Document
RT9181
150mA LDO Regulator with PGOOD
General Description
The RT9181 is a low dropout voltage regulator with an output 2% accuracy and supply a continuous 150mA current within operating range from a +3V to +5.5V input. The power good function monitors the output voltage and indicates by pulling low the power good output (open drain).
The RT9181 requires a small output capacitor with low ESR for stabilizing output voltage. The device also minimizes output overshoot during power up.
The RT9181 uses an internal PMOS as the pass device, which consumes 160μA supply current independent of load and dropout conditions. The EN pin controls the output and consumes no input bias current. Other features include current limiting, over temperature protection, and under voltage lockout.
Features
z Low Dropout Voltage Regulator z Up to 150mA Output Current z Power Good (PGOOD) Function z Chip Enable/Shutdown Function z Load Independent, Low Quiescent Current, 160μA z Current Limiting and Thermal Protection z Under Voltage Lockout (UVLO) z Low Variation Due to Load and Line Regulation z Output Stable with Low ESR Capacitors z SOT-23-5 Package z RoHS Compliant and 100% Lead (Pb)-Free
Applications
z Processor Power-Up Sequencing z Laptop, Notebook, and Palmtop Computers
Ordering Information
RT9181-
Pin Configurations
(TOP VIEW)
Package Type B : SOT-23-5 Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commer-
cial Standard) Output Voltage Default : 1.2V 18 : 1.8V
Note : RichTek Pb-free and Green products are :
`RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
`Suitable for use in SnPb or Pb-free soldering processes. `100% matte tin (Sn) plating.
Marking Information
For marking information, contact our sales representative directly or through a RichTek distributor located in your area, otherwise visit our website for detail.
VIN 1 5 VOUT GND 2
EN 3 4 PGOOD
SOT-23-5
Typical Application Circuit
VIN CIN 1uF
+
1 VIN PGOOD 4
Chip Enable 3 EN VOUT 5
GND 2
10K PGOOD
VOUT COUT 1uF
DS9181-14 March 2007
www.richtek.com 1
RT9181
Function Block Diagram
VIN
Shutdown
Undervoltage
Current
EN
Control
Lockout
Limit
Thermal Control
Gate Control
VREF
+
-
Fault
Output Voltage Detection
GOOD Delay Timer
Power Good Control
Functional Pin Description
Pin Name VIN GND EN PGOOD VOUT
Pin Function Power Input Voltage Ground Chip Enable (Active High) Power Good Indicator Output Voltage
Timing Diagram
VOUT
90% max of VOUT (normal) VPGOODH
tD (PG) 2.0ms typ.
PGOOD
www.richtek.com 2
VOUT PGOOD GND
VPGOODL 85% min of VOUT (normal)
DS9181-14 March 2007
RT9181
Absolute Maximum Ratings (Note 1)
z Supply Input Voltage, VIN -------------------------------------------------------------------------------------------- 7V z Enable Input Voltage -------------------------------------------------------------------------------------------------- 7V z Power Good Output Voltage ---------------------------------------------------------------------------------------- 7V z Power Dissipation, PD @ TA = 25°C
SOT-23-5 ---------------------------------------------------------------------------------------------------------------- 0.4W z Package Thermal Resistance (Note 6)
SOT-23-5, θJA ----------------------------------------------------------------------------------------------------------- 250°C/W z Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------- 260°C
z Storage Temperature Range ---------------------------------------------------------------------------------------- −65°C to 150°C
z ESD Susceptibility (Note 2) HBM (Human Body Mode) ------------------------------------------------------------------------------------------ 2kV MM (Machine Mode) -------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions (Note 3)
z Supply Input Voltage -------------------------------------------------------------------------------------------------- 3V to 5.5V z Enable Input Voltage -------------------------------------------------------------------------------------------------- 0V to 5.5V
z Junction Temperature Range ---------------------------------------------------------------------------------------- −40°C to 110°C
Electrical Characteristics
(VIN = 5V, CIN = COUT = 1μF, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min Typ Max Units
Output Voltage Accuracy Current Limit
ΔVOUT ILIM
IOUT = 25mA IOUT = 0.1mA, TA = 0°C to 70°C (Note 4) RLOAD = 1Ω
−1.5 −2 160
--300
1.5 +2 --
% mA
Quiescent Current (Note 5) IQ
IOUT = 0mA
90 160 250 μA
Line Regulation
ΔVLINE VIN = 3V to 5.5V, IOUT = 0.1mA
−0.3 -- +0.3 %
Load Regulation (Note 4)
EN Threshold
Logic-Low Logic-High
ΔVLOAD VIL VIH
IOUT = 0.1mA to 150mA VIN = 3V to 5.5V, Shutdown VIN = 3V to 5.5V, Enable
-- 1.5 +3 -- -- 0.8 2.0 -- --
% V V
EN .