LTC3823: Fast No RSENSE Step-Down DC/DCController with Differential Output Sensing, Tracking & PLL
Linear Technology Corporation introduces theLTC3823, a synchronous step-down DC/DC controller with differentialoutput voltage sensing, fast transient response, integratedphase-lock loop synchronization and output voltage tracking. Thedifferential amplifier provides true differential remote outputvoltage sensing of both the positive and negative terminals. Thisenables high accuracy regulation in high current applications whereIR losses occur through via and trace run interconnect.
The LTC3823 can operate at very low duty cycles, ranging from 2%to 90% and is able to develop output voltages from 0.6V to 90% VIN(0.6V to 3.3V with remote sense). The input voltage range is from4.5V to 30V. The LTC3823’s constant on-time architectureallows the control loop to respond instantly to load steps.
This IC uses current mode control and can operate without asense resistor by sensing the voltage drop across the synchronouspower MOSFET. For systems where control of maximum output currentis important, a sense resistor can be used in series with thesource of the lower MOSFET. In either case the current limit isuser-programmable, allowing optimum system efficiency and excellentcontrol over the maximum output current.
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