Diodes AP2213 - Manual (Page 17)

17
BCD Semiconductor Manufacturing Limited
500mA LOW NOISE LDO REGULATOR AP2213
Data Sheet
Dec. 2012 Rev. 2. 0
Input Capacitor
A 1
μF minimum capacitor is recommended to be
placed between V
IN
and GND.
Output Capacitor
It is required to prevent oscillation. 1
μF minimum is
recommended when C
BYP
is unused. 2.2 μF mini-
mum is recommended when C
BYP
is 100pF. The out-
put capacitor may be increased to improve transient
response.
Noise Bypass Capacitor
Bypass capacitor is connected to the internal voltage
reference. A small capacitor connected from BYP to
GND make this reference quiet, resulting in a
significant reduction in output noise, but the ESR
stable area will be narrowed. In order to keep the
output stability, it is recommended to use the bypass
capacitor no more than 100pF.
The start-up speed of the AP2213 is inversely
proportional to the value of reference bypass
capacitor. In some cases, if output noise is not a
major concern and rapid turn-on is necessary, omit
C
BYP
and leave BYP open.
Power Dissipation
Thermal shutdown may take place if exceeding the
maximum power dissipation in application. Under all
possible operating conditions, the junction tempera-
ture must be within the range specified under abso-
lute maximum ratings to avoid thermal shutdown.
To determine if the power dissipated in the regulator
reaches the maximum power dissipation (see figure
16, 17), using:
T
J
= P
D
* θ
JA
+ T
A
P
D
=(V
IN
-V
OUT
)*I
OUT
+V
IN
*I
GND
Where: T
J
≤T
J(max)
, T
J(max)
is absolute maximum rat-
ings for the junction temperature; V
IN
*I
GND
can be
ignored due to its small value.
T
J(max)
is 150
o
C, θ
JA
is 90
o
C/W for TO-252-2 (1)/
TO-252-2 (3) package and 160 o C/W for SOIC-8
package.
Example: For 2.5V version packaged in SOIC-8,
I
OUT
=500mA, T
A
=50
o
C, V
IN(Max)
is:
(150
o
C-50
o
C)/(0.5A*160
o
C/W)+2.5V=3.75V
Therefore, for good performance, please make sure
that input voltage is less than 3.75V without heatsink
when T
A
=50 o C.
Application Information