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RS7225
1A Adjustable & Fixed Voltage LDO Linear Regulator with Enable, Fast Discharge & Soft-Start
General Description
The RS7225 series is a low-dropout linear regulator with ON/OFF control that operates in the input voltage range from +2.4V
to +7.0V and delivers 1.0A output current.
The RS7225 is available fixed output voltage type is preset at an internally trimmed voltage 1.8V, 2.5V, or 3.3V. Other options
1.0V, 1.2V, 1.5V, 2.85V, 3.0V and 3.6V are available by special order only.
The RS7225 series consists of a 0.95V bandgap reference, an error amplifier, and a P-channel pass transistor. Other features
include soft-start function, short-circuit protection and thermal shutdown protection. The RS7225 series devices are available
in SOT-223-5, & TO-252-5 packages.
Features
◎
Operating Voltage Range：+2.4V to +7.0V
◎
Output Voltages：+1.0V to +5.0V (0.1V Step) (Fixed),
+1.25V to +5.0V (ADJ Type)
◎
Dropout Voltage：700mV@600mA (Fixed)
◎
Fast Response in Power-on：35uS
◎
Low Current Consumption：60μA (Typ.)
◎
Low ESR Capacitor Compatible
◎
High Ripple Rejection：55dB (Typ.)
◎
Short Circuit Protection：600mA (Typ.)
◎
Thermal Overload Shutdown Protection
◎
SOT-223-5 & TO-252-5 packages
◎
RoHS Compliant and 100% Lead (Pb)-Free and Green
(Halogen Free with Commercial Standard)
Applications
◎
◎
◎
◎
◎
◎
◎
◎
Battery-Powered Equipments
Graphic Card, Peripheral Card
PCMCIA & New Card
Mini PCI & PCI-Express Cards
Digital Still Camera
CDMA/GSM Cellular Handsets
Laptop, Palmtops, Notebook Computers
Portable Information Application
Application Circuits
Soft-Start Function
This integrated circuit can be damaged by ESD. Orister Corporation recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
DS-RS7225-02
September, 2009
www.Orister.com
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Pin Assignments
SOT-223-5
TO-252-5
PACKAGE
SOT-223-5
PIN
1
2
3
4
5
PIN
1
2
3
4
5
SYMBOL
VIN
VOUT
SS
EN
GND/ADJ
SYMBOL
VIN
VOUT
GND/ADJ
SS
EN
DESCRIPTION
Regulator Input Pin
Regulator Output Pin
Soft-Start Function
Enable Pin
Ground Pin or ADJ Terminal Pin for Adjustable.
DESCRIPTION
Regulator Input Pin
Regulator Output Pin
Ground Pin or ADJ Terminal Pin for Adjustable.
Soft-Start Function
Enable Pin
PACKAGE
TO-252-5
Ordering Information
DEVICE
DEVICE CODE
XX
is nominal output voltage (for example, AD=ADJ, 18 = 1.8V, 33 = 3.3V, 285 = 2.85V).
EEE
is CE Input Logic & Discharge Function Selection : (see CE & Discharge Function Selection Table)
YY
is package designator :
NE : SOT-25
SC : SC-70-5
S : SOP-8
Z
is Lead Free designator :
P: Commercial Standard, Lead (Pb) Free and Phosphorous (P) Free Package
G: Green (Halogen Free with Commercial Standard)
RS7225-XX EEE YY Z
CE & Discharge Function Selection Table
EEE
CODE
NHF
NLF
NHN
NLN
UHF
ULF
EN Type
Type 1
None
None
None
None
Pull High
Pull High
Type 2
High Active
Low Active
High Active
Low Active
High Active
Low Active
Discharge
Fast
Fast
Normal
Normal
Fast
Fast
EEE
CODE
UHN
ULN
DHF
DLF
DHN
DLN
EN Type
Type 1
Pull High
Pull High
Pull Low
Pull Low
Pull Low
Pull Low
Type 2
High Active
Low Active
High Active
Low Active
High Active
Low Active
Discharge
Normal
Normal
Fast
Fast
Normal
Normal
DS-RS7225-02
September, 2009
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Block Diagram
Absolute Maximum Ratings
Parameter
Input Voltage V
IN
to GND
Output Current Limit, I
(LIMIT)
Junction Temperature
Thermal Resistance
Power Dissipation
SOT-223-5
TO-252-5
SOT-223-5
TO-252-5
Symbol
V
IN
I
LIMIT
T
J
θ
JA
P
D
T
OPR
T
STG
-
Ratings
9.0
1.3
+155
155
90
900
1200
-40 ~ +85
-55~+150
+260
Units
V
A
o
C
o
C/W
mW
o
C
o
C
o
C
Operating Ambient Temperature
Storage Temperature
Lead Temperature (soldering, 10sec)
NOTES：
1
The power dissipation values are based on the condition that junction temperature T
J
and ambient temperature T
A
difference is 100°C.
2
Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
function operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied.
Exposure to absolute-maximum –rated conditions for extended periods may affect device reliability.
DS-RS7225-02
September, 2009
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Page No. : 4/10
Electrical Characteristics
(T
A
=25°C, V
IN
=5.0V unless otherwise specified)
Symbol
V
IN
Parameter
Input Voltage
Conditions
-
V
IN
=V
OUT
+1.0V, I
OUT
=1mA, V
OUT
≧1.8V
Fixed
V
IN
=V
OUT
+1.0V, I
OUT
=1mA, V
OUT
＜1.8V,
V
IN
Type
＞2.4V
V
IN
=V
OUT
+1.2V, I
OUT
=1mA, V
OUT
≧1.8V
ADJ
V
IN
=V
OUT
+1.2V, I
OUT
=1mA, V
OUT
＜1.8V,
V
IN
Type
＞2.4V
V
OUT
+1.0V≦V
IN
≦7.0V,
V
OUT
≧2.4V
I
OUT
=100mA, V
OUT
>3.0V
I
OUT
=1000mA, V
OUT
>3.0V
V
OUT
+1.0V≦V
IN
≦7V,
I
OUT
=1mA
V
IN
=V
OUT
+1V, 1mA≦I
OUT
≦100mA
I
LOAD
=0mA to 1.0A, V
IN
=V
OUT
+1.0V
V
IN
=V
OUT
+1V, EN=0V, No Load
-
I
OUT
=30mA, F=1KHz, C
OUT
=10uF
I
OUT
=100mA , F=1KHz, C
OUT
=10uF
V
IN
≦5.0V
V
IN
≦5.0V
V
EN
=0V, For Fixed Voltage Type
V
OUT
=3.3V to 0V, C
OUT
=1uF, For Fixed Voltage Type
V
OUT
=3.3V, C
SS
=0.1uF, C
IN
=C
OUT
=1uF
-
-
Min.
2.4
-2%
-35
-2%
-50
1.0
-
-
-
-
-
-
-
-
1.6
-
-
-
-
-
-
-
50
700
0.2
0.01
60
0.7
600
55
40
-
-
30
70
20
150
20
V
OUT
Typ.
-
Max.
7.0
+2%
+35
+2%
+50
-
-
-
0.3
0.02
-
-
-
-
-
-
0.3
100
100
-
-
-
Unit
V
V
mV
V
mV
A
mV
%/V
%/mA
uA
uA
mA
dB
uV
(rms)
V
V
Ω
us
ms
o
C
o
C
V
OUT
Output Voltage
I
MAX
V
DROP
ΔV
LINE
ΔV
LOAD
I
Q
I
SD
I
SC
PSRR
e
N
V
IH
V
IL
R
DIS
T
DIS
T
SS
T
SD
T
HYS
Output Current (see NOTE)
Dropout Voltage
Line Regulation
Load Regulation
Ground Pin Current
Shutdown Current
Short Circuit Current
Ripple Rejection
Output Noise
EN Pin Input Voltage “H”
EN Pin Input Voltage “L”
Discharge Resistor
Discharge Time
Soft-Start Time
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
NOTE：Measured
using a double sided board with 1” x 2” square inches of copper area connected to the GND pins for “heat spreading”.
DS-RS7225-02
September, 2009
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Detail Description
The RS7225 is a low-dropout linear regulator. The device provides preset 1.8V, 2.5V and 3.3V output voltages for output
current up to 600mA. Other mask options for special output voltages are also available. As illustrated in function block diagram,
it consists of a 0.95V bandgap reference, an error amplifier, a P-channel pass transistor and an internal feedback voltage
divider.
The 0.95V bandgap reference is connected to the error amplifier, which compares this reference with the feedback voltage and
amplifies the voltage difference. If the feedback voltage is lower than the reference voltage, the pass-transistor gate is pulled
lower, which allows more current to pass to the output pin and increases the output voltage. If the feedback voltage is too high,
the pass transistor gate is pulled up to decrease the output voltage.
The output voltage is feedback through an internal resistive divider connected to V
OUT
pin. Additional blocks include an output
current limiter, thermal sensor, and shutdown logic.
Internal P-channel Pass Transistor
The RS7225 features a P-channel MOSFET pass transistor. Unlike similar designs using PNP pass transistors, P-channel
MOSFETs require no base drive, which reduces quiescent current. PNP-based regulators also waste considerable current in
dropout when the pass transistor saturates, and use high base-drive currents under large loads. The RS7225 does not suffer
from these problems and consumes only 60μA (Typ.) of current consumption under heavy loads as well as in dropout
conditions.
Enable Function
EN pin starts and stops the regulator. When the EN pin is switched to the power off level, the operation of all internal circuit
stops, the build-in P-channel MOSFET output transistor between pins V
IN
and V
OUT
is switched off, allowing current consumption
to be drastically reduced. The V
OUT
pin enters the GND level through the internal discharge path between V
OUT
and GND pins.
Soft Start Function
The capacitor can be connected between the BYPASS pin and GND. This capacitor can be a low cost Polyester Film variety. A
larger capacitor improves the AC ripple rejection, but also makes the output come up slowly. This "Soft" turn-on is desirable in
some applications to limit turn-on surges.
Fast Discharge Function
The RS7225 fixed type has fast discharge Function on EN pin disable. When user turns off the device, its internal pull-low
resistor will discharge output capacitor charge. It’ll avoid other device to arise wrong motions.
Output Voltage Selection
For fixed voltage type of RS7225, the output voltage is preset at an internally trimmed voltage. The first two digits of part
number suffix identify the output voltage (see Ordering Information). For example, the RS7225-33 has a preset 3.3V output
voltage.
Current Limit
The RS7225 also includes a fold back current limiter. It monitors and controls the pass transistor’s gate voltage, estimates the
output current, and limits the output current within 1.3A (Typ.)
Thermal Overload Protection
Thermal overload protection limits total power dissipation in the RS7225. When the junction temperature exceeds T
J
=+165°C, a
thermal sensor turns off the pass transistor, allowing the IC to cool down. The thermal sensor turns the pass transistor on again
after the junction temperature cools down by 20°C, resulting in a pulsed output during continuous thermal overload conditions.
Thermal overload protection is designed to protect the RS7225 in the event of fault conditions. For continuous operation, the
absolute maximum operating junction temperature rating of T
J
=+125°C should not be exceeded.
DS-RS7225-02
September, 2009
www.Orister.com
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