AIC1190_15 Datasheet, PDF (12/20 Pages) Analog Intergrations Corporation – Ultra LDO 1A Linear Regulator With

AIC1190
 ^{APPLICATION INFORMATION}
The AIC1190 is a high performance linear regulator
that provides low-dropout voltage and low quiescent-
current. The device is available in an adjustable
version and fixed output voltages ranging from 1.2V to
3.8V, and the device can supply loads up to 1A.
SHUTDOWN
By connecting EN(EN) pin to V_IN(ground), the AIC1190
can be shut down to reduce the supply current to
0.1A(typ.). At this operation mode, the output voltage
of AIC1190 is equal to 0V.
CURRENT LIMIT
The AIC1190 includes a current limiter, which monitors
and controls the maximum output current. If the output
is overloaded or shorted to ground, this can protect the
device from being damaged.
THERMAL PROTECTION
The AIC1190 includes a thermal-limiting circuit, which
is designed to protect the device against overload
condition. When the junction temperature exceeds
T_J=150ºC, the thermal-limiting circuit turns off the pass
transistor and allows the IC to cool. For continuous
load condition, maximum rating of junction temperature
must not be exceeded.
INPUT-OUTPUT CAPACITORS
Linear regulators require input and output capacitors to
maintain stability. Input capacitor at 2.2F with a 2.2F
ceramic output capacitor is recommended.
When choosing the input and output ceramic
capacitors, X5R and X7R types are recommended
because they retain their capacitance over wider
ranges of voltage and temperature than other types.
NOISE BYPASS CAPACITOR
A 22nF bypass capacitor at BP pin can reduce output
voltage noise. The bypass pin can be floating if it’s
unnecessary.
OUTPUT VOLTAGE PROGRAMMING
The output voltage of AIC1190 linear regulator can be
set by its internal feedback resistors when the ADJ pin
is grounded. In addition, the output voltage of AIC1190
linear regulator can be set by the external feedback
resistors when connecting a resistive divider R₁ and R₂.
While connecting a resistive divider, V_OUT can be
calculated as:
V_OUT

0.8  _{}1
R₁
R₂

The resistive divider should sit as close to ADJ pin as
possible.
POWER DISSIPATION
The maximum power dissipation of AIC1190 depends
on the thermal resistance of its case and circuit board,
the temperature difference between the die junction
and ambient air, and the rate of airflow. The rate of
temperature rise is greatly affected by the mounting
pad configuration on the PCB, the board material, and
the ambient temperature. When the IC mounting with
good thermal conductivity is used, the junction
temperature will be low even when large power
dissipation applies.
The power dissipation across the device is
P = I_OUT (V_IN-V_OUT)
The maximum power dissipation is:
PMAX

(T_J-max - T_A )
Rθ _JA
Where T_J-max is the maximum allowable junction
temperature (150C), and T_A is the ambient
temperature suitable in application.
As a general rule, the lower temperature is, the better
reliability of the device is. So the PCB mounting pad
should provide maximum thermal conductivity to
maintain low device temperature.
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