Technical Note
13/17
www.rohm.com
2010.06 - Rev.A
© 2010 ROHM Co., Ltd. All rights reserved.
BD7830NUV
●Thermal design of chip
The characteristics of the IC vary greatly depending on the use temperature, and when the maximum allowable junction
temperature is exceeded, components may deteriorate or become damaged. Thermal considerations are needed for this
chip from two standpoints: preventing instantaneous damage and improving long-term reliability. Note the following points
with caution.
The absolute maximum ratings for each chip include the maximum junction temperature (Tj
MAX
) and operating temperature
rate (Topr), and these values should be referred to when using the Pd-Ta characteristics (thermal dissipation curve).
Since the IC itself is designed with full consideration of thermal balance, there are no problems in terms of circuit operations,
but even when a more-than-adequate thermal design is implemented in order to get full use of the IC's performance features,
some moderation is often required for the sake of practical usage.
If there is an excessive input signal due to insufficient thermal dissipation, a TSD (thermal shutdown) operation may occur.
Thermal Dissipation Curve
The allowable loss value varies depending on the type of board used for mounting. When this chip is mounted on a
multi-layer board that is designed for thermal dissipation, the allowable loss becomes greater than shown in the above figure.
0.85W
Reference data
VSON008V2030
0.5
①
0
0 25 50 75 100 125 150
Ambient temperature Ta (°C)
Allowable loss Pd (W)
① When mounted on ROHM standard 1-layer board
Size: 70 mm × 70 mm × 1.6 mmt
No copper heat sink (only mounting pattern)
② When mounted on 4-layer board
Size: 76.2 mm × 76.2 mm × 1.6 mmt
Layers 2 & 3 Copper foil
No connection via thermal via
1.0
0.53W
②
(Note) These are measured values. They are not guaranteed.
