Datasheet LT3475, LT3475-1 (Analog Devices) - 5

LT3475/LT3475-1
W U TYPICAL PERFOR A CE CHARACTERISTICS Open-Circuit Output Voltage and Boost Pin Current Quiescent Current Input Current
35 7 50 14 TA = 25°C TA = 25°C TA = 25°C 45 INPUT CURRENT 30 6 LT3475-1 12 40 INPUT CURRENT (mA) 25 5 35 10 30 LT3475 20 4 8 25 LT3475-1 15 3 20 6 OUTPUT VOLTAGE 10 INPUT CURRENT (mA) 2 OUTPUT VOLTAGE (V) 15 4 BOOST PIN CURRENT (mA) LT3475 10 5 1 2 5 0 0 0 0 0 0.5 1.0 1.5 2.0 0 10 20 30 40 0 10 20 30 40 SWITCH CURRENT (A) VIN (V) VIN (V) 3475 G10 3475 G11 3475 G12
Minimum Input Voltage, Single Minimum Input Voltage, Two Series Reference Voltage 1.5A White LED Connected 1.5A White LEDs
1.28 6 10 TA = 25°C TA = 25°C TO START 1.27 5 9 1.26 4 TO RUN LED VOLTAGE 8 TO START (V) (V) 1.25 3 (V) IN REF IN V V V LED VOLTAGE 7 1.24 2 TO RUN 1.23 1 6 1.22 0 5 –50 –25 0 25 50 75 100 125 0 0.5 1 1.5 0 0.5 1 1.5 TEMPERATURE (˚C) LED CURRENT (A) LED CURRENT (A) 3475 G13 3475 G14 3475 G15
U U U PI FU CTIO S OUT1, OUT2 (Pins 1, 10):
The OUT pin is the input to the
BOOST1, BOOST2 (Pins 3, 8):
The BOOST pin is used to current sense resistor. Connect this pin to the inductor provide a drive voltage, higher than the input voltage, to and the output capacitor. the internal bipolar NPN power switch.
LED1, LED2 (Pins 2, 9):
The LED pin is the output of
GND (Pins 15, Exposed Pad Pin 21):
Ground. Tie the GND the current sense resistor. Connect the anode of the LED pin and the exposed pad directly to the ground plane. The here. exposed pad metal of the package provides both electrical contact to ground and good thermal contact to the printed
VIN (Pins 5, 6):
The VIN pins supply current to the internal circuit board. The exposed pad must be soldered to the circuitry and to the internal power switches and must be circuit board for proper operation. Use a large ground plane locally bypassed. and thermal vias to optimize thermal performance.
SW1, SW2 (Pins 4, 7):
The SW pin is the output of the internal power switch. Connect this pin to the inductor, switching diode and boost capacitor. 3475fb 5