LT3380 TYPICAL PERFORMANCE CHARACTERISTICSLDO1 to LDO3 Short-CircuitCurrent vs TemperatureLDO1 to LDO3 Load Step Response 800 750 VLDO = 1.8V 700 50mV/DIV 650 600 ILOAD = 220mA 550 500 100mA/DIV 10mA 450 400 LDO = 1µF 10µs/DIV 3380 G19 C LDO SHORT-CIRCUIT CURRENT (mA) 350 300–50 0 50 100 150 TEMPERATURE (°C) 3380 G18 PIN FUNCTIONS FB_L2 (Pin 1): Feedback Input for LDO2. Set output volt- capacitor. Voltage on VIN_L1 should not exceed voltage age using a resistor divider connected from LDO2 to this on VIN pin. pin to ground. FB_L1 (Pin 8): Feedback Input for LT3380 LDO1. Set VIN_L2 (Pin 2): Power Input for LDO2. This pin should output voltage using a resistor divider connected from be bypassed to ground with a 1μF or greater ceramic LDO1 to this pin to ground. capacitor. Voltage on VIN_L2 should not exceed voltage EN_L1 (Pin 9): Enable LDO1 Input for LT3380. Active on VIN pin. high enables LDO1. A weak pull-down pulls EN_L1 low LDO2 (Pin 3): Output Voltage of LDO2. Nominal output when left floating. voltage is set with a resistor feedback divider that servos EN_L3 (Pin 10): Enable LDO3 Input. Active high to a fixed 725mV reference. This pin must be bypassed to enables LDO3. A weak pull-down pulls EN_L3 low when ground with a 1µF or greater ceramic capacitor. left floating. LDO3 (Pin 4): Output Voltage of LDO3. Nominal output SW1 (Pin 11): Switch Pin for Step-Down Switching voltage is a fixed 1.8V. This pin must be bypassed to Regulator 1. Connect one side of step-down switching ground with a 1µF or greater ceramic capacitor. regulator 1 inductor to this pin. VIN_L3 (Pin 5): Power Input for LDO3. This pin should DV be bypassed to ground with a 1µF or greater ceramic DD (Pin 12): Supply Voltage for I2C Serial Port. This pin sets the logic reference level of SCL and SDA I2C capacitor. Voltage on VIN_L3 should not exceed voltage pins. DV on V DD resets I2C registers to power-on state when IN pin. driven to <1V. SCL and SDA logic levels are scaled to LDO1 (Pin 6): Output Voltage of LDO1. Nominal output DVDD. Connect a 0.1µF decoupling capacitor from this voltage is set with a resistor feedback divider that servos pin to ground. to a fixed 725mV reference. This pin must be bypassed to SDA (Pin 13): Data Pin for the I2C Serial Port. The I2C ground with a 1µF or greater ceramic capacitor. logic levels are scaled with respect to DVDD. VIN_L1 (Pin 7): Power Input for LDO1. This pin should SCL (Pin 14): Clock Pin for the I2C Serial Port. The I2C be bypassed to ground with a 1μF or greater ceramic logic levels are scaled with respect to DVDD. Rev. 0 8 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Introduction Step-Down Switching Regulators Slewing DAC Reference Operation Power On Sequencing Power Off Sequencing Fault Detectionand Reporting I2C Operation Applications Information Thermal Considerations and Board Layout Typical Applications Package Description Typical Application Related Parts