Princeton Technology Corp.

Tel: 886-2-29162151

Fax: 886-2-29174598

URL: http://www.princeton.com.tw

Infrared Remote Control Receiver

PT2249A / PT2250A Series

PT2249A/50A v 2.3

Page 4

Revised Dec. 1999

Application Note:

1. Combination of PT2248/PT2249A Series Code Bits

a) PT2249A Series Code Bit C1 is internally pulled high and thereby set

at a default value of “1”. Thus, PT2248 Code Bit C1 must be set at “1”.

b) PT2249A Series Code Bits C2 and C3 may be programmed as follows:

1) “0”, “0” (This combination is not available with TC9149.)

2) “0”, “1”

3) “1”, “0”

4) “1”, “1”

c) To set Code Bit to “1” on PT2248, diodes must be connected to Code

Terminal from the T1 ~ T3 terminals.

d) To set Code Bit to “0” on PT2248, the terminals must be kept floating,

except C1 - add one diode.

e) The Code Bits Combinations of PT2248 and PT2249A Series are shown

below:

PT2248

PT2249A Series

C1

C2

C3

C2

C3

1

0

000

1

0

101

1

1

010

1

1

111

f) Example : (Refer to Example 1 diagram)

The following example shows the case when PT2248 Code Bits C1 = 1,

C2 = 1, and C3 = 0. The CODE2 Pin of the PT2249A Series is

programmed in floating state and CODE3 pin is connected to Vss (C2 = 1,