Step down switching regulator features 100% duty cycle operation

The device's internal 1.5A switches are designed to deliver up to 1A of continuous output current per channel to voltages as low as 0.8V. The module also includes an onboard boost regulator, enabling each channel to operate at 100% duty cycle, even with 3.2V input voltage. Linear says this architecture makes the LT3504 suitable for applications requiring continuous output regulation, such as automotive cold crank and stop start scenarios. Switching frequency is user programmable from 250kHz to 2.2MHz and synchronisable throughout the range, enabling the designer to optimise efficiency while avoiding critical noise sensitive frequency bands. The company says the device's 28 lead 4 x 5mm QFN and high switching frequency keeps external inductors and capacitors small, thereby providing a compact, thermally efficient footprint for multiple output applications. The LT3504 uses four internal 1.5A switches for the step down conversion and a 220mA switch for the internal boost circuit, with the necessary oscillator, control and logic circuitry integrated into a single die. A new high voltage process is said to deliver efficiencies up to 88% over a wide input voltage range, while the LT3504's current mode topology enables fast transient response and excellent loop stability.