Datasheet

UNISONIC TECHNOLOGIES CO., LTD
L1913
Preliminary
CMOS IC
150mA LOW-DROPOUT LINEAR
REGULATORS
„
DESCRIPTION
The UTC L1913 is a low supply current, low dropout linear
regulator. It is operating at 2.5V - 5.5V. The supply current is as low
as 55μA in the no–load condition. In the shutdown mode, the
maximum supply current is less than 1μA.
A built-in over-temperature protection circuit is designed to protect
the device from being damaged by thermal overload. The
over-current protection limit is set at 250mA (TYP.) and 150mA
(MIN.).
The UTC L1913 can be operated on the following two modes.
When the SET pin is connected to ground, the output of L1913 is a
pre-set value and the external components are not needed to decide
the output voltage. When an output other than the preset value is
needed, two external resistors should be used as voltage dividers
and then the output voltage is decided by the resistor ratio.
The UTC L1913 is generally used in notebook computers, cellular
phones, PDAs, digital still camera and video recorders and other
hand-held devices.
„
FEATURES
* Low No-Load Supply Current: 55µA
* Guaranteed 150mA Output Current
* Dropout Voltage is 70mV @ 50mA Load
* OTP (Over-Temperature Protection) and Short-Circuit Protection
* Two Modes Of Operation:
Fixed Mode: 3.3V,1.5V.
Adjustable Mode: 1.25V - 5.5V
* Maximum Supply Current In Shutdown Mode is Less than 1µA
* Low Output Noise at 220µ VRMS
* Stability with Lost Cost Ceramic Capacitors
„
ORDERING INFORMATION
Note:
Ordering Number
Lead Free
Halogen Free
L1913L-xx-AF5-R
L1913G-xx-AF5-R
xx: Output Voltage, refer to Marking Information.
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Copyright © 2011 Unisonic Technologies Co., Ltd
Package
Packing
SOT-25
Tape Reel
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L1913
„
Preliminary
CMOS IC
MARKING INFORMATION
PACKAGE
VOLTAGE CODE
MARKING
15:1.5V
SOT-25
33:3.3V
„
PIN CONFIGURATION
„
PIN DESCRIPTION
PIN NO.
PIN NAME
1
SHDN
2
GND
3
IN
4
OUT
5
SET
DESCRIPTION
Active-Low Shutdown Input. A logic low reduces the supply current to less than 1µA.
Connect to IN for normal operation.
Ground. This pin also functions as a heatsink. Solder to large pads or the circuit board
ground plane to maximize thermal dissipation.
Regulator Input. Supply voltage can range from +2.5V to +5.5V. Bypass with 1µF to GND
Regulator Output. Fixed or adjustable from 1.25V to +5.5V. Sources up to 150mA.
Bypass with a 1µF, <0.2Ω typical ESR capacitor to GND.
Feedback Input for Setting the Output Voltage. Connect to GND to set the output voltage
to the preset voltage. Connect to an external resistor divider for adjustable-output
operation.
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L1913
„
Preliminary
CMOS IC
BLOCK DIAGRAM
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Preliminary
CMOS IC
ABSOLUTE MAXIMUM RATING
PARAMETER
SYMBOL
RATINGS
UNIT
Output Short-Circuit Duration
Infinite
VIN to GND
-0.3~7
V
SET to GND
-0.3~7
V
SHDN to GND
-0.3~7
V
SHDN to IN
-7~0.3
V
OUT to GND
-0.3~(VIN+0.3)
V
Power Dissipation (TA=25°C)
PD
520
mW
Junction Temperature
TJ
150
°C
Operating Temperature
TOPR
-40~85
°C
Storage Temperature
TSTG
-65~160
°C
Notes: Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.
„
THERMAL DATA
PARAMETER
Junction to Ambient
„
SYMBOL
θJA
RATINGS
240
UNIT
°C/W
ELECTRICAL CHARACTERISTICS
(VIN =+3.6V, VSHDN =VIN, TA =TJ =+25°C, unless otherwise specified.) (Note 1)
PARAMETER
Input Voltage (Note 2)
SYMBOL
VIN
Output Voltage Accuracy
VOUT
Adjustable Output Voltage Range
(Note 3)
Maximum Output Current
Current Limit (Note 4)
Ground Pin Current
Dropout Voltage (Note 5)
Line Regulation
Load Regulation
Output Voltage Noise
(10Hz~100kHZ)
SHUTDOWN
SHDN Input Threshold
SHDN Input Bias Current
Shutdown Supply Current
SET INPUT
TEST CONDITIONS
Variation from specified VOUT,
IOUT=1mA
VOUT
MAX
5.5
UNIT
V
-2
2
%
VSET
5.5
V
TYP
150
ILIMIT
IQ
VDROP
ΔVLNR
ΔVLDR
eN
VIH
VIL
ISHDN
IQSHDN
SET Reference Voltage (Note 3)
VSET
SET Input Leakage Current
ISET
SET=GND
ILOAD=0mA
ILOAD=50mA
IOUT=1mA
IOUT=50mA
IOUT=150mA
SET=GND, VIN=V(STD)+0.1V ~ 5.5V ,
IOUT=1mA
SET tide to OUT, VIN=2.5V ~ 5.5V ,
IOUT=1mA
SET tide to OUT
IOUT= 0mA ~150mA
SET=GND
VIN=1.2V,
COUT=1µF
IOUT=150mA
300
0.1
0.28
0.08
0.4
0.02
0.8
1.0
120
µA
mV
220
VIN-0.7
VIN= 2.5V ~ 5.5V,
IOUT= 1mA
1.225
TA= +25°C
TA= TMIN to TMAX
VSET= 1.3V (Note 3) TA= +25°C
mA
mA
250
55
145
2
70
230
%/V
Regulator enabled
Regulator shutdown
VSHDN = VIN
TA= +25°C
VOUT= 0V
TA= +25°C
UNISONIC TECHNOLOGIES CO., LTD
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MIN
2.5
0.003
0.2
1.25
1.25
5
%/mA
µVRMS
0.4
0.1
1
1.275
30
V
µA
µA
V
nA
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Preliminary
CMOS IC
ELECTRICAL CHARACTERISTICS (Cont.)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP MAX UNIT
THERMAL PROTECTION
Thermal Shutdown Temperature
TSHDN
150
°C
Thermal Shutdown Hysteresis
ΔTSHDN
15
°C
Notes: 1.Limits is 100% production tested at TA= +25°C. Low duty pulse techniques are used during test to maintain
junction temperature as close to ambient as possible.
2.Guaranteed by line regulation test.
3.Adjustable mode only.
4.Not tested. For design purposes, the current limit should be considered 150mA minimum to 420mA
maximum.
5.The dropout voltage is defined as (VIN-VOUT) when VOUT is 100mV below the value of VOUT for VIN = VOUT+2V.
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Preliminary
CMOS IC
APPLICATION INFORMATION
The UTC L1913 contains an error amplifier, 1.25V bandgap reference, PMOS output transistor, internal feedback
voltage divider, mode comparator, shutdown logic, over current protection circuit, and over temperature protection
circuit as shown in the block diagram.
The process of operation is like this: the mode comparator compares the voltage of SET pin with a pre-set voltage
reference of 0.12 V. If the voltage of SET pin is smaller than 0.12 V, the internal feedback voltage divider’s central
tap is connected to the error amplifier’s non-inverting input. Then, the error amplifier compares non-inverting input
with the 1.25V bandgap voltage reference. If the feedback voltage is larger than the voltage reference 1.25V, the
error amplifier’s output becomes higher. This makes the PMOS output transistor’s VGS (gate-to-source voltage)
smaller, in that condition, the current carrying capability of the PMOS output transistor is reduced, as a result the
output voltage decreases until the feedback voltage becomes equal to 1.25V. Similarly, when the feedback voltage is
less than 1.25V, the error amplifier causes the output PMOS to conductor more current to pull the feedback voltage
up to 1.25V. Thus, through this feedback action, the error amplifier, output PMOS, and the voltage dividers
effectively form a unity-gain amplifier with the feedback voltage force to be the same as the 1.25V bandgap
reference.
The output voltage, VOUT, can be calculated as follows:
VOUT = 1.25 (1 + R1/R2).
(1)
Alternatively, the relationship between R1 and R2 is expressed in the following:
R1 = R2 (VOUT /1.25 - 1).
(2)
In order to reduce power dissipation and loop stability, it is recommended that R2 is 100KΩ. For UTC L1913
(pre-set VOUT is 3.30V), R1 is 164K.
In Fig.2, the SET pin voltage will be larger than 120mV when external voltage divider functions in the operation.
The non-inverting input of the amplifier will be connected to the external voltage divider. The conditions of equations
1 and 2 are still true since the operation of the feedback loop is the same. Equation 1 still presents the output
voltage.
OUT
SHDN
UTC
L1913
IN
+
BATTERY -
CIN
1µ
OUTPUT
R1
COUT
1µ
SET
RL
R2
GND
Fig. 2 Adjustable Output Using External Feedback Resistors
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Preliminary
CMOS IC
APPLICATION INFORMATION (Cont.)
Over Current Protection
To monitor the output current, the UTC L1913 applies a current mirror. A portion of the PMOS output transistor’s
current is mirrored to a resistor such that the voltage across this resistor is proportional to the output current. Once
the output current exceeds limit threshold, UTC L1913 would be protected with a limited output current. Further more,
when the output is short to ground, the output current would be folded-back to a less limit.
Note: the input bypass capacitor of 1µF must be placed in the circuit in order to filter out the input voltage spike
caused by the surge current due to the inductive effect of the package pin and the printed circuit board’s routing wire.
Otherwise, the actual voltage at the IN pin may exceed the absolute maximum rating.
Over Temperature Protection
Over-temperature protection circuit is designed to prevent this device from being damaged due to abnormal
temperature during operation. It is used to turn off the output MOSFET if the temperature is higher than 150°C, the
switch does not turn on until the temperature drops to 135°C.
Shutdown Mode
The UTC L1913 enters shutdown mode if the SHDN pin is applied to a logic low voltage. Under the shutdown
state, all the analog circuits are turned off completely, which reduces the current consumption to only the leakage
current. The UTC L1913 output pass transistor would get into high impedance level. There is an internal discharge
path to help to shorten discharge delay time..
Operating Region and Power Dissipation
The UTC L1913 is a linear regulator, so the power dissipation can be expressed by: P = IOUT (VIN – VOUT). And the
maximum power dissipation is calculated by:
PD(MAX) = (TJ–TA)/θJA,=(150°C -25°C)/240°C/W= 520mW
(Where (TJ–TA) is the temperature difference the die and the ambient air; θJA, is the thermal resistance of the
chosen package to the ambient air.)
For surface mount device, heat sinking is accomplished by using the heat spreading capabilities of the PC board
and its copper traces. The die attachment area of the UTC L1913’s lead frame is connected to pin 2, which is the
GND pin. Therefore, the GND pin of UTC L1913 can carry away the heat of the UTC L1913 die very effectively.
Connecting the GND pin to ground using a large ground plane near the GND pin can improve the power
consumption.
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Preliminary
CMOS IC
APPLICATIONS INFORMATION
Capacitor Selection and Regulator Stability
A 1µF capacitor on the input and a 1µF capacitor on the output are recommended for most applications of the U
TC L1913. To get a better supply-noise rejection and transient response, input capacitors with larger values and
lower ESR are needed. A higher-value input capacitor (10µF) may be necessary if large, fast transients are
anticipated and the device is located several inches from the power source.
Power-Supply Rejection and Operation from Sources Other than Batteries
The UTC L1913 is particularly designed to deliver low dropout voltages and low quiescent currents in batterypowered systems. Power-supply rejection is 42dB at low frequencies. As the frequency increases above 20kHz, the
output capacitor is the major contributor to the rejection of power-supply noise.
When operating from sources other than batteries, improve supply-noise rejection and transient response by
increasing the values of the input and output capacitors, and using passive filtering techniques.
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 UTC
L1913 use a P-channel MOSFET pass transistor, their dropout voltage is a function of RDS(ON) multiplied by the load
current.
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Preliminary
CMOS IC
TYPICAL APPLICATION CIRCUIT
OUT
SHDN
OUTPUT
UTC
L1913
+
BATTERY -
COUT
1µ
SET
IN
CIN
1µ
GND
Fixed mode
OUT
SHDN
UTC
L1913
IN
+
BATTERY -
CIN
1µ
OUTPUT
R1
SET
GND
COUT
1µ
R2
Adjustable Mode
UTC assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or
other parameters) listed in products specifications of any and all UTC products described or contained
herein. UTC products are not designed for use in life support appliances, devices or systems where
malfunction of these products can be reasonably expected to result in personal injury. Reproduction in
whole or in part is prohibited without the prior written consent of the copyright owner. The information
presented in this document does not form part of any quotation or contract, is believed to be accurate
and reliable and may be changed without notice.
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