150 mA C-MOS L.D.O. Regulator
Typical Application Circuit
•
+
+
Battery
(To CMOS
Logic or Tie to
Vin if unused)
1uF
Gnd
+
470pF
Reference
Bypass
Cap(Optional)
Vin
SHDN
LM1185SF
Vout
BP
+
•
1uF
Vout
Detail Description
1. Output Capacitor
1uF(min) capacitor from V
OUT
to Gnd 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. Bypass Input
470pF capacitor connected from the Bypass input to ground reduces noise present on the internal
reference,which in turn significantly reduces output noise. If output noise is not aconcern, this input
maybe left unconnected. Larger capacitor values maybe used,but results in alonger time period to
rated output voltage when power is initially applied.
3. THERMAL CONSIDERATIONS
3.1 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.
3.2 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:
0702 Taejin Technology Co.,Ltd.
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