LT3695 Series 1A Fault Tolerant Micropower Step-Down Regulator FEATURESDESCRIPTION n Wide Input Range: The LT®3695 series are adjustable frequency (250kHz to Operation from 3.6V to 36V 2.2MHz) monolithic buck switching regulators that accept Overvoltage Lockout Protects Circuits Through input voltages up to 36V and can safely sustain transient 60VTransients voltages up to 60V. The devices include a high effi ciency n FMEA Fault Tolerant: switch, a boost diode, and the necessary oscillator, control Output Stays at or Below Regulation Voltage and logic circuitry. Current mode topology is used for fast During Adjacent Pin Short or When a Pin Is Left transient response and good loop stability. A SYNC pin Floating allows the user to synchronize the part to an external clock, n 1A Output Current and to choose between low ripple Burst Mode operation n Low Ripple (< 15mVP-P) Burst Mode® Operation and standard PWM operation. IQ = 75μA for 12VIN to 3.3VOUT with No Load The LT3695 regulators tolerate adjacent pin shorts or n Adjustable Switching Frequency: 250kHz to 2.2MHz an open pin without raising the output voltage above its n Short-Circuit Protected programmed value. n Synchronizable Between 300kHz and 2.2MHz n Output Voltage: 0.8V to 20V Low ripple Burst Mode operation maintains high effi - n Power Good Flag ciency at low output currents while keeping output ripple n Fixed Output Voltage Versions for 3.3V and 5V Available below 15mV in a typical application. Shutdown reduces n Small, Thermally Enhanced 16-Pin MSOP Package input supply current to less than 1μA while a resistor and capacitor on the RUN/SS pin provide a controlled output APPLICATIONS voltage ramp (soft-start). Protection circuitry senses the current in the power switch and external Schottky catch n Automotive Battery Regulation diode to protect the LT3695 regulators against short-circuit n Automotive Entertainment Systems conditions. Frequency foldback and thermal shutdown n Distributed Supply Regulation provide additional protection. n Industrial Supplies L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks of The LT3695 series is available in a thermally enhanced Linear Technology Corporation. All other trademarks are the property of their respective owners. 16-pin MSOP package. TYPICAL APPLICATIONEffi ciency5V Step-Down Converter 100 VIN VOUT VOUT = 5V 6.9V TO 36V 5V 90 TRANSIENT TO 60V 0.9A, V V IN > 6.9V IN BD 1A, VIN > 12V 2.2μF ON OFF RUN/SS BOOST VOUT = 3.3V 0.22μF 10μH 80 VC SW LT3695 RT 70 EFFICIENCY (%) PG DA 16.2k 40.2k 536k SYNC FB 60 VIN = 12V 470pF GND PGND 102k 10μF L = 10μH f = 800kHz 3695 TA01a 50 f = 800kHz 0 0.2 0.4 0.6 0.8 1 LOAD CURRENT (A) 3695 TA01b 3695fa 1