CD74HC221PWT Equivalent & Substitute Parts

Part Overview

The CD74HC221PWT is a monostable multivibrator logic integrated circuit manufactured by Texas Instruments. This device features dual independent circuits with Schmitt trigger inputs, designed for timing and pulse generation applications. The part is discontinued at DiGi Electronics, making equivalent substitute parts necessary for ongoing production and maintenance applications. The CD74HC221PWT operates across a wide supply voltage range of 2V to 6V with a propagation delay of 18 nanoseconds, suitable for general-purpose logic timing circuits.

Substiute Parts

CD74HC221PWT

Texas InstrumentsIn Stock: 1850CD74HC221PWT Datasheet

Current PartRFQ

CD74HC221PWR

Texas InstrumentsIn Stock: 5176CD74HC221PWR Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the CD74HC221PWT is determined by strict equivalence across the following critical parameters:

• Logic type and circuit configuration (monostable multivibrator with 2 independent circuits)
• Propagation delay specification (18 ns)
• Supply voltage range (2V to 6V)
• Output current capability (5.2mA high and low)
• Operating temperature range (-55°C to 125°C)
• Package and pinout compatibility (16-TSSOP)
• Schmitt trigger input functionality
• Compliance certifications (RoHS3, REACH Unaffected)

The CD74HC221PWR qualifies as a direct substitute based on identical electrical specifications and package configuration. The primary distinction between these parts is packaging format: the CD74HC221PWT is supplied in Tape & Reel format, while the CD74HC221PWR is available in Cut Tape and Digi-Reel formats.

Parameter Comparison

Engineering Selection Recommendations

The CD74HC221PWR is the direct equivalent substitute for the CD74HC221PWT. Both parts share identical electrical characteristics, functional specifications, and package geometry. The CD74HC221PWR maintains active product status with Texas Instruments, ensuring continued availability and supply chain reliability. Both parts meet ROHS3 compliance and REACH unaffected status, satisfying regulatory requirements for industrial and commercial applications.

Selection between these parts depends on packaging requirements. The CD74HC221PWR is available in Cut Tape and Digi-Reel formats, providing flexibility for both manual assembly and automated pick-and-place operations. The CD74HC221PWT's Tape & Reel format is no longer actively distributed through DiGi Electronics, making the CD74HC221PWR the recommended choice for new designs and production continuity.

Frequently Asked Questions (FAQ)

Q: Can the CD74HC221PWR directly replace the CD74HC221PWT in existing designs?

A: Yes. Both parts are electrically and mechanically identical. The 16-TSSOP package pinout, electrical specifications, and functional behavior are equivalent. Substitution requires no circuit modifications.

Q: What is the difference between Tape & Reel and Cut Tape packaging?

A: Tape & Reel packaging supplies components on continuous carrier tape wound on reels, optimized for high-volume automated assembly. Cut Tape provides individual tape segments, suitable for lower-volume production and manual assembly. Digi-Reel is a proprietary format combining benefits of both formats. All three formats contain identical components with the same electrical and mechanical specifications.

Q: Are there any compliance or certification differences between these parts?

A: No. Both the CD74HC221PWT and CD74HC221PWR carry identical RoHS3 compliance and REACH unaffected status. Moisture sensitivity level is 1 (Unlimited) for both parts, indicating no special storage or handling requirements.

Q: What is the significance of the 18 nanosecond propagation delay specification?

A: The 18 ns propagation delay defines the maximum time required for the output to respond to an input change. This specification is critical for timing-sensitive applications and determines the maximum frequency at which the monostable multivibrator can operate reliably. Both substitute parts maintain this specification.

Q: Can these parts operate at different supply voltages?

A: Yes. Both the CD74HC221PWT and CD74HC221PWR operate across the 2V to 6V supply voltage range. This wide range accommodates both legacy 5V logic systems and modern 3.3V applications without modification.

Q: What does Schmitt trigger input mean for this device?

A: Schmitt trigger inputs provide hysteresis, improving noise immunity by requiring different voltage thresholds for rising and falling edges. This feature enhances reliability in noisy environments and is present in both substitute parts.