74ACT299TTR

Overview

The STMicroelectronics 74ACT299TTR is an advanced high-speed CMOS 8-bit parallel-in/parallel-out shift register with three-state outputs, fabricated using sub-micron silicon gate and double-layer metal wiring C2MOS technology. It operates within a supply voltage range of 4.5V to 5.5V. The device features low power dissipation with a maximum quiescent current of 8μA at 25°C. It supports a typical maximum clock frequency of 240MHz at 5V and provides symmetrical output impedance with a minimum drive capability of 24mA for both high and low states. The component includes balanced propagation delays and improved latch-up immunity.

Feature Summary

• Supports four operational modes: Hold, Shift Left, Shift Right, and Load Data via function select inputs.
• Features asynchronous clear function that resets the register independently of the clock signal.
• Includes protection circuits against static discharge providing 2kV ESD immunity on all inputs and outputs.
• Capable of driving 50Ω transmission lines with symmetrical output impedance.

Applications

• High-speed data storage and transfer in digital systems
• Interface between High-Speed CMOS systems and TTL, NMOS, or CMOS logic levels
• Bus driver applications requiring three-state control
• Sequential logic circuits requiring parallel input/output conversion

Procurement Notes

Verify the ordering code suffix matches the required package type. The TTR suffix indicates a TSSOP-20 package supplied in tape and reel format. Confirm that the specific variant aligns with the intended manufacturing process and environmental specifications. Ensure compatibility with existing board layouts regarding pin configuration and mechanical dimensions before finalizing procurement decisions.

Selection Notes

Select this component when designing systems requiring fast 8-bit serial-to-parallel or parallel-to-serial conversion with high noise immunity. The 74ACT series ensures compatibility with standard TTL voltage levels while offering CMOS speed advantages. Consider the TSSOP package size for space-constrained designs. Verify that the operating temperature range meets the application's thermal requirements and that the 3-state outputs are properly managed to prevent bus contention.

Part Context

The 74ACT299 belongs to the 74ACT family of advanced high-speed CMOS logic devices manufactured by STMicroelectronics. This family is designed to bridge the performance gap between older TTL logic and standard CMOS technologies. The 74ACT299 specifically serves as an 8-bit shift register, distinct from simpler gate or inverter functions within the same product line. Its design emphasizes speed and low power consumption suitable for complex digital signal processing tasks.

Replacement Considerations

The 74ACT299B (DIP) and 74ACT299M (SOP) are functionally equivalent parts within the same family but differ in packaging. Direct replacement requires verifying that the alternative package fits the PCB footprint and assembly process. No other part numbers are confirmed as direct substitutes in the provided documentation.