Datasheet

UNISONIC TECHNOLOGIES CO., LTD
L11831A/B
Preliminary
CMOS IC
MAXIMUM 3A, ULTRA LOW
DROPOUT REGULATOR WITH
ENABLE

DESCRIPTION
The UTC L11831A/B is a positive voltage regulator with high
performance. It has low dropout voltage and low input voltage,
besides its output voltage can be fixed at 1V,1.05V, 1.2V, 1.5V,
1.8V, or 2.5V depending on internal feedback resistors or ADJ (not
connected to the ground) with external feedback resistors. The
input voltage of UTC L11831A/B can be low to 1.4V. There are two
additional pin in the UTC L11831A/B. One is EN pin and the other
is POK pin.
The UTC L11831A/B is specially made for applications with low
input voltage, low dropout voltage, and low output voltage which is
almost the same as the input voltage. Typical applications include
motherboards, notebooks, set top boxes, network cards and
peripheral cards.

FEATURES
* VIN as low as 1.4V and VDD voltage 5V
* Maximum 3A low-dropout voltage regulator
* High accuracy output voltage ±1.5%
* When disable VO pull low resistance
* Internal over current and over temperature protection

ORDERING INFORMATION
Ordering Number
Note:
L11831AG-xx-SH2-R
L11831BG-xx-SH2-R
xx: Output Voltage, refer to Marking Information.
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Copyright © 2014 Unisonic Technologies Co., Ltd
Package
Packing
HSOP-8
HSOP-8
Tape Reel
Tape Reel
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L11831A/B

Preliminary
MARKING INFORMATION
PACKAGE
VOLTAGE CODE
HSOP-8
12: 1.2v
15 : 1.5V
18: 1.8V
25: 2.5V

CMOS IC
MARKING
PIN CONFIGURATION
POK
1
EN
2
8
GND
7
ADJ
GND

VIN
3
6
VOUT
VDD
4
5
NC
PIN DESCRIPTION
PIN NO.
PIN NAME
1
POK
2
3
4
5
6
EN
VIN
VDD
NC
VOUT
7
ADJ
8
GND
DESCRIPTION
This pin will indicate high under this situation: VO reaches 90% of its rating voltage.
Open-drain output.
Chip enable (active-high) / (active-low)
The pin of input voltage.
This pin is for input voltage to control circuit.
No internal connection
Output voltage
When this pin connected to the ground, VOUT will be set by the internal feedback
resistors. Otherwise, if using external feedback resistors to decide the VOUT, VOUT =
0.8(R1+R2)/R2 Volts.
Ground.
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
Preliminary
CMOS IC
BLOCK DIAGRAM
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
Preliminary
CMOS IC
ABSOLUTE MAXIMUM RATING
PARAMETER
SYMBOL
RATINGS
UNIT
Input Voltage
VDD, VIN
6
V
Power Dissipation
PD
Internally limited
Junction Temperature
TJ
150
°C
Operation Temperature
TOPR
-40~+85
°C
Storage Temperature
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.

RECOMMENDED OPERATING CONDITIONS (Note 1)
PARAMETER
Supply Voltage
Control Voltage (VDD≥VOUT+1.5V)
Junction Temperature Range
Ambient Temperature Range

SYMBOL
VIN
VDD
TJ
TA
RATINGS
1.4~5.5
3~5.5
-40~125
-40~85
UNIT
V
V
°C
°C
SYMBOL
θJA
θJC
RATINGS
143
14
UNIT
°C/W
°C/W
THERMAL DATA
PARAMETER
Junction to Ambient
Junction to Case
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
Preliminary
CMOS IC
ELECTRICAL CHARACTERISTICS
(VIN=VOUT+500mV, VEN=VDD=5V, CIN=COUT=10µF, TA=TJ=25°C, unless otherwise specified)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP MAX UNIT
POR Threshold
2.4
2.7
3
V
POR Hysteresis
0.2
V
Adjustable Pin Threshold
VTH_ADJ IOUT=1mA
0.2
0.4
V
Reference Voltage (ADJ Pin Voltage)
VADJ
IOUT=1mA
0.788
0.8 0.812
V
Fixed Output Voltage Range
∆VOUT
-1.5
0
1.5
%
Line Regulation (VIN)
∆VLINE_IN VIN=VOUT+0.5V to 5V, IOUT=1mA
0.2
0.6
%
Load Regulation (Note 2)
∆VLOAD VIN=VOUT+1V, IOUT=1mA~3A
0.4
1
%
IOUT=2A
200 250
mV
Dropout Voltage (Note 3)
VDROP
IOUT=3A
300 350
mV
Quiescent Current (Note 4)
IQ
VDD=5.5V
0.9
mA
Current Limit
ILIM
3.2
5.5
A
Short Circuit Current
VOUT<0.2V
0.5
1.8
A
VOUT Pull Low Resistance
VEN=0V
100
Ω
Chip Enable
EN Input Bias Current
IEN
VEN=0V
12
µA
L11831A
10
20
µA
VDD Shutdown Current
ISHDN
VEN=0V
L11831B
1
µA
Logic-High
VENH
VDD=5V
1.2
V
EN Threshold Voltage
Logic-Low
VENL
VDD=5V
0.7
V
Power Good
POK Rising Threshold
90
93
%
POK Hysteresis
3
10
%
POK Sink Capability
IPOK=10mA
0.2
0.4
V
POK Delay
0.5
1.5
5
ms
Thermal Protection
Thermal Shutdown Temperature
TSD
160
°C
Thermal Shutdown Hysteresis
∆TSD
30
°C
Notes: 1. The device is not guaranteed to function outside its operating conditions.
2. Regulation is measured at constant junction temperature by using a 2ms current pulse. Devices are tested
for load regulation in the load range from 1mA to 3A.
3. The dropout voltage is defined as VIN-VOUT, which is measured when VOUT is VOUT(NORMAL)-100mV.
4. Quiescent, or ground current, is the difference between input and output currents. It is defined by
IQ=IIN-IOUT under no load condition (IOUT=0mA). The total current drawn from the supply is the sum of the
load current plus the ground pin current.
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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.
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