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PT2249A_PT2250A V2.6

- 5 -

May, 2007

Remote Control Receiver IC

PT2249A_PT2250A

FUNCTIONAL DESCRIPTION

OSCILLATION CIRCUIT

Timing with transmitter signal and internal operating clock are all decided by this oscillator.

Using CMOS Technology, the oscillator of PT2248 transmitter is constructed through a combination of

a linear amplifier by connecting C and R between the oscillator terminal and Vss.

Notes:

1. R=39K±5%

2. C=100pF±5%

RECEIVING SIGNAL INPUT CIRCUIT

The signal is received by IR receiver module and the wave is infused into the IC.

The RXIN has a built-in Schmitt trigger circuit for shaping received signal waveform to eliminate

rounding. PTC has made available various options to suit IR receiving module with positive or negative

output. PT2249A Series / PT2250A Series with “N” Option was specially designed for IR modules with

negative output. PT2249A Series / PT2250A Series without the “N” Option were specially designed for

IR receiving modules with positive output. In these two options, IR signals without external inversion

can be fed into the RXIN directly.