Texas Instruments CD74HCT4511E

Overview

CD74HCT4511E from Texas Instruments is a BCD-to-7-segment latch/decoder/driver IC designed for direct interface with common-anode LED displays. It features active-low blanking (BL), lamp-test (LT), and latch-enable (LE) inputs, operates from 4.5 V to 5.5 V, sources up to 7.5 mA per output at 4.5 V, and supports TTL-compatible logic levels (VIL ≤ 0.8 V, VIH ≥ 2.0 V).

For engineers reviewing the CD74HCT4511E datasheet, CD74HCT4511E pinout, CD74HCT4511E application, or CD74HCT4511E equivalent, this page delivers verified functional modes, timing constraints (e.g., LE pulse width ≥16 ns), output drive capability, latch behavior, and real-world display interface design considerations.

Technical Context

The CD74HCT4511E implements a synchronous latching architecture: when LE is high, the four BCD inputs (D0–D3) are stored in internal latches; when LE is low, outputs follow BCD inputs transparently. Its decoder logic maps valid BCD codes (0–9) to active-low segment outputs (a–g), with illegal codes (10–15) forcing all segments low (blanked).

It integrates TTL-compatible input thresholds and CMOS-level output drive, enabling direct connection to microcontroller GPIOs without level-shifting. The BL input overrides all outputs to high-impedance (blanking), while LT forces all segments low (lamp test), both active-low and independent of latch state.

Key Specifications

Pinout & Package

CD74HCT4511E is supplied in a 16-pin plastic dual in-line package (PDIP, N package), body size 19.31 mm × 6.35 mm, with through-hole mounting and standard 0.1-inch pin pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LS47N and CD74HC4511E, the CD74HCT4511E uniquely bridges TTL logic compatibility and CMOS efficiency - it accepts standard 5 V TTL signals natively while delivering higher drive and integrated latch/blanking functions absent in LS47, and avoids the input-level mismatch issues of the HC variant.

Availability

CD74HCT4511E is available at Aetrix Electronics and suitable for industrial panel meters, test equipment displays, embedded control consoles, and legacy system upgrades requiring stable component supply and long-term obsolescence management.

Supply support for CD74HCT4511E 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 solutions, with decades of experience in high-reliability industrial and automotive-grade components.

The CD74HCT4511E belongs to TI's 74HCT logic family, engineered specifically for seamless interoperability between TTL and CMOS systems in cost-sensitive, noise-resilient display and control applications.

FAQ

What is the maximum supply voltage for CD74HCT4511E?

The absolute maximum supply voltage for CD74HCT4511E is 7 V, but the recommended operating range is strictly 4.5 V to 5.5 V. Operating outside this window risks violating input threshold specifications and may cause unreliable decoding or increased ICC. Always use a regulated 5 V ±5% supply with local 0.1 μF bypass capacitance for stable CD74HCT4511E operation.

Can CD74HCT4511E drive common-cathode LED displays?

No, CD74HCT4511E is designed exclusively for common-anode LED displays, as its segment outputs (a–g) are active-low open-drain equivalents with internal sourcing transistors. Driving a common-cathode display would require external inverters or PNP/N-channel buffer stages - which defeats the purpose of its integrated driver architecture. Use CD74HCT4543E for common-cathode applications.

How does the ripple blanking output (RBO) work on CD74HCT4511E?

The RBO pin on CD74HCT4511E is an active-low open-collector output that goes low only when the latched BCD code is zero (0000) AND BL is inactive (high). In cascaded multi-digit displays, RBO of the most-significant digit connects to BI of the next-lower digit, blanking leading zeros automatically. This eliminates firmware-based zero suppression and reduces CPU load in CD74HCT4511E-based systems.

Is CD74HCT4511E pin-compatible with CD74HC4511E?

Yes, CD74HCT4511E and CD74HC4511E share identical pinout, package (PDIP-16), and functional block diagram. However, they differ critically in input voltage thresholds: CD74HCT4511E accepts TTL-level inputs (VIH ≥ 2.0 V), while CD74HC4511E requires CMOS-level inputs (VIH ≥ 3.15 V at 4.5 V). Swapping them without verifying source logic family may cause misreads - CD74HCT4511E remains the correct choice for 5 V TTL interfacing.

What is the minimum pulse width required on the LE input for reliable latching in CD74HCT4511E?

The minimum LE low pulse width for guaranteed BCD capture in CD74HCT4511E is 16 ns at TA = 25°C and VCC = 4.5 V, per Section 5.9 of the datasheet. For robust operation across temperature and voltage extremes, maintain ≥20 ns. Shorter pulses risk incomplete latch enable, resulting in metastable outputs or partial digit corruption - critical in high-speed multiplexed displays where LE is toggled per digit.