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- LM3500
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- Last added
- 2012-04-11
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National Semiconductor LM3500 Synchronous Step‑up DC/DC Converter Datasheet
The LM3500 is a fixed‑frequency, synchronous step‑up DC/DC converter offered in a compact 8‑bump thin micro SMD package. It is designed for white LED applications such as cellular phone back‑lighting, LCD bias supplies, and handheld devices, providing up to 3‑4 LEDs in series from a single Li‑ion or NiMH battery.
Key features include synchronous rectification without an external Schottky diode, a 1 MHz switching frequency, true shutdown isolation, input undervoltage lockout, and over‑voltage protection. The device operates from 2.7 V to 7 V input and requires only a small 16 V ceramic capacitor at the output.
National Semiconductor LM3500 specifications
| Input voltage range | 2.7 V to 7 V |
|---|---|
| Switching frequency | 0.85 – 1.15 MHz |
| Package type | 8‑bump thin micro SMD |
| Maximum LED strings | Up to 3 or 4 low‑voltage white LEDs in series |
Source: National Semiconductor LM3500 Synchronous Step‑up DC/DC Converter Datasheet
All National Semiconductor LM3500 documents by type
Ratings, dimensions and ordering codes, for selection and design work.
Questions answered in these manuals
What is the input voltage range of the LM3500?
The LM3500 operates from 2.7 V to 7 V input.
From: National Semiconductor LM3500 Synchronous Step‑up DC/DC Converter Datasheet
How many white LEDs can be driven in series?
It can drive up to three or four low‑voltage white LEDs in series.
From: National Semiconductor LM3500 Synchronous Step‑up DC/DC Converter Datasheet
What is the input voltage range for the LM3500?
The LM3500 operates from 2.7 V to 7 V input.
From: National Semiconductor LM3500 Synchronous Step‑up DC/DC Converter Datasheet
How is the LED current set?
A single external resistor from the FB pin to GND sets the LED current, and it can be adjusted with a PWM signal on the SHDN pin.
From: National Semiconductor LM3500 Synchronous Step‑up DC/DC Converter Datasheet