WELCOME TO

                      BURR-BROWN CORPORATION
                      SPICE BASED MACROMODEL
                       6730 S. TUCSON BLVD.
                       TUCSON,  AZ  85706
                          800-548-6132



INTRODUCTION
	This is a collection of SPICE macromodels of BURR-BROWN op amps,
	difference amps, instrumentation amps, isolation amps, and analog 
	function circuits. There are four different levels of model topologies
	used, which are:
		Level I:   Standard Macromodel, STD_MOD
		Level II:  Enhanced Macromodel, ENH_MOD
		Level III: Multiple Pole/Zero Macromodel, MPZ_MOD
		Level IV:  Simplfied Circuit Model, CIR_MOD

	* The Standard macromodels were derived using standard simulation
	  software. This software uses the common Boyle op amp model structure.
	* The second level of macromodel is an enhanced version of the standard
	  model, which is indicated by the suffix "E" in the model's name.
          These models offer improved behaviour in terms of input bias current
	  and quiescent power. Also, voltage and current noise as well
	  as input capacitance is added.
	* The Multiple Pole/Zero macromodels uses the same input stage as the 
	  standard or enhanced op amp macromodel, but has multiple poles and 
	  pole/zero pairs in the mid-section. These models have the designation
          "M", and are primarily used for wide bandwidth op amps.
	* In some instances, a fourth type of model is available, which are
	  designated by either a "X", "X1" or a "X2" suffix. The models of this
	  level are not a "macromodel", but rather a simplified circuit model
	  at the transistor level.

	These Spice macromodels are complemented by the application bulletin 
        AB-020F, which contains more information and details on the topologies used.
        If you did not receive a copy of the AB-020F, please write or call BURR-BROWN
	at the address and number given above in order to obtain one.



APPLICATION INFORMATION

	Each model net-list starts with a header containing the part number,
	the revision date, and the license statement. The structure of the 
	net-list conforms to the standard SPICE format, which most SPICE based
	simulators will accept.
	Also, the format of the file specification has been changed in order
	to provide a better and faster overview. The 'date' following the file
	name now reflects the actual date of creation of each model. The 'time'
	is now used as an indicator for the revision status of each model. 
	For example:
		OPA131E.MOD   1-15-95  1:00:00 am   ---> REV.A
		OPA121E.MOD   3-21-92  2:00:00 am   ---> REV.B    etc.


Happy simulation!!