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7
PRODUCT SPECIFICATION
RC4200
Extended Range Divider
Figure 6. Extended Range Divider
As with the extended range multiplier, resistors R
az
and R
ao
are added to cancel the cross-product error caused by the
biasing resistors, i.e.
To cancel cross-product and arithmetic offset:
R
ao
R
b
= R
0
R
d
, R
az
R
b
= R
4
R
c
and R
a
R
b
= R
c
R
d
and the result is:
65-4200-08
RC4200
Multiplier
V
X
(Input)
S
O
S
ao
az
Ra
Rb
R1
R
R
-V
I
3
R
V
O
(Output)
+V
S
-V
3
6
4
5
8
7
1
2
Rc
Rd
I
2
I
1
I
4
+V
REF
+V
REF
RC5534
V
Z
(Output)
R4
R1
Rao
+
Raz
VRa
+
+
è
÷
è
VRb
÷
R0
VRC
+
è
÷
è
R4
VRD
+
÷
=
VR1Rb
RaoRb
RazRb
RaRb
+
+
+
R0R4
VR0Rd
VR4Rc
RcRd
+
+
+
V
V
R
1
R
b
---------------------
V
V
R
0
R
4
-------------- or V
0
=
V
V
Z
K
-----------
=
where K = V
R
R
4
---------------------------
R
1
R
b
Notice that it is necessary to match the above resistor cross-
products to within the amount of error tolerable in the out-
put offset, i.e., with a 10V F.S. output, 0.1% resistor cross-
product match will give 0.1% x 10V. untrimmable output
offset voltage.
Resistor Values
Inputs:
V
X
(min.)
£
V
X
£
V
X
(max.)
D
V
X
= V
X
(max.) = V
X
(min.)
V
Z
(min.)
£
V
Z
£
V
Z
(max.)
D
V
Z
= V
Z
(max.) = V
Z
(min.)
V
REF
= Constant (+7V to +18V)
Outputs:
V
0
(min.)
£
V
0
£
V
0
(max.)
D
V
0
= V
0
(max.) = V
0
(min.)
K
V
V
V
X
-------------- Design Requirement
)
=
R
0
D
V
750
m
A
----------------, R
b
D
V
250
m
A
-----------------, R
4
D
V
200
m
A
----------------
=
=
=
R
c
D
V
V
700
m
A V
0
max.
–
750
m
A
D
V
0
(
)
------------------------------------------------------------------------------
=
R
d
D
V
V
200
m
A V
Z
max.
–
250
m
A
D
V
Z
(
)
-------------------------------------------------------------------------------
=
R
a
R
R
R
b
------------, R
az
R
R
R
b
------------, R
ao
R
R
d
R
b
-------------
=
=
=
R
1
D
V
D
V
Z
600
m
AK
----------------------
=