SN54LS221J Equivalent & Substitute Parts

Part Overview

The SN54LS221J is a dual monostable multivibrator logic integrated circuit manufactured by Texas Instruments. This component generates precise timing pulses and is classified as an active product with full production support. The device operates across military-grade temperature ranges (-55°C to 125°C) and is housed in a 16-CDIP through-hole package. Substitute parts are identified when equivalent functional performance can be maintained within the allowed electrical and mechanical parameter tolerances for monostable multivibrator applications.

Substiute Parts

SN54LS221J

Texas InstrumentsIn Stock: 2224SN54LS221J Datasheet

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SN74LS221N

Texas InstrumentsIn Stock: 2179SN74LS221N Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN54LS221J is determined by the following critical parameters:

• Functional equivalence: Both parts must be dual monostable multivibrators with 2 independent circuits
• Logic family compatibility: Both parts operate within the LS (Low-Power Schottky) logic family
• Package compatibility: Both parts must use through-hole mounting with 16-pin DIP configuration and 0.300" (7.62mm) body width
• Electrical performance: Supply voltage ranges, output current ratings, and propagation delay must fall within acceptable tolerances for the application
• Compliance and status: Both parts must maintain active product status and equivalent RoHS/REACH certifications

The SN74LS221N qualifies as a substitute based on these parameters, with documented differences in operating temperature range and propagation delay specifications.

Parameter Comparison

Engineering Selection Recommendations

SN54LS221J is the primary selection for applications requiring military-grade temperature operation (-55°C to 125°C) with extended supply voltage tolerance (4.5 V ~ 5.5 V). This part maintains active product status and full ROHS3 compliance.

SN74LS221N serves as a substitute for commercial-grade applications operating within 0°C to 70°C temperature range and 4.75 V to 5.25 V supply voltage. The SN74LS221N offers faster propagation delay (45 ns versus 50 ns) and maintains equivalent ROHS3 compliance and active product status. Both parts are functionally equivalent dual monostable multivibrators in compatible 16-pin DIP packages.

Selection between these parts depends on the specific operating environment temperature requirements and supply voltage constraints of the target application.

Frequently Asked Questions (FAQ)

Q: Can SN74LS221N replace SN54LS221J in all applications?

A: Substitution is valid only when the application operates within the SN74LS221N temperature range (0°C ~ 70°C) and supply voltage range (4.75 V ~ 5.25 V). Applications requiring military-grade temperature operation (-55°C ~ 125°C) must use the SN54LS221J.

Q: Are the package dimensions identical between these parts?

A: Both parts use 16-pin DIP packages with 0.300" (7.62mm) body width and are compatible with standard through-hole PCB layouts. The SN54LS221J uses CDIP packaging while the SN74LS221N uses PDIP packaging; both are mechanically compatible in 16-DIP footprints.

Q: What is the significance of the propagation delay difference?

A: The SN74LS221N has a 45 ns propagation delay compared to the SN54LS221J at 50 ns. This 5 ns difference represents faster pulse generation in the substitute part and is acceptable for most timing applications where the original 50 ns specification provides design margin.

Q: Do both parts have identical output current ratings?

A: No. The SN54LS221J provides 4 mA output high current and 400 µA output low current. The SN74LS221N provides 400 µA output high current and 8 mA output low current. Application circuits must accommodate these differences in output drive capability.

Q: Are both parts RoHS compliant?

A: Yes. Both the SN54LS221J and SN74LS221N are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.