µA at 5 V), making it suitable for battery-backed or low-power digital subsystems where deterministic decoding without timing overhead is required.

Key Specifications

Pinout & Package

CD4028BE is supplied in a 16-pin plastic dual-in-line package (PDIP-N), with 0.3-inch body width, 0.1-inch lead pitch, and through-hole mounting compatibility. Pin 1 is located at the left end of the top row, identified by a notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar BCD-to-decimal decoding applications.

Compared with CD4028BM96 and 74HC42, the CD4028BE uniquely combines through-hole manufacturability, extended temperature operation, and 3–18 V flexibility - making it the only option for legacy industrial upgrades requiring zero-layout change and full environmental qualification.

Availability

CD4028BE is available at Aetrix Electronics and suitable for digital instrumentation, industrial control panels, and automotive dashboard indicator systems requiring stable component supply over long production lifecycles.

Supply support for CD4028BE 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 founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial, automotive, and aerospace qualifications.

The CD4000B series - including CD4028BE - was designed for robust, low-power digital logic in harsh environments, emphasizing wide voltage tolerance, radiation-hardened variants, and long-term reliability over speed-optimized performance.

FAQ

What is the maximum supply voltage rating for CD4028BE?

The CD4028BE supports a maximum supply voltage of 18 V DC, verified per the TI CD4000B family datasheet (SCHS033C, October 2003). Operation above this voltage risks permanent damage to internal oxide layers. At 18 V, output drive capability reaches ±4.2 mA, enabling direct LED drive with appropriate current-limiting resistors. Always use a 0.1 µF ceramic bypass capacitor between V_DD and V_SS pins.

Does CD4028BE decode all 4-bit binary inputs or only valid BCD values?

The CD4028BE decodes only valid BCD inputs (0000 to 1001, representing decimal 0–9); inputs 1010 through 1111 are treated as invalid and force all ten outputs (Y0–Y9) low. This behavior is hardwired in the logic array and requires no external circuitry. The CD4028BE does not assert any output for invalid codes - a key safety feature in display and control applications.

Can CD4028BE directly drive standard 20 mA LEDs?

Yes, CD4028BE can directly drive standard 20 mA LEDs when operated at ≥12 V supply, as its output sink/source capability reaches ±4.2 mA at 15 V and scales linearly with V_DD. For 20 mA operation, use a series current-limiting resistor calculated as R = (V_DD − V_F) / 20 mA. At 5 V, max output current is ~1.5 mA - insufficient for full-brightness LEDs without external transistor buffering.

Is CD4028BE pin-compatible with the TTL 7442 decoder?

No, CD4028BE is not pin-compatible with the 7442. While both perform BCD-to-decimal decoding, the 7442 uses active-low outputs and different pin assignments (e.g., 7442 places V_CC on pin 16 but GND on pin 8, whereas CD4028BE places V_DD on pin 16 and V_SS on pin 8). Direct substitution requires rewiring or an adapter board; however, logic function and truth table alignment allow functional replacement with layout modification.

What is the propagation delay of CD4028BE at 5 V supply?

The CD4028BE has a maximum propagation delay (t_PD) of 120 ns at V_DD = 5 V, as specified in the TI SCHS033C datasheet. This value represents the worst-case delay from any input transition to corresponding output transition under load conditions defined in the test setup. Delay decreases with higher supply voltage - e.g., 70 ns at 10 V and 45 ns at 15 V - enabling timing-critical use in systems with tight setup/hold margins.