UC3847N Equivalent & Substitute Parts

Part Overview

The UC3847N is a multi-topology DC-DC controller IC manufactured by Texas Instruments, designed for boost, flyback, forward converter, half-bridge, and push-pull regulator applications. It provides positive output step-up and step-up/step-down functionality with integrated current mode PWM control. The UC3847N is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support. Substitute parts maintain functional and electrical compatibility while offering improved availability and active product status.

Substiute Parts

UC3847N

Texas InstrumentsIn Stock: 3876UC3847N Datasheet

Current PartRFQ

UC3846N

Texas InstrumentsIn Stock: 7323UC3846N Datasheet

Parametric EquivalentRFQ

UC3847DW

UnitrodeIn Stock: 13103UC3847DW Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the UC3847N are qualified based on strict electrical and mechanical parameter matching. The following criteria determine substitution eligibility:

Critical Matching Parameters:

• Output Type: Transistor Driver
• Function: Step-Up, Step-Up/Step-Down
• Output Configuration: Positive
• Topology Support: Boost, Flyback, Forward Converter, Half-Bridge, Push-Pull
• Number of Outputs: 2
• Output Phases: 1
• Voltage Supply Range: 6.95V ~ 40V
• Switching Frequency: 500kHz
• Maximum Duty Cycle: 50%
• Synchronous Rectifier: Yes
• Clock Sync: Yes
• Control Features: Current Limit, Enable, Frequency Control, Soft Start
• Operating Temperature Range: 0°C ~ 70°C (TA)

Package Compatibility Considerations: Substitutes may differ in mounting type (through-hole versus surface mount) and package form factor (16-DIP versus 16-SOIC), provided the electrical parameters remain identical. Pin-to-pin compatibility and functional equivalence are maintained across qualified substitutes.

Parameter Comparison

Engineering Selection Recommendations

UC3846N (Parametric Equivalent): The UC3846N is a direct parametric equivalent to the UC3847N, maintaining identical electrical specifications and through-hole 16-DIP packaging. The UC3846N holds active product status from Texas Instruments and carries ROHS3 compliance certification. This substitute is suitable for applications requiring pin-for-pin compatibility and identical board layout without modification.

UC3847DW (MFR Recommended): The UC3847DW is the manufacturer-recommended substitute, offering identical electrical functionality with surface-mount 16-SOIC packaging. This part is actively produced by Unitrode and provides superior availability. The UC3847DW requires PCB layout modification to accommodate surface-mount technology but eliminates through-hole assembly processes. Selection of this substitute depends on design flexibility and manufacturing process capability.

Both substitutes maintain full electrical and functional equivalence to the obsolete UC3847N across all critical parameters: output type, topology support, voltage supply range, switching frequency, duty cycle, synchronous rectifier capability, clock synchronization, and control features.

Frequently Asked Questions (FAQ)

Q: Can UC3846N be used as a direct replacement for UC3847N? A: Yes. The UC3846N is a parametric equivalent with identical electrical specifications, output type, topology support, voltage supply range, switching frequency, duty cycle, and control features. Both parts use 16-DIP through-hole packaging with matching pin configurations.

Q: What is the difference between UC3846N and UC3847DW? A: Both parts maintain identical electrical functionality and specifications. The primary difference is packaging: UC3846N uses through-hole 16-DIP mounting, while UC3847DW uses surface-mount 16-SOIC. UC3847DW requires PCB redesign for surface-mount assembly but offers higher availability.

Q: Why is UC3847N classified as obsolete? A: The UC3847N has reached end-of-life status. Equivalent and substitute parts with active product status (UC3846N and UC3847DW) are available to support ongoing production and new designs.

Q: Are there any compliance differences between the substitutes? A: UC3846N carries ROHS3 compliance certification. UC3847DW compliance status is not specified in available documentation. Both parts are REACH Unaffected and carry EAR99 ECCN classification.

Q: Can UC3847DW be used in a through-hole design? A: No. UC3847DW is a surface-mount component in 16-SOIC packaging. Through-hole designs require UC3846N or equivalent through-hole packages. PCB redesign is necessary to accommodate surface-mount technology.

Q: What are the key electrical parameters that determine substitution? A: Substitution is determined by matching output type (transistor driver), function (step-up/step-up-step-down), output configuration (positive), topology support (boost, flyback, forward converter, half-bridge, push-pull), number of outputs (2), output phases (1), voltage supply range (6.95V ~ 40V), switching frequency (500kHz), maximum duty cycle (50%), synchronous rectifier capability, clock sync, control features (current limit, enable, frequency control, soft start), and operating temperature range (0°C ~ 70°C).

Q: Is inventory availability a factor in substitute selection? A: Inventory levels are provided for reference: UC3847N (3,850 pcs), UC3846N (7,300 pcs), and UC3847DW (13,039 pcs). Availability may vary by supplier and time. Consult current inventory status with your component distributor.