P6SMB91AT3G Equivalent & Substitute Parts

Part Overview

The P6SMB91AT3G is a unidirectional Zener transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc. in the DO-214AA (SMB) surface mount package. This component is rated for 77.8V reverse standoff voltage with a 125V maximum clamping voltage and 4.8A peak pulse current capacity. The part is currently listed as obsolete, making identification of equivalent and substitute components essential for ongoing design support and procurement.

Substiute Parts

P6SMB91AT3G

Littelfuse Inc.In Stock: 2929P6SMB91AT3G Datasheet

Current PartRFQ

P6SMB91A

Eaton - Electronics DivisionIn Stock: 30307P6SMB91A Datasheet

DirectRFQ

1KSMB91A

Taiwan Semiconductor CorporationIn Stock: 94271KSMB91A Datasheet

MFR RecommendedRFQ

P6SMB91A

Eaton - Electronics DivisionIn Stock: 30307P6SMB91A Datasheet

DirectRFQ

SMBJ70E3/TR13

Microchip TechnologyIn Stock: 823SMBJ70E3/TR13 Datasheet

MFR RecommendedRFQ

SMBJP6KE91A-TP

Micro Commercial CoIn Stock: 2484SMBJP6KE91A-TP Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the P6SMB91AT3G is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

• Reverse standoff voltage: 77.8V (±tolerance)
• Breakdown voltage minimum: 86.5V
• Clamping voltage maximum: 125V
• Unidirectional configuration (single channel)
• Surface mount package: DO-214AA or SMB equivalent
• Peak pulse current rating: minimum 4.8A

Secondary Compatibility Factors:

• Operating temperature range (minimum -55°C to 150°C required)
• RoHS compliance status
• Moisture sensitivity level (MSL 1 acceptable)

Parts are grouped into two categories based on electrical performance alignment:

Group A - Direct Electrical Equivalents (77.8V Standoff): Parts maintaining identical reverse standoff voltage and clamping specifications. These provide direct functional replacement with minimal circuit impact.

Group B - Voltage-Variant Alternatives (70V Standoff): Parts with reduced reverse standoff voltage (70V) but identical clamping voltage. These require circuit-level evaluation for voltage margin compatibility.

Parameter Comparison

Engineering Selection Recommendations

Preferred Substitutes (Group A - Direct Equivalents):

P6SMB91A (Eaton - Electronics Division) and SMBJP6KE91A-TP (Micro Commercial Co) are the primary substitutes. Both maintain the 77.8V reverse standoff voltage and 125V clamping voltage specifications identical to the P6SMB91AT3G. Both are active products with current manufacturing status and full RoHS3 compliance. P6SMB91A offers the highest inventory availability (30,200 pcs) and is suitable for telecom applications. SMBJP6KE91A-TP provides extended operating temperature range (-55°C to 175°C) and is available in tape and reel packaging.

1KSMB91A (Taiwan Semiconductor Corporation) is a secondary equivalent offering enhanced performance characteristics. This part maintains identical voltage specifications while providing 8A peak pulse current (versus 4.8A) and 1000W peak pulse power rating. The extended temperature range (-55°C to 175°C) and active product status support long-term availability. This substitute is suitable for applications requiring higher transient current handling capacity within the same voltage envelope.

Alternative Substitute (Group B - Voltage-Variant):

SMBJ70E3/TR13 (Microchip Technology) operates at 70V reverse standoff voltage with 77.8V minimum breakdown voltage. This represents a 7.8V reduction in standoff margin compared to the P6SMB91AT3G. This substitute is applicable only in circuits where the reduced voltage margin does not compromise protection requirements. The part maintains identical 125V clamping voltage and 4.8A peak pulse current. Active product status and ROHS3 compliance are confirmed. Limited inventory (766 pcs) may impact procurement timelines.

Compliance and Certification:

All substitute parts maintain ROHS3 compliance and MSL 1 moisture sensitivity rating, ensuring compatibility with standard manufacturing and storage protocols. ECCN classification (EAR99) and HTSUS code (8541.10.0080) are consistent across all alternatives.

Frequently Asked Questions (FAQ)

Q: Can P6SMB91A directly replace P6SMB91AT3G without circuit modification?

A: Yes. P6SMB91A maintains identical reverse standoff voltage (77.8V), breakdown voltage (86.5V), and clamping voltage (125V) specifications. The 0.1A increase in peak pulse current (4.9A versus 4.8A) is within normal manufacturing tolerance and does not require circuit redesign. Both parts use the DO-214AA (SMB) package with identical pinout and footprint.

Q: What is the difference between 1KSMB91A and P6SMB91A?

A: Both parts maintain identical voltage specifications (77.8V standoff, 125V clamping). The primary differences are: 1KSMB91A provides 8A peak pulse current and 1000W peak pulse power (versus 4.8A and 600W for P6SMB91A), and 1KSMB91A supports extended operating temperature to 175°C (versus 150°C). Select 1KSMB91A for applications requiring higher transient current capacity or wider temperature operation.

Q: Is SMBJ70E3/TR13 a suitable replacement?

A: SMBJ70E3/TR13 is a voltage-variant alternative with 70V reverse standoff voltage instead of 77.8V. This 7.8V reduction in standoff margin may be acceptable in circuits with adequate voltage headroom, but requires engineering evaluation. The part maintains identical 125V clamping voltage and 4.8A peak pulse current. Use this substitute only when circuit analysis confirms the reduced standoff voltage does not compromise transient protection.

Q: Are all substitutes available in the same package?

A: Yes. All substitute parts use the DO-214AA surface mount package, commonly designated as SMB or SMBJ. Footprint and pinout are identical, enabling direct PCB-level substitution without layout modification.

Q: What is the inventory status for each substitute?

A: P6SMB91A (Eaton) has the highest availability at 30,200 pcs. 1KSMB91A (TSC) has 9,400 pcs available. SMBJP6KE91A-TP (MCC) has 2,454 pcs. SMBJ70E3/TR13 (Microchip) has limited inventory at 766 pcs. Procurement timelines should account for these availability levels.

Q: Do all substitutes meet RoHS compliance requirements?

A: Yes. All substitute parts are ROHS3 compliant and carry MSL 1 (unlimited) moisture sensitivity rating, meeting standard environmental and manufacturing requirements.