SRDA3.3-4.TBT Equivalent & Substitute Parts

Part Overview

The SRDA3.3-4.TBT is a transient voltage suppressor (TVS) diode manufactured by Semtech Corporation, designed for rail-to-rail steering applications with 4 unidirectional channels in an 8-SO surface mount package. This component provides transient voltage protection with a 3.3V reverse standoff voltage and 15V maximum clamping voltage at peak pulse current.

The SRDA3.3-4.TBT carries a "Not For New Designs" product status, making identification of equivalent and substitute parts essential for ongoing production support and design continuity. Substitute parts must maintain compatibility across reverse standoff voltage, breakdown voltage, clamping characteristics, peak pulse current ratings, and package form factor to ensure functional equivalence in protection circuits.

Substiute Parts

SRDA3.3-4.TBT

Semtech CorporationIn Stock: 16983SRDA3.3-4.TBT Datasheet

Current PartRFQ

SRDA3.3-4BTG

Littelfuse Inc.In Stock: 3496SRDA3.3-4BTG Datasheet

DirectRFQ

CDNBS08-SRDA3.3-4

Bourns Inc.In Stock: 47660CDNBS08-SRDA3.3-4 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SRDA3.3-4.TBT are qualified based on the following electrical and mechanical parameters:

Electrical Compatibility Criteria:

• Reverse standoff voltage: 3.3V maximum
• Breakdown voltage minimum: 4.6V or higher
• Unidirectional channel count: 4 channels
• Package type: 8-SOIC surface mount form factor
• Power line protection capability: Yes
• RoHS3 compliance and MSL Level 1 rating

Functional Equivalence Parameters: Substitute parts must support the same rail-to-rail steering topology and general-purpose transient protection applications. Variations in clamping voltage, peak pulse current, and operating temperature range are permitted provided the substitute meets or exceeds the minimum electrical protection requirements of the original design.

The SRDA3.3-4BTG (Littelfuse Inc.) and CDNBS08-SRDA3.3-4 (Bourns Inc.) both satisfy these substitution criteria with identical reverse standoff and breakdown voltage specifications, matching package geometry, and equivalent power line protection functionality.

Parameter Comparison

Engineering Selection Recommendations

SRDA3.3-4BTG (Littelfuse Inc.) is suitable for applications requiring active product support and extended operating temperature range to 125°C. This substitute maintains identical voltage protection thresholds while providing increased peak pulse current capacity (30A vs. 25A) and higher peak pulse power (600W vs. 500W). Littelfuse classification as an active product ensures ongoing availability and technical support.

CDNBS08-SRDA3.3-4 (Bourns Inc.) is the manufacturer-recommended substitute, offering the lowest clamping voltage (10.9V) and highest peak pulse current rating (43A) among available options. This part supports the widest operating temperature range (-55°C to 150°C) and is optimized for Ethernet applications. Bourns active product status provides long-term supply continuity and compliance documentation.

Both substitutes maintain full RoHS3 compliance, MSL Level 1 moisture sensitivity rating, and identical 8-SOIC package geometry, ensuring direct PCB compatibility without layout modifications. Selection between these options depends on application-specific requirements for operating temperature range, clamping voltage tolerance, and peak current handling capacity.

Frequently Asked Questions (FAQ)

Q: Can SRDA3.3-4BTG directly replace SRDA3.3-4.TBT on existing PCBs?

A: Yes. Both parts use identical 8-SOIC package geometry (0.154" width, 3.90mm) with matching pin assignments for 4-channel unidirectional steering configuration. No PCB layout modifications are required.

Q: What is the significance of the higher clamping voltage in SRDA3.3-4BTG (17.7V vs. 15V)?

A: The clamping voltage represents the maximum voltage across the diode during transient suppression. SRDA3.3-4BTG's 17.7V clamping voltage is within acceptable limits for 3.3V rail protection circuits and indicates slightly different internal clamping characteristics. Both parts maintain the same 3.3V reverse standoff voltage threshold.

Q: Why does CDNBS08-SRDA3.3-4 have a lower clamping voltage (10.9V)?

A: Lower clamping voltage indicates more aggressive transient suppression with faster voltage limiting. This characteristic is beneficial for sensitive circuit protection but requires verification that downstream components tolerate the lower clamping threshold.

Q: Are there packaging differences between the three parts?

A: All three parts use 8-SOIC surface mount packages with identical 0.154" (3.90mm) width specifications. SRDA3.3-4.TBT is supplied in Cut Tape (CT) & Digi-Reel format, while SRDA3.3-4BTG uses Tape & Reel (TR) packaging. CDNBS08-SRDA3.3-4 is supplied in Cut Tape (CT) & Digi-Reel format. These packaging differences do not affect electrical performance or PCB compatibility.

Q: Which substitute is recommended for new production designs?

A: CDNBS08-SRDA3.3-4 (Bourns) is the manufacturer-recommended substitute with active product status, widest operating temperature range, and highest peak current capacity. SRDA3.3-4BTG (Littelfuse) is an alternative active substitute with extended temperature support to 125°C.

Q: Do all three parts meet the same compliance standards?

A: Yes. All parts are RoHS3 compliant, carry MSL Level 1 (Unlimited) moisture sensitivity rating, and are REACH unaffected. ECCN classification is EAR99 for all three parts.