Document
UNISONIC TECHNOLOGIES CO., LTD
L5100
LINEAR INTEGRATED CIRCUIT
WHITE LED STEP-UP CONVERTER
DESCRIPTION
The UTC L5100 is a STEP-UP DC/DC Converter and designed for driving white LEDs with a constant current. It can drive several LEDs in series by a Li-Ion cell. UTC L5100 switches at a high frequency 1.2MHz, so it can allow the use of tiny external components. The output capacitor can be as small as 0.22μF; saving space and cost compare with alternative other solutions. The low 95mV feedback voltage minimizes power loss in the current setting resistor can have better efficiency.
FEATURES
* Inherently Matched LED Current * High Efficiency: 83% Typical * Drives Up to Four LEDs from a 3.2V Supply * Drives Up to Six LEDs from a 5V Supply * 36V Rugged Bipolar Switch * 1.2MHz Switching Frequency * Uses Tiny 1mm Tall Inductors * Output Capacitor can be Small to only 0.22μF
ORDERING INFORMATION
Ordering Number L5100G-AF5-R
Package SOT-25
Packing Tape Reel
MARKING
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L5100
PIN CONFIGURATION
LINEAR INTEGRATED CIRCUIT
PIN DESCRIPTION
PIN NO. 1 2
3
4 5
PIN NAME SW GND
FB
SHDN VIN
DESCRIPTION Switch. Connect inductor/diode here. Minimize trace area at this pin to reduce EMI. Ground. Connect directly to local ground plane. Feedback. Reference voltage is 95mV. Connect cathode of lowest LED and resistor here. Calculate resistor value according to the formula: RFB = 95mV/ILED
Shutdown. Connect to 1.5V or higher to enable device; 0.4V or less to disable device.
Input Supply Pin. Must be locally bypassed.
BLOCK DIAGRAM
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QW-R103-024.F
L5100
LINEAR INTEGRATED CIRCUIT
ABSOLUTE MAXIMUM RATINGS
PARAMETER
SYMBOL
RATINGS
UNIT
Input Voltage Switch Voltage
VIN 12 V VSW 36 V
Feedback Voltage Shutdown Voltage
VFB VSHDN
12 12
V V
Junction Temperature Operating Junction Temperature
TJ
+125
°C
TJ
-40~+85
°C
Storage Temperature Range
TSTG
-65~+150
°C
Note: Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.
THERMAL RESISTANCES CHARACTERISTICS
PARAMETER Junction to Ambient (in free air)
SYMBOL θJA
RATINGS 256
UNIT °C/W
ELECTRICAL CHARACTERISTICS (TA=25°C, VIN=3V, VSHDN =3V, unless otherwise specified.)
PARAMETER Operating Voltage Feedback Voltage Shutdown Voltage ON Shutdown Voltage OFF Switch VCESAT Switch Current Limit
Supply current
Switch Leakage Current Shutdown Pin Bias Current Feedback Pin Bias Current Switching Frequency Maximum Duty Cycle
SYMBOL VIN VFB VON VOFF
VCESAT(SW) ISW
ICC
ISW(OFF) ISHDN
IFB fOSC DC
TEST CONDITIONS ISW=100mA, Duty Cycle=66%
ISW=250mA SHDN =0V VSW=5V
MIN TYP MAX UNIT
2.5 12 V
87 95 104 mV
1.5 V
0.3 V
360 mV
320 mA
1.8 2.5 mA
0.1 1.0 µA
0.01 5
µA
60 µA
10 45 100 nA
0.8 1.2 1.6 MHz
85 90
%
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QW-R103-024.F
L5100
TYPICAL APPLICATION CIRCUITS
LINEAR INTEGRATED CIRCUIT
EFFICIENCY(%)
EFFICIENCY (%)
EFFICIENCY (%)
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L5100
TYPICAL APPLICATION CIRCUITS (Cont.)
VIN 3V ~ 5V
CIN 1μF
L=22μH
D
VDC DIMMING
COUT 0.22μF
VIN SW
SHDN FB GND
90k 5k
R1 4Ω
LINEAR INTEGRATED CIRCUIT
Five LED Efficiency 85
80 VIN=3V
75 VIN=3.6V
70
Li - Ion to Five White LEDs
V IN 5V
C IN 1µF
L=22μH
D
VDC DIMMING
VIN SW
SHDN FB GND
90 k 5k
R1 4Ω
65 0
85
2 4 6 8 10 12 LOAD CURRENT (mA)
Six LED Efficiency
C OUT 0. 22µF
80
75
70
5 V to Six White LEDs
65 0
5
1 0
LOAD CURRENT (mA)
1 5
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IQ (mA) CURRENT LIMIT (mA)
L5100
TYPICAL CHARACTERISTICS
Quiescent Current 2 .2 2.0 25°C 1.8
80°C
1.6 1 .4 1.2 1 .0 0.8 0 .6 0 .4 0 .2
0 0 2 4 6 8 10 VIN (V)
* UTC L5100 is guaranteed the operating temperature range of 0°C ~ 75°C.
LINEAR INTEGRATED CIRCUIT
350 300 250 200 150 100 50
0 0
Current Limit vs Duty Cycle
20 40 60 80 DUTY CYCLE (%)
100
UTC assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all UTC products described or contained herein. UTC products are not designed for use in life support appliances, devices or systems where
malfunction of these products can be reasonably expected to result in personal injury. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.
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