Cooling of the Camera
-------------------------
Total heat dissipated in the camera is right at 30 Watts.
Volume Flow and Velocity
------------------------
cfm = 1.76 Watts / delta_T in C
so for 30 Watts cfm = 52.8 / delta_T in C
so 25 cfm should give a 2 to 3 degree C rise.
Cross section of the camera box perpendicular to the air flow is about
6.5" x 4.5" = 30 sq inches = 0.203 sq feet. 25 cfm through a 0.203 sq ft
cross section gives a linear velocity of 123 feet/minute.
Differential Pressure
---------------------
Now a rough look at the expected differential pressure. The following is
based on "typical" electronic construction with 60% fill factor
P = 1.35E-3 H (Q/A)**2
P is differential pressure in inches of water
Q is the cfm through the system
A is the cross-sectional area in sq inches
H is the system length parallel to the air flow in inches
Thus the estimated static pressure is 0.01 to 0.02 inches of water, i.e. no
problem for any electronics type fan.
Silicon Temperature
-------------------
The ADS-946 thermal resistance using the heat sink is a very good 9 C/W
(without the heat sink it is 23 C/W). It dissipates right about 2 Watts so
its silicon temperature will be about 18C above the air temperature.
The MAX477 thermal resistance in the SOIC-8 package is about 125 C/W.
In the quiescent state it will dissipate about 150 mW. This comes from:
8ma x 10V = 80 mW Static
10ma x (5V + 1.4V) = 64 mW Load
The 150 mW dissipation will put its silicon about 19C above air
temperature.