SN74LS109AD Equivalent & Substitute Parts

Part Overview

The SN74LS109AD is a dual 1-bit JK-type flip-flop logic integrated circuit manufactured by Texas Instruments in 16-SOIC surface mount packaging. This component functions as a Set(Preset) and Reset element with complementary outputs, operating at a maximum clock frequency of 33 MHz. The SN74LS109AD is currently in Last Time Buy status, indicating discontinued production. Identifying equivalent substitute parts is necessary to ensure design continuity and maintain supply chain reliability for applications requiring this specific logic function.

Substiute Parts

SN74LS109AD

Texas InstrumentsIn Stock: 1658SN74LS109AD Datasheet

Current PartRFQ

SN74LS109ADR

Texas InstrumentsIn Stock: 3365SN74LS109ADR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SN74LS109AD is determined by strict equivalence across the following critical parameters:

Functional Parameters: Type (JK Type), Number of Elements (2), Number of Bits per Element (1), Output Type (Complementary), Trigger Type (Positive Edge), and Function (Set/Preset and Reset).

Electrical Parameters: Clock Frequency (33 MHz), Max Propagation Delay (40ns @ 5V, 15pF), Voltage Supply Range (4.75V ~ 5.25V), Current Output specifications (400µA High, 8mA Low), Quiescent Current (8 mA), and Operating Temperature Range (0°C ~ 70°C).

Physical Parameters: Package / Case (16-SOIC with 0.154" / 3.90mm Width) and Mounting Type (Surface Mount).

Compliance Parameters: RoHS3 Compliance, MSL Level 1, and REACH Unaffected status.

The SN74LS109ADR qualifies as a direct substitute based on identical functional, electrical, physical, and compliance specifications. The primary distinction is packaging format: the main part uses Tube packaging while the substitute uses Tape & Reel (TR) packaging. Both are 16-SOIC surface mount devices with identical electrical performance and environmental compliance.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS109ADR is a direct functional and electrical equivalent to the SN74LS109AD. Both parts maintain identical specifications across all critical parameters: logic function, electrical performance, timing characteristics, supply voltage range, output current capabilities, and operating temperature range.

The SN74LS109AD is designated Last Time Buy, indicating end-of-life status. The SN74LS109ADR maintains Active product status with higher inventory availability (3340 Pcs vs. 1552 Pcs), ensuring long-term supply chain continuity.

Both parts are ROHS3 Compliant, REACH Unaffected, and carry MSL Level 1 (Unlimited) moisture sensitivity rating, meeting equivalent environmental and regulatory requirements.

The only distinction between these parts is packaging format: Tube versus Tape & Reel (TR). This difference affects handling, storage, and automated assembly processes but does not impact electrical performance or functional compatibility. Selection between these formats depends on manufacturing process requirements and inventory management practices.

Frequently Asked Questions (FAQ)

Q: Can the SN74LS109ADR replace the SN74LS109AD in existing designs?

A: Yes. The SN74LS109ADR is electrically and functionally identical to the SN74LS109AD. All logic function, timing, voltage, current, and temperature specifications are equivalent. The parts are pin-compatible and interchangeable at the circuit level.

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

A: Tube packaging contains loose components in a plastic tube, suitable for manual handling and small-quantity applications. Tape & Reel (TR) packaging places components on a continuous carrier tape wound on a reel, designed for automated pick-and-place assembly equipment. Both formats contain identical components with no electrical differences.

Q: Why is the SN74LS109AD marked as Last Time Buy?

A: Last Time Buy status indicates the manufacturer has discontinued production of this part number. Existing inventory is available for final orders, but no future production is planned. The SN74LS109ADR, with Active status, represents the current production equivalent.

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

A: No. Both the SN74LS109AD and SN74LS109ADR carry identical RoHS3 Compliance, REACH Unaffected status, and MSL Level 1 (Unlimited) ratings. They meet the same environmental and regulatory requirements.

Q: What are the key parameters that determine substitution eligibility?

A: Substitution is based on equivalence across functional parameters (JK Type, 2 Elements, 1 Bit per Element, Complementary Output, Positive Edge Trigger), electrical parameters (33 MHz clock frequency, 40ns propagation delay, 4.75V–5.25V supply, specified output and quiescent currents, 0°C–70°C operating range), physical parameters (16-SOIC package, surface mount), and compliance certifications (RoHS3, REACH, MSL Level 1).

Q: Can the SN74LS109ADR be used in high-volume automated assembly?

A: Yes. The Tape & Reel (TR) packaging format of the SN74LS109ADR is specifically designed for automated pick-and-place assembly equipment, making it suitable for high-volume manufacturing processes.