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Remote Control Encoder
PT2268
FUNCTION DESCRIPTION
KEY INPUT
Up to eight (8) keys can be directly connected to pins I1 ~ I8. Please refer to the diagram below.
VCC
I1
I2
I3
I4
PT2268
I5
I6
I7
I8
Furthermore, PT2268 has a built-in pull-low resistor of about 60K ~ 110KΩ which reduces the need for
external components.
OSCILLATOR
An oscillation circuit can be constructed using the CMOS Inverter and Built-in Feedback Resistor,
455KHz Crystal and two 220pF capacitors. The carrier frequency is 38KHz.
PT2268
OSC1
OSC2
455KHz
220pF
220pF
Unless any of the 8 keys (I1 ~ I8) is being operated, the oscillation is automatically stopped. Thus,
power consumption is considerably reduced.
PT2268 V2.5
- 4 -
April, 2006
PTC [ PRINCETON TECHNOLOGY CORP ]
