Datasheet

UNISONIC TECHNOLOGIES CO., LTD
L4120
Preliminary
CMOS IC
40V/1.2A INTEGRATED
POWER LED DRIVER

1
DESCRIPTION
The UTC L4120 is a continuous conduction mode inductive
step-down converter, designed for driving single or multiple series
connected LEDs. Using a few external components.
The UTC L4120 has a build-in power switch, based on different
input voltage, The UTC L4120 can drive several 1W or 3W LEDs.
The device has the function of thermal shutdown protection and
LED short-circuit/open-circuit protection.

SOT-89-5
FEATURES
* Up to 1.2A output current
* High efficiency (up to 97%)
* Wide input voltage range: 5V~30V
* Typical ±5% output current accuracy
* Single DIM pin on/off and brightness control using DC voltage or
PWM signal
* Internal thermal shutdown protection.
* Adjustable Constant LED Current

ORDERING INFORMATION
Ordering Number
L4120G-AB5-R
Package
SOT-89-5
Packing
Tape Reel
L4120G-AB5-R

(1)Packing Type
(1) R: Tape Reel
(2)Package Type
(2) AB5: SOT-89-5
(3)Green Package
(3) G: Halogen Free and Lead Free
MARKING
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Copyright © 2015 Unisonic Technologies Co., Ltd
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L4120
Preliminary

PIN CONFIGURATION
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PIN DESCRIPTION
PIN NO.
1
2
3
4
5

PIN NAME
LX
GND
ADJ
ISENSE
VIN
CMOS IC
DESCRIPTION
Switch pin
Ground
Multi-function On/Off and brightness control pin
Current sense input
Input voltage
BLOCK DIAGRAM
+
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
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L4120

Preliminary
CMOS IC
ABSOLUTE MAXIMUM RATING
PARAMETER
RATINGS
UNIT
-0.3~+40
V
VIN≥5V
VIN+0.3~VIN-5
V
ISENSE Voltage
VISENSE
VIN<5V
VIN+0.3~ -0.3
V
LX Output Voltage
VLX
-0.3~+40
V
Adjust Pin Input Voltage
VADJ
-0.3~+6
V
Switch Output Current
ILX
1.5
A
Power Dissipation
PD
0.5
W
Junction Temperature
TJ
150
°C
Operating Temperature
TOP
-40~105
°C
Storage Temperature
TSTG
-55~150
°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.
Input Voltage

THERMAL DATA
PARAMETER
Junction to Ambient

SYMBOL
VIN
SYMBOL
θJA
RATINGS
180
UNIT
°C/W
ELECTRICAL CHARACTERISTICS (VIN=12V, TAMB=25°C unless otherwise stated) (Note 1)
PARAMETER
Input Voltage
Quiescent Supply Current with Output Off
Quiescent Supply Current with Output
Switching
Mean Current Sense Threshold Voltage
Sense Threshold Hysteresis
External Control Voltage Range On ADJ Pin
for DC Brightness Control
DC Voltage On ADJ Pin to Switch Chip from
Active (On) State to Quiescent (Off) State
DC Voltage On ADJ Pin to Switch Chip from
Quiescent (Off) State to Active (On) State
Resistance Between ADJ Pin and VREF
Continuous LX Switch Current
LX Switch “On” Resistance
LX Switch Leakage Current
Minimum Switch “ON” Time
Minimum Switch “OFF” Time
Typical Dimming Ratio
SYMBOL
TEST CONDITIONS
VIN
IINQoff ADJ Pin Grounded
IINQon
MIN
6
TYP
ADJ Pin Floating
VSENSE
VSENSEHYS
UNIT
V
μA
1000
μA
115
±15
VADJ
0.3
mV
%
1.2
V
VADJoff
VADJ Falling
0.15
0.2
0.25
V
VADJon
VADJ Rising
0.2
0.25
0.3
V
RADJ
ILXmean
RLX
ILX(leak)
TONmin LX Switch “ON”
TOFFmin LX Switch “OFF”
F=100Hz, VIN=15V, 1LED,
Ddim
L=27μH
500
1.2
0.4
1
200
200
UNISONIC TECHNOLOGIES CO., LTD
KΩ
A
Ω
μA
ns
ns
1200:1
Recommended Maximum Operating
fLXmax
Frequency
Recommended Duty Cycle Range of Output
DLX
0.3
Switch at fLXmax
Internal Comparator Propagation Delay
TPD
Thermal Shutdown Temperature
TSD
Thermal Shutdown Hysteresis
TSD-HYS
Note: Production testing of the chip is performed at 25°C. Functional operation of the chip and
are guaranteed by design, characterization and process control in other temperature.
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MAX
40
400
1
0.7
MHz
0.9
50
ns
150
°C
20
°C
parameters specified
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
Preliminary
CMOS IC
TYPICAL APPLICATION CIRCUIT
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.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
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