Diodes AP2210 - Manual (Page 28)

300mA RF ULDO REGULATOR AP2210
Data Sheet
28
Jan. 2012 Rev. 1. 6 BCD Semiconductor Manufacturing Limited
Input Capacitor
A 1
µ F minimum capacitor is recommended to be
placed between V
IN
and GND.
Output Capacitor
It is required to prevent oscillation. 1.0
µ F minimum
is recommended when C
BYP
is unused. 2.2 µ F 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 AP2210 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 200 o C /W, no heatsink is
required since the package alone will dissipate
enough heat to satisfy these requirements unless the
calculated value for power dissipation exceeds the
limit.
Example (3.0V version):
I
OUT
=300mA, T
A
=50 o C, V
IN(Max)
is:
(150 o
C -50 o
C )/(0.3A*200 o
C/W )+3.0V=4.67V
Therefore, for good performance, please make sure
that input voltage is less than 4.67V without heatsink
when T
A
=50 o C.
Application Information