upd75212a Renesas Electronics Corporation., upd75212a Datasheet - Page 47

• Manufacturer Part Number: upd75212a
• Description: 4-bit Single-chip Microcomputer
• Manufacturer: Renesas Electronics Corporation.

* 1. Calculation of total loss
Example
2. Except the system clock oscillator, display controller and timer/pulse generator.
3. The operating voltage range varies depending on the cycle time. Refer to the section describing AC
Design so that the sum of the following three power consumption values for the PD75212ACW/GF will be
less than the total loss P
characteristics.
CPU loss
Output pin loss
Pull-down register loss : Power loss due to a pull-down resistor incorporated in the display output pin
Suppose 4-LED output with 9
Further, let the voltage of fluorescent display tube (V
PT =
In this example, since the allowable total loss is 600 mW for the shrink DIP package, it is necessary to
3 mA, 15 mA and up to 10 mA flow to the segment pin, timing pin and LED output pin, respectively.
decrease power consumption by decreasing the number of on-chip pull-down resistors. In this example,
power consumption can be adjusted to 577.8 mW by incorporating pull-down resistors in only 11 digit
outputs and 7 segment outputs and externally mounting pull-down resistors to the 2 remaining segment
outputs.
CPU loss : 5.5 V
Pin loss : Segment pin ..... 2 V
Pull-down resistor loss ........
+
+
Timing pin ......... 2 V
LED output ........
= 690.6 mW
T
(It is recommended to use the system with 80 % or less of the rating).
9.0 mA = 49.5 mW
: Given as V
: There are normal output pin loss and display output pin loss. It is necessary
to add a loss derived from the flow of maximum current to each output pin.
by mask option.
SEG
(30 + 5.5 V)
11
10
15
25 k
DD
DIGIT
3 mA
15 mA = 30 mW
(MAX.)
2 V
, V
DD
2
= 5 V + 10 % and 4.19 MHz oscillation and let a current of
9 = 54 mW
10 = 504.1 mW
10 mA
I
DD1
LOAD
(MAX.)
voltage) be –30 V and normal voltage be small.
4 = 53 mW
PD75212A
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