ETC RT9166

RT9166/A
Preliminary
300/500mA, Ultra-Fast Transient Response LDO Regulator
General Description
Features
The RT9166/A series are CMOS low dropout regulators
optimized for ultra-fast transient response. The devices
are capable of supplying 300mA or 500mA of output
current with a dropout voltage of 230mV or 430mV
respectively.
The RT9166/A series are is optimized for CD/DVD-ROM,
CD/RW or wireless communication supply applications.
The RT9166/A regulators are stable with output capacitors
as low as 1µF. The other features include ultra low dropout
voltage, high output accuracy, current limiting protection,
and high ripple rejection ratio.
The devices are available in fixed output voltages range
of 1.2V to 4.5V with 0.1V per step. The RT9166/A
regulators are available in 3-lead SOT-23, SOT-89,
SOT-223 and TO-92 packages.
Ordering Information
RT9166/A -
µA)
Low Quiescent Current (Typically 220µ
Guaranteed 300/500mA Output Current
Low Dropout Voltage: 230/430mV at 300/500mA
Wide Operating Voltage Ranges: 3V to 5.5V
Ultra-Fast Transient Response
Tight Load and Line Regulation
Current Limiting Protection
Thermal Shutdown Protection
Only low-ESR Ceramic Capacitor Required for
Stability
Custom Voltage Available
Applications
CD/DVD-ROM, CD/RW
Wireless LAN Card/Keyboard/Mouse
Battery-Powered Equipment
XDSL Router
PCMCIA Card
Pin Configurations
Package Type
VL : SOT-23 (L-Type)
X : SOT-89
XL : SOT-89 (L-Type)
G : SOT-223
GL : SOT-223 (L-Type)
Z : TO-92
Operating Temperature Range
C : Commercial Standard
P : Pb Free with Commercial Standard
Output Voltage
12 : 1.2V
13 : 1.3V
:
45 : 4.5V
(TOP VIEW)
VIN
3
1
2
GND
VOUT
GND
1
VIN
3
1
VIN
GND
2
VOUT GND
(TAB)
VOUT
2
TO-92
(RT9166/A)
SOT-23 (L-Type)
(RT9166)
1
3
2
3
VIN VOUT
(TAB)
SOT-89 (L-Type)
SOT-89
500mA Output Current
300mA Output Current
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.
DS9166/A-06 April 2004
1
2
VOUT GND
(TAB)
3
VIN
SOT-223
1
GND
2
3
VIN VOUT
(TAB)
SOT-223 (L-Type)
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RT9166/A
Preliminary
Typical Application Circuit
RT9166/A
VIN
CIN
1uF
VIN
VOUT
COUT
1uF
GND
VOUT
µF minimum X7R or X5R dielectric is strongly recommended if ceramics are
Note: To prevent oscillation, a 1µ
used as input/output capacitors. When using the Y5V dielectric, the minimum value of the input/output
µF. (see Application
capacitance that can be used for stable over full operating temperature range is 3.3µ
Information Section for further details)
Functional Pin Description
Pin Name
Pin Function
VIN
Supply Input
VOUT
Regulator Output
GND
Common Ground
Function Block Diagram
VIN
VOUT
Thermal
Shutdown
Error Amp
-
+
Current
Limiting
Sensor
1.2V
Reference
GND
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DS9166/A-06 April 2004
RT9166/A
Preliminary
Absolute Maximum Ratings(Note 1)
Supply Input Voltage ------------------------------------------------------------------------------------------------- 6.5V
Power Dissipation, PD @ TA = 25°C
SOT-23 ------------------------------------------------------------------------------------------------------------------ 0.25W
SOT-89 ------------------------------------------------------------------------------------------------------------------ 0.5W
SOT-223 ----------------------------------------------------------------------------------------------------------------- 2W
Package Thermal Resistance
SOT-23, θJA ------------------------------------------------------------------------------------------------------------- 250° C/W
SOT-89, θJC ------------------------------------------------------------------------------------------- 100° C/W
SOT-89, θJA ------------------------------------------------------------------------------------------------------------- 180° C/W
SOT-223, θJC ----------------------------------------------------------------------------------------- 15° C/W
SOT-223, θJA ----------------------------------------------------------------------------------------------------------- 60° C/W
Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------- 260°C
Junction Temperature ------------------------------------------------------------------------------------------------ 150°C
Storage Temperature Range --------------------------------------------------------------------------------------- – 65°C to 150°C
ESD Susceptibility (Note 2)
HBM ---------------------------------------------------------------------------------------------------------------------- 2kV
MM ------------------------------------------------------------------------------------------------------------------------ 200V
Recommended Operating Conditions
(Note 3)
Supply Input Voltage ------------------------------------------------------------------------------------------------- 2.8V to 5.5V
Junction Temperature Range -------------------------------------------------------------------------------------- – 40°C to 125°C
Electrical Characteristics
(VIN = VOUT + 1V or VIN = 2.8V whichever is greater, CIN = 1µF, COUT = 1µF, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Output Voltage Accuracy
Current Limit
RT9166
RT9166A
Quiescent Current (Note 6)
Dropout Voltage (Note 4)
RT9166
RT9166A
Load Regulation (Note 5)
RT9166
RT9166A
Min
Typ
Max
Units
−1
--
+3
%
300
--
--
500
--
--
∆VOUT
IOUT = 1mA
ILIM
RLOAD = 1Ω
IQ
IOUT = 0mA
--
220
300
IOUT = 300mA
--
230
--
IOUT = 500mA
--
430
--
--
0.2
--
1mA < IOUT < 300mA
--
15
35
1mA < IOUT < 500mA
--
25
50
f = 1kHz, COUT = 1µF
--
−55
--
dB
VDROP
∆VLINE
Line Regulation
Test Conditions
∆VLOAD
VIN = (VOUT + 0.3V) to 5.5V,
IOUT = 1mA
mA
µA
mV
%/V
mV
Power Supply Rejection Rate
PSRR
Thermal Shutdown Temperature
TSD
--
170
--
°C
Thermal Shutdown Hysteresis
∆TSD
--
40
--
°C
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RT9166/A
Preliminary
Note 1. Stresses beyond those listed under “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 for extended periods may affect device reliability.
Note 2. Devices are ESD sensitive. Handling precaution recommended. The human body model is a 100pF capacitor
discharged through a 1.5kΩ resistor into each pin.
Note 3. The device is not guaranteed to function outside its operating conditions.
Note 4. Dropout voltage is defined as the input to output differential at which the output voltage drops 1% below its nominal
value measured at 1V differential. Dropout voltage does not apply to some lower voltage versions since the dropout
voltage limited by input voltage range limitations.
Note 5. Regulation is measured at constant junction temperature by using a 20ms current pulse. Devices are tested for load
regulation in the load range from 1mA to 300mA and 500mA respectively.
Note 6. 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.
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DS9166/A-06 April 2004
RT9166/A
Preliminary
Typical Operating Characteristics
Dropout Voltage vs. Output Current
Power Supply Rejection Ratio
600
0
CIN = 1uF
COUT = 1uF
500
TJ = 125°C
400
VIN = 5V
CIN = 1uF
COUT = 1uF
-10
-20
TJ = 25°C
300
-30
TJ = −40°C
200
100mA
-40
1mA
100
-50
0
-60
0
100
200
300
400
10
500
100
Output Current (mA)
Output Noise Signal (µV)
(Ω)
COUT = 10uF
Unstable Region
1
Stable Region
10k
100k
1M
Output Noise
Range of Stable ESR
100
10
1k
Frequency (Hz)
COUT = 1uF
0.1
ILOAD = 100mA
COUT = 1uF
VIN = 5V
CIN = 1uF
400
200
0
-200
-400
f = 10Hz to 100KHz
0.01
0
100
200
300
400
Time (1ms/DIV)
500
Output Current (mA)
Current Limit vs. Input voltage
Current Limit vs. Input voltage
900
900
850
850
800
800
VIN = 5V
CIN = 1uF
COUT = 1uF
RL = 0.5Ω
750
700
3
3.5
750
RT9166-33CX
700
4
4.5
Input voltage (V)
DS9166/A-06 April 2004
VIN = 5V
CIN = 1uF
COUT = 1uF
RL = 0.5Ω
5
5.5
3
3.5
RT9166-33CVL
4
4.5
5
5.5
Input voltage (V)
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RT9166/A
Preliminary
Current Limit vs. Temperature
Current Limit vs. Temperature
900
900
850
850
800
800
VIN = 5V
CIN = 1uF
COUT = 1uF
RL = 0.5Ω
750
700
-40
-50
-25
VIN = 5V
CIN = 1uF
COUT = 1uF
RL = 0.5Ω
750
RT9166-33CX
700
0
25
50
75
100
125
-50
-40
Temperature (°C)
Quiescent Current vs. Temperature
260
240
240
220
220
200
200
180
180
VIN = 5V
CIN = 1uF
COUT = 1uF
140
-40
-50
-25
160
RT9166-33CX
140
0
25
50
75
Temperature (°C)
100
0
25
50
75
100
125
Temperature (°C)
Quiescent Current vs. Temperature
260
160
-25
RT9166-33CVL
VIN = 5V
CIN = 1uF
COUT = 1uF
-50
-40
125
RT9166-33CVL
-25
0
25
50
75
Temperature (°C)
100
125
Temperature Stability
Temperature Stability
3.4
3.4
3.35
3.35
3.3
3.3
3.25
3.25
VIN = 5V
CIN = 1uF
COUT = 1uF
3.2
-40
-50
-25
RT9166-33CX
0
25
50
Temperature (°C)
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75
100
125
3.2
-50
-40
VIN = 5V
CIN = 1uF
COUT = 1uF
-25
RT9166-33CVL
0
25
50
75
100
125
Temperature (°C)
DS9166/A-06 April 2004
RT9166/A
Preliminary
VIN = 5V, ILOAD = 1 to 150mA
CIN = COUT = 1uF (Ceramic, X7R)
Load Current
(mA)
200
100
0
20
0
-20
Load Transient Response
RT9166-33CX
Time (100us/DIV)
Output Voltage
Deviation (mV)
Output Voltage
Deviation (mV)
Load Current
(mA)
Load Transient Response
200
VIN = 5V, ILOAD = 1 to 150mA
CIN = COUT = 1uF (Ceramic, X7R)
100
0
20
0
-20
RT9166-33CVL
Time (100us/DIV)
Output Voltage
Deviation (mV)
Input Voltage
Deviation (V)
Line Transient Response
5
VIN = 4 to 5V
CIN = 1uF
COUT = 1uF
4
20
0
-20
Time (100us/DIV)
DS9166/A-06 April 2004
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RT9166/A
Preliminary
Application Information
Like any low-dropout regulator, the RT9166/A series
requires input and output decoupling capacitors. These
capacitors must be correctly selected for good
performance (see Capacitor Characteristics Section).
Please note that linear regulators with a low dropout
voltage have high internal loop gains which require care
in guarding against oscillation caused by insufficient
decoupling capacitance.
INPUT CAPACITOR
An input capacitance of ≅ 1µF is required between the
device input pin and ground directly (the amount of the
capacitance may be increased without limit). The input
capacitor MUST be located less than 1 cm from the device
to assure input stability (see PCB Layout Section). A lower
ESR capacitor allows the use of less capacitance, while
higher ESR type (like aluminum electrolytic) require more
capacitance.
Capacitor types (aluminum, ceramic and tantalum) can
be mixed in parallel, but the total equivalent input
capacitance/ESR must be defined as above to stable
operation.
There are no requirements for the ESR on the input
capacitor, but tolerance and temperature coefficient must
be considered when selecting the capacitor to ensure the
capacitance will be ≅ 1µF over the entire operating
temperature range.
OUTPUT CAPACITOR
The RT9166/A is designed specifically to work with very
small ceramic output capacitors. The recommended
minimum capacitance (temperature characteristics X7R
or X5R) is 1µF to 4.7µF range with 10mΩ to 50mΩ range
ceramic capacitor between LDO output and GND for
transient stability, but it may be increased without limit.
Higher capacitance values help to improve transient. The
output capacitor's ESR is critical because it forms a zero
to provide phase lead which is required for loop stability.
(When using the Y5V dielectric, the minimum value of
the input/output capacitance that can be used for stable
over full operating temperature range is 3.3µF.)
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NO LOAD STABILITY
The device will remain stable and in regulation with no
external load. This is specially important in CMOS RAM
keep-alive applications.
INPUT-OUTPUT (DROPOUT) VOLTAGE
A regulator's minimum input-to-output voltage differential
(dropout voltage) determines the lowest usable supply
voltage. In battery-powered systems, this determines the
useful end-of-life battery voltage. Because the device uses
a PMOS, its dropout voltage is a function of drain-tosource on-resistance, RDS(ON), multiplied by the load
current:
VDROPOUT = VIN - VOUT = RDS(ON) x IOUT
CURRENT LIMIT
The RT9166/A monitors and controls the PMOS' gate
voltage, minimum limiting the output current to 350mA
for RT9166 and 550mA for RT9166A. The output can be
shorted to ground for an indefinite period of time without
damaging the part.
SHORT-CIRCUIT PROTECTION
The device is short circuit protected and in the event of a
peak over-current condition, the short-circuit control loop
will rapidly drive the output PMOS pass element off. Once
the power pass element shuts down, the control loop will
rapidly cycle the output on and off until the average power
dissipation causes the thermal shutdown circuit to
respond to servo the on/off cycling to a lower frequency.
Please refer to the section on thermal information for
power dissipation calculations.
CAPACITOR CHARACTERISTICS
It is important to note that capacitance tolerance and
variation with temperature must be taken into
consideration when selecting a capacitor so that the
minimum required amount of capacitance is provided over
the full operating temperature range. In general, a good
tantalum capacitor will show very little capacitance
variation with temperature, but a ceramic may not be as
good (depending on dielectric type).
DS9166/A-06 April 2004
Preliminary
Aluminum electrolytics also typically have large
temperature variation of capacitance value.
Equally important to consider is a capacitor's ESR change
with temperature: this is not an issue with ceramics, as
their ESR is extremely low. However, it is very important
in Tantalum and aluminum electrolytic capacitors. Both
show increasing ESR at colder temperatures, but the
increase in aluminum electrolytic capacitors is so severe
they may not be feasible for some applications.
RT9166/A
Tantalums also have good temperature stability: a good
quality tantalum will typically show a capacitance value
that varies less than 10~15% across the full temperature
range of 125°C to -40°C. ESR will vary only about 2X
going from the high to low temperature limits.
The increasing ESR at lower temperatures can cause
oscillations when marginal quality capacitors are used (if
the ESR of the capacitor is near the upper limit of the
stability range at room temperature).
Ceramic:
Aluminum:
For values of capacitance in the 10µF to 100µF range,
ceramics are usually larger and more costly than
tantalums but give superior AC performance for bypassing high frequency noise because of very low ESR
(typically less than 10mΩ). However, some dielectric types
do not have good capacitance characteristics as a function
of voltage and temperature.
This capacitor type offers the most capacitance for the
money. The disadvantages are that they are larger in
physical size, not widely available in surface mount, and
have poor AC performance (especially at higher
frequencies) due to higher ESR and ESL.
Z5U and Y5V dielectric ceramics have capacitance that
drops severely with applied voltage. A typical Z5U or Y5V
capacitor can lose 60% of its rated capacitance with half
of the rated voltage applied to it. The Z5U and Y5V also
exhibit a severe temperature effect, losing more than 50%
of nominal capacitance at high and low limits of the
temperature range.
X7R and X5R dielectric ceramic capacitors are strongly
recommended if ceramics are used, as they typically
maintain a capacitance range within ±20% of nominal over
full operating ratings of temperature and voltage. Of
course, they are typically larger and more costly than
Z5U/Y5U types for a given voltage and capacitance.
Tantalum:
Compared by size, the ESR of an aluminum electrolytic
is higher than either Tantalum or ceramic, and it also varies
greatly with temperature. A typical aluminum electrolytic
can exhibit an ESR increase of as much as 50X when
going from 25°C down to -40°C.
It should also be noted that many aluminum electrolytics
only specify impedance at a frequency of 120Hz, which
indicates they have poor high frequency performance.
Only aluminum electrolytics that have an impedance
specified at a higher frequency (between 20kHz and
100kHz) should be used for the device. Derating must be
applied to the manufacturer's ESR specification, since it
is typically only valid at room temperature.
Any applications using aluminum electrolytics should be
thoroughly tested at the lowest ambient operating
temperature where ESR is maximum.
Solid tantalum capacitors are recommended for use on
the output because their typical ESR is very close to the
ideal value required for loop compensation. They also
work well as input capacitors if selected to meet the ESR
requirements previously listed.
DS9166/A-06 April 2004
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RT9166/A
Preliminary
THERMAL CONSIDERATIONS
The RT9166/A series can deliver a current of up to 300/
500mA over the full operating junction temp-erature range.
However, the maximum output current must be derated
at higher ambient temperature to ensure the junction
temperature does not exceed 125°C. With all possible
conditions, the junction temperature must be within the
range specified under operating conditions. Power
dissipation can be calculated based on the output current
and the voltage drop across regulator.
PD = (VIN - VOUT) IOUT + VIN IGND
The final operating junction temperature for any set of
conditions can be estimated by the following thermal
equation:
It should be noted that stability problems have been seen
in applications where “ vias” to an internal ground plane
were used at the ground points of the device and the
input and output capacitors. This was caused by varying
ground potentials at these nodes resulting from current
flowing through the ground plane. Using a single point
ground technique for the regulator and it’ s capacitors fixed
the problem. Since high current flows through the traces
going into VIN and coming from VOUT, Kelvin connect the
capacitor leads to these pins so there is no voltage drop
in series with the input and output capacitors.
Optimum performance can only be achieved when the
device is mounted on a PC board according to the diagram
below:
PD (MAX) = ( TJ (MAX) - TA ) / θJA
Where TJ(MAX) is the maximum junction temperature of
the die (125° C) and T A is the maximum ambient
temperature. The junction to ambient thermal resistance
(θJA) for SOT-23 package at recomm-ended minimum
footprint is 250°C/W, 180°C/W for SOT-89 package and
60°C/W for SOT-223 package (θJA is layout dependent).
Visit our website in which “Recommended Footprints for
Soldering Surface Mount Packages” for detail.
IN
GND
VOUT
PCB LAYOUT
SOT-23 Board Layout
Good board layout practices must be used or instability
can be induced because of ground loops and voltage
drops. The input and output capacitors MUST be directly
connected to the input, output, and ground pins of the
device using traces which have no other currents flowing
through them.
The best way to do this is to layout CIN and COUT near the
device with short traces to the VIN, VOUT, and ground pins.
The regulator ground pin should be connected to the
external circuit ground so that the regulator and its
capacitors have a “single point ground”.
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DS9166/A-06 April 2004
RT9166/A
Preliminary
Outline Dimension
H
D
L
C
B
e
A
A1
b
Symbol
Dimensions In Millimeters
Dimensions In Inches
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 Surface Mount Package
DS9166/A-06 April 2004
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RT9166/A
Preliminary
D
D1
A
B
C
C1
e
e
H
A
b
Symbol
b1
b
Dimensions In Millimeters
Dimensions In Inches
Min
Max
Min
Max
A
1.397
1.600
0.055
0.063
b
0.356
0.483
0.014
0.019
B
2.388
2.591
0.094
0.102
b1
0.406
0.533
0.016
0.021
C
--
4.242
--
0.167
C1
0.787
1.194
0.031
0.047
D
4.394
4.597
0.173
0.181
D1
1.397
1.753
0.055
0.069
e
1.448
1.549
0.057
0.061
H
0.355
0.432
0.014
0.017
3-Lead SOT-89 Surface Mount Package
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DS9166/A-06 April 2004
RT9166/A
Preliminary
D
D1
H
C
B
L
e
e
A
A1
b
Symbol
Dimensions In Millimeters
Dimensions In Inches
Min
Max
Min
Max
A
--
1.803
--
0.071
A1
0.020
0.100
0.0008
0.0047
b
0.610
0.787
0.024
0.031
B
3.302
3.708
0.130
0.146
C
6.706
7.290
0.264
0.287
D
6.299
6.706
0.248
0.264
D1
2.896
3.150
0.114
0.124
e
2.261
2.362
0.089
0.093
H
0.229
0.330
0.009
0.013
L
0.914
--
0.036
--
3-Lead SOT-223 Surface Mount Package
DS9166/A-06 April 2004
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RT9166/A
Preliminary
A
D
E
L
b
e
C
D1
A1
Symbol
Dimensions In Millimeters
Dimensions In Inches
Min
Max
Min
Max
A
3.175
4.191
0.125
0.165
A1
1.143
1.372
0.045
0.054
b
0.406
0.533
0.016
0.021
C
0.406
0.533
0.016
0.021
D
4.445
5.207
0.175
0.205
D1
3.429
--
0.135
--
E
4.318
5.334
0.170
0.210
e
1.143
1.397
0.045
0.055
L
12.700
--
0.500
--
3-Lead TO-92 Plastic Package
RICHTEK TECHNOLOGY CORP.
RICHTEK TECHNOLOGY CORP.
Headquarter
Taipei Office (Marketing)
5F, No. 20, Taiyuen Street, Chupei City
8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City
Hsinchu, Taiwan, R.O.C.
Taipei County, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Tel: (8862)89191466 Fax: (8862)89191465
Email: [email protected]
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DS9166/A-06 April 2004