LT3215 Linear Technology, LT3215 Datasheet

no-image

LT3215

Manufacturer Part Number
LT3215
Description
700mA Low Noise High Current LED Charge Pump
Manufacturer
Linear Technology
Datasheet
FEATURES
TYPICAL APPLICATIO
APPLICATIO S
High Efficiency Operation: 1x, 1.5x or 2x Boost
Modes with Automatic Mode Switching
Ultralow Dropout I
Output Current up to 700mA
Low Noise Constant Frequency Operation*
Wide V
Open/Shorted LED Protection
LED Disconnect in Shutdown
Low Shutdown Current: 2.5µA
4% LED Current Programming Accuracy
Automatic Soft-Start Limits Inrush Current
No Inductors
Tiny Application Circuit (All Components <1mm
Profile)
3mm × 3mm 10-Lead DFN Package
LED Torch/Camera Light Supply for Cell Phones,
PDAs and Digital Cameras
General Lighting and/or Flash/Strobe Applications
2.9V TO 4.4V
DISABLE ENABLE
IN
2.2µF
C
Range: 2.9V to 4.4V
IN
LED1: AOT2015 HPW 1751B
U
C1
V
EN
IN
LED
2.2µF
+
I
SET
C1
20k
1%
C1
Current Control
LTC3215
C2
+
2.2µF
C2
CPO
I
C2
LED
U
3215 TA01a
I
200mA
LED1
LED
C
4.7µF
CPO
*Protected by U.S. Patent 6411531.
DESCRIPTIO
The LTC
DC/DC converter designed to power high current LEDs.
The part includes an accurate programmable current
source capable of driving loads up to 700mA from a 2.9V
to 4.4V input. 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. High switching frequency enables the
use of small external capacitors. LED current is pro-
grammed with an external resistor. The LED is discon-
nected from V
An ultralow dropout current source maintains accurate
LED current at very low I
switching optimizes efficiency by monitoring the voltage
across the LED current source and switching modes only
when I
a low profile 3mm × 3mm 10-Lead DFN package.
Current LED Charge Pump
, LTC and LT are registered trademarks of Linear Technology Corporation.
LED
700mA Low Noise High
®
3215 is a low noise, high current charge pump
dropout is detected. The LTC3215 is available in
100
90
80
70
60
50
40
30
20
10
0
2.8
IN
LED = AOT2015 HPW 1751B
V
F
= 3V TYP AT 200mA
3.0
during shutdown.
U
3.2
Efficiency vs V
3.4
LED
V
IN
3.6
(V)
voltages. Automatic mode
3.8
I
LED
IN
= 200mA
4.0
4.2
3215 TA01b
LTC3215
4.4
1
3215f

Related parts for LT3215

LT3215 Summary of contents

Page 1

... LED current at very low I switching optimizes efficiency by monitoring the voltage across the LED current source and switching modes only when I LED a low profile 3mm × 3mm 10-Lead DFN package. , LTC and LT are registered trademarks of Linear Technology Corporation. *Protected by U.S. Patent 6411531. – LED1 C CPO 4.7µ ...

Page 2

LTC3215 ABSOLUTE AXI U RATI GS (Note GND ............................................... –0.3V to 5.5V IN CPO to GND ............................................. –0.3V to 5.5V EN ................................................... –0. (Note 2) ........................................... 1000mA CPO ILED ...

Page 3

ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T PARAMETER I SET V ISET I ISET Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Based on long-term current ...

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 ...

Page 5

CTIO – – (Pins 10): Charge Pump Flying Capacitor Pins. A 2.2µF X5R or X7R ceramic capacitor should be connected from C1 ...

Page 6

LTC3215 U OPERATIO The LTC3215 uses a fractional switched capacitor charge pump to power a high current LED with a programmed regulated current. The part starts up into the 1x mode. In this mode directly connected to CPO. ...

Page 7

U OPERATIO – 3215 F01 Figure 1. Charge Pump Open-Loop Thevenin-Equivalent Circuit R is dependent on a number of factors including OL the oscillator frequency, flying capacitor values and switch resistances. From ...

Page 8

LTC3215 U U APPLICATIO S I FOR ATIO V , CPO Capacitor Selection IN The value and type of capacitors used with the LTC3215 determine several important parameters such as regulator control loop stability, output ripple, charge pump strength and ...

Page 9

U U APPLICATIO S I FOR ATIO compare the amount of achievable capacitance for a given case size rather than comparing the specified capacitance value. For example, over rated voltage and temperature conditions, a 1µF, 10V, Y5V ceramic capacitor in ...

Page 10

LTC3215 U U APPLICATIO S I FOR ATIO Power Efficiency To calculate the power efficiency (η white LED driver chip, the LED power should be compared to the input power. The difference between these two numbers repre- sents ...

Page 11

... TOP MARK (SEE NOTE 6) Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights Package 10-Lead Plastic DFN (3mm × ...

Page 12

... I = 25µA/50µA, I OUT(MAX 5.25V 28µA, I <1µA OUT(MAX 2.7V to 4.5V 2.5mA, I IN(MAX 40V 1.2mA, I < 1µA OUT(MAX 40V 2µA, I < 1µA OUT(MAX LT/TP 0305 1K • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 2005 <1µA < 6µA SD 3215f ...

Related keywords