Controller cuts out current sense resistor

The LTC3809 is a synchronous step-down controller with spread spectrum modulation in 3 x 3mm DFN-10 or MSOP-10 packaging.

Linear Technology has announced the LTC3809, a synchronous step-down controller with spread spectrum modulation in 3 x 3mm DFN-10 or MSOP-10 packaging.

The device's constant frequency operation and current mode architecture with MOSFET VDS sensing eliminates the need for a current sense resistor while delivering efficiencies as high as 95%.

The LTC3809's input voltage range of 2.75 to 9.8V makes it ideal for single or dual Li-ion or multicell iMH/NiCd/alkaline applications as well as standard 3.3 and 5V inputs.

The LTC3809 can be configured with burst mode operation to operate with only 100uA of quiescent current.

For noise sensitive applications, burst mode operation can be inhibited with the sync/mode pin to reduce noise and RF interference.

The LTC3809 can also be externally synchronised or adjusted from 250 to 750kHz using its on-chip phase locked loop.

To further reduce EMI, the LTC3809 incorporates a user selectable spread spectrum frequency modulation technique.

Other features include internal soft-start circuitry, a power good output voltage monitor, auxiliary winding regulation and output overvoltage protection.

The LTC3809EDD and LTC3809EMS8E are both available from stock in 3 x 3mm DFN-10 and MSOP-10 packages, respectively.

Pricing starts at $2.50 each in 1000-piece quantities.

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