From: Tim Mitchell
Subject: Re: 8051-compatible chip drawing ~200mA. Should be < 20mA
Date: Tue, 3 Dec 2002 12:11:52 +0000
Organization: Sabre Technology (Hull) Ltd
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In article , siliconpi
>I am working in a lab and we usually use a power supply which outputs
>a constant 5V to power our circuits. The project I'm working on
>requires the circuit to run off a 9V battery.
>I measured the current draw from the power supply and it was ~200mA,
>out of which the 8051 type chip is taking in ~150mA. I checked by
>putting the 8051 in another breadboard and hooking only the Ground and
>I have tried the: ATMEL AT89C51, Intel 8751H chips - both of which
>state in their datasheets that the maximum value of Icc is 20mA. I
>dont think I've hooked it up properly - or else a whole batch of these
>were incorrectly used by others and therefore went bad.
>BTW, they work fine. I can program them, use them, juggle with them,
>throw them around, beat my head on them - no problem! ;)
What is the 8051 doing in the software and how are the ports set? Does
it take 150ma even with only gnd & vcc connected?
I have sometimes accidentally inserted 8051s backwards, they often work
fine afterwards but draw more current than they should. 150mA is a lot
though, is it getting hot?