74HC221DB,112 Equivalent & Substitute Parts

Part Overview

The 74HC221DB,112 is a monostable multivibrator logic IC manufactured by NXP USA Inc. in a 16-SSOP surface mount package. This component features dual independent circuits with Schmitt trigger inputs, operating across a 2V to 6V supply range with a propagation delay of 19 ns. The part is classified as obsolete, making equivalent substitutes necessary for ongoing design support and procurement.

Substiute Parts

74HC221DB,112

NXP USA Inc.In Stock: 73074HC221DB,112 Datasheet

Current PartRFQ

CD74HC221PW

Texas InstrumentsIn Stock: 1648CD74HC221PW Datasheet

MFR RecommendedRFQ

CD74HC221PWR

Texas InstrumentsIn Stock: 5176CD74HC221PWR Datasheet

MFR RecommendedRFQ

CD74HC221PWT

Texas InstrumentsIn Stock: 1850CD74HC221PWT Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 74HC221DB,112 is based on the following critical parameters that must remain compatible:

• Base Product Number: All substitutes must be 74HC221 series devices
• Logic Type: Monostable multivibrator with dual independent circuits
• Schmitt Trigger Input: Required functionality
• Supply Voltage Range: 2 V ~ 6 V compatibility
• Output Current Capability: 5.2 mA minimum for both high and low states
• Mounting Type: Surface mount only
• RoHS Compliance: ROHS3 Compliant

The Texas Instruments CD74HC221 series parts meet these substitution criteria. While package geometry differs (16-TSSOP vs. 16-SSOP), both are 16-pin surface mount packages with compatible pinouts for the 74HC221 function. The propagation delay specification of 18 ns for Texas Instruments parts is superior to the original 19 ns specification, maintaining functional compatibility. Operating temperature range extends to -55°C on substitute parts, providing enhanced environmental coverage.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: CD74HC221PWR (Texas Instruments) is the recommended substitute. This part maintains active product status, ensuring long-term availability and supply chain stability. It is supplied in Cut Tape and Digi-Reel packaging formats, supporting both prototype and production volume requirements.

Alternative Substitutes: CD74HC221PW and CD74HC221PWT are functionally equivalent alternatives, though both are discontinued at DiGi Electronics. These parts are suitable for applications where existing inventory is available or where specific packaging formats (Tube or Tape & Reel) are required.

Compliance Considerations: All substitute parts maintain ROHS3 compliance and unlimited moisture sensitivity rating, matching the original part's environmental certifications. The extended operating temperature range (-55°C to 125°C) on Texas Instruments parts provides additional environmental margin compared to the original specification (-40°C to 125°C).

Package Transition: The shift from 16-SSOP to 16-TSSOP packaging requires PCB layout verification. Both packages maintain 16-pin configurations with compatible pinouts for the 74HC221 function. The 16-TSSOP package is narrower (4.40mm vs. 5.30mm width), which may require footprint adjustment on existing designs.

Frequently Asked Questions (FAQ)

Q: Can CD74HC221PWR be used as a direct replacement for 74HC221DB,112?

A: Yes. Both parts are 74HC221 monostable multivibrators with identical logic functionality, dual independent circuits, Schmitt trigger inputs, and matching electrical specifications (2V-6V supply, 5.2mA output current). The primary difference is package geometry (16-TSSOP vs. 16-SSOP), which requires PCB footprint verification but does not affect electrical compatibility.

Q: What is the difference between CD74HC221PW, CD74HC221PWR, and CD74HC221PWT?

A: These three parts are electrically identical 74HC221 monostable multivibrators from Texas Instruments. The differences are packaging formats only: CD74HC221PW is supplied in Tube packaging, CD74HC221PWR in Cut Tape and Digi-Reel format, and CD74HC221PWT in Tape & Reel format. Selection depends on procurement volume and handling requirements.

Q: Why is the propagation delay specification different (19 ns vs. 18 ns)?

A: The Texas Instruments CD74HC221 series specifies 18 ns propagation delay, which is superior to the NXP 74HC221DB,112 specification of 19 ns. This represents improved performance and maintains full backward compatibility with designs based on the original 19 ns specification.

Q: Are there any temperature range considerations when substituting?

A: The substitute parts operate across -55°C to 125°C, compared to the original -40°C to 125°C range. This extended lower temperature limit provides additional environmental margin and is fully compatible with applications designed for the original temperature range.

Q: What is the impact of changing from 16-SSOP to 16-TSSOP packaging?

A: Both packages are 16-pin surface mount configurations with compatible pinouts for the 74HC221 function. The 16-TSSOP package is narrower (4.40mm vs. 5.30mm width). PCB layout and footprint must be updated to accommodate the new package dimensions, but no electrical redesign is required.

Q: Which substitute part should be selected for new designs?

A: CD74HC221PWR is recommended for new designs due to its active product status, ensuring long-term availability and supply chain continuity. This part is available in standard Cut Tape and Digi-Reel packaging suitable for both prototype development and production manufacturing.