A705 ADDTEK [ADDtek Corp], A705 Datasheet - Page 4

• Manufacturer Part Number: A705
• Description: 200mA ~ 300mA ADVANCED CURRENT REGULATOR
• Manufacturer: ADDTEK [ADDtek Corp]

The Maximum Power Dissipation on Regulator:
Thermal Consideration:
conditions. However, maximum junction temperature ratings should not be exceeded under continuous normal load
conditions. The thermal protection circuit of A705 prevents the device from damage due to excessive power dissipation.
When the device temperature rises to approximately 150°C, the regulator will be turned off. When power consumption
is over about 700mW (SOT-89 package, at T
is required to control the junction temperature below 120°C.
of copper foil required. For multi-layered PCB, these layers can also be used as a heat sink. They can be connected with
several through-hole vias.
Copyright © 2007 ADDtek Corp.
PCB heat sink size (mm
PCB θ
P
The A705 has internal power and thermal limiting circuitry designed to protect the device under overload
The junction temperature is:
T
If PC Board copper is going to be used as a heat sink, below table can be used to determine the appropriate size
D(MAX)
J
= P
V
I
I
V
θ
θ
θ
P
OUT(NOM)
Q
D
D
OUT(MAX)
IN(MAX)
SA
JT
CS
SA
= the quiescent current the regulator consumes at I
= V
(θ
(°C /W)
: Dissipated power.
:  T hermal resistance from the junction to the mounting tab of the package.
:  T hermal resistance through the interface between the IC and the surface on which it is mounted.
:  T hermal resistance from the mounting surface to ambient (thermal resistance of the heat sink).
JT
OUT(MAX)
= the maximum input voltage.
= the nominal output current;
= the maximum voltage on output pin;
+θ
(typically, θ
2
CS
)
+θ
× I
SA
500
59
OUT(NOM)
CS
) + T
< 1.0°C /W)
APPLICATION INFORMATION
A
A
+ V
=70°C) or 1000mW (TO-252 package, at T
1000
45
IN(MAX)
1500
4
× I
38
Q
OUT(MAX)
2000
;
33
3000
27
A
=70°C), additional heat sink
DD077_A -- AUGUST 2007
4000
24
A705
5000
21