| Number of channels (#) | 1 |
| Vin (Min) (V) | 2.7 |
| Vin (Max) (V) | 5.5 |
| Vout (Min) (V) | 10 |
| Vout (Max) (V) | 17.5 |
| Type | Inductive |
| Switching frequency (Max) (kHz) | 850 |
| LED current per channel (mA) | 30 |
| Peak efficiency (%) | 85 |
| Topology | Boost |
| Features | OVP |
| Operating temperature range (C) | -30 to 85 |
- Drives 4 Series White LEDs with up to 30mA
- >80% Peak Efficiency
- Up to 100kHz PWM Brightness Control
- Accurate ±5% LED Current Regulation across VIN range
- Internal Synchronous PFET (No Schottky Diode Required)
- True Shutdown Isolation
- Output Short-Circuit Protection
- 17.5V Over-Voltage Protection
- Internal Soft-Start Eliminates Inrush Current
- Wide Input Voltage Range: 2.7V to 5.5V
- 850kHz Fixed Frequency Operation
- Low Profile 9-Bump DSBGA Package (1.514mm x 1.514mm x 0.6mm)
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The LM3508 is a synchronous boost converter (no external Schottky diode required) that provides a constant current output. It is designed to drive up to 4 series white LEDs at 30mA from a single-cell Li-Ion battery. A single low power external resistor is used to set the maximum LED current. The LED current can be adjusted by applying a PWM signal of up to 100kHz to the DIM pin. Internal soft-start circuitry is designed to eliminate high in-rush current at start-up. For maximum safety, the device features an advanced short-circuit protection when the output is shorted to ground. Additionally, over-voltage protection and an 850kHz switching frequency allow for the use of small, low-cost output capacitors with lower voltage ratings. During shutdown, the output is disconnected from the input preventing a leakage current path through the LEDs to ground. The LM3508 is available in a tiny 9-bump chip-scale DSBGA package.
