UPD17010 Datasheet, PDF (410/424 Pages) NEC – 4-BIT SINGLE-CHIP MICROCONTROLLER WITH HARDWARE DEDICATED TO DIGITAL TUNING SYSTEM

µPD17010
Calculation of Total Dissipation
The µPD17010 dissipates the following three types of powers, and the sum of these three types of powers must
be lower than total dissipation Pt (use at lower than about 80% of the rated dissipation is recommended).
<1> CPU dissipation
: Calculated as VDD (MAX.) × IDD (MAX.)
<2> Output pin dissipation
: Total of dissipation when maximum current is allowed to flow into
each output pin
<3> Dissipation by pull-down resistor : Power dissipation by internal pull-down resistor
Here is an example:
Example Assume that the following currents flow into the output pins:
• High-level output : P2A0 pin
: 12 mA
LCD0 pin
: 12 mA
LCD1 pin
: 1 mA
P0B0-P0B2 pins : 12 mA
P0B3 pin
: 4 mA
• Low-level output : P0A0-P0A2 pins : 15 mA
P0A3 pin
: 5 mA
P0C0, P0C1 pins : 10 mA
Also assume that a current of 0.3 mA flows into the P0D0 through P0D3 pins with the internal resistor on.
<1> CPU dissipation: 5.5 V × 15 mA = 82.5 mW
<2> Output pin dissipation : P2A0 pin
... 2.4 V × 12 mA = 28.8 mW
LCD0 pin
... 3 V × 12 mA
= 36 mW
LCD1 pin
... 1 V × 1 mA
= 1 mW
Total of P0B0-P0B2 pins ... 2.4 V × 12 mA × 3 = 86.4 mW
P0B3 pin
... 1 V × 4 mA
= 4 mW
Total of P0A0-P0A2 pins ... 2 V × 15 mA × 3 = 90 mW
P0A3 pin
... 2 V × 5 mA
= 10 mA
Total of P0C0, P0C1 pins ... 2 V × 10 mA × 2 = 40 mW
<3> Pull-down resistor dissipation: total of P0D0-P0D3 pins ... 5.5 V × 0.3 mA × 4 = 6.6 mW
Pt = <1> + <2> + <3> = 82.5 + (28.8 + 36 + 1 + 86.4 + 4 + 90 + 10 + 40) + 6.6 = 385.3 mW
Because the absolute maximum value of the total dissipation is 450 mW, it is considered that this rating is not
exceeded in the above example.
However, design your system taking into consideration the above description.
410