[Lowfer] DDS 50 ohms buffer!

[Stewart Nelson]

I believe that a simple emitter follower should be adequate.
If the output swing is 1 V p-p, that's 2.5 mW into 50 ohms.

With a PNP transistor, you shouldn't need any biasing parts.
Hook the base to Iout (along with the usual 300 ohms to ground).
Ground the collector, and use ~100 ohms from emitter to +5 V.
Capacitively couple to your 50 ohm load.

73,

Stewart KK7KA

----- Original Message ----- 
From: "Gilles Auger" <augergilles@videotron.ca>
To: <Lowfer@mailman.qth.net>
Sent: Sunday, February 22, 2004 9:36 PM
Subject: [Lowfer] DDS 50 ohms buffer!


> Hi.
> 
> I try to figure out what can be the amplifier that can match the AD9835 300 
> ohms output impedance to 50
> 
> ohms with a gain of about 8 db at 13.5 Mhz.
> 
> Is this can be done with a simple transistor or a monolithic amplifier ?
> 
> I have take look on the net and they always use it unbuffered !
> 
> Thanks in advance for any information.
> 
> Gilles Auger  VE2DRW