HTC LM1108SF5 300ma c-mos l.d.o. regulator Datasheet

LM1108F/SF
300mA C-MOS L.D.O. Regulator
SOT-23
FEATURES
②
• Extremely Low Supply Current(50µA,Typ.)
• Very Low Dropout Voltage
• 300mA Output Current
• High Output Voltage Accuracy +/- 1.4 %
• Standardor Custom Output Voltages
• Over Currentand Over Temperature Protection
• Small input/output differential : 0.3V for full load
①
SOT-23-5L
(SOT-25)
APPLICATIONS
SOT-89
• Battery Operated Systems
• Portable Computers
• Portable Cameras and Video Recorders
①
• Medical Instruments
• Instrumentation
• Cellular/GSM/PHS Phones
• Linear Post-Regulators for SMPS
1.Vss 2.Vin 3.Vout 4. NC 5. NC
ORDERING INFORMATION
• Pagers
Device
Marking
Package
HXX
LM1108 SF
SOT-23
HXX
LM1108 SF5
SOT-25
1108
X.X
LM1108 F
SOT-89
(Note : "XX" is Output Voltage for SOT-23 Pkg,
1.5V=H15, 1.8V=H18….3.3V=H33)
DESCRIPTION
The LM1108 is a fixed output,high accuracy(typically ±0.5%) C MOS low drop-out regulator.
Total supply current is typically 50µA at full load (20 to 60 times lower than in bipolar regulators).
LM1108 key features include ultra low noise operation, very low dropout voltage (typically 240mV at full
load), and fast response to step changes in load.
The LM1108 in corporates both over temperature and over current protection.
The LM1108 is stable with an output capacitor of only1µF and has a maximum out put current of 300mA.
It is available in a SOT-23 & SOT-89 package
TYPICAL APPLICATION CIRCUIT
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LM1108F/SF
300mA C-MOS L.D.O. Regulator
ABSOLUTE MAXIMUM RATING (Note 1)
Supply Voltage (Vin)
Output Current (Iout)
Output Voltage (Vout)
Total Power Dissipation (Pd) SOT-89
SOT-23
Operating Ambient Temperature (Topr)
Lead Temperature (soldering, 5 sec)
Storage Temperature (Tstg)
+6.5V
300 mA
Vss-0.3 to Vin+0.3V
500 mW
230 mW
-30 ~ +80 °C
260°C
-40 ~ +125 °C
ELECTRICAL CHARACTERISTICS
Note.1 : Load Regulation is measured using pulse techniques with duty cycle<5%
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LM1108F/SF
300mA C-MOS L.D.O. Regulator
Detail Description
- The LM1108 is aprecision, fixed output LDO.
Un like bipolar regulators, the LM1108’s supply current does not increase with load current.
In addition,VOUT remains stable and with in regulation over theen tire 0mA to IOUT MAX operating
load currentrange, (an important consideration in RTC and CMOS RAM battery back-up applications).
Figure3-1shows a typical application circuit.
1. Output Capacitor
1uF(min) capacitor from VOUT to ground is required.
The output capacitor hould have an effective series resistance greater than 0.1 Ω and less than .0Ω.
1uF capacitor should be connected from VIN to GND if there is more than 10 inche sofwire between
the regulator and the AC filter capacitor ,or if a battery is used as the power source. Aluminum
electrolytic or tantalum capacitor types can be used. (Since many aluminum electrolytic capacitors
freeze at approximately -30°C, solid tantalums are recommended for applications operating below -25°
C.)
When operating from sources other than batteries,supply-noise rejection and transient response can
be improved by increasing the value of the input and output capacitors and employing passive filtering
techniques.
2. THERMAL CONSIDERATIONS
2.1 Thermal Shutdown
Integrated thermal protection circuitry shuts the regulator off when die temperature exceeds150°C.
The regulator remains off until the die temperature drops to approxi mately 140°C.
2.2 Power Dissipation
The amount of power the regulator dissipate is primarily a function of input and output voltage, and
output current. The following equation is used to calculate worst case actual power dissipation:
TABLE 2-1 :
EQUATION 2-1:
The maximum allowable power dissipation (Equation
2-2) is a function of the maximum ambient
temperature(TAMAX), the maximum allowable die
temperature(TJMAX) and the thermal resistance
from junction-to-air(θJA).
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0702-01 Taejin Technology Co.,Ltd.
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LM1108F/SF
300mA C-MOS L.D.O. Regulator
EQUATION 2-2:
Table 2-1 shows various values of θJA for the LM1108 versus board copper area.
TABLE 2-1 : THERMAL RESISTANCE GUIDELINES FOR LM1108
Equation 2-1can be used in conjunction with Equation 2-2 to ensure regulator thermal operation is within limits.
Forexample:
In this example, the LM1108 dissipates a maximum of 260mW; below the allow able limit of 508 mW . In a
similar manner, Equation 2-1 and Equation 2-2 can be used to calculate maximum current and/or input voltage
limits. For example, the maximum allowable VIN, is found by sustituting the maximum allowable power
dissipation of 508 mW into Equation 2-1, from which VINMAX = 4.6V.
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