FAKE MAXIM MAX038 from Hong Kong

Thread Starter

Kurke

Joined Sep 17, 2017
1
I bought 2 to repair my Waveform Generator, being of a suspicious nature I tested them in a breadboard with a 80mA current limited power supply. The supply pins would not rise above about + and - 0.8V. I suspected that these could be a different device remarked as MAXIM so I tried +5V on pin 20 and 0V on pin 10- typical logic supplies. Under these conditions the device draws about 4mA. On a genuine MAX038 connected like this the supply voltage is limited to 0.8V by I suspect a substrate diode.
Other bad buys on Ebay from far east suppliers include-
Low capacity Lithium cells listed as high capacity.
IRF1404 Power Mosfets with higher ON resistance than specified by IR
Constant Current LED power supply- half specified current

Kurke
 

DickCappels

Joined Aug 21, 2008
6,003
Yes, you were probably looking at a substrate diode.

You might want to double-check those connections. My working MAX038 is connected much differently has -5V on pin 20, and + 5V on pin 17. Pin 10 is the frequency control current input.

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