UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 439

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

15.4 CAUTIONS
(1) As the D/A converter output impedance is high, a current cannot be taken from the ANOn pin (n = 0, 1). If the load
(2) As the D/A converter output voltage varies in steps, the signal output by the D/A converter should generally be passed
(3) The D/A converter incorporated in the PD784026 is in the output high impedance state while RESET is low. The design
input impedance is low, a buffer amp should be inserted between the load and the ANOn pin. Also, the wiring to the
buffer amp and load should be kept as short as possible (since the output impedance is high). If the wiring is long,
measures such as enclosure with a ground pattern should be taken.
through a low-pass filter before use.
should therefore make provision for high impedance input in the load side circuitry.
(a) Inverting amp
(b) Voltage floor
PD784026
PD784026
ANOn
Figure 15-4 Example of Buffer Amp Insertion
ANOn
CHAPTER 15 D/A CONVERTER
R
R
1
1
• Buffer amp input impedance = R
• If R
R
be undefined when RESET is low.
• Buffer amp input impedance = R
1
were omitted, the output would
C
–
+
C
R
2
+
–
1
1
399