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URL: http://www.princeton.com.tw
Remote Control Decoder IC
PT2270
SINGLE RESISTOR OSCILLATOR
The built-in oscillator circuitry of PT2270 allows a precision oscillator to be constructed with only an
external resistor. For the PT2270 to decode correctly the waveform that was received, the oscillator
frequency of PT2270 must be 1/16 ~ 4 (or 2 to 30) times that of the transmitting PT2260 (or PT2262).
It is a good practice to center the PT2270 oscillator frequency in this window to gain best window
margin at both sides. The typical oscillator with various resistor values are shown below for PT2260,
PT2262 and PT2270.
100
R=510K
R=1M
R=2M
10
R=3.3M
R=4.7M
KHz
50 0
40 0
R=680K
30 0
25 0
20 0
10 0
R=820K
R=1M
R=2M
R=470K
KHz
1
3
6
9
Voltage
12
15
1
2
3
Voltage (V)
4
5
6
PT2262 Encoder OSC Frequency
160
FREQUENCY (KHz)
140
120
100
80
60
40
20
0
2
4
6
VOLTAGE (V)
8
PT2260 Encoder OSC Frequency
Rosc =510 K Ohms
Rosc=620K Ohms
Rosc=1.0 M Ohms
Rosc=1.2 M Ohms
Rosc=2.2 M Ohms
10
PT2270 Decoder OSC Frequency
Suggested oscillator resistor values are shown below.
PT2260
PT2270
820KΩ
1.0MΩ
1.0MΩ
1.2MΩ
2.0MΩ
2.2MΩ
PT2262
1.2MΩ
1.5MΩ
3.3MΩ
PT2270
120KΩ
160KΩ
390KΩ
PT2270 V1.3
-7-
May, 2006
PTC [ PRINCETON TECHNOLOGY CORP ]
