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RT9198T
300mA, Thermal Folded Back CMOS LDO Regulator
General Description
Features
The RT9198T is designed for portable RF and wireless
applications with demanding performance and space
requirements. The RT9198T performance is optimized for
battery-powered systems to deliver ultra low noise and
low quiescent current. Regulator ground current increases
only slightly in dropout, further prolonging the battery life.
The RT9198T also works with low-ESR ceramic capacitors,
reducing the amount of board space necessary for power
applications, critical in hand-held wireless devices. The
RT9198T consumes less than 0.01uA in shutdown mode
and has fast turn-on time less than 50μs. RT9198T is short
circuit thermal folded back protected. RT9198T lowers its
OTP trip point from 165°C to 110°C when output short
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Short Circuit Thermal Folded Back Protection
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circuit occurs (VOUT < 0.4V) providing maximum safety to
end users. The other features include ultra low dropout
voltage, high output accuracy, current limiting protection,
and high ripple rejection ratio. Available in the SOT-23-3,
SOT-23-5 and SC-70-5 packages, the RT9198T also offers
a range of 1.5V to 3.5V with 0.1V per step.
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Low-Noise for RF Application
Fast Response in Line/Load Transient
Quick Start-Up (Typically 50us)
< 0.01uA Standby Current When Shutdown
Low Dropout : 220mV @ 300mA
Wide Operating Voltage Ranges : 2.5V to 5.5V
TTL-Logic-Controlled Shutdown Input
Low Temperature Coefficient
Current Limiting Protection
Thermal Shutdown Protection
Only 1uF Output Capacitor Required for Stability
High Power Supply Rejection Ratio
Custom Voltage Available
RoHS Compliant and 100% Lead (Pb)-Free
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Applications
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Ordering Information
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RT9198T-
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Package Type
U5 : SC-70-5
U5R : SC-70-5 (R-Type)
V : SOT-23-3
B : SOT- 23-5
BR : SOT- 23-5 (R-Type)
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Note :
Output Voltage
15 : 1.5V
16 : 1.6V
:
34 : 3.4V
35 : 3.5V
1H : 1.85V
2H : 2.85V
Richtek products are :
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RoHS compliant and compatible with the current require-
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Suitable for use in SnPb or Pb-free soldering processes.
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CDMA/GSM Cellular Handsets
Battery-Powered Equipment
Laptop, Palmtops, Notebook Computers
Hand-Held Instruments
PCMCIA Cards
Portable Information Appliances
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Pin Configurations
(TOP VIEW)
VIN
3
2
GND
VOUT
SOT-23-3
ments of IPC/JEDEC J-STD-020.
DS9198T-04 April 2011
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RT9198T
VIN
VOUT
VOUT
NC
5
4
5
4
2
3
2
3
EN NC GND
VIN GND EN
SOT-23-5/SC-70-5
SOT-23-5/SC-70-5 (R-Type)
Typical Application Circuit
RT9198T
VIN
VIN
CIN
1uF
VOUT
COUT
1uF
Chip Enable
EN
VOUT
GND
Functional Pin Description
Pin Name
EN
Pin Function
Chip Enable (Active High). Note that this pin is high impedance. There should be a pull low 100kΩ
resistor connected to GND when the control signal is floating.
NC
No Connection
GND
Ground
VOUT
Output Voltage
VIN
Input Voltage
Function Block Diagram
EN
Shutdown
and
Logic Control
VIN
VREF
+
-
Error
Amplifier
MOS Driver
VOUT
Current-Limit
and
Thermal
Protection
GND
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DS9198T-04 April 2011
RT9198T
Absolute Maximum Ratings
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(Note 1)
Supply Input Voltage ---------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C
SOT-23-3 ------------------------------------------------------------------------------------------------------------------SOT-23-5 ------------------------------------------------------------------------------------------------------------------SC-70-5 -------------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2)
SOT-23-3, θJA ------------------------------------------------------------------------------------------------------------SOT-23-5, θJA ------------------------------------------------------------------------------------------------------------SC-70-5, θJA --------------------------------------------------------------------------------------------------------------Junction Temperature --------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ----------------------------------------------------------------------------Storage Temperature Range ------------------------------------------------------------------------------------------ESD Susceptibility (Note 3)
HBM (Human Body Mode) --------------------------------------------------------------------------------------------MM (Machine Mode) ----------------------------------------------------------------------------------------------------
Recommended Operating Conditions
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6V
0.4W
0.4W
0.3W
250°C/W
250°C/W
333°C/W
150°C
260°C
−65°C to 150°C
2kV
200V
(Note 4)
Supply Input Voltage ---------------------------------------------------------------------------------------------------- 2.5V to 5.5V
Operation Ambient Temperature Range ----------------------------------------------------------------------------- −40°C to 85°C
Operation Junction Temperature Range ----------------------------------------------------------------------------- −40°C to 125°C
Electrical Characteristics
(VIN = VOUT + 1V, CIN = COUT = 1uF, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Output Voltage Accuracy
ΔVOUT
IOUT = 1mA
−2
--
+2
%
Current Limit
ILIM
RLOAD = 1Ω
360
400
--
mA
Quiescent Current
IQ
VEN >= 1.2V, IOUT = 0mA
--
90
130
uA
IOUT = 200mA
--
170
200
IOUT = 300mA
--
220
330
VIN = (VOUT + 1V) to 5.5V,
IOUT = 1mA
--
--
0.3
%
Dropout Voltage
(Note 5)
V DROP
mV
Line Regulation
ΔVLINE
Load Regulation
ΔVLOAD 1mA < IOUT < 300mA
--
--
0.6
%
Standby Current
ISTBY
VEN = GND, Shutdown
--
0.01
1
uA
EN Input Bias Current
IIBSD
VEN = GND or VIN
--
0
100
nA
V IL
VIN = 3V to 5.5V, Shutdown
--
--
0.4
1.2
--
--
--
−60
--
--
−30
--
EN Threshold
Power Supply
Rejection Rate
Logic-Low Voltage
Logic-High Voltage V IH
f = 100Hz
f = 10kHz
PSRR
VIN = 3V to 5.5V, Start-Up
COUT = 1uF, IOUT = 100mA
V
dB
Thermal Shutdown Temperature
T SD
--
165
--
°C
Thermal Shutdown Temperature
Hysteresis
ΔT SD
--
30
--
°C
--
110
--
°C
Thermal Folded Back
DS9198T-04 April 2011
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RT9198T
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 is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
Note 5. The dropout voltage is defined as VIN -VOUT, which is measured when VOUT is VOUT(NORMAL) − 100mV.
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DS9198T-04 April 2011
RT9198T
Typical Operating Characteristics
Quiesent Current vs. Temperature
Output Voltage vs. Temperature
100
VIN = 5V
CIN = COUT = 1uF
RT9198T-15PB
VIN = 3.3V
CIN = COUT = 1uF
95
Quiescent Current (uA)
Output Voltage (V)
2
1.9
1.8
No Load
1.7
90
85
80
75
70
65
60
1.6
-50
-25
0
25
50
75
100
-50
125
-25
0
EN Pin Shutdown Threshold vs. Temperature
Current Limit (mA)
EN Pin Threshold Voltage (V)
0.75
0.5
125
RT9198T-15PB
CIN = COUT = 1uF
500
450
400
350
0.25
300
-50
-25
0
25
50
75
100
125
2
2.5
3
Temperature (°C)
20
RT9198T-33PB
CIN = COUT = 1uF
3.5
4
4.5
5
5.5
6
6.5
Input Voltage (V)
Dropout Voltage vs. Load Current
TJ = 125°C
250
PSRR
VOUT = 2.5V
CIN = COUT = 1uF, X7R
0
200
TJ = 25°C
PSRR (dB)
Dropout Voltage (mV)
100
550
1
300
75
Current Limit vs. Input Voltage
600
RT9198T-15PU5
VIN = 3.3V
CIN = COUT = 1uF
1.25
50
Temperature (°C)
Temperature (°C)
1.5
25
150
TJ = -40°C
100
-20
-40
ILOAD = 100mA
-60
50
ILOAD = 10mA
-80
0
0
0.05
0.1
0.15
0.2
Load Current (A)
DS9198T-04 April 2011
0.25
0.3
10
0.01
100
0.1
1K
1
10K
10
100K
100
1M
1000
Frequency (kHz)
(Hz)
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RT9198T
Line Transient Response
Input Voltage
Deviation (V)
CIN = COUT = 1uF
ILOAD = 50mA
5
4
Output Voltage
Deviation (mV)
Output Voltage
Deviation (mV)
3
Input Voltage
Deviation (V)
Line Transient Response
20
0
-20
CIN = COUT = 1uF
4
3
50
0
-50
Time (100μs/Div)
Time (100μs/Div)
Output Voltage
Deviation (mV)
0
50
0
-50
10
Load Current
(mA)
50
VOUT = 1.5V
ILOAD = 1mA to 250mA
200
0
50
0
-50
Time (100μs/Div)
Start Up
EN Pin Shutdown Response
VIN = 5V
CIN = COUT = 1uF
5
0
2
1
0
Time (10μs/Div)
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400
VIN = 3.3V
CIN = COUT = 1uF
Time (100μs/Div)
VOUT = 1.8V
ILOAD = 1mA
Output Voltage
(V)
EN Pin Voltage
(V)
Output Voltage
(V)
VOUT = 1.5V
ILOAD = 1mA to 50mA
Load Transient Response
EN Pin Voltage
(V)
100
Output Voltage
Deviation (mV)
Load Current
(mA)
Load Transient Response
VIN = 3.3V
CIN = COUT = 1uF
ILOAD = 250mA
5
10
VOUT = 1.8V
ILOAD = 1mA
VIN = 5V
CIN = COUT = 1uF
5
0
2
1
0
Time (1ms/Div)
DS9198T-04 April 2011
RT9198T
Noise
Noise
VOUT = 1.8V
ILOAD = 150mA
400
400
200
200
0
-200
-400
0
-200
-400
f = 10Hz to 100kHz
Time (5ms/Div)
DS9198T-04 April 2011
VOUT = 1.8V
No Load
VIN = 4.5V
CIN = COUT = 1uF
Noise (μV)
Noise (μV)
VIN = 4.5V
CIN = COUT = 1uF
f = 10Hz to 100kHz
Time (5ms/Div)
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RT9198T
Applications Information
Like any low-dropout regulator, the external capacitors used
with the RT9198T must be carefully selected for regulator
stability and performance. Using a capacitor whose value
is > 1μF on the RT9198T input and the amount of
capacitance can be increased without limit. The input
capacitor must be located a distance of not more than
0.5 inch from the input pin of the IC and returned to a
clean analog ground. Any good quality ceramic or tantalum
can be used for this capacitor. The capacitor with larger
value and lower ESR (equivalent series resistance) provides
better PSRR and line-transient response.
Enable Function
The output capacitor must meet both requirements for
minimum amount of capacitance and ESR in all LDOs
application. The RT9198T is designed specifically to work
with low ESR ceramic output capacitor in space-saving
Thermal Considerations
and performance consideration. Using a ceramic capacitor
whose value is at least 1μF with ESR is > 20mΩ on the
RT9198T output ensures stability. The RT9198T 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 RT9198T
and returned to a clean analog ground.
The RT9198T features an LDO regulator enable/disable
function. To assure the LDO regulator will switch on, the
EN turn on control level must be greater than 1.2 volts.
The LDO regulator will go into the shutdown mode when
the voltage on the EN pin falls below 0.4 volts. For to
protecting the system, the RT9198T have a quickdischarge function. If the enable function is not needed in
a specific application, it may be tied to VIN to keep the
LDO regulator in a continuously on state.
Thermal protection limits power dissipation in RT9198T.
When the operation junction temperature exceeds 165°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.
RT9198T lowers its OTP trip level from 165°C to 110°C
when output short circuit occurs (VOUT < 0.4V) as shown
in Figure 2. This limits IC case temperature under 100°C
and provides maximum safety to end users when output
short circuit occurs.
VOUT Short to GND
0.4V
Region of Stable COUT ESR vs. Load Current
VOUT
100.00
100
C OUT ESR (Ω)
IOUT
Instable
10
10.00
COUT = 1uF
1.001
165 °C 110 C
°
OTP Trip Point
110 °C
Stable
0.10
0.01
0.00
TSD
IC Temperature
0
50
80 °C
Simulation Verify
RT9198T-15PU5
CIN = 1μF, X7R
100
150
200
Load Current (mA)
250
300
Figure 2. Short Circuit Thermal Folded Back Protection
when Output Short Circuit Occurs
Figure 1
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DS9198T-04 April 2011
RT9198T
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
Where T J(MAX) is the maximum operation junction
temperature 125°C, TA is the ambient temperature and the
θJA is the junction to ambient thermal resistance.
450
Maximum Power Dissipation (mW)
For continuous operation, do not exceed absolute
maximum operation junction temperature 125°C. The
power dissipation definition in device is :
SOT-23-3, SOT-23-5
400
350
SC 70-5
300
250
200
150
100
50
0
0
25
50
75
100
125
Ambient Temperature (°C )
Figure 3. Derating Curve for Packages
For recommended operating conditions specification of
RT9198T, where T J(MAX) is the maximum junction
temperature of the die (125°C) and TA is the maximum
ambient temperature. The junction to ambient thermal
resistance (θJA is layout dependent) for SC-70 package is
333°C/W, 250°C/W is for SOT-23-3 and SOT-23-5 package
on standard JEDEC 51-3 thermal test board. The
maximum power dissipation at TA = 25°C can be calculated
by following formula :
PD(MAX) = (125°C−25°C)/250 = 400 mW (SOT-23-3/
SOT-23-5)
PD(MAX) = (125°C−25°C)/333 = 300 mW (SC-70-5)
The maximum power dissipation depends on operating
ambient temperature for fixed T J(MAX) and thermal
resistance θJA. For RT9198T packages, the Figure 3. of
derating curves allows the designer to see the effect of
rising ambient temperature on the maximum power
allowed.
DS9198T-04 April 2011
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RT9198T
Outline Dimension
H
D
L
C
B
e
A
A1
b
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
0.508
0.014
0.020
C
2.591
2.997
0.102
0.118
D
2.692
3.099
0.106
0.122
e
1.803
2.007
0.071
0.079
H
0.080
0.254
0.003
0.010
L
0.300
0.610
0.012
0.024
SOT-23-3 Surface Mount Package
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DS9198T-04 April 2011
RT9198T
H
D
L
B
C
b
A
A1
e
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
SOT-23-5 Surface Mount Package
DS9198T-04 April 2011
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RT9198T
H
D
L
B
C
b
A
A1
e
Dimensions In Millimeters
Dimensions In Inches
Symbol
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
SC-70-5 Surface Mount Package
Richtek Technology Corporation
Richtek Technology Corporation
Headquarter
Taipei Office (Marketing)
5F, No. 20, Taiyuen Street, Chupei City
5F, No. 95, Minchiuan Road, Hsintien City
Hsinchu, Taiwan, R.O.C.
Taipei County, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Tel: (8862)86672399 Fax: (8862)86672377
Email: [email protected]
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.
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DS9198T-04 April 2011