RC4200M Fairchild Semiconductor, RC4200M Datasheet - Page 14

• Manufacturer Part Number: RC4200M
• Manufacturer: Fairchild Semiconductor

Specifications of RC4200M

• Number Of Elements: 1
• Output Type: Single
• Power Supply Requirement: Single
• Single Supply Voltage (typ): -15V
• Single Supply Voltage (min): -9V
• Single Supply Voltage (max): -18V
• Dual Supply Voltage (typ): Not RequiredV
• Dual Supply Voltage (min): Not RequiredV
• Dual Supply Voltage (max): Not RequiredV
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 8
• Package Type: SOIC N
• Lead Free Status / RoHS Status: Compliant

RC4200
Reducing Mismatch Errors
You need not use 0.01% resistors to reduce resistor product
mismatch errors. Here are a couple of ways to obtain
maximum accuracy out of the extended range multiplier
(see Figure 4) using 1% resistors.
Method 1
V
V
Also, if V
V
feedthrough of ± V
±V
Total feedthrough:
±V
By carefully abusing X
equation can be made to very nearly equal zero and the
feedthrough error will practically disappear.
A residual of set will probably remain which can be trimmed
outwith V
Method 2
Notice that the ratios of R
both dependent of R
functions of the maximum input requirements. By designing
a multiplier for the same input ranges on both V
then R
able to design a four quadrant multiplier and use only two
quadrants of it.)
14
X
OSY
X
Y
X
V
feedthrough, for example, occurs when V
V
V
OSZ
OSX
OSY
1
= R
0. This V
. A resistor-product error of
OSZ
OS
, ±V
±V
2
(R
, R
Y
16
Y
CX
V
0, there is a V
V
) at the output of amp.
X
OSX
OSZ
= R
feedthrough will equal ±V
X
d
. Likewise, V
also that R
OS
± V
CY
and ± V
1
(R
R
and R
X
5
b
), Y
:R
± V
X
CX
Y
feedthrough equal to
1
OS
a
, R
= R
Y
Y
R
(R
d
2
±(V
feedthrough errors are:
, R
and R
b
9
. (Note: it is accept-
) and Z
will cause a V
a
X
and R
+ V
2
Y
R
X
OS
Y
a
= 0 and
X
:R
V
b
) V
(R
OSY
are all
and V
CY
OSZ
20
R
.
X
) this
d
Y
are
Select R
value. This will cause
tive) by nearly the same amount. Now the effective value of
R
pin 5.
This technique causes: a slight gain error which can be com-
pensated with the R
can be trimmed with V
Extended Range Divider
The only cross-product error of interest is the V
feedthrough (V
with X
Resistor product mismatch will cause scaling errors (gain)
that could be a problem for very low values of V
ments to Y
accuracy.
Square Root and Squaring
These circuits are functions of single variables so
feedthrough, as such, is not a consideration. Cross product
errors will effect incremental accuracy that can be corrected
Y
d
OS
can be trimmed with an offset adjustment Z
(R
OS
14
d
) or Z
(R
to be 1% or 2% below (or above) the calculated
OS
5
). See Figure 6.
(R
OS
X
18
= 0 and V
(R
) can be made to improve the high gain
0
10
value, and an output of offset error that
). See Figure 9 and Figure 11.
OS
and to both be positive (or nega-
(R
OSX
16
) on the output op amp.
0) which is easily adjusted
PRODUCT SPECIFICATION
REV. 1.2.1 6/14/01
OS
Z
Z
(R
. Adjust-
20
) on