ETC RT9168

RT9168/A
200mA/500mA Fixed Output Voltage LDO Regulator
General Description
Features
The RT9168/A is a 200mA/500mA low dropout and
z
Stable with Low-ESR Output Capacitor
micropower
portable
z
Low Dropout Voltage (220mV at 200mA)
applications. The output voltages range from 1.5V to
z
Low Operation Current - 80µ
µA Typical
5.0V in 100mV increments and 2% accuracy. The
z
Shutdown Function
RT9168/A is designed for use with very low ESR
z
Low Temperature Coefficient
capacitors. The output remains stable even with a
z
Current and Thermal Limiting
1µF ceramic output capacitor.
z
Custom Voltage Available
z
SOT-25 and SOP-8 Packages
regulator
suitable
for
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
Pin Configurations
Part Number
Pin Configurations
suitable for battery-powered devices. Other features
RT9168/A-……CBR
include current limiting and over temperature
(Plastic SOT-25)
TOP VIEW
5
4
1.
2.
3.
4.
5.
protection. The SOP-8 and SOT-25 packages are
also available for larger power dissipation and
1
2
3
design flexibility.
TOP VIEW
RT9168/A-……CS
Applications
z
Cellular Telephones
z
Laptop, Notebook, and Palmtop Computers
z
Battery-powered Equipment
z
Hand-held Equipment
RT9168/A-……CSH
OUT 1
8 IN
(Plastic SOP-8)
GND 2
7 GND
GND 3
6 GND
NC 4
Ordering Information
RT9168/A-…… … ……
Operating temperature range
C: Commercial standard
Output voltage
5 SHDN/SHDN
Typical Application Circuit
Package type
BR : SOT-25
S : SOP-8
SH : SOP-8, High shutdown
OUT
GND
IN
SHDN
NC
RT9168
VIN
IN
CIN
1µF
COUT
1µF
GND
SHDN
SHDN
VOUT
OUT
NC
15 : 1.5V
16 : 1.6V
:
:
49 : 4.9V
50 : 5.0V
500mA Output current
200mA Output current
DS9168/A-03 May 2001
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1
RT9168/A
Marking Information
Part Number
Part Number
Marking
RT9168-15CBR
L0
RT9168A-15CBR
M0
RT9168-16CBR
L1
RT9168A-16CBR
M1
RT9168-17CBR
L2
RT9168A-17CBR
M2
RT9168-18CBR
L3
RT9168A-18CBR
M3
RT9168-19CBR
L4
RT9168A-19CBR
M4
RT9168-20CBR
L5
RT9168A-20CBR
M5
RT9168-21CBR
L6
RT9168A-21CBR
M6
RT9168-22CBR
L7
RT9168A-22CBR
M7
RT9168-23CBR
L8
RT9168A-23CBR
M8
RT9168-24CBR
L9
RT9168A-24CBR
M9
RT9168-25CBR
LA
RT9168A-25CBR
MA
RT9168-26CBR
LB
RT9168A-26CBR
MB
RT9168-27CBR
LC
RT9168A-27CBR
MC
RT9168-28CBR
LD
RT9168A-28CBR
MD
RT9168-29CBR
LE
RT9168A-29CBR
ME
RT9168-30CBR
LF
RT9168A-30CBR
MF
RT9168-31CBR
LG
RT9168A-31CBR
MG
RT9168-32CBR
LH
RT9168A-32CBR
MH
RT9168-33CBR
LJ
RT9168A-33CBR
MJ
RT9168-34CBR
LK
RT9168A-34CBR
MK
RT9168-35CBR
LL
RT9168A-35CBR
ML
RT9168-36CBR
LM
RT9168A-36CBR
MM
RT9168-37CBR
LN
RT9168A-37CBR
MN
RT9168-38CBR
LP
RT9168A-38CBR
MP
RT9168-39CBR
LQ
RT9168A-39CBR
MQ
RT9168-40CBR
LR
RT9168A-40CBR
MR
RT9168-41CBR
LS
RT9168A-41CBR
MS
RT9168-42CBR
LT
RT9168A-42CBR
MT
RT9168-43CBR
LU
RT9168A-43CBR
MU
RT9168-44CBR
LV
RT9168A-44CBR
MV
RT9168-45CBR
LW
RT9168A-45CBR
MW
RT9168-46CBR
LX
RT9168A-46CBR
MX
RT9168-47CBR
LY
RT9168A-47CBR
MY
RT9168-48CBR
LZ
RT9168A-48CBR
MZ
RT9168-49CBR
CL
RT9168A-49CBR
CN
RT9168-50CBR
CM
RT9168A-50CBR
CP
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Marking
DS9168/A-03 May 2001
RT9168/A
Pin Description
Pin Name
Pin Function
IN
Input
GND
Ground
SHDN (SHDN)
Active Low (High) Shutdown Input
NC
No Connection
OUT
Output
Function Block Diagram
SHDN
or
SHDN
Shutdown
and
Logic Control
IN
VREF
+
_
Error Amp
MOS Driver
Current-Limit
and
OUT
Thermal
Protection
GND
DS9168/A-03 May 2001
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RT9168/A
Absolute Maximum Ratings
z
Input Voltage
8V
z
Power Dissipation, PD @ TA = 25°C
SOT-25
0.25W
SOP-8
0.625W
z
Operating Junction Temperature Range
−40°C to 125°C
z
Storage Temperature Range
−65°C to 150°C
z
Package Thermal Resistance
z
SOT-25, θJA
250°C/W
SOP-8, θJA
160°C/W
Lead Temperature (Soldering, 5 sec.)
260°C
Electrical Characteristics
(VIN = 5.0V, CIN = 1µF, COUT = 1µF, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Input Voltage Range
VIN
Output Voltage Accuracy
∆VOUT
Maximum Output
Current
Current Limit
RT9168
RT9168A
RT9168
RT9168A
RT9168
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
IOUT = 500mA
--
90
150
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
IMAX
ILIMIT
RT9168/A
GND Pin Current
Test Conditions
IG
RT9168A
RT9168/A
(Note)
Dropout Voltage
RT9168/A
(VOUT(Nominal)≥3.0V
RT9168/A
Version)
RT9168A
VDROP
Line Regulation
∆VLINE
Load Regulation
∆VLOAD
RLOAD = 1 Ohm
VIN = (VOUT+0.15) to 7V, IOUT = 1mA
Units
V
µA
%/mA
SHDN, SHDN Input High Threshold VIH
VIN = 3V to 5.5V
2.2
--
--
V
SHDN, SHDN Input Low Threshold
VIL
VIN = 3V to 5.5V
--
--
0.4
V
SHDN, SHDN Bias Current
ISD
--
--
100
nA
Shutdown Supply Current
IGSD
--
0.01
1
µA
Thermal Shutdown Temperature
TSD
--
155
--
°C
Ripple Rejection
PSRR
--
58
--
dB
VOUT = 0V
F = 100Hz, CBP = 10nF, COUT = 10µF
Notes: Dropout voltage definition: VIN - VOUT when VOUT is 50 mV below the value of VOUT at VIN = VOUT + 0.5V
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DS9168/A-03 May 2001
RT9168/A
Typical Operating Charateristics
GND Current vs. Temp.
120
3.32
105
GND Current ( µ A)
Output Voltage (V)
Output Voltage vs. Temp.
3.33
3.31
3.30
3.29
3.28
90
75
60
45
30
3.27
15
3.26
VOUT = 3.3V
3.25
-50
-25
0
25
50
75
100
125
VOUT = 3.3V
0
-50
150
-25
0
Dropout Voltage vs. Output Current
75
100
125
150
Current Limit vs. Temp.
480
300
420
Current Limit (mA)
85°C
250
Dropout Voltage (mV)
(V)
50
Temperature ( °C
°C ))
°C))
Temperature (°C
25°C
200
-40°C
150
100
360
300
240
180
120
50
RT9168
VOUT = 3.3V
60
VOUT = 3.3V
0
0
25
50
75
100
125
150
175
0
-50
200
-25
0
25
50
75
100
125
150
Temperature (°C
(°C )
Output Current (mA)
Current Limit vs. Temp.
900
70
800
60
700
PSRR
50
PSRR (dB)
Current Limit (mA)
25
600
500
400
40
30
20
300
RT9168A
VOUT = 3.3V
200
100
-50
-25
0
25
50
75
100
Temperature (°C ))
DS9168/A-03 May 2001
125
ILOAD = 1mA, COUT = 4.7µF
VOUT = 3.3V
10
150
0
10
10
100
100
1K
1000
10K
10000
100K
100000
1M
100000
Frequency (KHz)
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RT9168/A
Load Transient Response
Output Voltage
Deviation (mV)
20
TT
02 >
≈
T
11 >
-50
Time (50µS/Div)
COUT = 1µF
100 VOUT = 3.0V
Loading = 1mA
50
TT
02 >
-50
≈
≈
5
T
4
1↓
TT
02 >
-20
Output Voltage (mV)
Line Transient Response
150
20
≈
50
≈
≈
50
T
11 >
-50
Time (50µS/Div)
Line Transient Response
150
COUT = 1µF
100 VOUT = 3.0V
Loading = 50mA
50
TT
02 >
-50
≈
≈
5
T
4
1↓
Input Voltage (V)
Output Voltage (mV)
Line Transient Response
COUT = 4.7µF
100 VOUT = 3.0V
Loading = 1mA
50
TT
2>
0
-50
≈
5
≈
T
4
1↓
Time (500µS/Div)
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Time (1mS/Div)
Line Transient Response
60
COUT = 4.7µF
40 VOUT = 3.0V
Loading = 50mA
20
TT
2>
0
-20
Input Voltage (V)
Output Voltage (mV)
Time (1mS/Div)
150
VOUT = 3.0V
VIN = 4V
COUT = 4.7µF
40 CIN = 10µF
Load Current
(mA)
Load Current
(mA)
Output Voltage (mV)
VOUT = 3.0V
VIN = 4V
COUT = 1µF
40 CIN = 10µF
-20
Input Voltage (V)
Load Transient Response
60
Input Voltage (V)
Output Voltage
Deviation (mV)
60
≈
5
≈
T
4
1↓
Time (500µS/Div)
DS9168/A-03 May 2001
RT9168/A
Applications Guides
Capacitor Selection and Regulator Stability
Region of Stable COUT ESR vs. Load Current
100
Like any low-dropout regulator, the external capacitors
COUT = 4.7µF
used with the RT9168/A must be carefully selected for
10
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
COUT ESR (mΩ)
(Ω)
Ω
regulator stability and performance.
COUT = 1µF
1
0.1
0.01
quality ceramic or tantalum can be used for this
capacitor. The capacitor with larger value and lower
ESR (equivalent series resistance) provides better
0.001
0
40
80
PSRR and line-transient response.
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
160
200
Fig. 1
The output capacitor must meet both requirements for
minimum amount of capacitance and ESR in all LDO
120
Load Current (mA)
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.
capacitor of other types due to the wide stable ESR
Load-Transient Considerations
range. Fig.1 shows the curves of allowable ESR range
The RT9168/A load-transient response graphs (see
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
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.
stability at temperatures below -10°C in this case. Also,
Shutdown Input Operation
tantalum capacitors, 2.2µF or more may be needed to
The RT9168/A is shutdown by pulling the SHDN
maintain capacitance and ESR in the stable region for
strict application environment.
input low, and turned on by driving the input high. If
this feature is not to be used, the SHDN input should
be tied to VIN to keep the regulator on at all times
(the SHDN input must not be left floating).
DS9168/A-03 May 2001
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7
RT9168/A
To ensure proper operation, the signal source used to
prevent regulator mis-operation, a Schottky diode
drive the SHDN input must be able to swing above and
should
below the specified turn-on/turn-off voltage thresholds
input/output voltage conditions can cause the
which guarantee an ON or OFF state (see Electrical
internal diode to be turned on (see Fig.3). As shown,
Characteristics). The ON/OFF signal may come from
the Schottky diode is connected in parallel with the
either CMOS output, or an open-collector output with
internal parasitic diode and prevents it from being
pull-up resistor to the RT9168/A input voltage or
turned on by limiting the voltage drop across it to
another logic supply. The high-level voltage may
about 0.3V. < 100 mA to prevent damage to the part.
be
used
in
any
applications
where
exceed the RT9168/A input voltage, but must remain
within the absolute maximum ratings for the SHDN pin.
Internal P-Channel Pass Transistor
The RT9168/A features a typical 1.1Ω P-channel
MOSFET
pass
transistor.
It
provides
VIN
VOUT
several
advantages over similar designs using PNP pass
Fig. 2
transistors, including longer battery life. The P-channel
MOSFET requires no base drive, which reduces
quiescent current considerably. PNP-based 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
VIN
VOUT
quiescent current whether in dropout, light-load, or
heavy-load applications.
Fig. 3
Input-Output (Dropout) Voltage
A
regulator’s
minimum
input-output
voltage
differential (or dropout voltage) determines the
Current Limit and Thermal Protection
lowest usable supply voltage. In battery-powered
The RT9168 includes a current limit which monitors
systems, this will determine the useful end-of-life
and controls the pass transistor’s gate voltage limiting
battery voltage. Because the RT9168/A uses a P-
the output current to 300mA Typ. (700mA Typ. for
channel MOSFET pass transistor, the dropout
RT9168A). Thermal-overload protection limits total
voltage is a function of drain-to-source on-resistance
power dissipation in the RT9168/A. When the junction
[RDS(ON)] multiplied by the load current.
temperature exceeds TJ = +155°C, the thermal sensor
signals the shutdown logic turning off the pass
Reverse Current Path
The power transistor used in the RT9168/A has an
inherent diode connected between the regulator
input and output (see Fig.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
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8
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. Thermal-overloaded protection is designed
to protect the RT9168/A in the event of fault conditions.
Do not exceed the absolute maximum junctiontemperature rating of TJ = +150°C for continuous
operation. The output can be shorted to ground for an
DS9168/A-03 May 2001
RT9168/A
indefinite amount of time without damaging the part by
cooperation of current limit and thermal protection.
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-03 May 2001
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RT9168/A
Package Information
D
C
B
b
H
A
e
Symbol
L
A1
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
0.559
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
0.102
0.254
0.004
0.010
L
0.356
0.610
0.014
0.024
SOT- 25 Surface Mount Package
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DS9168/A-03 May 2001
RT9168/A
H
A
M
J B
F
C
D
Symbol
I
Dimensions In Millimeters
Dimensions In Inches
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
0.178
0.254
0.007
0.010
I
0.102
0.254
0.004
0.010
J
5.791
6.198
0.228
0.244
M
0.406
1.270
0.016
0.050
8–Lead SOP Plastic Package
DS9168/A-03 May 2001
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RT9168/A
RICHTEK TECHNOLOGY CORP.
RICHTEK TECHNOLOGY CORP.
Headquarter
Taipei Office (Marketing)
6F, No. 35, Hsintai Road, 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)5510047 Fax: (8863)5537749
Tel: (8862)89191466 Fax: (8862)89191465
Email: marketing@richtek-ic.com.tw
DS9168/A-03 May 2001
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