MAS9171A Micro Analog Systems, MAS9171A Datasheet - Page 7

• Manufacturer Part Number: MAS9171A
• Description: Octal Port Protecton
• Manufacturer: Micro Analog Systems

APPLICATION INFORMATION
Fig. 5 shows how to use the MAS9171A to detect the condition of switches
Fig. 5: Application Circuit (Detection of Switches)
IMPORTANT !
The MAS9171A shall be placed closely to the microprocessor to avoid voltage spikes at the
uC inputs caused by currents on the Supply Pins and/or Pins OUT1 to OUT8.
A block capacitor of 33nF close to the Supply Pins is recommended
It is important to connect external Pull-Up resistors to V
current into the MAS9171A (Note: MAS9171A has internal pull-down of 225Koms to Gnd).
V Ignition
V Bat
4x47K
4x47K
Filter+
Protection
MAS9171
Vdd
Voltage-
Regulator
+Reset
ignition
in order to prevent quiescent
Res
Xtal1
µC
Xtal2
Vdd
DA9171A.000
July 31, 1997
Vdd
7