Newsgroups: comp.robotics
Path: brunix!sgiblab!swrinde!cs.utexas.edu!uunet!ftpbox!mothost!lmpsbbs!eck001@email.mot.com
From: eck001@email.mot.com (Chris Kerlin)
Subject: Re: Rx (bias set) Resistor on SAA1027 Stepper Driver?
Organization: Motorola Land Mobile
Date: Wed, 12 Jan 1994 16:38:25 GMT
Message-ID: <1994Jan12.163825.7867@lmpsbbs.comm.mot.com>
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Recommended 12Vdc power supply.
Unipolar type drive.
Motor current per phase: (Iq) max = 350 mA.
Bias current (into pin 4): (Ib) max = 80 mA.
Bias current (mA) when Rb not specified: (Ib) = 0.2 * (Iq) + 10
Example 1: Airpax L82101-P2 12 volt unipolar stepper
           118 ohm per winding
           270 ohm 1/2 watt Rb recommended
           250 mA Nominal system current
Example 2: Airpax K83701-P2 12 volt unipolar stepper
           36 ohm per winding
           100 ohm 1 watt Rb recommended
           800 mA Nominal system current

In article <CJHG19.4su@cbnews.cb.att.com>, wrb@cbnews.cb.att.com (wallace.r.blackburn) writes:
> 
> Anybody out there use the (old) SAA1027 stepper driver?  It has an input
> that you connect to the supply voltage through a resistor called Rx.  The
> purpose is to set the bias for the internal driver transistors.  It's hard
> to understand from the data sheet how to determine the value of resistor to
> use.  Any help appreciated.
> -- 
>    Wally Blackburn		   Clinton-Gore - Socialist Leadership
>    wrb@ccsitn.att.com			          for the 90s!
>    Amateur Radio Station AA8DX	   I'm the NRA.
>       *More people have died in Ted Kennedy's car than from my gun!*
> 
> 
