TL H 5695
LH0094
Multifunction
Converter
February 1995
LH0094 Multifunction Converter
General Description
The LH0094 multifunction converter generates an output
voltage per the transfer function
E
O
e
V
y
V
Z
V
X
J
m
0 1
s
m
s
10 m continuously adjustable
m is set by 2 resistors
Features
Y
Low cost
Y
Versatile
Y
High accuracy
b
0 05%
Y
Wide supply range
b
g
5V to
g
22V
Y
Minimum component count
Y
Internal matched resistor pair for setting m
e
2 and
m
e
0 5
Applications
Y
Precision divider multiplier
Y
Square root
Y
Square
Y
Trigonometric function generator
Y
Companding
Y
Linearization
Y
Control systems
Y
Log amp
Block and Connection Diagrams
Order Number LH0094CD
See NS Package Number D16D
Dual-In-Line Package
Simplified Schematic
TL H 5695 1
C1995 National Semiconductor Corporation
RRD-B30M115 Printed in U S A
Absolute Maximum Ratings
(Note 1)
If Military Aerospace specified devices are required
please contact the National Semiconductor Sales
Office Distributors for availability and specifications
Supply Voltage
g
22V
Input Voltage
g
22V
Output Short-Circuit Duration
Continuous
Operating Temperature Range
LH0094CD
b
25 C to
a
85 C
Storage Temperature Range
LH0094CD
b
55 C to
a
125 C
Lead Temperature
(Soldering 10 seconds)
260 C
Electrical Characteristics
V
S
e
g
15V T
A
e
25 C unless otherwise specified Transfer function E
O
e
V
Y
V
Z
m
V
X
0 1
s
m
s
10 OV
s
V
X
V
Y
V
Z
s
10V
Parameter
Conditions
LH0094C
Units
Min
Typ
Max
ACCURACY
Multiply
E
O
e
V
Z
V
Y
(0 03
s
V
Y
s
10V 0 01
s
V
Z
s
10V)
% F S
Untrimmed
(Figure 2)
0 45
0 9
(10V)
External Trim
(Figure 3)
0 1
% F S
vs Temperature
0 2
mV C
Divide
E
O
e
10V
Z
V
X
Untrimmed
(Figure 4) 0 5
s
V
X
s
10 0 01
s
V
Z
s
10)
0 45
0 9
% F S
External Trim
(Figure 5) (0 1
s
V
X
s
10 0 01
s
V
Z
s
10)
0 1
% F S
vs Temperature
0 2
mV C
Square Root
E
O
e
10
0
V
Z
10
Untrimmed
(Figure 8) (0 03
s
V
Z
s
10
0 45
0 9
% F S
External Trim
(Figure 9) (0 01
s
V
Z
s
10
0 15
% F S
Square
E
O
e
10 (V
Z
10)
2
(0 1
s
V
Z
s
10)
Untrimmed
(Figure 6)
1 0
2 0
% F S
External Trim
(Figure 7)
0 15
% F S
Low Level
E
O
e
0
10V
Z
5 0mV
s
V
Z
s
10V
(Figure 10)
0 05
% F S
Square Root
Exponential
m
e
0 2 E
O
e
10 (V
Z
10)
2
(Figure 11) (0 1
s
V
Z
s
10)
0 08
% F S
Circuits
m
e
5 0 E
O
e
10 (V
Z
10)
5
(Figure 11) (1 0
s
V
Z
s
10)
0 08
% F S
OUTPUT OFFSET
V
X
e
10V V
Y
e
V
Z
e
0
5 0
10
mV
AC CHARACTERISTICS
3 dB Bandwidth
m
e
1 0 V
X
e
10V V
Y
e
0 1 V
rms
10
kHz
Noise
10 Hz to 1 0 kHz m
e
1 0 V
Y
e
V
Z
e
OV
V
X
e
10V
100
m
V rms
V
X
e
0 1V
300
m
V rms
EXPONENT
m
0 2 to
0 1 to
5 0
10
INPUT CHARACTERISTICS
Input Voltage
(For Rated Performance)
0
10
V
Input Impedance
(All Inputs)
98
100
kX
OUTPUT CHARACTERISTICS
Output Swing
(R
L
s
10k)
10
12
V
Output Impedance
1 0
X
Supply Current
(V
S
e
g
15V) (Note 1)
3 0
5 0
mA
Note 1
Refer to RETS0094D drawing for specifications of the military LH00940 version
2
Applications Information
GENERAL INFORMATION
Power supply bypass capacitors (0 1 mF) are recommended
for all applications
The LH0094 series is designed for positive input signals
only However negative input up to the supply voltage will
not damage the device
A clamp diode (
Figure 1 ) is recommended for those applica-
tions in which the inputs may be subjected to open circuit or
negative input signals
For basic applications (multiply divide square square root)
it is possible to use the device without any external adjust-
ments or components Two matched resistors are provided
internally to set m for square or square root
When using external resistors to set m such resistors
should be as close to the device as possible
SELECTION OF RESISTORS TO SET m
Internal Matched Resistors
R
A
and R
B
are matched internal resistors
They are
100X
g
10% but matched to 0 1%
(a) m
e
2
(b) m
e
0 5
TL H 5695 2
No external resistors required strap as indicated
External Resistors
The exponent is set by 2 external resistors or it may be
continuously varied by a single trim pot (R1
a
R2
s
500X
(a) m
e
1
TL H 5695 3
(b) m
k
1
m
e
R2
R1
a
R2
R1
a
R2
200X
(c) m
l
1
m
e
R1
a
R2
R2
TL H 5695 4
ACCURACY (ERROR)
The accuracy of the LH0094 is specified for both externally
adjusted and unadjusted cases
Although it is customary to specify the errors in percent of
full-scale (10V) it is seen from the typical performance
curves that the actual errors are in percent of reading Thus
the specified errors are overly conservative for small input
voltages An example of this is the LH0094 used in the mul-
tiplication mode The specified typical error is 0 25% of full-
scale (25 mV) As seen from the curve the unadjusted error
is
25 mV at 10V input but the error is less than 10 mV for
inputs up to 1V Note also that if either the multiplicand or
the multiplier is at less than 10V (5V for example) the unad-
justed error is less Thus the errors specified are at full-
scale
the worst case
The LH0094 is designed such that the user is able to exter-
nally adjust the gain and offset of the device
thus trim out
all of the errors of conversion In most applications the gain
adjustment is the only external trim needed for super accu-
racy
except in division mode where a denominator offset
adjust is needed for small denominator voltages
EXPONENTS
The LH0094 is capable of performing roots to 0 1 and pow-
ers up to 10 However care should be taken when applying
these exponent
otherwise results may be misinterpreted
For example consider the
th power of a number i e
0 001 raised to 0 1 power is 0 5011 0 1 raised to the 0 1
power is 0 7943 and 10 raised to the 0 1 power is 1 2589
Thus it is seen that while the input has changed 4 decades
the output has only changed a little more than a factor of 2
It is also seen that with as little as 1 mV of offset the output
will also be greater than zero with zero input
3
Applications Information
(Continued)
1 CLAMP DIODE CONNECTION
E
O
e
V
y
V
Z
V
X
J
m
0 1
s
m
s
10
Note This clamp diode connection is
recommended for those applications
in which the inputs may be subject to
open circuit or negative signals
FIGURE 1 Clamp Diode Connection
2 MULTIPLY
FIGURE 2a LH0094 Used to Multiply (No External Adjustment)
FIGURE 2b Typical Performance of
LH0094 in Multiply Mode Without
External Adjustment
E
0
e
V
y
V
z
10
m
e
1
Trim Procedure
Set V
Z
e
V
Y
e
10V
Adjust R2 until output
e
10 000V
TL H 5695 5
FIGURE 3 Precision Multiplier (0 02% Typ) with 1 External Adjustment
4
Applications Information
(Continued)
3 DIVIDE
FIGURE 4a LH0094 Used to Divide (No External Adjustment)
FIGURE 4b Typical Performance
Divide Mode
Without External Adjustments
Trim Procedures
Apply 10V to V
Y
0 1V to V
X
and V
Z
Adjust R3 until E
O
e
10 000V
Apply 10 000V to all inputs
Adjust R2 until E
O
e
10 000V
Repeat procedure
FIGURE 5 Precision Divider (0 05% Typ)
4 SQUARE
E
O
e
V
y
V
Z
V
X
J
2
FIGURE 6a Basic Connection of LH0094 (m
e
2) without
External Adjustment Using Internal Resistors to Set m
FIGURE 6b Squaring Mode without
External Adjustment
TL H 5695 6
5
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