PM1608-331M Equivalent & Substitute Parts Reference

Part Overview

The PM1608-331M is a 330 µH unshielded drum core wirewound inductor manufactured by Bourns Inc., rated for 160 mA with a maximum DC resistance of 3.8Ohm. This component is classified as obsolete, which necessitates identification of active equivalent alternatives for ongoing design support and procurement continuity. The part is mounted as a surface mount device in a nonstandard package measuring 6.60mm × 4.45mm with a seated height of 2.92mm.

Substiute Parts

PM1608-331M

Bourns Inc.In Stock: 1089PM1608-331M Datasheet

Current PartRFQ

SDR6603-331M

Bourns Inc.In Stock: 1202SDR6603-331M Datasheet

DirectRFQ

SDR0703-331KL

Bourns Inc.In Stock: 1301SDR0703-331KL Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the PM1608-331M is determined by the following critical parameters:

Primary Matching Criteria:

• Inductance value: 330 µH (exact match required)
• Current rating: 160 mA minimum
• DC resistance: 3.8Ohm maximum (direct substitutes) or within acceptable tolerance for similar designs
• Core type: Ferrite, unshielded drum core wirewound
• Mounting: Surface mount, nonstandard package
• Physical dimensions: Compatible footprint (6.60mm × 4.45mm base dimensions)

Substitute Classification:

Direct Substitute (Electrical & Mechanical Equivalence):

• SDR6603-331M: Matches all primary criteria with identical inductance, current rating, and DC resistance specifications. Active product status with improved compliance profile.

Similar Substitute (Minor Parameter Variance):

• SDR0703-331KL: Matches inductance and current rating. DC resistance increased to 4.8Ohm maximum (1Ohm variance). Tighter inductance tolerance (±10% vs ±20%). Slightly different physical dimensions (6.50mm × 4.50mm, height 2.70mm vs 2.92mm). Active product status with improved compliance.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Preferred): SDR6603-331M is the primary substitute for PM1608-331M. This part maintains electrical equivalence across all critical parameters (inductance, current rating, DC resistance) while offering active product status and ROHS3 compliance. The extended operating temperature range (-40°C ~ 125°C vs -40°C ~ 85°C) provides additional thermal margin. Tape & Reel packaging enables standard procurement workflows.

For Applications with Relaxed DC Resistance Tolerance: SDR0703-331KL serves as an alternative where the 1Ohm increase in maximum DC resistance (4.8Ohm vs 3.8Ohm) is acceptable. This part offers tighter inductance tolerance (±10%) and higher saturation current (190 mA vs 180 mA). Marginal dimensional variance (6.50mm × 4.50mm footprint, 2.70mm height) requires PCB layout verification for mechanical clearance.

Both substitute parts provide ROHS3 compliance and active product status, eliminating obsolescence risk associated with the original PM1608-331M.

Frequently Asked Questions (FAQ)

Q: Can SDR6603-331M be used as a direct drop-in replacement for PM1608-331M? A: Yes. SDR6603-331M matches all electrical specifications (330 µH inductance, 160 mA current rating, 3.8Ohm maximum DC resistance) and maintains identical physical dimensions (6.60mm × 4.45mm, 2.92mm height). The part is electrically and mechanically equivalent.

Q: What is the difference between the two substitute parts? A: SDR6603-331M is a direct electrical equivalent. SDR0703-331KL introduces two parameter variations: DC resistance increases to 4.8Ohm maximum, and inductance tolerance tightens to ±10%. Physical dimensions differ slightly (6.50mm × 4.50mm footprint, 2.70mm height). Selection depends on circuit requirements for DC resistance and tolerance specifications.

Q: Are there compliance or regulatory differences between the main part and substitutes? A: Yes. PM1608-331M is RoHS non-compliant and obsolete. Both SDR6603-331M and SDR0703-331KL are ROHS3 compliant and active products. If RoHS compliance is required for your application, either substitute part is suitable.

Q: Does the extended operating temperature range of the substitutes affect compatibility? A: No. Both substitutes operate from -40°C ~ 125°C, which encompasses the original part's -40°C ~ 85°C range. The extended upper temperature limit provides additional design margin without introducing incompatibility.

Q: What packaging format do the substitute parts use? A: Both SDR6603-331M and SDR0703-331KL are supplied in Tape & Reel (TR) format, enabling automated assembly workflows. The original PM1608-331M used nonstandard packaging.

Q: If I select SDR0703-331KL, what design considerations apply to the higher DC resistance? A: The 1Ohm increase in maximum DC resistance (from 3.8Ohm to 4.8Ohm) results in proportionally higher power dissipation at rated current. At 160 mA, the additional dissipation is approximately 0.256 mW. Verify that thermal design and current budget accommodate this variance. Mechanical clearance must also be confirmed due to dimensional differences.