LTC3121
15V, 1.5A Synchronous
Step-Up DC/DC Converter
with Output Disconnect
Description Features
VIN Range: 1.8V to 5.5V, 500mV After Start-Up
Output Voltage Range: 2.2V to 15V
400mA Output Current for VIN = 5V and VOUT = 12V
Output Disconnects from Input When Shut Down
Synchronous Rectification: Up to 95% Efficiency
Inrush Current Limit
Up to 3MHz Adjustable Switching Frequency
Synchronizable to External Clock
n Selectable Burst Mode® Operation: 25µA I
Q
n Output Overvoltage Protectio Soft-Start
n 1.4V
Measured on VOUT, VFB > 1.4V 25
10 40
20 µA
µA N-channel MOSFET Switch Leakage Current VSW = 15V, VOUT = 15V, VC = 0V (Note 6) l 0.1 30 µA P-channel MOSFET Switch Leakage Current VSW = VIN = 0V, VOUT = 15V (Note 6) l 0.1 70 µA N-channel MOSFET Switch On-Resistance 0.121 Ω P-channel MOSFET Switch On-Resistance 0.188 Ω N-channel MOSFET Current Limit VIN = 3.3V l 1.5 1.8 Maximum Duty Cycle VFB = 1.0V l 90 94 Minimum Duty Cycle VFB = 1.4V l Switching Frequency 0.85 SYNC Frequency Range l 0.1 PWM/SYNC Input High l 0.9 •VCC PWM/SYNC Input Low l VPWM/SYNC = 5.5V CAP Clamp Voltage VOUT > 6.1V, Referenced to VOUT Error Amplifier Transconductance l SD Input Low
SD Input Current Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute …