Datasheet

UNISONIC TECHNOLOGIES CO., LTD
L1806
CMOS IC
3A, ULTRA LOW DROPOUT
(0.23V@3A) LINEAR
REGULATOR

DESCRIPTION
The UTC L1806 is a typical LDO with the features of very low
dropout voltage as low as 0.23V at output current 3A.
For normal operation, two supply voltages are necessary. One
called control voltage from other equipment can shutdown the
output voltage and it should pull and hold the voltage of EN pin less
than 0.5V. Another one is the main supply voltage whose purpose is
for main power conversion, to keep the power dissipation low, and
to make the dropout voltage lower.
Internally, in the UTC L1806, there’re many functions which
can be seen in the block figure to prevent the IC from being
damaged. Internal Power-On-Reset (POR) circuit can control the
two supply voltages to prevent fault operations of the circuit; the
thermal shutdown circuit is able to protect the device from over
thermal operation, and a current limit function will keep the device
work safely under current over-loads.
The UTC L1806 can be used as an ideal to provide well supply
voltage in the applications, such as front-side-bus termination on
motherboard, NB applications, front side bus VTT (1.2V/3A) and
note book PC applications.

FEATURES
* Low Dropout VD=0.23V(typ.)@ IOUT=3A
* Low ESR Output Capacitor
* VREF=0.8V
* Fast Transient Response
* Output Voltage Adjustable through External Resistors
* POR(Power-On-Reset) controlling VCNTL and VIN
* With internal Soft-Start

* Internal Current Limit Protection
* Internal Under Voltage Protection
* Hysteretic Thermal Shutdown
* With Power-OK Output (with a Delay Time)
* Low Shutdown Quiescent Current (<30 uA)
* Shutdown/Enable Control Function
ORDERING INFORMATION
Ordering Number
L1806G-SH2-R
L1806G-K10-3030-R
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Copyright © 2015 Unisonic Technologies Co., Ltd
Package
HSOP-8
DFN-10(3×3)
Packing
Tape Reel
Tape Reel
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L1806
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CMOS IC
MARKING
HSOP-8

DFN-10(3×3)
PIN CONFIGURATION
NC
1
10
VCNTL
VOUT
2
9
NC
NC
3
8
VIN
VOUT
FB
4
7
NC
NC
PG
5
6
EN
PG
1
8
GND
EN
2
7
FB
6
5
VIN
3
VCNTL
4
GND
GND
11
Top View
HSOP-8

DFN-10(3×3)
PIN DESCRIPTION
HSOP-8
PIN NO.
DFN-10(3×3)
PIN NAME
1
5
PG
2
6
EN
3
8
VIN
4
10
VCNTL
5
6
1, 3, 7,9
2
NC
VOUT
7
4
FB
8
11
GND
DESCRIPTION
Power Good.Output open drain to indicate the status of VOUT via
monitoring the FB pin. This pin is pulled low when the voltage is
outside the limits, during thermal shutdown and if either VCNTL or VIN
go below their thresholds.
Enable Pin. Driving this pin low will disable the part. When left
floating an internal current source will pull this pin high and enable
it.
Power Input Pin for current supply. Connect a decoupling capacitor
(≥10µF) as close as possible to the pin for noise filtering
BIAS supply for the controller, recommended 5V. Connect a
decoupling capacitor (≥1µF) as close as possible to the pin for
noise filtering.
No Connection
Power output pin
Feedback to set the output voltage via an external resistor divider
between VOUT and GND
Ground
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L1806

CMOS IC
BLOCK DIAGRAM
VCNTL
EN
Power On
Reset
FB
FB
UV
+
Soft-Start and
Control Logic
VIN
0.4V
-
Thermal
Limit
EAMP
+
VREF
0.8V
VOUT
Current Limit
+
POK
-
Dealy
PG
90%
VREF
GND
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
CMOS IC
ABSOLUTE MAXIMUM RATING
PARAMETER
SYMBOL
RATINGS
UNIT
Supply Voltage (VCNTL to GND)
VCNTL
-0.3 ~ +7
V
Supply Voltage (VIN to GND)
VIN
-0.3 ~ + 4.0
V
EN and FB to GND
VI/O
-0.3 ~ VCNTL+0.3
V
PG to GND
VPG
-0.3 ~ +7
V
Junction Temperature
TJ
150
°С
Storage Temperature
TSTG
-65 ~ +150
°С
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
PARAMETER
Supply Voltage
Supply Voltage
Control
Input
VCNTL=3.3±5%
VCNTL=5.0±5%
Output Voltage
SYMBOL
VCNTL
VIN
VOUT
Output Current

IOUT
RATINGS
3~ 5.5
1.2~ 3.65
0.8 ~ 1.2
+0.8 ~ VIN-0.2
0~4
UNIT
V
V
V
V
A
THERMAL RESISTANCES CHARACTERISTICS
PARAMETER
SYMBOL
RATINGS
UNIT
HSOP-8
90 (Note 1)
°C/W
Junction to Ambient
θJA
DFN-10(3×3)
72 (Note 2)
°C/W
Notes: 1. θJA is measured with the component mounted on a high effective thermal conductivity test board in free air.
The exposed pad of HSOP-8 is soldered directly on the PCB.
2. The PCB area is 4 times larger than that of IC’s
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L1806

CMOS IC
ELECTRICAL CHARACTERISTICS
(TA = 25°C, VCNTL = 5V, VIN = 1.5V, VOUT = 1.2V, unless otherwise specified)
PARAMETER
SYMBOL
TEST CONDITIONS
VCNTL Nominal Supply Current
ICNTL
EN = VCNTL
VCNTL Shutdown Current
ISD
EN = GND
VCNTL
VCNTL Rising
VTHR
PG Threshold
VIN
VIN Rising
VCNTL
PG Hysteresis
VHYS
VIN
Reference Voltage
VREF
FB =VOUT
Output Voltage Accuracy
IOUT=0A~3A, TJ= -25 ~125°С
∆VOUT
Line Regulation
IOUT=10mA,VCNTL=3~5V
∆VIN × VOUT
∆VOUT
Load Regulation
IOUT=0A~3A
VOUT
Current Limit
ILIMIT
VCNTL=5V, TJ= 25°С
VOUT=2.5V TJ= 25°С
VCNTL=5V
Dropout Voltage
VD
VOUT=1.8V TJ= 25°С
IOUT=3A
VOUT=1.2V TJ= 25°С
Over Temperature Shutdown
OTS
TJ Rising
Over Temperature Hysteresis
OTH
Under-Voltage Threshold
VFB Falling
EN Logic High Threshold Voltage
VEN Rising
EN Hysteresis
EN Pin Pull-Up Current
EN=GND
PG Threshold Voltage for Power OK
VPG
VFB Rising
PG Threshold Voltage for Power Not OK
VPNOK
VFB Falling
PG Low Voltage
PG sinks 5mA
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MIN TYP MAX UNIT
1
1.5 mA
15
30
µA
2.5 2.7 2.9
V
0.8 0.9 1.0
V
0.4
V
0.5
V
0.8
V
-1.5
+1.5 %
-0.15
+0.15 %/V
0.06 0.25
4
5.7
0.26
0.24
0.23
150
30
0.4
0.5 0.8
100
5
90% 92%
81%
0.25
7
0.31
0.29
0.28
%
A
V
°С
°С
V
1.1
V
mV
μA
94% VREF
VREF
0.4
V
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CMOS IC
TYPICAL APPLICATION CIRCUIT
1. Using an Output Capacitor with ESR≥18mΩ
2. Using an MLCC as the Output Capacitor
R3=1kΩ
VCNTL +5V
CCNTL=1µF
4
VCNTL
POK
VIN 3
VIN +1.5V
CIN=22µF
1 PG
UTC
L1806
VOUT 6
VOUT +1.2V/3A
VOUT 6
R1=39kΩ
EN
2 EN
C1=56pF
COUT=22µF
FB 7
GND
8
Enable
R2=78kΩ
VOUT (V)
1.05
1.5
1.8
R1 (kΩ)
43
27
15
UNISONIC TECHNOLOGIES CO., LTD
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R2 (kΩ)
137.6
30.86
12
C1 (pF)
47
82
150
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CMOS IC
APPLICATION INFORMATION
1. Power Sequencing
When there’s no main voltage applied at VIN, it is suggested not to apply a voltage to VOUT for a long time.
Because the internal parasitic diode (between VOUT to VIN) will conduct and dissipate power, there’s no protection.
2. Output Capacitor
A proper output capacitor to maintain stability and improve transient response over temperature and current is
necessary. Proper ESR (equivalent series resistance) and capacitance of the output capacitor should be selected
properly for stability of the normal operation and good load transient response.
Many kinds of capacitors can be used as an output capacitor, such as ultra-low-ESR capacitors (like ceramic
chip capacitors), low-ESR bulk capacitors (like solid Tantalum, POSCap, and Aluminum electrolytic capacitors). And
also the value of the output capacitors’ can be increased without limit.
In the applications with large stepping load current, the low-ESR bulk capacitors are normally recommended.
Decoupling ceramic capacitors are recommended to be placed at the load and ground pins very closely and also
the impedance of the layout must be minimized.
3. Input Capacitor
In order to prevent the input rail from dropping, the proper input capacitor to supply current surge during stepping
load transients is required. Because the limited slew rate of the surge currents, more parasitic inductance needs more
input capacitance.
Ultra-low-ESR capacitors (>100mF, ESR<300mW) is recommended for the input capacitor.
4. Feedback Network
The following figure shows the feedback network between VOUT GND and FB pins. Working with the internal error
amplifier, the feedback network can provide proper frequency response for the UTC L1806.
VOUT
VOUT
R1
VERR
EAMP
FB
VFB
VREF
R2
C1
ESR
COUT
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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