SN74LS669D Equivalent & Substitute Parts

Part Overview

The SN74LS669D is a 4-bit binary counter IC manufactured by Texas Instruments, housed in a 16-SOIC surface mount package. This device functions as a synchronous counter with both up and down counting capability, operating at a maximum count rate of 32 MHz. The part is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and component procurement.

Substiute Parts

SN74LS669D

Texas InstrumentsIn Stock: 1118SN74LS669D Datasheet

Current PartRFQ

SN74LS193D

onsemiIn Stock: 16628SN74LS193D Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The SN74LS193D qualifies as a direct substitute for the SN74LS669D based on the following matching parameters:

• Logic Type: Binary Counter (identical)
• Number of Bits per Element: 4 (identical)
• Direction: Up, Down (identical)
• Count Rate: 32 MHz (identical)
• Trigger Type: Positive Edge (identical)
• Voltage - Supply: 4.75 V ~ 5.25 V (identical)
• Operating Temperature: 0°C ~ 70°C (identical)
• Package / Case: 16-SOIC (0.154", 3.90mm Width) (identical)
• Reset: Asynchronous (identical)
• Timing: Synchronous (identical)

All critical electrical and mechanical parameters align, confirming functional equivalence for circuit-level substitution.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS193D from onsemi provides complete functional equivalence to the SN74LS669D across all specified electrical and mechanical parameters. Both devices are classified as obsolete products within the 74LS logic family.

When selecting between these alternatives, consider the following compliance factors:

• The SN74LS669D carries ROHS3 compliance certification, while the SN74LS193D is RoHS non-compliant. Applications subject to RoHS regulatory requirements should prioritize the Texas Instruments variant.
• Both parts carry identical ECCN (EAR99) and HTSUS (8542.39.0001) classifications for export and tariff purposes.
• The onsemi SN74LS193D maintains higher current inventory availability (16,552 units) compared to the Texas Instruments SN74LS669D (1,076 units), which may influence procurement lead times.

Frequently Asked Questions (FAQ)

Q: Can the SN74LS193D directly replace the SN74LS669D in existing designs?

A: Yes. The SN74LS193D is functionally equivalent across all specified parameters: 4-bit binary counter, up/down counting direction, 32 MHz count rate, positive edge triggering, identical supply voltage range (4.75 V ~ 5.25 V), operating temperature range (0°C ~ 70°C), and 16-SOIC package dimensions. No circuit modifications are required.

Q: Are there package compatibility concerns?

A: No. Both the SN74LS669D and SN74LS193D use the 16-SOIC (0.154", 3.90mm Width) surface mount package. Pin-to-pin compatibility is confirmed, allowing direct PCB footprint reuse.

Q: What is the significance of the RoHS compliance difference?

A: The SN74LS669D is ROHS3 compliant, while the SN74LS193D is RoHS non-compliant. For applications or markets requiring RoHS certification (EU, automotive, medical), the Texas Instruments part is the appropriate selection. For applications without RoHS requirements, either part is acceptable.

Q: Why are both parts classified as obsolete?

A: Both the SN74LS669D and SN74LS193D are legacy 74LS logic family devices. Obsolete status indicates these parts are no longer in active production by their respective manufacturers, though inventory remains available through authorized distributors.

Q: How do supply voltage and operating temperature ranges affect substitution?

A: Both parts operate identically across the specified ranges: 4.75 V ~ 5.25 V supply voltage and 0°C ~ 70°C operating temperature. No derating or thermal management adjustments are necessary when substituting between these devices.