AMS3102C ADMOS [Advanced Monolithic Systems], AMS3102C Datasheet - Page 6

• Manufacturer Part Number: AMS3102C
• Description: 300mA LOW DROPOUT VOLTAGE REGULATOR
• Manufacturer: ADMOS [Advanced Monolithic Systems]

APPLICATION NOTES
Definition of Terms
Dropout Voltage
the circuit stops to regulate against further reduction in input
voltage. Measured when the output voltage has dropped 100mV
from the nominal voltage obtained at 1V input, dropout voltage is
dependent upon load current and junction temperature.
Input Voltage
respect to ground.
Input-Output Differential
unregulated input voltage and the regulated output voltage for
which the regulator will regulate.
Line Regulation
the input voltage. The line regulation is measured under conditions
of low dissipation or by using low duty cycle pulse testing such
that the average chip temperature is not significantly affected.
Load Regulation
load current at constant chip temperature.
Long term stability
life-test conditions after 1000 hours with maximum rated voltage
and junction temperature.
Output Noise Voltage
constant load and no input ripple, measured over a specified
frequency range.
Quiescent Current
does not contribute to the positive load current. The regulator
ground lead current.
Ripple Rejection
voltage to the peak-to-peak output ripple voltage at specified
frequency.
Temperature Stability of V
voltage for a thermal variation from room temperature to either
temperature extreme.
External capacitor
The AMS3102 series require an output capacitor of 2.2µF or
greater to ensure device stability. Without the capacitor the device
may oscillate.
Most type of tantalum or electrolytic capacitor can be used in the
applications. A critical characteristic of the capacitors is an ESR
value of 5Ω or less and a resonant frequency above 500kHz. The
value of this capacitor can be increased without limits.
For higher loads, the value of the capacitor should be increased,
specially when the output voltage is set for 2.5V or less. The
AMS3102 lowest fixed output voltage value is 2.0V.
Advanced Monolithic Systems, Inc. www.advanced-monolithic.com
: The DC voltage applied to the input terminal with
: The change in output voltage for a change in
: The change in output voltage for a change in
: The input-output voltage differential at which
: The ratio of the peak-to –peak input ripple
: That part of the positive input current that
: Output voltage stability under accelerated
: The rms AC voltage at the output, with
: The voltage difference between the
O
: The percentage change in output
Minimum Load
In circuits using the fixed output voltage versions, minimum load
is not required. For circuits using the adjustable device, the value
of R1 and R2 should be chosen such, that a current of
approximately 40µA flows through the network. The reference
voltage (1.235V) is measured between the adjust pin and V
The output voltage can be set by the two resistors R1 and R2
using the following equation:
The value of R1 is recommended to be between 25kΩ to 30 kΩ,
and the value of R2 will set the output voltage.
V
O
Typical application circuit (adjustable output)
=
10µF
V
REF
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⎛
⎜
⎝
R1
R1
+
OFF
ON
100k
R2
ON/OFF
⎞
⎟
⎠
ADJUSTABLE
GND
AMS3102
V
IN
ADJ
AMS3102
OUT
R
28k
R
1
2
+
22µF
C1
V
OUT
OUT
.