RT9170
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Features
zz
zz
zUltra-Low Quiescent Current (T ypically 15uA)
zz
zz
zGuara nteed 300mA Output Current
zz
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zLow Dropout : 240mV at 300mA
zz
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zWide Operating Voltage Ranges : 2V to 5.5V
zz
zz
zFast T ra nsient Re sponse
zz
zz
zT ight Load a nd Line Regulation
zz
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zTTL-Logic-Controlled En able In put
zz
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zCurrent Limiting & Thermal Protection
zz
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zOnly 1uF Output Capacitor Required for Stability
zz
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zHigh Power Supply Re je ction Ratio
zz
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zCustom Voltage Available
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zRoHS Compliant and 100% Lead (Pb)-Free
Applications
zCellular Phones and Pagers
zBattery-Powered Equipment
zLaptop, Palmtops, Notebook Computers
zHa nd-Held Instruments
zPCMCIA Cards
Pin Configurations
300mA CMOS LDO Regulator with 15μμ
μμ
μA Quiescent Current
General Description
The RT9170 is CMOS ultra low quiescent current a nd low
dropout (ULDO) regulators. The devices are capable of
supplying 300mA of output current continuously .
The RT9170's performance is optimized for battery-
powered systems to deliver 15uA ultra low quiescent
current and extremely low dropout voltage. Regulator
ground current increases only slightly in dropout, further
prolonging the battery life. The other features include ultra
low dropout voltage, high output accuracy , current limiting
protection, a nd high ripple rejection ratio.
The devices are available in fixed output voltages range of
1.2V to 3.3V with 0.1V per step. The RT9170 regulators
are available in SOT -23-3, SOT -23-5 a nd 3-lead SOT -89
packages.
Ordering Information
(TOP VIEW)
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
SOT-89
SOT-23-5SOT-23-3
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.
GND VOUT
VIN
2
3
GND VIN VOUT
NC
4
23
5
EN
231
GND VOUT
VIN
(TAB)
RT9170-
Package Type
V: SOT-23-3
B: SOT-23-5
X : SOT-89
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Output Voltage
12 : 1.2V
13 : 1.3V
:
32 : 3.2V
33 : 3.3V
RT9170
2DS9170-14 April 2011www.richtek.com
Function Block Diagram
Typical Application Circuit
Functional Pin Description
Pin No. Pin N ame Pin Functio n
SOT-23-3 SOT-23-5 SOT-89
3 2 2 VIN Power Input Voltage.
2 3 3 VOUT Output Voltage.
1 1 1 GND Ground.
- 5 -
EN Chip Enable (Ac tive Low).
- 4 - NC No Internal Connection.
+
-
Current Limit
&
Thermal Shutdown
EN
VIN
VOUT
GND
RT9170- xB
VIN
EN
VOUT
GND
CIN
1uF COUT
1uF
VOUT
Chip Enable
VIN
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DS9170-14 April 2011 www.richtek.com
Absolute Maximum Ratings (Note 1)
zSupply Input Voltage ------------------------------------------------------------------------------------------------ 7V
zPower Dissipation, PD @ TA = 25°C
SOT-23-3--------------------------------------------------------------------------------------------------------------- 0.4W
SOT-23-5--------------------------------------------------------------------------------------------------------------- 0.4W
SOT-89 ----------------------------------------------------------------------------------------------------------------- 0.571W
zPa ckage Thermal Resistance (Note 2)
SOT-23-3, θJA --------------------------------------------------------------------------------------------------------- 250°C/W
SOT-23-5, θJA --------------------------------------------------------------------------------------------------------- 250°C/W
SOT-89, θJA ----------------------------------------------------------------------------------------------------------- 175°C/W
zJunction T emperature ----------------------------------------------------------------------------------------------- 150°C
zStorage T emperature Range --------------------------------------------------------------------------------------- −65°C to 150°C
zESD Susceptibility (Note 3)
HBM (Human Body Mode) ----------------------------------------------------------------------------------------- 2kV
MM (Ma chine Mode) ------------------------------------------------------------------------------------------------ 200V
Recommended Operating Conditions (Note 4)
zSupply Input Voltage ------------------------------------------------------------------------------------------------ 2V to 5.5V
zEnable Input Voltage ------------------------------------------------------------------------------------------------ 0V to 5.5V
zJunction T emperature 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 I
OUT = 1mA −2 -- +2 %
Current Limit ILIM R
LOAD = 1Ω 300 -- --
mA
Quiescent Current (Note 5) IQ VEN ≤ 0.6V, IOUT = 0mA -- 15 -- μA
Dr opout Voltag e VDROP I
OUT = 300m A -- 240 -- mV
Line Regulation ΔVLINE VIN = (VOUT + 0.3V) to 5.5V,
IOUT = 1mA −0.3 0.018 +0.3 %/V
Load Regulation (Note 6) ΔVLOAD 1mA < IOUT < 300mA -- 0.01 0.04 %/mA
Standby Current (Note 7) ISTBY VEN ≥ 2V (Shutdown), VIN = 5.5V -- 0.1 -- μA
Logic-Low Voltage VIL V
IN = 2V to 5.5V, Enable -- -- 0.6
EN Threshold Logic-High Voltage VIH V
IN = 2V to 5.5V, Shutdown 2 -- -- V
Powe r Supply Reject ion PSRR f = 1kHz, COUT = 1μF -- −40 -- dB
Th erma l Shu tdown Tem perature TSD -- 150 -- °C
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4DS9170-14 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 is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions
Note 5. Quie scent, or ground current, is the difference between in put 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. 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.
Note 7. Standby current is the input current drawn by a regulator when the output voltage is disabled by a shutdown signal
(VEN 2V). It is measured with VIN = 5.5V.
≥
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Typical Operating Characteristics
Quiescent Current vs. Supply Voltage
0
2
4
6
8
10
12
14
16
18
22.533.544.555.5
Suppl y Voltage (V)
Quiescent Current (uA) 1
VOUT = 2.5V
CIN = 1uF (Ceramic)
COUT = 1uF (Ceramic)
No Load
ILOAD = 200mA
Quiescent Current v s. Temperature
0
2
4
6
8
10
12
14
16
18
-35-155 25456585105125
Temperature
Quiescent Current (uA) 1
VIN = 3.5V
VOUT = 2.5V
CIN = 1uF (Ceramic)
COUT = 1uF (Ceramic)
(°C)
No Load
ILOAD = 200mA
Dropout Voltage vs. Load Current
0
50
100
150
200
250
300
0 0.05 0.1 0.15 0.2 0.25 0.3
Load Current (A)
Dropout Voltage (mV)
TJ = 125°C
TJ = 25°C
TJ = -40°C
VOUT = 3.3V
Temperature Stability
2.35
2.37
2.39
2.41
2.43
2.45
2.47
2.49
2.51
2.53
2.55
-35 -15 5 25 45 65 85 105 125
Temperature
Output Voltage (V)1
VIN = 3.5V
VOUT = 2.5V
CIN = 1uF (Ceramic)
COUT = 1uF (Ceramic)
(°C)
No Load
ILOAD = 250mA
Quiescent Current vs. Load Current
10
11
12
13
14
15
16
17
18
0 0.05 0.1 0.15 0.2 0.25 0.3
Load Curre nt (A)
Quiescent Current (uA) 1
VIN = 3.5V
VOUT = 2.5V
CIN = 1uF (Ceramic)
COUT = 1uF (Ceramic)
Output Voltage vs. Supply Voltage
2.45
2.47
2.49
2.51
2.53
2.55
2.5 3 3.5 4 4.5 5 5.5
Suppl y Volta ge (V)
Output Voltage (V )1
VOUT = 2.5V
CIN = 1uF (Ceramic)
COUT = 1uF (Ceramic)
ILOAD = 1mA
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Current Limit vs. Temperature
0.60
0.80
1.00
1.20
1.40
1.60
-50-250 255075100125
Temperature
Current Limit (A)
VIN = 5V
VOUT = 3.3V
RL = 1Ω
(°C)
Current Limit
2.0
1.0
1.5
2.5
0.5
0
Time (5ms/Div)
CIN = 10uF (Ceramic) X5R
COUT = 10uF (Cera mic) X5R
Current Limit (A)
3.0 VIN = 5V
RL = 1Ω
Output V oltage (V)
0
1
2
3
1
0
Time (5ms/Div)
Enable Respone
VIN = 5V
VOUT = 3.3V
CIN = 1uF(Ceramic)
COUT = 1uF(Ceramic)
ILOAD = 300mA
2
EN V oltage (V)
Enable Respone
Output V oltage (V)
0
2
4
6
2
0
Time (25ms/DIV)
VIN = 5V
VOUT = 3.3V
CIN = 1uF (Ceramic)
COUT = 1uF (Cera mic)
ILOAD = 300mA
EN V oltage (V)
PSRR
-70
-60
-50
-40
-30
-20
-10
0
Frequency ( Hz)
PSRR(dB)1
VIN = 3.5V
VOUT = 2.5V
COUT = 1uF (Ceramic)
ILOAD = 10mA
ILOAD = 250mA
10 100 1K 10K 100K 1M
(°C)
Load Re gulation Deviation vs. Temperature
-0.0045
-0.004
-0.0035
-0.003
-0.0025
-0.002
-0.0015
-0.001
-0.0005
0
-35 -15 5 25 45 65 85 105 125
Temperature
Load Regulation Deviation (%/mA)
VOUT = 2.5V
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Noise
Noise(uV)
0
Times (2.5ms/Div)
CIN = 1uF (Ceramic)
COUT = 1uF (Ceramic)
100
VIN = 3.5V, VOUT = 2.5V
IOUT = 250mA
200
300
-100
-200
-300
Load Transient Response
Load Current (mA)
Output Voltage
Deviation (mV)
200
0
250
0
-200
Time (0.5ms/Div)
CIN = 1uF (Ceramic)
COUT = 1uF (Ceramic)
≈≈
VIN = 3.5V, VOUT = 2.5V
TA = 25°C
Time (0.5ms/Div)
Line Transient Response
Input Voltage
Deviation (V)
Output Voltage
Deviation (mV)
100
0
-100
≈≈
COUT = 1uF (Ceramic)
IOUT = 250mA
4
3
5
6VOUT = 2.5V
TA = 25°C
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Application Information
Like any low-dropout regulator, the RT9170 requires input
and output decoupling ca pacitors. The device is specifically
designed for portable applications requiring minimum board
spa ce a nd smallest components. The se ca pa citors must
be correctly selected for good performa nce (see Capacitor
Characteristics Section). Plea se 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 ca pacitance.
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
capa citor MUST be located less than 1 cm from the device
to a ssure 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.
Ca pacitor types (aluminum, cera mic and tantalum) ca n be
mixed in parallel, but the total equivalent input ca pacitance/
ESR must be defined a s above to stable operation.
There are no requirements for the ESR on the input
ca pacitor , but tolerance a nd temperature coefficient must
be considered when selecting the ca pacitor to ensure the
capacitance will be 1μF over the entire operating
temperature range.
Output Ca pacitor
The RT9170 is designed specifically to work with very
small ceramic output capacitors. A ceramic capacitor
(temperature characteristics X7R, X5R, Z5U, or Y5V) in
1μF to 10μF with 5mΩ to 50mΩ ra nge is suita ble f or the
RT9170 application. The recommended minimum
capacita nce for the device is 1μF, X5R or X7R dielectric
ceramic, between VOUT and GND for stability, but it may
be increa sed without limit. Higher ca pacitance values help
to improve transient.
The output capa citor's ESR is critical because it f orms a
zero to provide phase lead which is required for loop
stability.
No Load Stability
The device will remain stable and in regulation with no
external load. This is specially import in CMOS RAM keep-
alive a pplications.
Input-Output (Dropout) V olatge
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-to-
source on-resistance, RDS(ON), multiplied by the load
current :
VDROPOUT = VIN -VOUT = RDS(ON) x IOUT
Current Limit
The RT9170 monitors and controls the PMOS' gate voltage,
limiting the output current to 0.3A (min). The output can
be shorted to ground for a n indefinite period of time without
da maging the part.
Short-Circuit Protection
The device is short circuit protected a nd in the event of a
pea k over-current condition, the short-circuit control loop
will ra pidly drive the output PMOS pa ss element off. Once
the power pa ss element shuts down, the control loop will
ra pidly 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.
Ca pacitor Characteristics
It is important to note that capacitance tolerance and
variation with temperature must be taken into consideration
when selecting a ca pacitor so that the mini mum required
a mount of ca pa cita nce is provided over the full operating
temperature range. In general, a good tantalum ca pacitor
will show very little capacitance variation with temperature,
but a cera mic may not be as good (depending on dielectric
type).
≅
≅
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DS9170-14 April 2011 www.richtek.com
Aluminum electrolytics also typically have large
temperature variation of capacita nce value.
Equally important to consider is a capa citor's ESR change
with temperature: this is not an issue with ceramics, as
their ESR is extremely low. However, it is very importa nt
in Tantalum and aluminum electrolytic capacitors. Both
show increasing ESR at colder temperatures, but the
increa se in aluminum ele ctrolytic ca pa citors is so severe
they may not be feasible for some applications.
Ceramic :
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 by-
passing high frequency noise because of very low ESR
(typically less than 10mΩ). However, some dielectric types
do not have good ca pa citance chara cteristics as a function
of voltage a nd temperature.
Z5U and Y5V dielectric ceramics have capacitance that
drops severely with a pplied voltage. A typical Z5U or Y5V
capa citor can lose 60% of its rated capacitance with half
of the rated voltage applied to it. The Z5U a nd Y5V also
exhibit a severe temperature effect, losing more than 50%
of nominal capacitance at high and low limits of the
temperature ra nge.
X7R and X5R dielectric ceramic capacitors are strongly
recommended if ceramics are used, as they typically
maintain a ca pacitance 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 a nd capacitance.
Tantalum :
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 a s in put ca pacitors if selected to meet the ESR
requirements previously listed.
Tantalums also have good temperature sta bility: a good
quality tantalum will typically show a capacitance value
that varies less tha n 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 margin al quality ca pacitors are used (if
the ESR of the capacitor is near the upper limit of the
stability ra nge at room temperature).
Aluminum :
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 a nd ESL.
Compared by size, the ESR of an aluminum electrolytic
is higher than either Tantalum or cera mic, and it also varies
greatly with temperature. A typical aluminum ele ctrolytic
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 ma ny 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 ma nufacturer's ESR specification, since it
is typically only valid at room temperature.
Any a pplications using aluminum electrolytics should be
thoroughly tested at the lowest ambient operating
temperature where ESR is maximum.
Thermal Considerations
The RT9170 serie s ca n deliver a current of up to 300mA
over the full operating junction temperature range. However,
the maximum output current must be derated at higher
a mbient te mperature 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
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10 DS9170-14 April 2011www.richtek.com
The final operating junction temperature for any set of
conditions can be estimated by the following thermal
equation :
PD (MAX) = ( T J (MAX) - TA ) / θJA
Where TJ (MAX) is the maximum junction temperature of
the die (125°C) and TA is the maximum ambient
temperature. The junction to a mbient thermal resista nce
(θJA) for SOT-23-3 and SOT-23-5 packages at recommended
minimum footprint is 250°C/W, 175°C/W for SOT-89
package (θJA is layout dependent). Visit our website in
which “Recommended Footprints f or Soldering Surface
Mount Pa ckage s” f or detail.
PCB Layout
Good board layout practices must be used or instability
can be induced because of ground loops and voltage
drops. The in put and output capa citors 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
capa citors have a “single point ground”.
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 a nd output capa citors. 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 ca pacitors fixed
the problem. Since high current flows through the tra ce s
going into VIN a nd coming from VOUT, Kelvin connect the
capa citor le a ds to these pin s so there is no voltage drop
in series with the input a nd output capa citors.
Optimum performance can only be achieved when the
device is mounted on a PC board according to the diagram
below:
GND VIN
VOUT
EN NC
SOT-23-5 Board Layout
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Outline Dimension
A
bA1
B
D
C
e
H
L
SOT-23-3 Surface Mount Package
Dimensions In Millimeters Dimen sion s In Inch es
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
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12 DS9170-14 April 2011www.richtek.com
AA1
e
b
B
D
C
H
L
SOT-23-5 Surface Mount Pa ckage
Dimens ions In Millimet e rs Dimensions In Inch e s
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
RT9170
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Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserve s the right to make a ny 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
b
b1
b
H
A
B
D
C
e
e
C1
D1
A
3-Lead SOT-89 Surface Mount Package
Dim e nsions In Millimet e rs Dime nsion s In I nc hes
Symbol 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 3.937 4.242 0.155 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 0.356 0.432 0.014 0.017
