SD8585STR / SD8585S Step-Down DC-DC Converter IC — SOP-7/SOP-8, High Efficiency (5-Pack)

SD8585STR / SD8585S / SD45215SA Step-Down DC-DC Converter IC — SOP-7/SOP-8 (5-Pack)

The SD8585STR, SD8585S, and SD45215SA are synchronous step-down (buck) DC-DC converter ICs in compact SOP-7 and SOP-8 SMD packages. Integrating the power MOSFETs and PWM controller in a single package, they provide high-efficiency voltage regulation with minimal external components — typically just an inductor and output capacitor. Designed for consumer electronics, IoT devices, and embedded power supply applications requiring compact, efficient voltage step-down.

Key Specifications

Parameter	Value
Topology	Synchronous step-down (buck)
Package	SOP-7 / SOP-8 (SMD)
Integrated MOSFETs	Yes (high-side + low-side)
Control Mode	Current-mode PWM
Protection	OCP, OVP, thermal shutdown, soft-start
Efficiency	High (synchronous rectification)
Quantity	5 pieces

Why Choose SD8585STR / SD8585S?

• Integrated synchronous MOSFETs — no external rectifier diode needed, higher efficiency than non-synchronous designs
• Compact SOP-7/SOP-8 package — minimal PCB footprint for space-constrained designs
• Minimal external components — only inductor + capacitor needed for a complete buck converter
• Full protection suite — OCP/OVP/thermal shutdown prevents damage under fault conditions
• 5-pack value — sufficient for multiple designs and repair stock

Compatible With / Common Use Cases

• Consumer electronics power supply: Step down 5V USB to 3.3V for MCU and sensor supply
• IoT device power rail: Efficient 3.3V or 1.8V supply from Li-ion battery (3.7–4.2V input)
• Arduino / ESP32 power supply: Compact 3.3V regulator for battery-powered projects
• LED driver supply: Step-down voltage for LED string constant-voltage supply
• PCB repair: Replacement for failed step-down IC on consumer electronics power boards

Frequently Asked Questions

Q: What inductor value should I use with SD8585STR?
A: Refer to the SD8585 datasheet for the recommended inductor value based on your input/output voltage and switching frequency. Typically, a 4.7–22μH inductor with low DCR (<100mΩ) is used for 5V-to-3.3V conversion. Use a shielded inductor to minimize EMI.

Q: What is the difference between SD8585STR, SD8585S, and SD45215SA?
A: All three are synchronous step-down converter ICs in SOP-7/SOP-8 packages with similar functionality. SD8585STR is the tape-and-reel version of SD8585S (same IC, different packaging format). SD45215SA may have different voltage/current ratings — verify the datasheet for your specific application before substituting.

Q: Can I use SD8585S as a replacement for other SOP-8 buck converter ICs?
A: Only if the pinout and specifications match. SOP-8 buck converter ICs are not universally pin-compatible — always compare the datasheet pinout of the original IC with SD8585S before substituting. Common SOP-8 buck ICs include MP2307, XL4005, and LM2596S, but each has a different pinout.

Package Contents

• 5× SD8585STR / SD8585S / SD45215SA Step-Down DC-DC Converter IC (SOP-7/SOP-8)

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