RICHTEK RT9181CB Datasheet
Preliminary
RT9181
150mA LDO Regulator with POG
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 CE
pin controls the output and consumes no input bias
current. Other features include current limiting, over
temperature protection, and under voltage lockout.
Applications
Processor Power-Up Sequencing
z
Laptop, Notebook, and Palmtop Computers
z
Features
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Low Dropout Voltage Regulator, Output 1.2V
z
Up to 150mA Output Current
z
Power Good (POG) Function
z
Chip Enable/Shutdown Function
z
Load Independent, Low Ground Current, 160µµµµA
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
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SOT-25 Package
Pin Configurations
Part Number Pin Configurations
RT9181CB
(Plastic SOT-25)
54
3
21
TOP VIEW
1. VIN
2. GND
3. CE
4. POG
5. VOUT
Ordering Information
RT9181
Package type
B : SOT-25
Operating temperature range
C: Commercial standard
Typical Application Circuit
10K
C
IN
1µF
ON
VIN
CE
V
IN
OFF
POG
VOUT
GND
C
OU T
1µF
POG
V
OUT
DS9181-00 February 2002 www.richtek-ic.com.tw
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RT9181
Pin Description
Pin Name Pin Function
VIN Input Pin
GND Power Ground Pin
CE Enable/Shutdown Input (Active High)
POG Power Good Indicator
VOUT Output Pin
Function Block Diagram
VIN
CE
Shutdown
Control
Thermal
Sensor
Preliminary
Undervoltage
Loc kout
Gate
Control
Current
Limit
Verf
Fault
_
+
Output Voltage
Detection
GOOD
Delay
Timer
Power Good
Control
VOUT
POG
GND
www.richtek-ic.com.tw DS9181-00 February 2002
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Preliminary
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RT9181
Absolute Maximum Ratings
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Input Voltage, VIN 7V
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CE Input Voltage 7V
z
Power Good Output Voltage 7V
z
Power Dissipation, PD @ TA = 25°C
SOT-25 570mW
z
Junction Temperature Range -40°C ~ 125°C
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Storage Temperature Range -65°C ~ 150°C
z
Operating Temperature Range 0°C ~ 70°C
z
Lead Temperature (Soldering, 10 sec.) 260°C
Electrical Characteristics
(V
= 5V, CIN = C
IN
Parameter Symbol Test Conditions Min Typ Max Units
= 1µF, TA = 25°C, unless otherwise specified)
OUT
Input Voltage Range V
IN
3--5.5V
IL = 25mA 1.182 1.2 1.218
Output Voltage Accuracy ∆V
OUT
IL = 0.1mA, TA = 0°C to 70°C (Note) -2 -- +2
%
Output Load Current Continuous 150 -- -- mA
Current Limit I
GND Current I
LIMIT
G
Line Regulation ∆V
Load Regulation ∆V
Dropout Voltage V
DROPIL
R
= 1Ω 160 300 -- mA
LOAD
No Load 90 160 250 µA
LINEVIN
LOADIL
= 0.1mA to 150mA -- -- +3 %
= 3 to 5.5V, I
= 0.1mA -0.3 -- +0.3 %
OUT
= 150mA -- 1 -- V
CE Input High Threshold VIN = 3 to 5.5V 2 -- -- V
CE Input Low Threshold VIN = 3 to 5.5V -- -- 0.8 V
CE Input Bias Current CE = GND or V
IN
-- -- 100 nA
CE Supply Current CE = GND -- 0.01 -- µA
V
POGH
V
POGH
Power Good Low Threshold
Power Good High Threshold
Output falls % of V
timer
Power good
Output reaches % of V
dela
timer (power good
(power NOT
OUT
OUT
, start
85 -- -- %
-- -- 90 %
VOL Power Good Output Logic Low Fault condition, IOL = 100µA----0.4V
td
Power Up Overshoot
Thermal Shutdown Temperature T
Delay Time to Power Good See timing diagram 1 2 5 mS
(POG)
SD
Maximum voltage overshoot allowed
on output durin
power-up
-- 1 -- %
-- 150 -- °C
Thermal Shutdown Hysteresis -- 20 -- °C
Output Voltage AC PSRR 100Hz, C
OUT
= 1µF, R
= 100Ω -- 62 -- dB
LOAD
Note: Assured by design, not tested in production
DS9181-00 February 2002 www.richtek-ic.com.tw
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