GM6251-1.8ST89R GAMMA [Gamma Microelectronics Inc.], GM6251-1.8ST89R Datasheet - Page 7

• Manufacturer Part Number: GM6251-1.8ST89R
• Description: 300mA ULTRA LOW DROPOUT POSITIVE VOLTAGE REGULATOR
• Manufacturer: GAMMA [Gamma Microelectronics Inc.]

Application Note
Notes on Usage
1.
2.
3.
4.
The GM6251 series precision linear regulators include thermal shutdown and current limit circuitry to
protect the devices. However, high power regulators normally operate at high junction temperatures so
it is important to calculate the power dissipation and junction temperatures accurately to be sure that
you use and adequate heat sink.
The thermal characteristics of an IC depend four factors:
1.
2.
3.
4.
These relationship of these four factors is expressed by equation :
Maximum ambient temperature and power dissipation are determined by the design while the
maximum junction temperature and thermal resistance depend on the manufacturer and the package
type.
CALCULATING POWER DISSIPATION
It is recommended to operate the GM6251 series within the stipulated absolute maximum ratings
as the IC is liable to malfunction it is operated outside the ratings.
There is a possibility of heat or oscillation as a result of the impedance present between the
power supply and the IC's input. Where impedance is greater 10Ω, it is recommend to use a
capacitor (C
With a large output current, operations can be stabilized by increasing capacitor size (C
is
impedance. In such case, operation can be stabilized by either increasing the size of C
decreasing the size of C
Please ensure the output current (I
stipulated continuous for total power dissipation value (Pd) for the package.
Maximum Ambient Temperature T
Power Dissipation P
Maximum Junction Temperature T
Thermal Resistance Junction to ambient R
too
small and capacitance of (C
IN
) of at least 1µF at the input terminal.
D
(Watts)
L
.
L
A
J
OUT
) is increased, there is a possibility of oscillation due to input
(℃)
(℃)
) is less than Pd ÷ (V
JA
(℃/W)
POSITIVE VOLTAGE REGULATOR
300mA ULTRA LOW DROPOUT
IN
T
- V
J
OUT
= T
A
) and does not exceed the
+ P
D
GM6251
X R
JA
IN
IN
or
). If C
IN
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