S-8521B35MC-ATUT2G

Overview

The S-8521B35MC-ATUT2G is a CMOS step-down switching regulator controller from the ABLIC S-8520/8521 series. It utilizes PWM/PFM switching control to maintain high efficiency across varying load conditions. The device operates with an external Pch power MOS FET or PNP transistor, coil, capacitors, and diode. It features a built-in reference voltage source, oscillation circuit, error amplifier, and soft-start circuit to prevent startup overshoot. The IC supports a supply voltage range of 2.5V to 16V and operates within a temperature range of -40°C to 85°C.

Feature Summary

• Supports automatic switching between PWM and PFM control modes for optimized efficiency under light loads
• Integrates a soft-start circuit to prevent output voltage overshoot during startup
• Provides linear duty ratio variation from 0% up to 100% via PWM control

Applications

• Battery-powered portable electronic devices requiring efficient power management
• Industrial equipment utilizing step-down conversion for peripheral circuits
• Automotive domain controllers needing stable low-voltage regulation

Procurement Notes

Verify the specific suffix ATUT2G against the manufacturer's official datasheet to confirm pinout and marking codes. Ensure compatibility with external components such as the Pch MOSFET and inductor values specified in the design guidelines. Check for RoHS compliance status and lead-free certification requirements before finalizing procurement orders.

Selection Notes

Select this component when designing a non-synchronous buck converter topology using discrete external switches. It is suitable for applications requiring adjustable output voltages via external resistors rather than fixed outputs. Consider the 60kHz switching frequency and the need for external passive components when evaluating board space and cost constraints relative to integrated solutions.

Part Context

This part belongs to the S-8521 series of CMOS step-down switching regulator controllers. It shares core architectural features with the S-8520 series but adds PFM capability for improved light-load performance. The series is designed for general-purpose DC-DC conversion where high efficiency and transient response are critical.

Replacement Considerations

S-8521C27MC-BTMT2G and S-8521D27MC-BXMT2U are members of the same S-8521 family. Verify if the output voltage setting and supply voltage range differences align with the new application requirements before substituting.