RT9020
1
DS9020-04 April 2011 www.richtek.com
Pin Configurations
Applications
Digital Still Camera
CDMA/GSM Cellular Handsets
Portable Information Appliances
Laptop, Palmtops, Notebook Computers
Mini PCI & PCI-Express Cards
PCMCIA & New Cards
500mA, Low Dropout, Low Noise Ultra-Fast With Soft Start
CMOS LDO Regulator
Ordering Information
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
General Description
The RT9020 is a high-performance, 500mA LDO regulator,
offering extremely high PSRR and ultra-low dropout, ideal
for portable RF and wireless applications with demanding
performance and space requirements.
The RT9020 quiescent current is as low as 25μA, further
prolonging the battery life. The RT9020 also works with
low-ESR ceramic capacitors, reducing the amount of board
space necessary for power applications, critical in hand-
held wireless devices.
The RT9020 consumes typical 0.7μA in shutdown mode
and has fast turn-on time less than 70μs (without CSS).
The other features include ultra-low dropout voltage, high
output accuracy, current limiting protection, and high ripple
rejection ratio. Tiny packages SOT-23-5 and SC-70-5 are
available.
TOP VIEW
Features
Wide Operating Voltage Ranges : 2.2V to 5.5V
Low Dropout : 250mV at 500mA
5mA Discharge Current of VOUT when IC Shutdown
Ultra-Low-Noise for DSC Application
Ultra-Fast Response in Line/Load Transient
Current Limiting Protection
Thermal Shutdown Protection
High Power Supply Rejection Ratio
Output Only 1μμ
μμ
μF Capacitor Required for Stability
TTL-Logic-Controlled Shutdown Input
RoHS Compliant and 100% Lead (Pb)-Free
SOT-23-5 / SC-70-5
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.
VIN GND EN
VOUT SS
4
23
5
RT9020
Package Type
B : SOT-23-5
U5 : SC-70-5
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Fixed Output Voltage
15 : 1.5V
16 : 1.6V
:
32 : 3.2V
33 : 3.3V
1B : 1.25V
1H : 1.85V
2H : 2.85V
-
RT9020
2
DS9020-04 April 2011www.richtek.com
Typical Application Circuit
Functional Pin Description
Pin Number Pin Name Pin Function
1 VIN Supply Input.
2 GND Common Ground.
3 EN Enable Input Logic, Active High. When the EN goes to a logic low, the device will
be shutdown.
4 SS Soft Start.
5 VOUT Regulator Output.
Function Block Diagram
+
-
POR
OTP
SS
VIN
VOUT
GND
MOS
Driver
Current
Limit
VREF
EN
R
VIN
GND
VOUT
RT9020
1uF/
X7R
SS
EN
CIN
VIN VOUT
Chip Enable
CSS
0.5nF
1uF/
X7R
COUT
RT9020
3
DS9020-04 April 2011 www.richtek.com
Absolute Maximum Ratings (Note 1)
Supply Input Voltage ------------------------------------------------------------------------------------------------------ 6V
EN Input Voltage ----------------------------------------------------------------------------------------------------------- 6V
Power Dissipation, PD @ TA = 25°C
SOT-23-5 -------------------------------------------------------------------------------------------------------------------- 0.4W
SC-70-5 ---------------------------------------------------------------------------------------------------------------------- 0.3W
Package Thermal Resistance (Note 2)
SOT-23-5, θJA --------------------------------------------------------------------------------------------------------------- 250°C/W
SC-70-5, θJA ---------------------------------------------------------------------------------------------------------------- 333°C/W
Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- 260°C
Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
Storage Temperature Range -------------------------------------------------------------------------------------------- −65°C to 150°C
ESD Susceptibility (Note 3)
HBM -------------------------------------------------------------------------------------------------------------------------- 2kV
MM ---------------------------------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions (Note 4)
Supply Input Voltage ------------------------------------------------------------------------------------------------------ 2.2V to 5.5V
Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C
Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 85°C
Electrical Characteristics
Parameter Symbol Test Conditions Min Typ Max Unit
Input Voltage Range VIN 2.2 -- 5.5 V
Output Noise Voltage VON VOUT = 1.5V, COUT = 1μF, IOUT =
0mA, CSS = 1nF -- 40 -- μVRMS
Output Voltage Accuracy
(Fixed Output Voltage) ΔVOUT I
OU T = 10mA −2 0 +2 %
Quiescent Current (Note 5) IQ V
EN = 5V, IOU T = 0mA -- 25 50 μA
Standby Current ISTBY V
EN = 0V -- 0.7 1.5 μA
RLOAD = 0Ω, 2.2V ≤ VIN < 2.6V 0.4 0.7 1.05 A
Current Limit ILIM RLOAD = 0Ω, 2.7V ≤ VIN ≤ 5.5V 0.5 0.8 1.05 A
IOU T = 400mA, 2.2V ≤ VIN < 2.7V -- 160 320
Dropout Voltage (Note 6) VDROP IOU T = 500mA, 2.7V ≤ VIN ≤ 5.5V -- 250 400 mV
1mA < IOUT < 400mA
2.2V ≤ VIN < 2.7V -- -- 0.6
Load Regulation (Note 7)
(Fixed Output Voltage) ΔVLOAD 1mA < IOUT < 500mA
2.7V ≤ VIN ≤ 5.5V -- -- 1
%
Soft Start Time VOUT = 2.5V, CSS = 1nF -- 0.7 1 ms
(VIN = VOUT + 0.5V, VEN = VIN, CIN = COUT = 1μF (Ceramic), TA = 25°C unless otherwise specified)
To be continued
RT9020
4
DS9020-04 April 2011www.richtek.com
Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for
stress ratings. 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 for extended
periods may remain possibility to affect device reliability.
Note 2. θJA is measured in the natural convection at TA = 25°C on a low effective thermal conductivity test board of JEDEC 51-
3 thermal measurement standard.
Note 3. Devices are ESD sensitive. Handling precaution recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
Note 5. 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.
Note 6. The dropout voltage is defined as VIN -VOUT, which is measured when VOUT is VOUT(NORMAL) - 100mV.
Note 7. Regulation is measured at constant junction temperature by using a 2ms current pulse. Devices are tested for load
regulation in the load range from 10mA to 500mA.
Parameter Symbol Test Conditions Min Typ Max Unit
Logic-Low Voltage VIL 0 -- 0.6
EN Threshol d Logic-High Voltage VIH 1.6 -- 5.5 V
Enable Pin Current IEN 0.1 1 5 μA
Power Supply
Rejection Rate f = 10kHz PSRR IOU T = 10mA -- -55 -- dB
Line Regulation ΔVLINE VIN = (VOUT+0.5) to 5.5V,
IOUT = 1mA -- 0.01 0.2 %/V
Thermal Shutdown Temperature TSD -- 170 --
Thermal Shutdown Hysteresis ΔTSD -- 30 --
°C
RT9020
5
DS9020-04 April 2011 www.richtek.com
Dropout Voltage vs. Loa d Current
0
50
100
150
200
250
300
0 100 200 300 400 500
Load Current (mA)
Dropout Voltage (mV)
Typical Operating Characteristics
TJ = -40°C
TJ = 125°C
TJ = 25°C
VIN = 4.5V, VOUT = 3.1V, CSS = 22nF, No Load
Start Up
VEN
(5V/Div)
Time (10ms/Div)
VOUT
(1V/Div)
IIN
(50mA/Div)
EN Pin Shutdown Response
Time (5ms/Div)
VIN = 4.5V, VOUT = 3.3V, No Load
VEN
(5V/Div)
VOUT
(2V/Div)
IIN
(50mA/Div)
(CIN = COUT = 1uF/X7R, CSS = 1nF, unless otherwise specified)
Quiescent Current vs. Temperature
0
10
20
30
40
50
-50 -25 0 25 50 75 100 125
Temperature
Quiescent Current (uA)
VIN = 4.5V, VOUT = 3.3V
(°C)
VOUT = 3.3V
Output Voltage vs. Temperature
3.10
3.15
3.20
3.25
3.30
3.35
3.40
-50-25 0 255075100125
Temperature
Output Voltage (V)
(°C)
VIN = 5.0V
Soft Start Time
0
2000
4000
6000
8000
10000
012345678910
Css (nF)
Soft Start Time (us)
VIN = 5.0V, VOUT = 3.3V
10
8
6
4
2
(ms)
RT9020
6
DS9020-04 April 2011www.richtek.com
VIN = 4.5V (By battery), VOUT = 3.3V, No Load
Noise
Time (10ms/Div)
Noise (μV/Div)
300
200
100
0
-100
-200
-300
Line Transient Response
VIN
(V)
Time (100μs/Div)
VOUT
(10mV/Div)
5
4
VIN = 4V to 5V, VOUT = 3.1V, ILOAD = 100mA
Load Transient Response
Time (250μs/Div)
ILOAD
(200mA/Div)
VOUT
(100mV/Div)
VIN = 4.5V, VOUT = 3.1V, ILOAD = 1mA to 300mA
Load Transient Response
Time (10μs/Div)
ILOAD
(200mA/Div)
VOUT
(100mV/Div)
VIN = 4.5V, VOUT = 3.1V, ILOAD = 50mA to 250mA
Line Transient Response
VIN
(V)
Time (100μs/Div)
VOUT
(10mV/Div)
5
4
VIN = 4V to 5V, VOUT = 3.1V, ILOAD = 10mA
PSRR
-70
-60
-50
-40
-30
-20
-10
0
10
20
10 100 1000 10000 100000 1000000
Frequency (Hz)
PSRR(dB)
0.01 0.1 1 10 100 1000
Frequency (kHz)
VIN = 4.5V, VOUT = 3.3V
VIN,AC = 100m VP-P
ILOAD = 10mA
ILOAD = 100mA
RT9020
7
DS9020-04 April 2011 www.richtek.com
Applications Information
Like any low-dropout regulator, the external capacitors used
with the RT9020 must be carefully selected for regulator
stability and performance. The recommended input and
output capacitors should be 1μF or greater X7R/X5R
ceramic.The input capacitor must be located a distance
not more than 0.5 inch from the input pin of the IC and
returned to a clean analog ground. The capacitor with larger
value and lower ESR (equivalent series resistance) provides
better PSRR and line-transient response.
The output capacitor must meet both requirements for
minimum amount of capacitance and ESR in all LDOs
application. The RT9020 is designed specifically to work
with low ESR ceramic output capacitor in space-saving
and performance consideration. Using a ceramic capacitor
whose value is at least 1μF with ESR > 20mΩ on the
RT9020 output ensures stability. The RT9020 still works
well with output capacitor of other types due to the wide
stable ESR range. Figure 1. shows the curves of allowable
ESR range as a function of load current for various output
capacitor values. Output capacitor of larger capacitance
can reduce noise and improve load transient response,
stability, and PSRR. The output capacitor should be located
not more than 0.5 inch from the VOUT pin of the RT9020
and returned to a clean analog ground.
Enable
The RT9020 goes into shutdown mode when the EN pin
is in a logic low condition. During this condition, the
RT9020 has an EN pin to turn on or turn off regulator,
When the EN pin is logic high, the regulator will be turned
on. The supply current in shutdown mode is as low as
0.7μA typically. The EN pin may be directly tied to VIN to
keep the part on.
PSRR
The power supply rejection ratio (PSRR) is defined as the
gain from the input to output divided by the gain from the
supply to the output. The PSRR is found to be
⎟
⎠
⎞
⎜
⎝
⎛
×= ΔSupply
Error ΔGain
log20 PSRR
Note that when heavy load measuring, Δsupply will cause
Δtemperature. And Δtemperature will cause Δoutput
voltage change. So the heavy load PSRR measuring
includes temperature effect.
Current limit
The RT9020 contains an independent current limiter, which
monitors and controls the pass transistor's gate voltage,
limiting the output current to 0.7A (typ.). The output can
be shorted to ground indefinitely without damaging the
part.
Thermal Considerations
Thermal protection limits power dissipation in RT9020.
When the operation junction temperature exceeds 170°C,
the OTP circuit starts the thermal shutdown function and
turns the pass element off. The pass element turn on again
after the junction temperature cools by 30°C.
For continuous operation, do not exceed absolute
maximum operation junction temperature 125°C. The
power dissipation definition in device is :
PD = (VIN − VOUT) x IOUT + VIN x IQ
The maximum power dissipation depends on the thermal
resistance of IC package, PCB layout, the rate of
surroundings airflow and temperature difference between
junction to ambient. The maximum power dissipation can
be calculated by following formula :
PD(MAX) = ( TJ(MAX) − TA ) /θJA
Figure 1
Region of Stable COUT ESR vs. Load Current
0.001
0.01
0.1
1
10
100
0 100 200 300 400 500
Load Current (mA)
Region of Stable COUT ESR (Ω)
RT9020-33PB, VIN = 5V
CIN = COUT = 1μF/X7R
Unstable Range
Unstable Range by Simulation
Stable Range
RT9020
8
DS9020-04 April 2011www.richtek.com
Figure 2. Derating Curves for RT9020 Packages
Where TJ(MAX) is the maximum operation junction
temperature, TA is the ambient temperature and the θJA is
the junction to ambient thermal resistance.
For recommended operating conditions specification of
RT9020, where TJ(MAX) is the maximum junction
temperature of the die (125°C) and TA is the operated
ambient temperature. The junction to ambient thermal
resistance θJA (θJA is layout dependent) for SOT-23-5
package is 250°C/W and SC-70-5 package is 333°C/W
on the standard JEDEC 51-3 single-layer thermal test
board. The maximum power dissipation at TA = 25°C can
be calculated by following formula :
PD(MAX) = (125°C − 25°C) / 250 = 0.400 W for SOT-23-5
packages
PD(MAX) = (125°C − 25°C) / 333 = 0.300 W for SC-70-5
packages
The maximum power dissipation depends on operating
ambient temperature for fixed TJ(MAX) and thermal
resistance θJA. For RT9020 packages, the Figure 2 of
derating curves allows the designer to see the effect of
rising ambient temperature on the maximum power
allowed.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 12.5 25 37.5 50 62.5 75 87.5 100 113 125
Ambient Temperature
Power Dissipation (W)
(°C)
Single Layer PCB
SOT-23-5
SC-70-5
RT9020
9
DS9020-04 April 2011 www.richtek.com
Outline Dimension
AA1
e
b
B
D
C
H
L
SOT-23-5 Surface Mount Package
Dimensions In Millimeters Dimensions In Inches
Symbol Min Max Min Max
A 0.889 1.295 0.035 0.051
A1 0.000 0.152 0.000 0.006
B 1.397 1.803 0.055 0.071
b 0.356 0.559 0.014 0.022
C 2.591 2.997 0.102 0.118
D 2.692 3.099 0.106 0.122
e 0.838 1.041 0.033 0.041
H 0.080 0.254 0.003 0.010
L 0.300 0.610 0.012 0.024
RT9020
10
DS9020-04 April 2011www.richtek.com
Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit
design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be
guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek.
Richtek Technology Corporation
Headquarter
5F, No. 20, Taiyuen Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Richtek Technology Corporation
Taipei Office (Marketing)
5F, No. 95, Minchiuan Road, Hsintien City
Taipei County, Taiwan, R.O.C.
Tel: (8862)86672399 Fax: (8862)86672377
Email: marketing@richtek.com
AA1
e
b
B
D
C
H
L
SC-70-5 Surface Mount Package
Dimensions In Millimeters Dimensio ns In Inches
Symb ol Min Max Min Max
A 0.800 1.100 0.031 0.044
A1 0.000 0.100 0.000 0.004
B 1.150 1.350 0.045 0.054
b 0.150 0.400 0.006 0.016
C 1.800 2.450 0.071 0.096
D 1.800 2.250 0.071 0.089
e 0.650 0.026
H 0.080 0.260 0.003 0.010
L 0.210 0.460 0.008 0.018
