AD531_15 Datasheet, PDF (1/6 Pages) Analog Devices – MULTIPLIERS DIVIDERS

T
MULTIPLIERSjDIVIDERS
427, 424, 425, 426, 432, 428, 429, 422, AD530, AD531
OBSOLETE ^~,
\
r
~
I
t
~
t
MULTIPLIER CLASSIFICATION AND PRODUCT
t
DESCRIPTION
I
To assist in selecting the best multiplier for the application,
r
we have classified products according to the technique used
to develop the multiply function which essentially determines
~
the capabilities of the device. Analog Devices has focused
Unlike most high accuracy multipliers embodying the
modulation principle, 427's high carrier frequency allows
a bandwidth rating of 100kHz for -3dB response with no carrier
I
on the pulse-width/height technique and the variable trans-
conductance technique to develop the multiply/divide
ripple on output. Depending on how it is connected, the 427 can
be used for multiplying, dividing, squaring, or square rooting.
function. These two approaches are considered comple-
mentary and were selected because of their inherent ability
1
to provide a good balance between performance and cost.
I
t
PULSE-WIDTH-HEIGHT MODULATION
PRECISION MULTIPLIERS (PWH)
,I
The pulse-width-height modulation technique is capable of
The ttUe capability of a multiplier can be best demonstrated
when the unit is used in the divide mode, particularly with
small denominators. Because the 427 featUres excellent
small signal linearity, the errors are very much smaller than
one would predict using 10/x for divider error.
MODEL 424 (HIGH ACCURACY): The model 424 ]/K
producing multipliers of the highest precision. Typical
is an untrimmed multiply-only module with performance
specifications include accuracies from 0.1 % to 0.25%, offset
drifts to 1OOllV / C, output noise of 50llV rms and band-
comparable to that of model 427. In evety respect, except
for the divide and external trim featUres, the 424 will
widths to 100kHz. Multipliers in this group should be used
perform the 427 task at lower component cost and should
r
for wide temperatUre range applications, for analog
c<nnputing elements, for dividers because of their inherently
be considered for laboratory and industrial applications
where external trimming may be conveniently performed
good drift, noise and low non-linearities, and, in general, for
to achieve the highest possible accuracies. When externally
exacting multiplier/divider applications where wide dynamic
signal swings are anticipated. Products in this group include
trimmed, model 424 will perform with 0.2% (424]) and .
0.1 % (424K) accuracies with bandwidths to 100kHz (- 3d B).
models 427. 424, and 425.
It may be used to perform division when operated with an
MODEL 427 (HIGH ACCURACY): Based on the highly
successful Model 424, the 427K is internally trimmed to
specified accuracy and requires no external adjustments for
external op amp.
MODEL 425: Customers may purchase the model 424
mounted on a PC card which contains all necessary adjust-
multiplication. It uses pulse-width modulation to obtain
accuracies to 0.2% (FS), offset drifts as low as 2001lV/ C,
ment potentiometers to trim the multiplier to its rated
accuracies. Designated model 425] (with 424]) and 425K
and nonlinearity of 0.04% maximum, for both inputs. All
semiconductors used-in this design are hermetically sealed.
(with 424K), these models are faCtory trimmed and offered
at a nominal cost above that of 424 alone.
MUL TIPLIERS/DIVIDERS 129