APL5312
Typical Characteristics (Cont.)
Region of Stable C
OUT
ESR vs.
Load Current
100
10
C
OUT
ESR (Ω)
Instable
1
V
OUT
=2.5V
C
IN
=C
OUT
=1uF,Y5V
0.1
Stable
Instable
0
50
100
150
200
250
300
0.01
Output Current (mA)
Application Information
Output Voltage Selection
The APL5312 are supplied with factory-set output
voltages from 1.5V to 3.5V.
Capacitor Selection and Regulation Stability
The APL5312 uses at least a 1µF capacitor on the
input. This capacitor can use Aluminum, Tantalum or
Ceramic capacitors. Input capacitor with large value
and low ESR provides better PSRR and line-transient
response. The output capacitor also can use Aluminum,
Tantalum or Ceramic capacitor, and its proper values
is at least 1µF, ESR must be above 25mΩ. Large
output capacitor values can reduce noise and improve
load-transient response, stability, and PSRR. With X5R
and Y5V dielectrics, 1µF is sufficient at all operating
temperatures. The selection of output capacitor’ is
s
important because it with C
OUT
form a zero to provide
the sufficient phase margin (see the Figure C
OUT
ESR
Copyright
©
ANPEC Electronics Corp.
Rev. A.1 - Sep., 2005
9
vs. Load Current).
Bypass Capacitor
Use a 10nF bypass capacitor at BP for low-output
voltage noise. The leakage current going into the BP
pin should be less than 10nA. Increasing the capacitance
slightly decreases the output noise. Value above 0.1µF
and below 1nF are not recommended (see the Figure
Output Noise vs. BP Capacitance).
Noise, PSRR, and Load-Transient Response
The APL5312 is designed to deliver ultra-low noise
and high PSRR, as well as low dropout and low
quiescent currents in battery–powered systems.
When operating from sources other than batteries,
improve PSRR and transient response can be
achieved by increasing input and output capacitors,
and bypass capacitor to from the passive filtering
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