CD74HCT4514E

Overview

The CD74HCT4514E is a high-speed silicon-gate CMOS device featuring a 4-bit strobed latch and a 4-line to 16-line decoder. It operates on a single 4.5-V to 5.5-V supply voltage. The component provides direct LSTTL input logic compatibility with a maximum low-level input voltage of 0.8 V and a minimum high-level input voltage of 2 V. It supports a wide operating temperature range from -55°C to +125°C and utilizes a 24-pin PDIP package.

Feature Summary

• Integrates a 4-bit strobed latch that isolates inputs when the latch enable signal is low, maintaining previous output states.
• Provides direct compatibility with LSTTL logic levels for simplified interfacing in mixed-logic systems.
• Supports demultiplexing functionality by utilizing the enable input as a data line and select inputs as addresses.

Applications

• Address decoding in memory systems
• Demultiplexing data streams using address lines
• Cascaded chip selection control

Procurement Notes

Verify the specific ordering suffix 'E' corresponds to the PDIP tube packaging configuration. Confirm the device variant matches the required polarity (active-high outputs for the 4514). Ensure the application environment remains within the specified 4.5-V to 5.5-V supply voltage limits and the -55°C to +125°C temperature range for reliable operation.

Selection Notes

Select this component when LSTTL-compatible inputs are required alongside latch functionality. The HCT series ensures CMOS power efficiency while maintaining standard TTL noise margins. Verify that the 24-pin through-hole package fits the target PCB layout constraints and that the 16-output capacity meets the system addressing requirements.

Part Context

This part belongs to the Texas Instruments CD74HCT451x family of decoders and demultiplexers. It shares architectural similarities with the CD74HC4514 but differs in input threshold specifications to accommodate LSTTL interfaces. The device is functionally related to the CD74HCT4515, which features inverted outputs compared to the non-inverted outputs of the CD74HCT4514.

Replacement Considerations

CD74HCT4515E: Offers identical pinout and latch functionality but provides inverted (active-low) outputs instead of active-high outputs.

FAQ

How does the latch enable (LE) input affect the decoder outputs?

When LE is high, the outputs follow changes at the A0–A3 inputs. When LE is low, the outputs are isolated from input changes and retain their last state.

What is the role of the enable (E) input during demultiplexing?

In demultiplexing mode, the E input serves as the data input, while the A0–A3 pins act as the address selectors to route the data to the appropriate output.