RT9167B

RT9167B
Low-Noise, Fixed Output Voltage, 300mA LDO Regulator
General Description
Features
The RT9167B is a 300mA low dropout and low noise
micropower regulator suitable for portable applications.
The output voltages range from 1.5V to 5V in 100mV
increments and 2% accuracy. The RT9167B is designed
for use with very low ESR capacitors. The output remains
stable even with 1μF ceramic output capacitor.
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Stable with Low-ESR Output Capacitor
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Low Dropout Voltage (350mV @ 300mA)
μA Typical
Low Operation Current −80μ
Shutdown Function
Low Noise Output
Low Temperature Coefficient
Current and Thermal Limiting
Custom Voltage Available
MSOP-8 Package
RoHS Compliant and 100% Lead (Pb)-Free
The RT9167B uses an internal PMOS as the pass device,
which does not cause extra GND current in heavy load
and dropout conditions. The shutdown mode with nearly
zero operation current makes the IC suitable for batterypowered devices. Other features include a reference
bypass pin to improve low noise performance, current
limiting, and over temperature protection.
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Applications
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Ordering Information
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RT9167B-
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Package Type
F : MSOP-8
Cellular Telephones
Laptop, Notebook, and Palmtop Computers
Battery-powered Equipment
Hand-held Equipment
Pin Configurations
Lead Plating System
P : Pb Free
Output Voltage
15 : 1.5V
16 : 1.6V
:
49 : 4.9V
50 : 5.0V
2H : 2.85V
Note :
(TOP VIEW)
NC
VIN
GND
VOUT
compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
`Suitable
3
6
4
5
Typical Application Circuit
VIN
CIN
1uF
for use in SnPb or Pb-free soldering processes.
Chip Enable
Marking Information
7
MSOP-8
Richtek products are :
`RoHS
NC
EN
BP
NC
8
2
RT9167B
2 IN
VOUT 4
3 GND
7 EN
BP
COUT
1uF
VOUT
6
CBP
10nF
For marking information, contact our sales representative
directly or through a RichTek distributor located in your
area.
DS9167B-01 April 2011
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RT9167B
Functional Pin Description
Pin No.
Pin Name
Pin Function
1, 5, 8
NC
No Internal Connection.
2
VIN
Power Input Voltage.
3
GND
Ground.
7
EN
Chip Enable (Active High).
6
BP
Reference Noise Bypass.
4
VOUT
Output Voltage.
Function Block Diagram
Shutdown
and
Logic Control
EN
VIN
VREF
BP
+
MOS Driver
-
Error
Amplifier
Current-Limit and
Thermal Protection
VOUT
R1
R2
GND
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DS9167B-01 April 2011
RT9167B
Absolute Maximum Ratings
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(Note1)
Input Voltage --------------------------------------------------------------------------------------------------------------EN Input Voltage ---------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C
MSOP-8 -------------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note2)
MSOP-8, θJA --------------------------------------------------------------------------------------------------------------Junction Temperature ---------------------------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------
Recommended Operating Conditions
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8V
6V
0.823W
120°C/W
150°C
−65°C to 150°C
260°C
(Note 3)
Supply Input Voltage, VIN ----------------------------------------------------------------------------------------------EN Input Voltage ---------------------------------------------------------------------------------------------------------Junction Temperature Range ------------------------------------------------------------------------------------------Ambient Temperature Range -------------------------------------------------------------------------------------------
2.7V to 7V
2.7V to 5.5V
−40°C to 125°C
−40°C to 85°C
Electrical Characteristics
(VIN = 5.0V, CIN = 1μF, COUT = 1μF, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Input Voltage Range
V IN
Output Voltage Accuracy
ΔVOUT
Maximum Output Current
IMAX
Current Limit
ILIM
Quiescent Current
IQ
Dropout Voltage
(Note 4)
(VOUT(Normal) = 3V Version)
V DROP
Test Conditions
Min
Typ
Max
2.9
--
7
IL = 50mA
2.7
--
7
IL = 1mA
−2
--
2
%
300
--
--
mA
400
--
--
mA
No Load
--
80
150
IOUT = 300mA
--
90
150
IOUT = 1mA
--
1.1
5
IOUT = 50mA
--
55
100
IOUT = 300mA
--
350
450
V IN= (VOUT + 0.15) to 7V, IOUT =1mA
--
--
6
mV/V
--
--
30
mV
R LOAD = 1Ω
Line Regulation
ΔVLINE
Load Regulation
ΔVLOAD IOUT = 0mA to 300mA
EN Input Threshold
Unit
V
μA
mV
Logic-High VIH
V IN= 3V to 5.5V
1.6
--
--
Logic-Low
V IN = 3V to 5.5V
--
--
0.4
--
--
100
nA
--
0.01
1
μA
--
155
--
°C
--
58
--
dB
VIL
EN Bias Current
ISD
Shutdown Supply Current
IGSD
Thermal Shutdown Temperature
TSD
Ripple Rejection
PSRR
DS9167B-01 April 2011
V OUT = 0V
F = 100Hz, CBP = 10nF, COUT = 10μF
V
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RT9167B
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 natural convection at TA = 25°C on a high effective thermal conductivity four-layer test board of
JEDEC 51-7 thermal measurement standard.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The dropott voltage is defined as VIN − VOUT, which is measured when VOUT is VOUT (NORMAL) −100mV
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DS9167B-01 April 2011
RT9167B
Typical Operating Characteristics
Quiescent Current vs. Temperature
120
3.32
105
Quiescent Current (μA)1
Output Voltage (V)
Output Voltage vs. Temperature
3.33
3.31
3.30
3.29
3.28
3.27
3.26
90
75
60
45
30
15
VOUT = 3.3V
VOUT = 3.3V
0
3.25
-50
-25
0
25
50
75
100
125
-50
150
-25
0
25
Temperature (°C)
75
100
125
150
Current Limit vs. Temperature
Dropout Voltage vs. Load Current
700
250
650
200
125°C
Current Limit (mA)
Dropout Voltage (mV)
50
Temperature (°C)
25°C
150
-40°C
100
50
600
550
500
450
400
350
VOUT = 5V
VOUT = 5V
0
300
0
0.05
0.1
0.15
0.2
0.25
-50
0.3
-25
0
Load Transient Response
CIN = 10μF
COUT = 1μF
CBP = 10nF
20
VIN = 4V
VOUT = 3V
Output Voltage
Deviation (mV)
40
0
-20
≈
≈
50
1
-50
75
100
125
CIN = 10μF
COUT = 4.7μF
CBP = 10nF
40
20
VIN = 4V
VOUT = 3V
0
-20
≈
≈
50
1
-50
Time (50μs/Div)
DS9167B-01 April 2011
50
Load Transient Response
60
Load Current
(mA)
Load Current
(mA)
Output Voltage
Deviation (mV)
60
25
Temperature (°C)
Load Current (mA)
Time (50μs/Div)
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RT9167B
Line Transient Response
Output Voltage
Deviation (mV)
0
-50
≈
≈
5
4
Input Voltage
Deviation (V)
50
Line Transient Response
150
Loading = 1mA
VOUT = 3V
COUT = 1μF
CBP = 10nF
100
Input Voltage
Deviation (V)
Output Voltage
Deviation (mV)
150
100
50
VOUT = 3V
COUT = 1μF
CBP = 10nF
0
-50
≈
≈
5
4
Time (1ms/Div)
Time (1ms/Div)
Line Transient Response
Line Transient Response
VOUT = 3V
COUT = 4.7μF
CBP = 10nF
60
Loading = 1mA
Output Voltage
Deviation (mV)
100
50
0
≈
≈
5
4
Input Voltage
Deviation (V)
-50
Input Voltage
Deviation (V)
Output Voltage
Deviation (mV)
150
Loading = 50mA
40
20
VOUT = 3V
COUT = 4.7μF
CBP = 10nF
Loading = 50mA
0
-20
≈
≈
5
4
Time (500μs/Div)
Time (500μs/Div)
PSRR
70
60
PSRR (dB)
50
40
30
20
10
VOUT = 3.3V, ILOAD = 1mA
COUT = 4.7μF, CBP = 10nF
0
10
10
100
100
1K
1000
10K
10000
100K
100000
1M
1000000
Frequency (kHz)
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DS9167B-01 April 2011
RT9167B
Application Information
Capacitor Selection and Regulator Stability
Like any low-dropout regulator, the external capacitors used
with the RT9167B must be carefully selected for regulator
stability and performance.
Using a capacitor whose value is > 1μF on the RT9167B
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" 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.
The output capacitor must meet both requirements for
minimum amount of capacitance and ESR in all LDOs
application. The RT9167B 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 is > 5mΩ on the
RT9167B output ensures stability. The RT9167B 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 voltages and capacitor values. Output capacitor of
larger capacitance can reduce noise and improve loadtransient response, stability, and PSRR. The output
Region of Stable COUT ESR vs. Load Current
capacitor should be located not more than 0.5" from the
VOUT pin of the RT9167B and returned to a clean analog
ground.
Note that some ceramic dielectrics exhibit large
capacitance and ESR variation 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
application 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 sufficient for the application
by the manufacture.
Use a 10nF bypass capacitor at BP for low output voltage
noise. The capacitor, 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. Increasing the capacitance will slightly decrease
the output noise, but increase the start-up time. The
capacitor connected to the bypass 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 response.
100.000
100
COUT = 1μF
Unstable Region
C
CBP
1nF
BP= =10nF
1.000
1
Voltage
(0.5V/Div)
Voltage
(0.5V
/ DIV)
COUT ESR (Ω)
()
10.000
10
Stable Region
0.100
0.1
0.010
0.01
CBP
10nF
BP==10nF
Unstable Region
0.001
0
50
100
150
200
Load Current (mA)
Figure 1
DS9167B-01 April 2011
250
OUT = 3V
VVOUT
=3.0V
300
00
5.0
10.0
15.0
15.0
Time (ms)
Figure 2
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RT9167B
Load-Transient Considerations
power dissipation is : PMAX = (TJ − TA) /θJA
The RT9167B load-transient response graphs (see Typical
Operating Characteristics) 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. Typical 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 capacitor.
Increasing the output capacitor's value and decreasing the
ESR attenuates the overshoot.
where TJ − TA is the temperature difference between the
RT9167B die junction and the surrounding environment,
θJA is the thermal resistance from the junction to the
surrounding environment. The GND pin of the RT9167B
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.
Shutdown Input Operation
The RT9167B 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 pullup resistor to the RT9167B input voltage or another logic
supply. The high-level voltage may exceed the
RT9167B input voltage, but must remain within the
absolute maximum ratings for the EN pin.
Input-Output (Dropout) Voltage
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
RT9167B uses a P-Channel MOSFET pass transistor, the
dropout voltage is a function of drain-to-source onresistance [RDS(ON)] multiplied by the load current.
Operating Region and Power Dissipation
The maximum power dissipation of RT9167B depends on
the thermal resistance of the case and circuit board, the
temperature difference between the die junction and
ambient air, and the rate of airflow. The power dissipation
across the device is P = IOUT (VIN − VOUT). The maximum
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Current Limit and Thermal Protection
The RT9167B includes a current limit which monitors and
controls the pass transistor's gate voltage limiting the
output current to 400mA min. Thermal-overload protection
limits total power dissipation in the RT9167B. When the
junction temperature exceeds TJ = 155°C, the thermal
sensor signals the shutdown logic turning off the pass
transistor and allowing the IC to cool. The thermal sensor
will turn the pass transistor on again after the IC's junction
temperature cools by 10°C, resulting in a pulsed output
during continuous thermal-overload conditions. Thermaloverloaded protection is designed to protect the RT9167B
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 amount of time without damaging the part
by cooperation of current limit and thermal protection.
Thermal Considerations
For continuous operation, do not exceed absolute
maximum junction temperature. The maximum power
dissipation depends on the thermal resistance of the IC
package, PCB layout, rate of surrounding airflow, and
difference between junction and ambient temperature. The
maximum power dissipation can be calculated by the
following formula :
PD(MAX) = (TJ(MAX) − TA) / θJA
where TJ(MAX) is the maximum junction temperature, TA is
the ambient temperature, and θJA is the junction to ambient
thermal resistance.
For recommended operating condition specifications of
the RT9167B, the maximum junction temperature is 125°C
and TA is the ambient temperature. The junction to ambient
thermal resistance, θJA, is layout dependent. For MSOP-
DS9167B-01 April 2011
RT9167B
8 packages, the thermal resistance, θJA, is 120°C/W on a
standard JEDEC 51-7 four-layer thermal test board. The
maximum power dissipation at TA = 25°C can be calculated
by the following formula :
PD(MAX) = (125°C − 25°C) / (120°C/W) = 0.833W for
MSOP-8 package
The maximum power dissipation depends on the operating
ambient temperature for fixed T J(MAX) and thermal
resistance, θJA. For the RT9167B package, the derating
curve in Figure 3 allows the designer to see the effect of
rising ambient temperature on the maximum power
dissipation.
Maximum Power Dissipation (W)1
0.90
Four-Layer PCB
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 3. Derating Curves for RT9167B Packages
DS9167B-01 April 2011
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RT9167B
Outline Dimension
D
L
E1
E
e
A2
A
A1
b
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
0.810
1.100
0.032
0.043
A1
0.000
0.150
0.000
0.006
A2
0.750
0.950
0.030
0.037
b
0.220
0.380
0.009
0.015
D
2.900
3.100
0.114
0.122
e
0.650
0.026
E
4.800
5.000
0.189
0.197
E1
2.900
3.100
0.114
0.122
L
0.400
0.800
0.016
0.031
8-Lead MSOP Plastic 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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DS9167B-01 April 2011