a702gft-he ADD Microtech Inc., a702gft-he Datasheet - Page 6

• Manufacturer Part Number: a702gft-he
• Description: 6 Channels Adjustable Constant Current Led Driver
• Manufacturer: ADD Microtech Inc.

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 A701/2 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 467mW (MSOP-10 package, at T
additional heat sink 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 © 2009 ADDtek Corp.
PCB heat sink size (mm
The A701/2 has internal power and thermal limiting circuitry designed to protect the device under overload
The junction temperature is:
T
P
If PC Board copper is going to be used as a heat sink, below table can be used to determine the appropriate size
PCB θ
J
D
= P
=
V
I
V
I
n = 1 ~ 6.
θ
θ
θ
P
∑
OUTn
DD
n
D
D
6
OUTn
DD(MAX)
=
JC
CS
SA
1
( θ
= the supply current to the regulator at I
(
SA
V
= the nominal output current through output pin OUTn;
: Dissipated power.
:  T hermal resistance from the junction to the mounting tab (case) 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).
= the maximum voltage on output pin OUTn;
OUTn
(°C /W)
JC
= the maximum input voltage;
+ θ
⋅
(typically, θ
I
OUTn
CS
2
)
+ θ
)
+
V
SA
500
DD
59
CS
) + T
(
MAX
< 1.0°C /W)
APPLICATION INFORMATION
)
A
⋅
I
DD
1000
45
OUTn
1500
;
38
6
A
=70°C) or 980mW (QFN 3 × 3 package, at T
2000
33
3000
27
DD082_B -- JULY 2009
4000
24
A701/2
5000
21
A
=70°C),