FT838D1-BL-RT

Overview

The FT838D1-BL-RT is an offline flyback switch controller from Fremont Micro Devices Ltd, packaged in a SOT-23-5 (SC-74A) surface-mount case. It operates with a Vcc range of 6.6V to 30V and features a startup voltage of 17.6V. The device supports up to 18W output power and includes comprehensive fault protection mechanisms such as current limiting, open circuit detection, over-temperature shutdown, and overvoltage protection. It functions within an ambient temperature range of -40°C to 125°C.

Feature Summary

• Primary-side control architecture eliminates the need for opto-couplers and TL431 components
• Built-in power NPN transistor and cable compensation capabilities
• Cycle-by-cycle current limiting and over-temperature protection
• Voltage lockout and leading edge blanking for stable operation

Applications

• Adapters and chargers for cell phones, PDAs, and MP3 players
• Standby and auxiliary power supplies
• Set-top boxes (STB)
• AC/DC LED driver applications

Procurement Notes

Verify the specific suffix BL-RT against official Fremont Micro Devices documentation to confirm tape-and-reel packaging specifications and pin configuration. Ensure the selected variant matches the required thermal performance for the intended application environment. Cross-reference the part number with authorized distributors to confirm availability and authenticity. Check for any recent updates to the datasheet regarding electrical characteristics or recommended operating conditions.

Selection Notes

Select this component for low-power offline AC/DC conversion where primary-side regulation is preferred. The SOT-23-5 package suits space-constrained designs. Consider the 18W power limit and the wide operating temperature range when designing the thermal management strategy. Verify that the built-in protections align with the safety requirements of the target end-product.

Part Context

The FT838 series represents a family of low-power offline switch controllers optimized for constant-current and constant-voltage applications. The FT838D1-BL-RT specifically utilizes a small outline transistor package, distinguishing it from other variants like the FT838NB which may use different housing styles. This model integrates proprietary technology for high efficiency and fast dynamic response without audible noise.

FAQ

Does the FT838D1-BL-RT require an opto-coupler?

No, the device uses primary-side feedback control, which eliminates the need for an opto-coupler and TL431.

What protection features are integrated into the FT838D1-BL-RT?

It includes cycle-by-cycle current limiting, over-temperature protection, Vcc overvoltage protection, and open circuit protection.