has released the LT3486, a dual step-up DC/DC converter specifically designed to drive up to 16 white LEDs (8 LEDs in series per channel) with constant current.
In addition true PWM dimming delivers constant current to the LEDs, keeping the emitted light at a constant colour. Dimming is controlled with the duty cycle of the PWM driver. This method allows for a wide 1000:1 dimming range.
The LT3486’s current mode and fixed frequency operation is said to ensure uniform LED brightness, low noise and maximum battery life. Its two independent converters are capable of driving asymmetric LED strings (up to 8 in a series per converter) from an input voltage of 2.5V to 24V, delivering efficiencies up to 85%.
Linear says the LT3486’s 5mm x 3mm DFN package and small externals provide a compact footprint for space-constrained handheld applications. Its 2.5V to 24V input voltage range enables it to operate in applications from Li-Ion powered handheld devices to automotive backlighting applications.
The LT3486 switching frequency can be set between 200kHz and 2MHz via a single resistor, enabling the designer to minimise solution footprint and maximise efficiency.
Because the LT3486 utilises constant frequency architecture, noise is minimised, eliminating potential interference with any onboard RF or audio circuitry. Additional features include internal soft-start/inrush current limiting, and open LED protection.
The LT3486EDHC is available from stock in a 5mm x 3mm DFN-16 package while the LT3486EFE is in a TSSOP-16E package. Pricing starts at $2.50each and $2.60 each respectively for 1,000 piece quantities. Both parts are available from stock.