®
RT9018A/B
Maximum 3A, Ultra Low Dropout Regulator
General Description
The RT9018A/B is a high performance positive voltage
regulator designed for use in applications requiring very
low Input voltage and very low dropout voltage at up to
3A(Peak). It operates with a VIN as low as 1.4V and VDD
voltage 3V with output voltage programmable as low as
0.8V. The significant feature includes ultra low dropout,
ideal for applications where VOUT is very close to VIN.
Additionally, there is an enable pin to further reduce power
dissipation while shutdown. The RT9018A/B provides
excellent regulation over variations in line, load and
temperature. and provides a power OK signal to indicate
if the voltage level of Vo reaches 90% of its rating value.
The RT9018A/B is available in the SOP-8 (Exposed Pad)
and WDFN-10L 3x3 packages with 1V, 1.05V, 1.2V, 1.5V,
1.8V and 2.5V internally preset outputs that are also
adjustable using external resistors.
Features
Maximum 3A Low-Dropout Voltage Regulator
High Accuracy Output Voltage
±
1.5%
Typically 210mV Dropout at 3A
Power Good Output
Output Voltage Pull Low Resistance when Disable
Thermal and Over Current Protection
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Front Side Bus VTT (1.2V/3A)
NoteBook PC Applications
Motherboard Applications
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Ordering Information
RT9018A/B-
Package Type
SP : SOP-8 (Exposed Pad-Option 1)
QW : WDFN-10L 3x3
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Z : ECO (Ecological Element with
Halogen Free and Pb free)
Output Voltage
10 : 1V/Adj
1K : 1.05V/Adj
12 : 1.2V/Adj
15 : 1.5V/Adj
18 : 1.8V/Adj
25 : 2.5V/Adj
Enable Pin Function
A : Internal Pull High
B : Internal Pull Low
Note :
Richtek products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
Pin Configurations
(TOP VIEW)
PGOOD
EN
VIN
VDD
2
3
4
8
7
GND
6
9
5
GND
ADJ
VOUT
NC
SOP-8 (Exposed Pad)
WDFN-10L 3x3
is a registered trademark of Richtek Technology Corporation.
DS9018A/B-09 April 2012
9
VOUT
VOUT
VOUT
ADJ
PGOOD
1
2
3
4
5
GND
11
10
9
8
7
VDD
VIN
VIN
VIN
EN
www.richtek.com
1
RT9018A/B
Typical Application Circuit
V
OUT
=
0.8
×
R1
+
R2
R2
V
IN
10µF
Chip Enable
V
DD
1µF
V
OUT
VIN
VOUT
10µF
Chip Enable
V
DD
1µF
V
OUT
V
OUT
V
IN
10µF
VIN
VOUT
C
Dummy
R1
V
OUT
10µF
RT9018A/B
EN
VDD
GND
ADJ
PGOOD
100k
RT9018A/B
EN
VDD
GND
ADJ
PGOOD
R2
100k
Figure 1. Fixed Voltage Regulator
Figure 2. Adjustable Voltage Regulator
Function
Pin Description
Pin No.
SOP-8
(Exposed Pad)
3
2
4
1
7
6
WDFN-10L 3x3
7, 8, 9
6
10
5
4
1, 2, 3
Pin
Name
VIN
EN
VDD
PGOOD
ADJ
VOUT
Supply Input Voltage.
Chip Enable (Active-High).
Supply Voltage of Control Circuitry.
Power Good Open Drain Output.
Set the output voltage by the internal feedback resistors when
ADJ is grounded. If external feedback resistors is used, V
OUT
=
0.8V x (R1 + R2)/R2.
Output Voltage.
No Internal Connection.
Ground. The exposed pad must be soldered to a large PCB
and connected to GND for maximum power dissipation.
Pin Function
5
--
NC
8,
11 (Exposed Pad) GND
9 (Exposed Pad)
Function Block Diagram
VIN
OCP
Driver
Error
Amplifier
VOUT
OTP
+
-
EN
VDD
POR
0.8V
Mode
-
0.72V
+
ADJ
PGOOD
GND
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS9018A/B-09 April 2012
RT9018A/B
Absolute Maximum Ratings
(Note 1)
1V to 6V
3V to 6V
0.8 to 6V
1.33W
1.67W
Supply Voltage, VIN ------------------------------------------------------------------------------------------------------
Control Voltage, VDD -----------------------------------------------------------------------------------------------------
Output Voltage, VOUT ---------------------------------------------------------------------------------------------------
Power Dissipation, P
D
@ T
A
= 25°C
SOP-8 (Exposed Pad) ---------------------------------------------------------------------------------------------------
WDFN-10L 3x3 -------------------------------------------------------------------------------------------------------------
Package Thermal Resistance (Note 2)
SOP-8 (Exposed Pad),
θ
JA
---------------------------------------------------------------------------------------------- 75°C/W
SOP-8 (Exposed Pad),
θ
JC
--------------------------------------------------------------------------------------------- 15°C/W
WDFN-10L 3x3,
θ
JA
------------------------------------------------------------------------------------------------------- 60°C/W
Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- 260°C
Storage Temperature Range --------------------------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Mode) ---------------------------------------------------------------------------------------------- 2kV
MM (Machine Mode) ------------------------------------------------------------------------------------------------------ 200V
Recommended Operating Conditions
(Note 4)
1.4V to 5.5V
3V to 5.5V
4.5V to 5.5V
−40°C
to 125°C
−
40°C to 85°C
Supply Voltage, V
IN
-------------------------------------------------------------------------------------------------------
Control Voltage, VDD (V
DD
> V
OUT
+ 1.5V) --------------------------------------------------------------------------
Control Voltage with PGOOD, VDD (Note 8) -----------------------------------------------------------------------
Junction Temperature Range --------------------------------------------------------------------------------------------
Ambient Temperature Range --------------------------------------------------------------------------------------------
Electrical Characteristics
(V
IN
= V
OUT
+ 500mV, V
EN
= V
DD
= 5V, C
IN
= C
OUT
= 10μF, T
A
= T
J
= 25°C, unless otherwise specified)
Parameter
POR Threshold
POR Hysteresis
Adjustable Pin Threshold
Fixed Output Voltage Range
Line Regulation (V
IN
)
Load Regulation
(Note 5)
Symbol
Test Conditions
Min
2.4
0.15
Typ
2.7
0.2
0.2
0.8
0
0.2
0.2
150
210
0.6
4.5
Max
3
--
0.4
0.812
1.5
0.6
1
250
350
1.2
--
Unit
V
V
V
V
%
%
%
mV
mA
A
V
TH_ADJ
ΔV
OUT
ΔV
LINE_IN
ΔV
LOAD
V
DROP
I
Q
I
LIM
I
OUT
= 1mA
I
OUT
= 1mA
V
IN
= V
OUT
+ 0.5V to 5V,
I
OUT
= 1mA
V
IN
= V
OUT
+ 1V,
I
OUT
= 1mA to 3A
I
OUT
= 2A
I
OUT
= 3A
V
DD
= 5.5V
--
0.788
−1.5
--
--
--
--
--
3.2
Reference Voltage (ADJ Pin Voltage) V
ADJ
Dropout Voltage (Note 6)
Quiescent Current (Note 7)
Current Limit
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9018A/B-09 April 2012
www.richtek.com
3
RT9018A/B
Parameter
Short Circuit Current
In-rush Current
V
OUT
Pull Low Resistance
Chip Enable
EN Input Bias Current
VDD Shutdown
Current
EN Threshold Voltage
Power Good
PGOOD Rising Threshold
PGOOD Hysteresis
PGOOD Sink Capability
PGOOD Delay
Thermal Protection
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
Thermal Shutdown Temperature
Fold-back
T
SD
ΔT
SD
V
OUT
< 0.4V
--
--
--
160
30
110
--
--
--
°C
°C
°C
I
PGOOD
= 10mA
--
3
--
0.5
90
10
0.2
1.5
93
--
0.4
5
%
%
V
ms
RT9018A
RT9018B
Logic-Low
Logic-High
I
EN
I
SHDN
V
ENL
V
ENH
V
EN
= 0V
V
EN
= 0V
V
DD
= 5V
V
DD
= 5V
--
--
--
--
1.2
12
10
--
--
--
--
20
1
0.7
--
μA
μA
V
Symbol
Test Conditions
V
OUT
< 0.2V
C
OUT
= 10μF, Enable Start-up
V
EN
= 0V
Min
0.5
--
--
Typ
1.8
0.6
150
Max
--
--
--
Unit
A
A
Ω
Note 1.
Stresses beyond those listed
“Absolute
Maximum Ratings” may cause permanent damage to the device. These are
stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in
the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may
affect device reliability.
Note 2.
θ
JA
is measured at T
A
= 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7.
θ
JC
is
measured at the exposed pad of the package.
Note 3.
Devices are ESD sensitive. Handling precaution recommended.
Note 4.
The device is not guaranteed to function outside its operating conditions.
Note 5.
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.
Note 6.
The dropout voltage is defined as V
IN
-V
OUT
, which is measured when V
OUT
is V
OUT(NORMAL)
- 100mV.
Note 7.
Quiescent, or ground current, is the difference between input and output currents. It is defined by I
Q
= I
IN
- I
OUT
under no
load condition (I
OUT
= 0mA). The total current drawn from the supply is the sum of the load current plus the ground pin
current.
Note 8.
The control voltage must within 4.5V to 5.5V when using PGOOD function.
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS9018A/B-09 April 2012
RT9018A/B
Typical Operating Characteristics
Load Transient Response
V
DD
= 5V, V
IN
= 1.8V, V
OUT
= 1.2V
Load Transient Response
V
DD
= 5V, V
IN
= 1.8V, V
OUT
= 1.2V
V
OUT
(20mV/Div)
V
OUT
(20mV/Div)
I
OUT
(1A/Div)
Time (2.5ms/Div)
I
OUT
(1A/Div)
Time (2.5ms/Div)
V
IN
Line Transient Response
V
DD
= 5V, V
OUT
= 1.2V, I
OUT
= 0A
V
IN
Line Transient Response
V
DD
= 5V, V
OUT
= 1.2V, I
OUT
= 2A
V
IN
3
2
V
IN
3
2
V
OUT
(20mV/Div)
V
OUT
(20mV/Div)
Time (250μs/Div)
Time (250μs/Div)
V
DD
Line Transient Response
V
IN
= 1.8V, V
OUT
= 1.2V, I
OUT
= 0A
V
DD
Line Transient Response
V
IN
= 1.8V, V
OUT
= 1.2V, I
OUT
= 2A
V
DD
5
4
V
DD
5
4
V
OUT
(20mV/Div)
V
OUT
(20mV/Div)
Time (250μs/Div)
Time (250μs/Div)
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9018A/B-09 April 2012
www.richtek.com
5
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