National Semiconductor LM3500 Synchronous Step-up DC DC Converter Data Sheet & User's Manual for White LED Applications
Summary
The LM3500 is an ultra-efficient synchronous step-up DC/DC converter expertly designed for white LED back-lighting applications. This component powers multiple LEDs (2 to 4) from low input voltages, featuring comprehensive protection against overvoltage and thermal issues in a tiny micro SMD package. Ideal for designers creating portable electronics, including handheld devices, digital cameras, and cell phone lighting solutions. The accompanying manual provides detailed technical specifications, pin descriptions, and application circuitry necessary for seamless integration into your next project.
Manual Details
| Brand | National |
|---|---|
| Pages | 15 |
| File Size | 602.27 KB |
| Published | June 04, 2026 |
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Frequently Asked Questions
How do I set the maximum output current for the white LEDs?
The white LED current is adjusted using a small resistor connected from the FB pin to GND.
What input voltage range can the LM3500 operate with?
It accepts an input voltage (V IN) ranging from 2.7V to 7V.
Does the converter require an external Zener diode for overvoltage protection?
No, the LM3500 uses special circuitry to prevent overvoltage and eliminate the need for an extra protection Zener diode.
What pin must be used to control the device in a low-power state?
Use the SHDN (Shutdown) pin A2; applying a voltage less than 0.3V will disable the device.