RT9167/A
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DS9167/A-29 April 2011 www.richtek.com
Pin Configurations
Low-Noise, Fixed Output Voltage,300mA/500mA LDO Regulator
Ordering Information
(TOP VIEW)
General Description
The RT9167/A is a 300mA/500mA low dropout and low
noise micropower regulator suitable for portable
a pplications. The output voltages ra nge from 1.5V to 5V
in 100mV increments and 2% accuracy . The RT9167/A is
designed for use with very low ESR capacitors. The output
remains stable even with 1μF cera mic output ca pa citor.
The RT9167/A uses an internal P-MOSFET as the pass
device, which does not cause extra GND current in heavy
load and dropout conditions. The shutdown mode of nearly
zero operation current makes the IC suitable f or battery-
powered devices. Other features include a reference
bypass pin to improve low noise performance, current
limiting, a nd over temperature protection.
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Features
zz
zz
zSta ble with Low-ESR Output Capa citor
zz
zz
zLow Dropout Voltage (350mV @ 300mA)
zz
zz
zLow Operation Current −−
−−
−80μμ
μμ
μA Typical
zz
zz
zShutdown Function
zz
zz
zLow Noise Output
zz
zz
zLow Temperature Coefficient
zz
zz
zCurrent and Thermal Limiting
zz
zz
zCustom Voltage Available
zz
zz
zSOT-23-5 and SOP-8 Package s
zz
zz
zRoHS Compliant and 100% Lead (Pb)-Free
Applications
zCellular T elephones
zLa ptop, Notebook, and Palmtop Computers
zBattery-powered Equipment
zHand-held Equipment
SOP-8
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.
SOT-23-5 (R-T ype)
SOT-23-5
VIN GND EN
VOUT BP
4
23
5
VOUT GND VIN
BP EN
4
23
5
EN
VIN
VOUT
BP
GND
GND
GND
GND
2
3
45
6
7
8
RT9167/A-
Package Type
B : SOT-23-5
BR : SOT-23-5 (R-Type)
S : SOP-8
Output Voltage
15 : 1.5V
16 : 1.6V
:
49 : 4.9V
50 : 5.0V
2H : 2.85V
500mA Output Current
300mA Output Current
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
RT9167/A
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Function Block Diagram
Typical Application Circuit
Functional Pin Description
Pin Name Pin Function
VIN Power Inp ut Vol tage
GND Ground
EN Chip Enable (Active High)
BP Reference Noise Bypass
VOUT Output Voltage
Current -Lim it an d
Thermal Protection
MOS Dri ver
+
-
VOUT
Shutdown
and
Logic Cont rol
R1
R2
VIN
Error
Amplifier
VREF
BP
EN
GND
IN
GND
OUT
RT9167/A
+
+
COUT
1µF
CIN
1µF
VIN VOUT
EN BP CBP
10nF
Chip Enable
RT9167/A
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DS9167/A-29 April 2011 www.richtek.com
Absolute Maximum Ratings
zInput V oltage ---------------------------------------------------------------------------------------------------------- 8V
zPower Dissipation, PD @ TA = 25°C
SOT-23-5--------------------------------------------------------------------------------------------------------------- 0.4W
SOP-8 ------------------------------------------------------------------------------------------------------------------ 0.625W
zPa ckage Thermal Resista nce (Note1)
SOT-23-5, θJA --------------------------------------------------------------------------------------------------------- 250°C/W
SOT-23-5, θJC--------------------------------------------------------------------------------------------------------- 130°C/W
SOP-8, θJA ------------------------------------------------------------------------------------------------------------ 160°C/W
SOP-8, θJC ------------------------------------------------------------------------------------------------------------ 60°C/W
zOperating Junction Temperature Range------------------------------------------------------------------------- −40°C to 125°C
zStorage T emperature Range --------------------------------------------------------------------------------------- −65°C to 150°C
zLead T emperature (Soldering, 10 sec.) ------------------------------------------------------------------------- 260°C
Electrical Characteristics
(VIN = 5.0V, CIN = 1μF, C OUT = 1μF, TA = 25° C, unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Unit
2.9 -- 7
Input Voltage Range VIN IL = 50 mA 2.7 -- 7 V
Output Voltage Accuracy ΔVOUT I
L = 1mA -2 -- 2 %
RT9167 300 -- --
Maxi mum Output
Current RT9167A IMAX 500 -- -- mA
RT9167 400 -- --
Current Limit RT9167A ILIM R
LOAD = 1Ω 500 700 -- mA
RT9167/A No Load -- 80 150
RT9167/A IOUT = 300mA -- 90 150
Quiescent Curre n t
RT9167A
IG
IOUT = 500mA -- 90 150
μA
RT9167/A IOUT = 1mA -- 1.1 5
RT9167/A IOUT = 50mA -- 55 100
RT9167/A IOUT = 300mA -- 350 450
Dropout Vo ltage (2)
(VOUT(Normal) = 3.0V
Version) RT9167 A
VDROP
IOUT = 500mA -- 600 750
mV
Line Regulation ΔVLINE V
IN= (VOUT+0.15) to 7V, IOUT =1mA -- -- 6 mV/V
RT9167/A IOUT = 0m A to 300mA -- -- 30
Load Regulation RT9167A ΔVLOAD IOUT = 0mA to 500m A -- -- 35 mV
E N Input High Threshold VIH V
IN= 3V to 5.5V 1.6 -- -- V
E N Input Low T hreshold VIL V
IN = 3V to 5.5V -- -- 0.4 V
E N Bias Cur rent ISD -- -- 100 nA
S h utdown Supply Curren t IGSD VOUT = 0V -- 0.01 1 μA
Th ermal Shutdown Temperature TSD -- 155 --
°C
To be continued
RT9167/A
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Note 1. 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. Pin 1 of SOP-8 and pin4 of SOT-23-5 packages are the case position for
θJA measurement.
Note 2. The dropout voltage is defined as VIN -VOUT, which is measured when VOUT is VOUT(NORMAL) − 100mV.
Parameter Symbol Test Conditions Min Typ Max Unit
Output Noise eNO C
BP = 10nF, COUT = 10μF -- 350 -- nV
Ripple Re jection PS RR F = 100Hz, C BP = 10nF, COUT = 10μF -- 58 -- dB
Hz
RT9167/A
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DS9167/A-29 April 2011 www.richtek.com
Typical Operating Characteristics
Current Limit vs. Temperature
200
300
400
500
600
700
800
900
-50-250 255075100125
Temperature
Curr ent Lim it (mA)
VOUT = 3.3V
RT9167A
(°C)
Dropout Voltage vs. Load Current
0
100
200
300
400
500
600
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Load Current (A)
Dropout Voltage ( m V)
VOUT = 3.3V
125°C
25°C
-40°C
RT9167A
Dropout Voltage vs. Load Current
0
50
100
150
200
250
0 0.05 0.1 0.15 0.2 0.25 0.3
Load Current (A)
Dropout Volt age (mV)
VOUT = 5V
25°C
-40°C
RT9167
125°C
Current Lim it v s . Tem perature
300
350
400
450
500
550
600
650
700
-50 -25 0 25 50 75 100 125
Temperature
Curr ent Lim it (mA)
VOUT = 5V
RT9167
(°C)
Quiescent Current vs. Temperature
0
15
30
45
60
75
90
105
120
-50 -25 0 25 50 75 100 125 150
Temperature
Quiescent Current (uA)1
VOUT = 3.3V
(°C)
Output Voltage vs. Temperature
3.25
3.26
3.27
3.28
3.29
3.30
3.31
3.32
3.33
-50 -25 0 25 50 75 100 125 150
Temperature
Output Voltage (V)
VOUT = 3.3V
(°C)
RT9167/A
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150
100
50
0
-50
5
4
Line Transient Response
Time (1ms/Div)
Output Voltage
Deviation (mV)
Input Voltage
Deviation (V)
Loading = 1mA
VOUT = 3V
COUT = 1μF
CBP = 10nF
≈ ≈
150
100
50
0
-50
5
4
Line Transient Response
Time (1ms/Div)
Output Voltage
Deviation (mV)
Input Voltage
Deviation (V)
Loading = 50mA
VOUT = 3V
COUT = 1μF
CBP = 10nF
≈ ≈
150
100
50
0
-50
5
4
Line Transient Response
Time (500μs/Div)
Output Voltage
Deviation (mV)
Input Voltage
Deviation (V)
Loading = 1mA
VOUT = 3V
COUT = 4.7μF
CBP = 10nF
≈ ≈
60
40
20
0
-20
5
4
Line Transient Response
Time (500μs/Div)
Output Voltage
Deviation (mV)
Input Voltage
Deviation (V)
Loading = 50mA
VOUT = 3V
COUT = 4.7μF
CBP = 10nF
≈ ≈
Load Transient Response
Time (50μs/Div)
Output Voltage
Deviation (mV)
Load Current
(mA)
60
40
20
0
-20
50
1
-50
VIN = 4V
VOUT = 3V
CIN = 10μF
COUT = 4.7μF
CBP = 10nF
≈ ≈
Load Transient Response
Time (50μs/Div)
Output Voltage
Deviation (mV)
Load Current
(mA)
60
40
20
0
-20
50
1
-50
VIN = 4V
VOUT = 3V
CIN = 10μF
COUT = 1μF
CBP = 10nF
≈ ≈
RT9167/A
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DS9167/A-29 April 2011 www.richtek.com
PSRR
0
10
20
30
40
50
60
70
10 100 1000 10000 100000 1000000
Frequen cy (kHz )
PSRR (dB)
VOUT = 3.3V, ILOAD = 1mA
COUT = 4.7μF, CBP = 10nF
10 100 1K 10K 100K 1M
RT9167/A
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10.0 15.0 0 5.0
CBP = 10nF
Time (ms)
CBP = 1nF
Voltage (0.5V / DIV)
VOUT=3.0V
Application Information
Capacitor Selection and Regulator Stability
Like any low-dropout regulator, the external ca pacitors used
with the RT9167/A must be carefully selected for regulator
stability a nd performa nce.
Using a ca pacitor whose value is > 1μF on the RT9167/A
input and the amount of capacitance can be increased
without limit. The input capacitor must be located a
distance of not more tha n 0.5" from the input pin of the IC
and returned to a clea n an alog 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.
The output capacitor must meet both requirements for
minimum amount of capacitance and ESR in all LDOs
a pplication. The RT9167/A is designed specifically to work
with low ESR ceramic output capacitor in space-saving
and performa nce consideration. Using a cera mic capacitor
whose value is at least 1μF with ESR is > 5mΩ on the
RT9167/A output ensures stability. The RT9167/A still
works well with output ca pa citor 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 voltages and ca pacitor values. Output ca pacitor of
larger capacitance can reduce noise and improve load-
transient response, stability, and PSRR. The output
capa citor should be located not more tha n 0.5" from the
VOUT pin of the RT9167/A and returned to a clean an alog
ground.
Note that some ceramic dielectrics exhibit large
ca pa cita nce a nd ESR vari ation with temperature. It may
be necessary to use 2.2μF or more to ensure stability at
temperatures below −10°C in this case. Also, tantalum
capacitors, 2.2μF or more may be needed to maintain
capacitance and ESR in the stable region for strict
a pplication environment.
Tantalum capacitors maybe suffer failure due to surge
current when it is connected to a low-impedance source
of power (like a battery or very large capacitor). If a tantalum
capacitor is used at the input, it must be guaranteed to
have a surge current rating suff icient for the application
by the manufacture.
Use a 10nF bypa ss ca pacitor at BP for low output voltage
noise. The ca pacitor, in conjunction with an internal 200kΩ
resistor, which connects bypass pin and the band-gap
reference, creates an 80Hz low-pass filter for noise
reduction. Increa sing the capacitance will slightly decrease
the output noise, but increase the start-up time. The
ca pa citor connected to the bypa ss pin for noise reduction
must have very low leakage. This capacitor leakage current
causes the output voltage to decline by a proportional
amount to the current due to the voltage drop on the internal
200kΩ resistor . Figure 2 shows the power on respon se.
Figure 1 Figure 2
0 5.0 10.0 15.0
Voltage (0.5V/Div)
CBP = 10nF
CBP = 10nF
VOUT = 3V
Region of Stable COUT ESR vs. Load Current
0.001
0.010
0.100
1.000
10.000
100.000
0 50 100 150 200 250 300
Load Current (mA)
COUT ESR ( )
10
1
0.1
0.01
0.001
COUT = 1μF
U n stable Region
Stable Region
U n stable Region
100
(Ω)
RT9167/A
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VIN VOUT
VIN VOUT
Figure 3
Figure 4
Load-T ransient Considerations
The RT9167/A load-transient response gra phs (see Typical
Operating Chara cteristics) show two components of the
output response: a DC shift from the output impedance
due to the load current change, and the transient response.
The DC shift is quite small due to the excellent load
regulation of the IC. T ypical output voltage transient spike
for a step change in the load current from 0mA to 50mA is
tens mV, depending on the ESR of the output capa citor.
Increa sing the output ca pacitor's value and decrea sing the
ESR attenuates the overshoot.
Shutdown Input Operation
The RT9167/A is shutdown by pulling the EN input low,
and turned on by driving the input high. If this feature is
not to be used, the EN input should be tied to VIN to keep
the regulator on at all times (the EN input must not be left
floating).
To ensure proper operation, the signal source used to
drive the EN input must be able to swing above and below
the specified turn-on/turn-off voltage thresholds which
guarantee an ON or OFF state (see Electrical
Characteristics). The ON/OFF signal may come from
either CMOS output, or an open-collector output with pull-
up resistor to the RT9167/A input voltage or another logic
supply. The high-level voltage may exceed the
RT9167/A input voltage, but must remain within the
absolute maximum ratings for the EN pin.
Intern al P-Channel Pa ss T ra nsistor
The RT9167/A features a typical 1.1Ω P-MOSFET pass
transistor. It provides several advantages over similar
designs using PNP pass transistors, including longer
battery life. The P-MOSFET requires no base drive, which
reduces quiescent current considerably. PNP-based
regulators waste considerable current in dropout when the
pa ss tra nsistor saturates. They also use high base-drive
currents under large loads. The RT9167/A does not suffer
from these problems and consume only 80μA of quiescent
current whether in dropout, light-load, or heavy-load
applications.
Input-Output (Dropout) V oltage
A regulator's minimum input-output voltage differential
(or dropout voltage) determines the lowest usable supply
voltage. In battery-powered systems, this will determine
the useful end-of-life battery voltage. Because the RT9167/
A uses a P-Channel MOSFET pa ss transistor , the dropout
voltage is a function of drain-to-source on-resistance
[RDS(ON)] multiplied by the load current.
Reverse Current Path
The power transistor used in the RT9167/A has an inherent
diode connected between the regulator input and output
(see Figure 3). If the output is forced above the input by
more than a diode-drop, this diode will become f orward
bia sed and current will flow from the VOUT terminal to VIN.
This diode will also be turned on by abruptly stepping the
input voltage to a value below the output voltage. T o prevent
regulator mis-operation, a Schottky diode should be used
in any a pplications where input/output voltage conditions
can cause the internal diode to be turned on (see Figure4).
As shown, the Schottky diode is connected in parallel
with the internal para sitic diode and prevents it from being
turned on by li miting the voltage drop across it to about
0.3V. < 100mA to prevent da mage to the part.
RT9167/A
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Operating Region and Power Dissipation
The maximum power dissipation of RT9167/A depends
on the thermal resistance of the case and circuit board,
the temperature difference between the die junction and
a mbient air, and the rate of airflow. The power dissipation
a cross the device is P = IOUT (VIN − VOUT). The maximum
power dissipation is: PMAX = (TJ − TA) /θJA
where TJ − TA is the temperature difference between the
RT9167/A die junction and the surrounding environment,
θJA is the thermal resistance from the junction to the
surrounding environment. The GND pin of the RT9167/A
performs the dual function of providing an electrical
connection to ground and channeling heat away . Connect
the GND pin to ground using a large pad or ground plane.
Current Limit and Thermal Protection
T9167 includes a current limit which monitors and controls
the pass transistor's gate voltage limiting the output current
to 350mA Typ. (700mA Typ. for RT9167A). Thermal-
overload protection limits total power dissipation in the
RT9167/A. When the junction temperature exceeds
TJ = 155°C, the thermal sensor signals the shutdown logic
turning off the pa ss transistor a nd allowing the IC to cool.
The thermal sensor will turn the pa ss tra nsistor on again
after the IC's junction temperature cools by 10°C, resulting
in a pulsed output during continuous thermal-overload
conditions. Thermal-overloaded protection is designed to
protect the RT9167/A in the event of fault conditions. Do
not exceed the absolute maximum junction-temperature
rating of TJ = 150°C for continuous operation. The output
can be shorted to ground for an indefinite a mount of time
without da maging the part by cooperation of current limit
and thermal protection.
Thermal Considerations
Thermal protection limits power dissipation in RT9167/A.
When the operation junction temperature exceeds 165°C,
the OTP circuit starts the thermal shutdown function and
turns the pa ss element off. The pa ss 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 f ollowing formula :
PD(MAX) = ( TJ(MAX) − TA ) / θJA
Where TJ(MAX) is the maximum operation junction
temperature 125°C, TA is the ambient temperature and
the θJA is the junction to a mbient thermal resista nce.
For recommended operating conditions specification of
RT9167/A, 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 is layout dependent. For SOT-23-5 package,
the thermal resistance θJA is 250°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 = 0.4W for
SOT-23-5 package
PD(MAX) = (125°C - 25°C) / 160 = 0.625W for
SOP-8 package
The maximum power dissipation depends on operating
ambient temperature for fixed TJ(MAX) and thermal
resistance θJA. For RT9167/A pa ck age s, the Figure 5 of
derating curves allows the designer to see the effect of
rising ambient temperature on the maximum power
allowed.
Figure 5. Derating Curves for RT9167/A Packages
0
100
200
300
400
500
600
700
0 20406080100120140
Am bien t Tempera tu re
Maximum Power Dissipation (mW) 1
SOT-23-5
SOP-8
RT9167/A
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The value of junction to case thermal resistance θJC is
popular for users. This thermal parameter is convenient
for users to estimate the internal junction operated
temperature of packages while IC operating. It's
independent of PCB layout, the surroundings airflow effects
and temperature difference between junction to a mbient.
The operated junction temperature can be calculated by
following formula :
TJ = TC + PD x θJC
Where TC is the pa ckage ca se temperature mea sured by
thermal sensor, PD is the power dissipation defined by
user’s function and the θJC is the junction to case thermal
resistance provided by IC manufacturer. Therefore it's easy
to esti mate the junction temperature by any condition.
For example, how to calculate the junction temperature
of RT9167A-28CB SOT-23-5 package. If we use input
voltage VIN = 3.3V at an output current IO = 500mA a n d
the case temperature (pin 4 of SOT-23-5 package)
TC = 70°C mea sured by thermal couple while operating,
then our power dissipation is as f ollows :
PD = (3.3V − 2.8V) x 500mA + 3.3V x 90μA ≅ 250mW
And the junction temperature TJ could be calculated as
following :
TJ = TC + PD x θJC
TJ = 70°C + 0.25W x 130°C/W
= 70°C + 32.5°C
= 102.5°C < TJ(MAX) =125°C
For this operation application, TJ is lower than absolute
maximum operation junction temperature 125°C a nd it’s
safe to use.
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12 DS9167/A-29 April 2011www.richtek.com
Outline Dimension
AA1
e
b
B
D
C
H
L
SOT-23-5 Surface Mount Pack age
Dimensions In Mill imeters 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
RT9167/A
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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
A
B
J
F
H
M
C
D
I
8-Lead SOP Plastic Package
Dim e nsions In Mill imet e rs Dimensions In I nc hes
Symbol Min Max Min Max
A 4.801 5.004 0.189 0.197
B 3.810 3.988 0.150 0.157
C 1.346 1.753 0.053 0.069
D 0.330 0.508 0.013 0.020
F 1.194 1.346 0.047 0.053
H 0.170 0.254 0.007 0.010
I 0.050 0.254 0.002 0.010
J 5.791 6.200 0.228 0.244
M 0.400 1.270 0.016 0.050
