78ST112SC DC DC Converter 12V Equivalent & Substitute Parts

Part Overview

The 78ST112SC is a non-isolated Point-of-Load (PoL) module DC DC converter manufactured by Texas Instruments, designed to deliver 12V output at 1.5A maximum current from a 14.5V to 30V input range. This component is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing system support, design updates, and procurement continuity. The part operates across industrial temperature ranges (-40°C to 85°C) and is suitable for ITE (Commercial) applications with integrated Over-Temperature Protection (OTP) and Short-Circuit Protection (SCP) features.

Substiute Parts

78ST112SC

Texas InstrumentsIn Stock: 83278ST112SC Datasheet

Current PartRFQ

R-78T12-1.0/FC-TRAY

Recom PowerIn Stock: 757R-78T12-1.0/FC-TRAY Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 78ST112SC are identified based on strict alignment with the following critical electrical and mechanical parameters:

Output Voltage Compatibility: The substitute must deliver 12V output to maintain circuit compatibility.

Output Current Capability: The substitute must support the required load current. The 78ST112SC provides 1.5A maximum output current; substitutes with equal or greater current capacity are acceptable.

Input Voltage Range: The substitute must accept the system input voltage range. The 78ST112SC operates from 14.5V to 30V input; substitutes must cover this range or a compatible superset.

Mounting and Package: Surface mount technology with compatible SMD module form factor ensures PCB integration without redesign.

Protection Features: Presence of Short-Circuit Protection (SCP) and Over-Temperature Protection (OTP) ensures functional safety equivalence.

Compliance and Environmental: RoHS3 compliance, MSL Level 1, and REACH unaffected status ensure regulatory and supply chain compatibility.

Product Status: Active product status ensures long-term availability and supply chain continuity.

The R-78T12-1.0/FC-TRAY from Recom Power meets these substitution criteria with compatible electrical specifications and active product status.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: The R-78T12-1.0/FC-TRAY is the manufacturer-recommended substitute for the 78ST112SC.

Current Capacity Consideration: The substitute provides 1A maximum output current compared to the original 1.5A. Selection of this substitute is appropriate only for applications where the load current requirement does not exceed 1A. Systems requiring the full 1.5A output current of the original part require alternative solutions.

Input Voltage Range: The substitute minimum input voltage is 15V, compared to the original 14.5V minimum. Systems operating below 15V input require verification that the substitute is suitable, or alternative parts must be evaluated.

Compliance Status: Both parts maintain ROHS3 compliance, MSL Level 1 rating, and REACH unaffected status, ensuring regulatory and environmental compatibility.

Product Availability: The R-78T12-1.0/FC-TRAY maintains active product status with 716 units in stock, providing supply chain continuity for the obsolete 78ST112SC.

Physical Integration: The substitute package dimensions are slightly larger (0.98" L x 0.91" W x 0.39" H versus 0.94" L x 0.90" W x 0.34" H). PCB layout and thermal management space must be verified before implementation. The substitute uses a 5-SMD module with 3 leads versus the original 3-SMD module; pinout and footprint compatibility must be confirmed through detailed datasheet review.

Efficiency Improvement: The substitute offers 95% efficiency compared to the original 90%, resulting in reduced thermal dissipation and improved power conversion performance.

Frequently Asked Questions (FAQ)

Q: Can the R-78T12-1.0/FC-TRAY directly replace the 78ST112SC without PCB modification?

A: Direct replacement without PCB modification is not guaranteed. While both parts are surface-mount non-isolated PoL modules with 12V output, the substitute uses a 5-SMD module configuration with 3 leads compared to the original 3-SMD module. Pinout, footprint, and lead spacing must be verified against detailed datasheets. Physical dimensions differ slightly, requiring confirmation that the substitute fits within available PCB space and thermal management provisions.

Q: What is the maximum load current I can support with the R-78T12-1.0/FC-TRAY substitute?

A: The R-78T12-1.0/FC-TRAY provides a maximum output current of 1A. If your application requires the full 1.5A output current of the original 78ST112SC, this substitute is not suitable. Load current requirements must not exceed 1A for this substitute to be used.

Q: Does the substitute support the same input voltage range as the original part?

A: The substitute input voltage range is 15V to 42V, compared to the original 14.5V to 30V. The substitute minimum input voltage is 0.5V higher than the original. If your system operates at input voltages below 15V, the substitute cannot be used. The substitute maximum input voltage of 42V exceeds the original 30V maximum, providing additional headroom for higher input voltage systems.

Q: Are both parts RoHS3 compliant?

A: Yes, both the 78ST112SC and R-78T12-1.0/FC-TRAY are ROHS3 compliant with MSL Level 1 (Unlimited) moisture sensitivity rating and REACH unaffected status. Regulatory and environmental compliance is equivalent between the two parts.

Q: What protection features does the substitute provide?

A: The R-78T12-1.0/FC-TRAY includes Short-Circuit Protection (SCP). The original 78ST112SC includes both Over-Temperature Protection (OTP) and SCP. The substitute specification does not explicitly list OTP; thermal management and operating temperature monitoring may require additional circuit design consideration if OTP functionality is critical to system safety.

Q: What is the efficiency difference between the original and substitute parts?

A: The original 78ST112SC operates at 90% efficiency, while the R-78T12-1.0/FC-TRAY operates at 95% efficiency. The substitute provides 5 percentage points higher efficiency, resulting in reduced power dissipation and lower thermal output for equivalent load conditions.

Q: Is the substitute part currently available?

A: Yes, the R-78T12-1.0/FC-TRAY is an active product with 716 units in stock. The original 78ST112SC is obsolete. The substitute provides supply chain continuity for new designs and system updates.