FT838NB1-RT

Overview

The FT838NB1-RT is an offline flyback switch manufactured by Fremont Micro Devices Ltd, designed for primary-side regulation. It integrates a power NPN transistor and operates within a Vcc range of 6.6V to 30V with a startup voltage of 17.6V. The device features a 700V breakdown voltage and supports cycle-by-cycle current limiting, over-temperature protection, open-circuit protection, and over-voltage protection. Packaged in an SOT-23-5 surface-mount case, it functions as a low-power AC/DC converter suitable for applications requiring high efficiency and fast dynamic response without external optocouplers.

Feature Summary

• Integrates proprietary primary-side control technology enabling constant-current and constant-voltage regulation without optocouplers or TL431 components.
• Includes built-in cable compensation and line compensation to enhance power supply accuracy and stability under varying load conditions.
• Provides comprehensive protection mechanisms including cycle-by-cycle current limiting, over-temperature shutdown, VCC over-voltage protection, and open-loop detection.

Applications

• Adapters and chargers for portable devices such as cell phones, PDAs, and MP3 players
• Standby and auxiliary power supplies for consumer electronics
• Set-top boxes (STB) requiring efficient low-power operation
• AC/DC LED driver applications

Procurement Notes

Verify the specific suffix 'RT' indicates the tape-and-reel packaging format when ordering. Confirm that the component meets RoHS3 compliance requirements for your manufacturing process. Ensure the design accommodates the SOT-23-5 surface-mount package dimensions and thermal characteristics specified in the official datasheet. Cross-reference the manufacturer part number FT838NB1-RT directly with Fremont Micro Devices Ltd documentation to avoid substitution errors.

Selection Notes

Select this component for designs prioritizing minimal external component count and high efficiency in low-power offline applications. The integrated primary-side feedback eliminates the need for secondary-side sensing circuits. Consider the SOT-23-5 package for space-constrained PCB layouts. Evaluate the thermal performance within the -40°C to 125°C operating range to ensure reliability under expected ambient conditions.

Part Context

This part belongs to the FT838 family of low-power off-line CC/CV switches from Fremont Micro Devices Ltd. The family includes variants like the FT838NB and FT838RNA, which share similar core functionalities but differ in packaging and specific application optimizations. The FT838 series is engineered to replace traditional solutions involving optocouplers, offering simplified designs with improved dynamic response and reduced standby power consumption.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided source material. Verify compatibility with existing designs before considering alternative manufacturers. Consult Fremont Micro Devices Ltd for potential cross-reference recommendations if direct replacement is required.