VP503 View Datasheet(PDF) - SANYO -> Panasonic
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VP503 Datasheet PDF : 11 Pages
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VP503
VP503 Thermal Design Example
Conditions: Using an fH = 64 kHz class monitor, fv = 85 MHz (clock)
VCC = 80 V, VBB = 10 V, VOUT = 50 Vp-p (CL = 10 pF)
Since this class of monitor can be operated up to Ta = 60°C, here we consider the case where the maximum clock
frequency is 85 MHz.
As mentioned previously, the chip with the largest loss is transistor Tr3. Determining the value gives:
Pc (Tr3) = 5.0 × 0.25 = 1.25 [W] ............................................................ (5)
We determine ∆Tj by substituting the value for θj-c in equation (5).
∆Tj = 1.25 × 30 = 38 [°C] ....................................................................... (6)
Here, ∆Tj is less than 50°C, and in the thermal design we only have to assure that Tc is less than 100°C. That is, we must
set θh so that Tc is less than 100°C when Pd (TOTAL) = Pd (one channel ) × 3
Here, ∆Tc will be ∆Tc = 100 – 60 = 40°C
Since θh = ∆Tc ÷ Pd (TOTAL) = 40 ÷ (5.0 × 3) ≈ 2.6°C/W
Thus the thermal resistance in this case is θh = 2.6°C/W.
In actual practice, the ambient temperature and operating conditions will allow a heat sink smaller than that indicated by
this calculation to be used. Therefore, design optimization taking the actual conditions into account is also required.
Surge Protection
Surge protection is required when this device is connected to a CRT. This product requires the same protection as earlier
products.
1. Termination spark gap
2. Surge suppression resistor (Recommended value: 33 to 39 Ω)
3. Surge suppression diode (Installed in the vicinity of the IC output pin.)
Note: The value of surge suppression resistors must be determined taking both the stipulated discharge test and the
required frequency bandwidth into account. Note that the surge withstanding capacity of these products as
independent video packs is equivalent to that of earlier products, e.g., the VPS Series.
No. 4933-9/11
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