LTC3775
LTC3775 is High Frequency Synchronous Step-Down Voltage Mode DC/DC Controller manufactured by Linear Technology.
Features n Wide VIN Range: 4.5V to 38V n Line Feedforward pensation n Low Minimum On-Time: t ON(MIN) < 30ns n Powerful Onboard MOSFET Drivers n Leading Edge Modulation Voltage Mode Control n ±0.75%, 0.6V Reference Voltage Accuracy Over
Temperature n VOUT Range: 0.6V to 0.8VIN n Programmable, Cycle-by-Cycle Peak Current Limit n Sense Resistor or RDS(ON) Current Sensing n Programmable Soft-Start n Synchronizable Fixed Frequency from 250k Hz to 1MHz n Selectable Pulse-Skipping or Forced Continuous
Modes of Operation n Low Shutdown Current: 14μA Typical n Thermally Enhanced 16-Lead MSOP and 3mm × 3mm
QFN Packages
APPLICATIONS n Automotive Systems n Tele and Industrial Power Supplies n Point of Load Applications
High Frequency Synchronous Step-Down
Voltage Mode DC/DC Controller
DESCRIPTION
The LTC®3775 is a high efficiency synchronous step-down switching DC/DC controller that drives an all N-channel power MOSFET stage from a 4.5V to 38V input supply voltage. A patented line feedforward pensation circuit and a high bandwidth error amplifier provide very fast line and load transient response.
High step-down ratios are made possible by a low 30ns minimum on-time, allowing extremely low duty cycles. MOSFET RDS(ON) current sensing maximizes efficiency. Alternatively, a sense resistor can be used for higher current limit accuracy. Continuous monitoring of the voltages across the top and bottom MOSFETs allows cycle-by-cycle control of the inductor current, configurable by external resistors.
The soft-start function controls the duty cycle during start-up, providing a smooth output voltage ramp up. The operating frequency is user programmable from 250k Hz to 1MHz and can be synchronized to an external clock.
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