Linear Technology Introduces High Voltage Synchronous Step-Down DC/DC Controller LTC3891

Photocoupler

Linear Technology Corporation (Linear Technology Corporation) introduced a high-pressure synchronous step-down DC / DC controller LTC3891, the device is in standby mode consuming only 50uA, and the output in a stable state. The 4V to 60V input supply range protects the device from high voltage transients, continuous operation when the car is cold, and covers a wide range of input power sources and battery chemistries. With output currents up to 20A and efficiencies as high as 95%, the output voltage can be set from 0.8V to 24V, making the device ideal for 12V, 24V or 48V automotive, heavy equipment, industrial control, robotics, and Applications such as telecommunications.

The LTC3891 features a powerful 1.1Ω internal MOSFET gate driver. It operates from an optional fixed frequency of 50kHz to 900kHz and can be synchronized to an external clock from 75kHz to 850kHz with its phase-locked loop (PLL). Users can select continuous, pulse skip and low ripple Burst Mode? operation at light loads. Its current mode architecture provides very easy loop compensation, fast transient response and excellent voltage regulation. Output current sensing is accomplished by measuring the voltage drop across the output inductor (DCR) for maximum efficiency, or an optional sense resistor for output current sensing. Current foldback limits the amount of heat generated by the MOSFET under overload conditions. Other features include a short 95ns minimum on-time to achieve high step-down ratios at high efficiency, up to 99% duty cycle for low dropout output, an internal LDO from input voltage or EXTVCC to the gate driver, And a power good signal.

The LTC3891 is available in a 20-lead 3mm x 4mm QFN and 20-lead TSSOP thermally enhanced package. The device is available in three operating junction temperature versions, from -40 to 125°C for extended and industrial temperature grades, from -40°C to 150°C for automotive grades, and from -55°C to 150°C. Military version. The 1,000-piece purchase price is $3.47 per piece. For more information, please visit

Photo description: High voltage DC/DC synchronous controller

Performance Summary: LTC3891

· Wide input voltage range: 4V to 60V

· 50uA quiescent current

· Wide output voltage range: 0.8V to 24V

· Synchronous rectification for up to 95% efficiency

· Very short 95ns minimum on-time to achieve high step-down ratio

· DCR or RSENSE current detection

· Optional low ripple burst mode operation, pulse skipping or continuous operation

· Optional fixed operating frequency from 50kHz to 900kHz

· 75kHz to 850kHz PLL can synchronize operating frequency

· Current mode control for fast transient response and very easy loop compensation

· Adjustable soft start or tracking

· Output overvoltage and overcurrent foldback protection

· Extended and industrial temperature grade versions: -40°C to 125°C operating junction temperature

· Automotive temperature grade version: Working junction temperature from -40 ° C to 150 ° C

· Military temperature grade version: working junction temperature from -55 ° C to 150 ° C