The XC9116 series is a fixed frequency, constant current step-up DC/DC converter ideal for driving LEDs used in backlighting applications such as cellular phones, PDAs and digital cameras. It can derive an output voltage of up to 17.5V, allowing for the driving of four white LEDs in series. The LED current can be set by an external resistor, ensuring all white LEDs can be turned on evenly. The converter has high efficiency and low feedback reference voltage, and utilizes an internal MOSFET with an RDSON of 2.0Ω. The high 1.0MHz switching frequency enables a low profile and small board area solution using a chip coil and an ultra small ceramic output capacitor (CL) of 0.22⎧F.
The XC9116 series is a step‑up DC/DC converter designed for backlight LED applications such as mobile phones, PDAs and digital cameras. It provides a constant‑current drive, PWM dimming via the CE pin, and includes a fault‑detection circuit in the B‑type version to protect against LED disconnection.
The device is supplied in a SOT‑25/USP‑6B package, features a 1 MHz internal switching frequency, and offers a typical application circuit with external inductor, Schottky diode and ceramic capacitors. Pin assignments include VIN, FB (voltage feedback), CE (chip enable), Lx (switch) and Vss (ground).
| Efficiency (B type) | 86 % (typ.) |
|---|---|
| Oscillation Frequency | 1.0 MHz (typ.) |
| Standby Current | 1.0 µA (max) |
| Package | SOT‑25, USP‑6B |
| Maximum Duty Cycle | 98 % (typ.) |
| Lx Overvoltage Limit (B type) | 19 V (typ.) |
The XC9116 operates at a fixed internal switching frequency of 1 MHz (typ.).
The B‑type includes a fault detection circuit that stops the internal MOSFET if LEDs are disconnected or damaged, preventing over‑voltage.
A high level on the CE pin enables the device, while a low level puts it into shutdown mode with minimal supply current.