SA77CB0 Equivalent & Substitute Parts

Part Overview

The SA77CB0 is a thermal cutoff (TCO) device manufactured by Bourns Inc., designed for AC/DC applications with a functioning temperature of 77°C (171°F) and a reset temperature of 40°C (104°F). This component operates as a single-pole, single-throw, normally closed (SPST-NC) breaker with a rated current of 12 A at 28 V DC.

The SA77CB0 is classified as obsolete. Identifying suitable substitute parts is necessary to maintain design continuity and ensure component availability for new production runs or field replacements where the original part is no longer readily available through standard distribution channels.

Substiute Parts

SA77CB0

Bourns Inc.In Stock: 1050SA77CB0 Datasheet

Current PartRFQ

SA77SB0

Bourns Inc.In Stock: 39473SA77SB0 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SA77CB0 is determined by the following critical parameters that must remain constant:

• Rated functioning temperature: 77°C (171°F)
• Reset temperature: 40°C (104°F)
• Voltage rating: 28 V DC
• Configuration: SPST-NC
• Manufacturer: Bourns Inc.
• Series: SA
• Approval agencies: cUL, TUV, UL

The SA77SB0 qualifies as a direct substitute based on these core thermal and electrical characteristics. The primary difference between the main part and the substitute is the current rating and product status. The SA77SB0 maintains all critical thermal and voltage parameters while offering an increased current rating of 25 A and active product status, making it suitable for applications requiring the same thermal protection threshold.

Parameter Comparison

Engineering Selection Recommendations

The SA77SB0 is the qualified substitute for the SA77CB0 based on the following factors:

Thermal characteristics are identical between both parts, with a functioning temperature of 77°C and reset temperature of 40°C, ensuring equivalent thermal protection performance in the target application.

Electrical ratings are compatible. While the SA77SB0 provides a higher current rating of 25 A compared to the SA77CB0's 12 A rating, this represents an increase in capability that does not compromise functionality in circuits designed for the original 12 A specification.

Regulatory compliance is maintained. Both parts carry identical approval certifications from cUL, TUV, and UL, and both meet ROHS3 and REACH requirements.

Product status transition from obsolete to active ensures long-term availability and supply chain continuity for the SA77SB0.

Frequently Asked Questions (FAQ)

Q: Can the SA77SB0 be used as a direct replacement for the SA77CB0?

A: Yes. The SA77SB0 maintains identical thermal functioning and reset temperatures, voltage rating, configuration, and regulatory certifications. The increased current rating of 25 A does not prevent its use in applications originally designed for 12 A operation.

Q: What is the primary difference between SA77CB0 and SA77SB0?

A: The SA77SB0 has a higher current rating (25 A versus 12 A) and is currently in active production status, whereas the SA77CB0 is obsolete. All thermal and voltage parameters remain identical.

Q: Are there packaging differences between these parts?

A: The SA77CB0 uses nonstandard packaging, while the SA77SB0 is supplied in Tape & Reel (TR) format. Both are surface-mount devices (SMD) with four leads.

Q: Do both parts meet the same regulatory standards?

A: Yes. Both the SA77CB0 and SA77SB0 carry identical approvals from cUL, TUV, and UL, and both comply with ROHS3 and REACH requirements.

Q: What thermal protection does this component provide?

A: This thermal cutoff device operates at a functioning temperature of 77°C (171°F) and resets at 40°C (104°F), providing automatic circuit interruption when the specified temperature threshold is exceeded.