Texas Instruments CD74HCT4511EG4

Overview

CD74HCT4511EG4 from Texas Instruments is a BCD-to-7-segment latch/decoder/driver IC with active-low blanking (BL), lamp-test (LT), and latch-enable (LE) inputs. It operates at 4.5–5.5 V, sources up to 7.5 mA per output at 4.5 V, and supports BCD code storage via internal latches - used in discrete 7-segment LED display systems requiring direct LSTTL-compatible logic interfacing.

For engineers reviewing the CD74HCT4511EG4 datasheet, CD74HCT4511EG4 pinout, CD74HCT4511EG4 application, or CD74HCT4511EG4 equivalent, key selection considerations include its TTL-compatible input thresholds (VIL ≤ 0.8 V, VIH ≥ 2.0 V), latch-controlled BCD decoding, lamp-test functionality, and PDIP-16 packaging for through-hole prototyping and industrial panel displays.

Technical Context

The CD74HCT4511EG4 integrates four BCD address inputs (D0–D3), a latch-enable input that controls transparent vs. latched operation, and dedicated BL/LT control lines. Its CMOS process ensures low static power consumption while maintaining full compatibility with bipolar TTL logic levels.

It decodes valid BCD codes (0–9) into active-high segment drive outputs (a–g), blanks all segments for illegal codes (>9), and provides simultaneous lamp-test activation (all segments ON) independent of latch state - enabling real-time display verification without disrupting stored BCD data.

Key Specifications

Pinout & Package

CD74HCT4511EG4 is supplied in a 16-pin plastic dual in-line package (PDIP-N), body size 19.31 mm × 6.35 mm, with 2.54 mm lead pitch and through-hole mounting.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD74HC4511E and SN74LS47N, the CD74HCT4511EG4 uniquely combines TTL-compatible inputs, integrated latching, lamp-test, and blanking in a single PDIP package - making it optimal for new 5 V designs requiring robust display control without external support circuitry.

Availability

CD74HCT4511EG4 is available at Aetrix Electronics and suitable for industrial panel meters, test equipment displays, and automotive dashboard indicators requiring stable component supply and long-term obsolescence management.

Supply support for CD74HCT4511EG4 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 delivering analog and embedded processing solutions, with over 90 years of innovation in precision logic, power management, and signal chain technologies.

The CD74HCT4511EG4 belongs to TI's legacy HCT logic family, engineered specifically for seamless migration from bipolar TTL systems to CMOS-based display interfaces while preserving pinout and electrical behavior.

FAQ

What is the recommended bypass capacitor for CD74HCT4511EG4?

A 0.1 µF ceramic capacitor is recommended between VCC (pin 16) and GND (pin 8), placed as close as possible to the device. This minimizes high-frequency noise coupling into the CD74HCT4511EG4 supply rail, ensuring stable segment output voltages and preventing false triggering of the lamp-test or blanking functions during rapid display updates.

Does CD74HCT4511EG4 support common-cathode LED displays?

No, CD74HCT4511EG4 features active-high segment outputs (a–g) designed exclusively for common-anode LED configurations. Driving common-cathode displays would require external inverters or NPN transistor buffers, which compromise timing accuracy and increase component count - the CD74HCT4511EG4 is not rated for sink-current operation.

How does the ripple-blank output (RBO) function in CD74HCT4511EG4?

The RBO pin (pin 2) acts as an open-drain output that goes low when the CD74HCT4511EG4 decodes an invalid BCD code (10–15) or when BL is asserted. In multi-digit displays, RBO connects to BI of the next most-significant digit, automatically blanking leading zeros - this eliminates firmware overhead for zero-suppression in applications like digital voltmeters using CD74HCT4511EG4.

Can CD74HCT4511EG4 operate at 3.3 V?

No, CD74HCT4511EG4 is specified only for 4.5–5.5 V operation per its Recommended Operating Conditions. At 3.3 V, input thresholds (VIH ≥ 2.0 V) may still be met, but output drive capability degrades significantly below 4.5 V, and VOH/VOL parameters are not guaranteed - use CD74HC4511E instead for true 3.3 V compatibility.

What happens to segment outputs when LE is low on CD74HCT4511EG4?

When LE (pin 3) is low, the CD74HCT4511EG4 enters transparent mode: segment outputs (a–g) respond immediately to changes on D0–D3 inputs with propagation delay (~60 ns). This allows real-time display updates without latching, useful for non-multiplexed or continuously refreshed single-digit applications where data stability is managed externally.