The LM3501 is a synchronous step-up DC/DC converter ideal for white LED applications, including cellular phone back-lighting, battery-powered applications, low current, and high efficiency.
The LM3501 is a fixed‑frequency synchronous step‑up DC/DC converter in a small 8‑bump thin micro SMD package. It is intended for white LED back‑lighting in cellular phones, handheld devices, digital cameras and other portable applications. The device can drive 2 to 4 white LEDs in series from a single Li‑ion or NiMH battery and uses a single external resistor to set LED current.
Key features include a 1 MHz operating frequency, high efficiency with synchronous rectification, true shutdown isolation, input undervoltage lockout, output overvoltage protection, and a wide 2.7 V‑7 V input range. The LM3501 requires only a small 16 V ceramic capacitor at the output and provides thermal shutdown protection.
| Input voltage range | 2.7 V to 7 V |
|---|---|
| Operating frequency | 1 MHz (fixed) |
| Maximum LED drive | Up to 3 (or 4 low‑V) white LEDs in series |
| Shutdown isolation | True shutdown, no LED leakage |
| Package type | 8‑bump thin micro SMD |
| Output overvoltage protection | Integrated, no external Zener required |
| Input undervoltage lockout | Enabled |
| Thermal shutdown | Enabled |
The LM3501 operates with an input voltage from 2.7 V to 7 V.
It can drive up to three, or four low‑voltage, white LEDs in series.
The device uses a fixed 1 MHz operating frequency.
When the SHDN pin is low (<0.3 V) the input and output are disconnected, providing true shutdown isolation.