Outputmatch of LNA (Convert differential output to single output without using balun)

[eason.RFIC]

Hi Guys :
I design a LNA with a differential output , but when tapeout , i want to measure the LNA individually ,so i want to convert the output node into a single output , but i don't want to use a balun ,i want use a circuit to achieve the convert . Anyone has some advise for me to design a circuit convert the differential output to a single output ! thanks

 

[johnjoe]

Hi,

which frequency and can you post your output stage?

Best regards

 

[BigBoss]

A carefully designed differential pair with buffer output stage will convert your diff. signal to single ended.

 

[eason.RFIC]

Thanks , now ,i design a buffer and then follow balun to achieve the convert ,but i don't know how to achieve this only by a buffer ,BigBoss, can you send my some papers about how to use a buffer to conver diff.sinal to single ended without balun ?

A carefully designed differential pair with buffer output stage will convert your diff. signal to single ended.

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This circuit works at 45GHz , the schematic may be not clear , the circuit is just a differential input and differential output LNA .My target is to achieve a 50ohm single output match , now i can achieve this by using a balun ,but the balun has some loss ,so i want to achieve a single output without balun ,thanks

Hi,

which frequency and can you post your output stage?

Best regards

 

[tony_lth]

You can use a hybird to achieve this. You can calculate the phases and then you can get single output.