Hello,

Finally I could solve the issue with TSOP1738.

BackGround:
When I bought this TSOP1738 , I never bothered to see the IC name printed.
The vendor has given me TSOP1138 instead of TSOP1738. I noticed this only when came home and when my first trial failed. Then I downloaded the datasheet of TSOP1138 only to know that the datasheet is 99% same for both TSOP1738 and TSOP1138. The only difference about the feature was that the former can rx bursts upto 2400BPS and the later can rx burst upto 4000BPS.

After all the struggle I could see another difference in H/W about the pull up resistor in output stage.In TSOP1738 it is 80K and in TSOP1138 it is 25k. To extend the operational range I guess the manufacturer has reduced the output pull up in TSOP1138 so that the output stage driver is not driven to saturation.

So to conclude, TSOP1138 cann't replace TSOP1738 directly but needs an Op-Amp to rx the IR properly and to drive the load if present.

Thanks and regards,
Danaraja