Linear Technology Corporation has introduced the LTC3812-5, a high input voltage synchronous step-down switching regulator controller that directly steps down voltages from 60 V to output voltages ranging from 0.8 V to 93% of VIN.
Using a single inductor, the device employs a constant on-time valley current mode control architecture that is said to deliver very low duty cycles and fast transient response with accurate cycle-by-cycle current limit without requiring a sense resistor. Applications include 48 V power conversion in automotive and other systems that must be compliant with high input voltage surges.
Onboard 1 ¿ gate drivers are designed to minimize switching transient losses associated with driving MOSFETs at high frequency and high voltage, according to the company. To optimize the size of inductors and capacitors, the switching frequency is selectable from 100 kHz to 1 MHz.
The LTC3812-5 can be configured for pulse skipping operation to maintain high efficiency at light loads. Its 0.8 V reference has ±0.75% accuracy over the operating temperature range of -40 °C to +85 °C. The programmable soft-start allows users to adjust the start-up time. Integrated bias control generates gate drive power from the input supply during start-up with the addition of a small external SOT23 MOSFET. Additional features include a power good signal, shutdown, undervoltage lockout and output overvoltage protection.
The LTC3812-5 is offered in a 16-lead thermally enhanced SSOP package.