DR74-681-R Equivalent & Substitute Parts

Part Overview

The DR74-681-R is a 680 µH shielded drum core wirewound inductor manufactured by Eaton - Electronics Division. This surface mount component is rated for 330 mA continuous current with a DC resistance of 2.58 Ohm and operates across the temperature range of -40°C to 125°C. The part maintains active product status with 1755 units currently in stock.

Substitute parts become necessary when the primary component experiences supply constraints, extended lead times, or when design requirements permit operation within alternative electrical and mechanical specifications. The DR74-681-R has been identified with one qualified equivalent: the SLF7045T-681MR20-PF from TDK Corporation.

Substiute Parts

DR74-681-R

Eaton - Electronics DivisionIn Stock: 1862DR74-681-R Datasheet

Current PartRFQ

SLF7045T-681MR20-PF

TDK CorporationIn Stock: 35460SLF7045T-681MR20-PF Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the DR74-681-R is determined by strict alignment of the following electrical and mechanical parameters:

Primary Substitution Criteria:

• Inductance value: 680 µH (fixed requirement)
• Inductance tolerance: ±20% (fixed requirement)
• Core type: Drum core, wirewound, ferrite shielded (fixed requirement)
• Mounting type: Surface mount (fixed requirement)
• Package format: Tape & Reel (TR) (fixed requirement)

Secondary Compatibility Parameters:

• Current rating: Must support minimum 330 mA continuous operation
• DC resistance: Lower values preferred to reduce power dissipation
• Saturation current: Must exceed 330 mA minimum operating current
• Operating temperature: Must encompass or exceed -40°C to 125°C range
• RoHS3 compliance: Required for regulatory alignment

The SLF7045T-681MR20-PF qualifies as a substitute based on matching inductance, tolerance, core type, shielding, and mounting specifications. Differences in current rating, DC resistance, and maximum operating temperature represent trade-offs that must be evaluated against specific circuit requirements.

Parameter Comparison

Engineering Selection Recommendations

Primary Selection: DR74-681-R (Eaton)

The DR74-681-R is the recommended component for new designs. It maintains active product status, ensuring long-term availability and supply chain stability. The part provides superior current handling capacity (330 mA vs. 270 mA) and higher saturation current margin (380 mA vs. 200 mA), delivering greater operational headroom in circuits approaching maximum current limits. The extended maximum operating temperature of 125°C accommodates thermal environments that the TDK substitute cannot support.

Substitute Selection: SLF7045T-681MR20-PF (TDK)

The SLF7045T-681MR20-PF qualifies as a substitute only when the DR74-681-R experiences supply unavailability. This part carries "Not For New Designs" status, indicating TDK has discontinued active development and support. Substitution is permissible only when all of the following conditions are met:

1. Circuit maximum operating current does not exceed 270 mA continuous
2. Circuit maximum saturation current does not exceed 200 mA
3. Maximum ambient operating temperature does not exceed 105°C
4. PCB layout accommodates the 0.6mm smaller footprint (7.00mm vs. 7.60mm)
5. PCB layout accommodates the 0.45mm greater height (4.80mm vs. 4.35mm)

The TDK substitute offers lower DC resistance (1.776 Ohm vs. 2.58 Ohm), reducing power dissipation by approximately 31% at rated current. This advantage applies only when current remains below 270 mA.

Frequently Asked Questions (FAQ)

Q: Can the SLF7045T-681MR20-PF replace the DR74-681-R in all applications?

A: No. The TDK substitute has lower current and saturation ratings. Substitution is valid only when circuit design operates below 270 mA continuous current and below 200 mA saturation current. Additionally, the maximum operating temperature is limited to 105°C with the TDK part.

Q: What is the impact of the 60 mA current rating difference?

A: The DR74-681-R supports 330 mA continuous current while the SLF7045T-681MR20-PF supports 270 mA. If your circuit requires more than 270 mA, the TDK substitute will not function reliably and may experience thermal stress or core saturation.

Q: How does the saturation current difference affect circuit performance?

A: The DR74-681-R saturates at 380 mA while the SLF7045T-681MR20-PF saturates at 200 mA. Saturation current represents the threshold beyond which inductance collapses. The Eaton part provides 180 mA additional margin before saturation occurs, offering greater protection against transient current spikes.

Q: Are there physical compatibility concerns between these parts?

A: Yes. The SLF7045T-681MR20-PF has a smaller footprint (7.00mm vs. 7.60mm) but greater height (4.80mm vs. 4.35mm). PCB layout must be verified to confirm the component fits within available space constraints, particularly in height-restricted applications.

Q: Why is the TDK part marked "Not For New Designs"?

A: This designation indicates TDK has discontinued active product development and support for the SLF7045T-681MR20-PF. New designs should use the DR74-681-R to ensure long-term component availability and manufacturer support.

Q: Does the lower DC resistance of the TDK part provide a performance advantage?

A: The SLF7045T-681MR20-PF exhibits lower DC resistance (1.776 Ohm vs. 2.58 Ohm), reducing power dissipation by approximately 31% at rated current. This advantage applies only when operating current remains below 270 mA. At higher currents, the Eaton part's superior current rating becomes the limiting factor.

Q: Are both parts RoHS3 compliant?

A: Yes. Both the DR74-681-R and SLF7045T-681MR20-PF are RoHS3 compliant and carry MSL Level 1 (Unlimited) moisture sensitivity ratings, indicating equivalent environmental and regulatory compliance.

Q: What is the inductance tolerance for both parts?

A: Both parts maintain ±20% inductance tolerance at 100 kHz test frequency. This tolerance is identical and does not differentiate substitution eligibility.