LTC3215 Linear Technology, LTC3215 Datasheet
LTC3215
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LTC3215 Summary of contents
Page 1
... Low external parts count (two flying capaci- tors, one programming resistor and two bypass capaci- tors) makes the LTC3215 ideally suited for small, battery- powered applications. Built-in soft-start circuitry prevents excessive inrush cur- rent during start-up ...
Page 2
... EN to LED Current 0mA CPO I = 0mA CPO I = 0mA CPO V = 3.4V, V < 4.6V 2.2µF IN CPO V = 3.2V, V < 5.1V 2.2µF IN CPO ORDER PART NUMBER – LTC3215EDD 9 GND – PART MARKING = 43°C/W LBPX = 4.7µF. CPO MIN TYP MAX UNITS ● 2.9 4.4 300 7 9.2 2.5 7 ● ...
Page 3
... IN CONDITIONS I = 50µA SET Note 3: The LTC3215E is guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the –40°C to 85°C ambient operating temperature range are assured by design, characterization and correlation with statistical process controls 25°C unless otherwise specified) ...
Page 4
... LTC3215 W U TYPICAL PERFOR A CE CHARACTERISTICS Input Shutdown Current vs Input Voltage 4.0 3 25° 85° –40°C A 2.0 1.5 1.0 0.5 0 2.9 3.1 3.5 3.7 3.9 4.1 4.5 3.3 4.3 INPUT VOLTAGE (V) 3216 G04 Efficiency 100 100mA 30 200mA 20 400mA AOT2015 HPW 1751B TYP AT 100mA F 0 2.8 3.0 3.2 3.4 3.6 V (V) IN 1.5x Mode CPO Output Ripple ...
Page 5
... C1 and from this pin and GND is used to set the LED current level. Connecting a resistor less will cause the LTC3215 to enter overcurrent shutdown mode. EN (Pin 6): Input. The EN is used to enable the part or put it into shutdown mode. V (Pin 7): Power. Supply voltage for the LTC3215 should be bypassed with a 2.2µ ...
Page 6
... Charge Pump Strength When the LTC3215 operates in either the 1.5x mode or 2x mode, the charge pump can be modeled as a Thevenin- equivalent circuit to determine the amount of current available from the effective input voltage and effective ...
Page 7
... This delay allows the LED to warm up and reduce its forward voltage which may remove the dropout condition. In order to reset the part back into 1x mode, the LTC3215 must be brought into shutdown (EN = LOW). Immediately after the part has been brought to shutdown, it may be enabled into the 1x mode via the EN pin ...
Page 8
... Both the style and value of the output capacitor can significantly affect the stability of the LTC3215. As shown in the block diagram, the LTC3215 uses a control loop to adjust the strength of the charge pump to match the current required at the output. The error signal of this loop is stored directly on the output charge storage capacitor ...
Page 9
... U pins can couple energy capacitively to adjacent PCB runs. Magnetic fields can also be generated if the flying capaci- tors are not close to the LTC3215 (i.e., the loop area is large). To decouple capacitive energy transfer, a Faraday shield may be used. This is a grounded PCB trace between the sensitive node and the LTC3215 pins. For a high quality AC ground, it should be returned to a solid ground plane that extends all the way to the LTC3215 ...
Page 10
... since the input current will be very close to the LED current. At moderate to high output power, the quiescent current of the LTC3215 is negligible and the expression above is valid. Once dropout is detected at the I LED enables the charge pump in 1.5x mode 1.5x boost mode, the efficiency is similar to that of a linear regulator with an effective input voltage of 1 ...
Page 11
... ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE LTC3215 R = 0.115 0.38 ± 0.10 TYP 6 10 ...
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... McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● High Power Camera Light and Flash 2.2µF 2.2µF + – 2.9V TO 4.4V V CPO IN 2.2µF µP LTC3215 2.8V I LED EN 2.8V 30k I SET 1% 10.5k 1% 3215 TA02 COMMENTS V : 1.6V to 18V Package 25V ...