DocumentationDatasheet
Reliability Data
LT Journal
Press Release
cad_symbol
Features
- Low Noise Constant-Frequency Operation
- Multi-Mode Operation: 1x or 2x Boost Mode
- Automatic Mode Switching
- High Output Current: 150mA (Continuous), 400mA (Pulsed) From Li-Ion/Polymer Input
- 2-Second Flash Current Timeout for LED Protection
- Automatic Soft-Start
- Output Disconnect
- No Inductors
- 220mΩ Internal High Side Current Sense Resistor
- Single Resistor Programming Capability
- Tiny Application Circuit (3mm × 2mm DFN Package, All Components < 1mm High)
Typical Application
Description
The LTC3218 is a low-noise, high-current charge pump DC/DC converter capable of driving high current LEDs at up to 400mA from a 2.9V to 4.5V input. A low external parts count (one flying capacitor, two programming resistors and two bypass capacitors at VIN and CPO) make the LTC3218 ideally suited for small, battery-powered applications.Built-in soft-start circuitry prevents excessive inrush current during start-up. High switching frequency enables the use of small external capacitors. A built-in 2-second timer protects the LED during flash mode.
Output current level is programmed by an external resistor. LED current is regulated using an internal high side 220mΩ sense resistor. Automatic mode switching optimizes efficiency by monitoring the voltage across the charge pump and switching modes only when dropout is detected. The part is available in a low profile 3mm × 2mm 10-lead DFN package.
3x2 DFN-10
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) |
Price (1k)* |
|---|---|---|---|---|---|
| LTC3218EDDB#PBF | DFN | 10 | E | $2.06 | |
| LTC3218EDDB#TRMPBF | DFN | 10 | E | $2.06 | $1.49 |
| LTC3218EDDB#TRPBF | DFN | 10 | E | $2.06 | $1.44 |
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.
| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC1030A | LTC3218EDDB Demo Board | Boost Charge Pump Camera LED Driver, 2.9V ≤ VIN ≤ 4.5V, VLED up to 4.5V @ 400mA | Contact Factory |