M74HCT652B1R

Overview

The M74HCT652B1R is an obsolete octal bus transceiver and register with 3-state outputs manufactured by STMicroelectronics. It operates within a supply voltage range of 4.5V to 5.5V and supports a maximum clock frequency of 55 MHz at 4.5V. The device features symmetrical output impedance with a minimum drive capability of 6mA for both high and low states. Propagation delays from bus to bus range from 20ns to 38ns depending on load capacitance, while clock-to-bus delays reach up to 55ns. Quiescent supply current is limited to 4µA maximum.

Feature Summary

• Combines octal bus transceiver circuits with internal D-type flip-flops for multiplexed data transmission
• Provides independent control pins to select between real-time bus data or stored register data
• Features edge-triggered clock inputs that capture data regardless of active select or enable states
• Includes protection circuits against static discharge and transient excess voltage on all inputs

Applications

• Multiplexed data transmission systems requiring bidirectional transfer
• Memory selection and address decoding applications
• Buffering interfaces between different logic families
• Data storage and retrieval in digital processing circuits

Procurement Notes

Verify component authenticity through authorized channels as this part is officially listed as obsolete. Confirm package integrity and pin alignment against the DIP-24 mechanical specifications provided in the datasheet. Ensure replacement strategies account for the discontinued status when designing new hardware.

Selection Notes

Select this component only if legacy compatibility with the 74 series 652 function is required. Evaluate the 4.5V to 5.5V operating voltage constraints against system power rails. Consider the 55 MHz maximum frequency limit for timing requirements and verify that the DIP-24 package fits the target board layout.

Part Context

This device belongs to the 74HCT logic family, utilizing advanced high-speed CMOS technology. It serves as a registered bus transceiver designed for interfacing microprocessors with memory or peripheral devices. The specific B1R suffix indicates the DIP-24 tube packaging format used for through-hole mounting.

Replacement Considerations

Direct substitutes include the CD74HCT652E from Texas Instruments. Verify functional equivalence regarding pinout and electrical characteristics before implementation.