se5509b seawardinc, se5509b Datasheet - Page 5

• Manufacturer Part Number: se5509b
• Description: 300ma Low Power Low Noise Ldo Cmos Voltage Regulator
• Manufacturer: seawardinc

Revision 4/30/2008
Application Hints
Like any low dropout regulator, SE5509B requires
external capacitors to ensure stability.
external capacitors must be carefully selected to
ensure performance.
Input Capacitor
An input capacitor of at least 1μF is required. The
inexpensive Electrolytic capacitor is preferred. The
value can be increased without upper limit.
Output Capacitor
An output capacitor is required for stability. It must
be placed no more than 1 cm away from the V
pin, and connected directly between V
pins. The inexpensive Electrolytic capacitor is
recommended. The minimum value is 1μF but may
Application Diagram
be increased without limit.
Preliminary and all contents are subject to change without prior notice
© Seaward Electronics Inc., 2006. • www.seawardinc.com • Page 5
LDO CMOS Voltage Regulator
300mA Low Power Low Noise
OUT
and GND
The
OUT
Thermal Considerations
It is important that the thermal limit of the package is
not exceeded. The SE5509B has built-in thermal
protection.
the IC will enter protection, and V
to ground.
application can be calculated as following:
The power dissipation (P
P
The thermal limit of the package is then limited to
P
temperature, TA is the ambient temperature, and
Θ
designed to enter thermal protection at 150°C. For
example, if T
limited to about 0.6W. In other words, if I
300mA, then [V
D
D(MAX)
JA
= I
is around 230°C/W for SE5509B. SE5509B is
OUT
= [T
* [V
J
When the thermal limit is exceeded,
IN
The power dissipation for a given
A
– T
– V
IN
is 25°C then the maximum P
– V
OUT
A
]/Θ
OUT
]
JA
] cannot exceed 2V.
D
where T
) is
OUT
J
SE5509B
is the junction
will be pulled
OUT(MAX)
D
is
=