RT9168/A - Richtek

RT9168/A
200mA/500mA Fixed Output Voltage LDO Regulator
General Description
Features
The RT9168/A is a 200mA/500mA low dropout and
micropower regulator suitable for portable applications.
The output voltages range from 1.5V to 5.0V in 100mV
increments and 2% accuracy. The RT9168/A is designed
for use with very low ESR capacitors. The output remains
stable even with a 1μF ceramic output capacitor.
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Stable with Low-ESR Output Capacitor
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Low Dropout Voltage (220mV at 200mA)
μA Typical
Low Operation Current −80μ
Shutdown Function
Low Temperature Coefficient
Current and Thermal Limiting
Custom Voltage Available
SOT-23-5 and SOP-8 Packages
RoHS Compliant and 100% Lead (Pb)-Free
The RT9168/A uses an internal PMOS 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 for batterypowered devices. Other features include current limiting
and over temperature protection. The SOT-23-5 and
SOP-8 packages are also available for larger power
dissipation and design flexibility.
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Applications
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Ordering Information
RT9168/A
Package Type
BR : SOT-23-5
S : SOP-8
SH : SOP-8, High Shutdown
Cellular Telephones
Laptop, Notebook, and Palmtop Computers
Battery-powered Equipment
Hand-held Equipment
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Pin Configurations
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
(TOP VIEW)
Output Voltage
15 : 1.5V
16 : 1.6V
:
:
49 : 4.9V
50 : 5.0V
500mA Output Current
200mA Output Current
Note :
Richtek products are :
`
RoHS compliant and compatible with the current require-
NC
EN
5
4
2
3
VOUT GND VIN
SOT-23-5
VOUT
8
VIN
GND
2
7
GND
GND
3
6
GND
NC
4
5
EN/EN
SOP-8
ments of IPC/JEDEC J-STD-020.
`
Suitable for use in SnPb or Pb-free soldering processes.
DS9168/A-18 April 2011
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RT9168/A
Typical Application Circuit
RT9168/A
VOUT
+
CIN
1uF
VIN
+
VIN
COUT
1uF
GND
VOUT
NC
EN/EN
Functional Pin Description
Pin Name
Pin Function
VIN
Input Voltage
GND
Ground
EN (EN)
Chip Enable Active High (Low)
NC
No Connection
VOUT
Output Voltage
Function Block Diagram
Shutdown
and
Logic Control
EN/EN
VIN
VREF
+
MOS Driver
-
Error
Amplifier
VOUT
Current-Limit and
Thermal Protection
R1
R2
GND
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DS9168/A-18 April 2011
RT9168/A
Absolute Maximum Ratings
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Input Voltage ---------------------------------------------------------------------------------------------------------- 8V
Power Dissipation, PD @ TA = 25°C
SOT-23-5 --------------------------------------------------------------------------------------------------------------- 0.4W
SOP-8 ------------------------------------------------------------------------------------------------------------------ 0.625W
Package Thermal Resistance (Note1)
SOT-23-5, θJA --------------------------------------------------------------------------------------------------------- 250°C/W
SOP-8, θJA ------------------------------------------------------------------------------------------------------------ 160°C/W
Operating Junction Temperature Range ------------------------------------------------------------------------- −40°C to 125°C
Storage Temperature Range --------------------------------------------------------------------------------------- −65°C to 150°C
Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------- 260°C
Electrical Characteristics
(VIN = 5.0V, CIN = 1μF, COUT = 1μF, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Min
Typ
Max
2.9
--
7
IL = 50mA
2.7
--
7
IL = 1mA
-2
--
+2
%
200
--
--
mA
500
--
--
mA
--
300
--
mA
--
700
--
mA
No Load
--
80
150
IOUT = 200mA
--
90
150
RT9168A
IOUT = 500mA
--
90
150
RT9168/A
IOUT = 1mA
--
1.1
5
mV
IOUT = 50mA
--
55
100
mV
IOUT = 200mA
--
220
300
mV
IOUT = 500mA
--
600
750
mV
-0.2
--
+0.2
%/V
IOUT = 0mA to 200mA
--
0.01
0.04
IOUT = 0mA to 500mA
--
0.01
0.04
Input Voltage Range
VIN
Output Voltage Accuracy
Maximum Output
Current
ΔVOUT
Test Conditions
RT9168
RT9168A
IMAX
RT9168
Current Limit
RT9168A
ILIM
RT9168/A
GND Pin Current
RT9168
IG
(2)
Dropout Voltage
RT9168/A
(VOUT(Nominal)≥3.0V
RT9168/A
Version)
RT9168A
VDROP
ΔVLINE
Line Regulation
RT9168/A
Load Regulation
RT9168A
ΔVLOAD
RLOAD = 1Ω
VIN = (VOUT+0.15) to 7V, IOUT = 1mA
Unit
V
μA
%/mA
EN, EN Input High Threshold
VIH
V IN = 3V to 5.5V
2.2
--
--
V
EN, EN Input Low Threshold
VIL
V IN = 3V to 5.5V
--
--
0.4
V
EN, EN Bias Current
ISD
--
--
100
nA
Shutdown Supply Current
IGSD
--
0.01
1
μA
Thermal Shutdown Temperature
T SD
--
155
--
°C
Ripple Rejection
PSRR
--
58
--
dB
DS9168/A-18 April 2011
V OUT = 0V
F = 100Hz, CB P = 10nF, COUT = 10μF
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RT9168/A
Note 1. θ JA 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 2. The dropout voltage is defined as VIN -VOUT, which is measured when VOUT is VOUT(NORMAL) − 100mV.
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DS9168/A-18 April 2011
RT9168/A
Typical Operating Characteristics
GND Current vs. Temperature
120
3.32
105
3.31
90
GND Current (uA)1
Output Voltage (V)
Output Voltage vs. Temperature
3.33
3.30
3.29
3.28
3.27
75
60
45
30
15
3.26
VOUT = 3.3V
VOUT = 3.3V
0
3.25
-50
-25
0
25
50
75
100
125
-50
150
-25
0
Temperature (° C)
50
75
125
150
Current Limit vs. Temperature
Dropout Voltage vs. Output Current
480
420
250
200
25°C
150
-40°C
100
Current Limit (mA)
85°C
360
300
240
180
120
50
RT9168
VOUT = 3.3V
60
VOUT = 3.3V
0
0
0
25
50
75
100
125
150
175
-50
200
-25
0
25
50
75
100
125
150
Temperature (° C)
Output Current (mA)
PSRR
Current Limit vs. Temperature
900
70
800
60
700
50
PSRR (dB)
Current Limit (mA)
100
Temperature (° C)
300
Dropout Voltage (mV)
25
600
500
400
40
30
20
300
RT9168A
VOUT = 3.3V
200
0
100
-50
-25
0
25
50
75
100
Temperature (° C)
DS9168/A-18 April 2011
125
150
VOUT = 3.3V, ILOAD = 1mA
COUT = 4.7V
10
10
10
100
100
1K
1000
10K
10000
100K
100000
1M
1000000
Frequency (kHz)
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RT9168/A
Load Transient Response
CIN = 10uF
COUT = 1uF
40
Load Transient Response
60
VIN = 4V
VOUT = 3.0V
Output Voltage
Deviation (mV)
Output Voltage
Deviation (mV)
60
20
0
≈
≈
50
1
-50
20
0
≈
≈
50
1
-50
Time (50us/Div)
Time (50us/Div)
Line Transient Response
VOUT = 3.0V
COUT = 1uF
100
Line Transient Response
150
Loading = 1mA
Output Voltage
Deviation (mV)
Output Voltage
Deviation (mV)
150
50
0
100
VOUT = 3.0V
COUT = 1uF
50
0
≈
≈
5
4
≈
≈
5
4
Time (1ms/Div)
Time (1ms/Div)
Line Transient Response
VOUT = 3.0V
100 COUT = 4.7uF
Line Transient Response
Loading = 1mA
50
0
60
Output Voltage
Deviation (mV)
150
Output Voltage
Deviation (mV)
Loading = 50mA
-50
Input Voltage
Deviation(V)
Input Voltage
Deviation(V)
-50
-50
40
VOUT = 3.0V
COUT = 4.7uF
Loading = 50mA
20
0
-20
≈
≈
5
4
Time (500us/Div)
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Input Voltage
Deviation(V)
Input Voltage
Deviation(V)
VIN = 4V
VOUT = 3.0V
-20
Load Current
(mA)
Load Current
(mA)
-20
CIN = 10uF
COUT = 4.7uF
40
≈
≈
5
4
Time (500us/Div)
DS9168/A-18 April 2011
RT9168/A
Application Information
Region of Stable Cout ESR v.s Load Current
Capacitor Selection and Regulator Stability
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Like any low-dropout regulator, the external capacitors used
with the RT9168/A must be carefully selected for regulator
stability and performance.
The output capacitor must meet both requirements for
minimum amount of capacitance and ESR in all LDO
applications. The RT9168/A is designed specifically to
work with low ESR ceramic output capacitor in spacesaving and performance consideration. Using a ceramic
capacitor whose value is at least 1μF with ESR is > 5mΩ
on the RT9168/A output ensures stability. The
RT9168/A 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 load-transient response, stability, and PSRR.
The output capacitor should be located not more than
0.5" from the VOUT pin of the RT9168/A 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.
DS9168/A-18 April 2011
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Cout ESR ( Ω )1
Using a capacitor whose value is > 1μF on the
RT9168/A input and the amount of capacitance can be
increased without limit. The input capacitor must be
located 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 linetransient response.
Unstable Region
COUT = 4.7uF
Stable Region
COUT = 1uF
1
0.1
Unstable Region
0.01
0.001
0
40
80
120
160
200
Load Current (mA)
Figure 1
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.
Load-Transient Considerations
The RT9168/A 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.
Shutdown Input Operation
The RT9168/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).
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RT9168/A
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
RT9168/A input voltage or another logic supply. The highlevel voltage may exceed the RT9168/A input voltage, but
must remain within the absolute maximum ratings for the
EN pin.
3). As shown, the Schottky diode is connected in parallel
with the internal parasitic diode and prevents it from being
turned on by limiting the voltage drop across it to about
0.3V. < 100 mA to prevent damage to the part.
VIN
VOUT
Internal P-Channel Pass Transistor
The RT9168/A features a typical 1.1Ω P-Channel MOSFET
pass transistor. It provides several advantages over similar
designs using PNP pass transistors, including longer
battery life. The P-channel MOSFET requires no base
drive, which reduces quiescent current considerably. PNPbased regulators waste considerable current in dropout
when the pass transistor saturates. They also use high
base-drive currents under large loads. The RT9168/A does
not suffer from these problems and consume only 80μA of
quiescent current whether in dropout, light-load, or heavyload applications.
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
RT9168/A 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.
Reverse Current Path
The power transistor used in the RT9168/A has an inherent
diode connected between the regulator input and output
(see Figure 2). If the output is forced above the input by
more than a diode-drop, this diode will become forward
biased 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. To prevent
regulator mis-operation, a Schottky diode should be used
in any applications where input/output voltage conditions
can cause the internal diode to be turned on (see Figure
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Figure 2
VIN
VOUT
Figure 3
Current Limit and Thermal Protection
The RT9168 includes a current limit which monitors and
controls the pass transistor's gate voltage limiting the
output current to 300mA Typ. (700mA Typ. for RT9168A).
Thermal-overload protection limits total power dissipation
in the RT9168/A. 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 thermaloverload conditions. Thermal-overloaded protection is
designed to protect the RT9168/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 amount of time without damaging the part by
cooperation of current limit and thermal protection.
DS9168/A-18 April 2011
RT9168/A
Operating Region and Power Dissipation
The maximum power dissipation of RT9168/A 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
power dissipation is: PMAX = (TJ - TA) /θJA
where TJ - TA is the temperature difference between the
RT9168/A die junction and the surrounding environment,
θJA is the thermal resistance from the junction to the
surrounding environment. The GND pin of the RT9168/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.
DS9168/A-18 April 2011
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RT9168/A
Outline Dimension
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
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DS9168/A-18 April 2011
RT9168/A
H
A
M
J
B
F
C
I
D
Dimensions In Millimeters
Dimensions In Inches
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
8-Lead SOP 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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