AME8865 Datasheet, PDF (14/25 Pages) Analog Microelectronics – 1.5A CMOS LDO

AME
AME8865
n Detailed Description
The AME8865 is low-dropout; low quiescent current
linear regulator designed for motherboard, notebook and
LCD monitor applications. The output voltage range from
0.8V to 4.5V, and can drive 1.5A loading current.
Capacitor Selection and Regulator Stability
Use 4.7µF for input capacitor and 4.7µF or greater for
output capacitor on the AME8865. Larger input capacitor
value and low ESR provide better supply noise rejection
and improve line transient response. To reduce output
noise and load transient response, use output capacitor
greater than 4.7uF. In addition, AME8865 can prevent
output voltage overshoot at power-on or enabled through
the EN/ENB pin.
1.5A CMOS LDO
Calculating the Maximum Output Power
The maximum output power of the AME8865 is limited
by the maximum power dissipation of the package. By
calculation the power dissipation of the package as a
function of the input voltage, output voltage and output
current, the maximum input voltage can be obtained. The
maximum power dissipation should not exceed the
package's maximum power rating.
P_MAX = (V_IN(MAX)-V_OUT) x I_OUT
Where: V_IN(MAX) = maximum input voltage
P_MAX = maximum power dissipation of the package
Adjustable Version
The adjustable version uses external feedback resis-
tors to generate an output voltage anywhere from 1.0V to
5.0V. By the equation:
V_OUT
= V_ADJ (1 +
R1 ₎
R2
Feedback resistors R1 and R2 should be high enough
to keep quiescent current low, but increasing R1 + R2
will reduce stability. In general, R1 and R2 in the 10’ s of
KΩ will produce adequate stability, given reasonable lay-
out precautions. To improve stability characteristics, keep
parasites on the ADJ pin to a minimum, and lower R1 and
R2 values.
14
Rev. A.04