AME
Low Dropout
600mA CMOS Regulator
AME8819
n Detailed Description
n Capacitor Selection and
Regulator Stability
The AME8819 is low-dropout, low quiescent-current linear
regulator designed primarily for battery-powered applications.
It is available with present output voltage ranging from 1.8V
to 3.6V, and can supply loads up to 600mA.
Use 1mF capacitor on the OUT. Larger input capaci-
tor values and lower ESR provide better supply noise
rejection and line transient response. To reduce out-
put noise and improve load transient voltage dips, use
larger output capacitors up to 4.7mF. For stable op-
eration over the full temperature range with load cur-
rents up to 600mA, input and output capacitors should
be a minimum of 2.2mF by X7R.
n Circuit Limit
The AME8819 contains current limiters which monitor and
control the pass transistor's Gate voltage, limiting the guar-
anteed maximum output current to 650mA minimum. The
output can be shorted to ground for an indefinite time without
damaging the part.
Note that some ceramic dielectrics large capacitance
and ESR variation with temperature. With dielectrics
such as Z5U and Y5V, it may be necessary to use
4.7mF or more for up to 600mA load current to ensure
stability at temperatures below -10oC. With X7R or
X5R dielectrics, 2.2mF is sufficient at all operating tem-
peratures. These regulators are optimized for ceramic
capacitors. Tantalum capacitors are not recommended.
n Thermal-Overload Protection
Thermal-overload protection limits total power dissipation
in the AME8819. When the junction temperature arrive TJ =
160oC approximately, the thermal sensor signals the shut-
down logic, turning off the pass transistor and allowing the IC
to cool.
n PSRR and Operation from
sources Other than Batteries
The AME8819 is designed to deliver low-dropout
voltage and low quiescent currents in battery-powered
system. Power-supply rejection ratio is 60dB(Typ.)
at 1KHz (see PSRR vs Frequency Curve).When op-
erating from sources other than batteries, PSRR and
transient response can be improved by increasing in-
put, output capacitors.
12
Rev.B.01
AME [ ANALOG MICROELECTRONICS ]
