LTC3404 WUTYPICAL PERFOR A CE CHARACTERISTICSLoad Step ResponseLoad Step ResponseLoad Step Response VOUT VOUT VOUT 100mV/DIV 100mV/DIV 100mV/DIV IL IL IL 500mA/DIV 500mA/DIV 500mA/DIV I I TH I TH TH 1V/DIV 1V/DIV 1V/DIV 40μs/DIV 40μs/DIV 40μs/DIV VIN = 3.6V CIN = 10μF VIN = 3.6V CIN = 10μF VIN = 3.6V CIN = 10μF VOUT = 1.5V COUT = 22μF VOUT = 1.5V COUT = 22μF VOUT = 1.5V COUT = 22μF L = 4.7μH ILOAD = 200mA TO 500mA 3404 G17 L = 4.7μH ILOAD = 50mA TO 500mA 3404 G18 L = 4.7μH ILOAD = 50mA TO 500mA 3404 G19 PULSE SKIPPING MODE PULSE SKIPPING MODE Burst Mode OPERATION UUUPI FU CTIO SRUN (Pin 1): Run Control Input. Forcing this pin below connects to the drains of the internal main and synchro- 0.4V shuts down the LTC3404. In shutdown all functions nous power MOSFET switches. are disabled drawing < 1μA supply current. Forcing this V pin above 1.2V enables the LTC3404. Do not leave RUN IN (Pin 6): Main Supply Pin. Must be closely decoupled to GND, Pin 4. floating. SYNC/MODE (Pin 7): External Clock Synchronization and ITH (Pin 2): Error Amplifier Compensation Point. The Mode Select Input. To synchronize with an external clock, current comparator threshold increases with this control apply a clock with a frequency between 1MHz and 1.7MHz. voltage. Nominal voltage range for this pin is from 0.5V To select Burst Mode operation, tie to V to 1.9V. IN. Grounding this pin selects pulse skipping mode. Do not leave this pin VFB (Pin 3): Feedback Pin. Receives the feedback voltage floating. from an external resistive divider across the output. PLL LPF (Pin 8): Output of the Phase Detector and Control GND (Pin 4): Ground Pin. Input of Oscillator. Connect a series RC lowpass network from this pin to ground if externally synchronized. If SW (Pin 5): Switch Node Connection to Inductor. This pin unused, this pin may be left open. 3404fb 6