MLT04 Datasheet, PDF (4/12 Pages) Analog Devices – Four-Channel, Four-Quadrant Analog Multiplier

MLT04
Feedthrough
In the ideal case, the output of the multiplier should be zero if
either input is zero. In reality, some portion of the nonzero input
will “feedthrough” the multiplier and appear at the output. This is
caused by the product of the nonzero input and the offset voltage of
the “zero” input. Introducing an offset equal to and opposite of the
“zero” input offset voltage will null the linear component of the
feedthrough. Residual feedthrough at the output of the multiplier
is then irreducible core nonlinearity.
Typical X- and Y-input feedthrough curves for the MLT04 are
shown in Figures 7 and 8, respectively. These curves illustrate
MLT04 feedthrough after “zero” input offset voltage trim.
Residual X-input feedthrough measures 0.08% of full scale,
whereas residual Y-input feedthrough is almost immeasurable.
X-INPUT: ±2.5V @ 10Hz
100
Y_OS NULLED
90
T_A = +25°C
10
0%
HORIZONTAL – 0.5V/DIV
Figure 7. X-Input Feedthrough with Y_OS Nulled
Y-INPUT: ±2.5V @ 10Hz
100
X_OS NULLED
90
T_A = +25°C
10
0%
HORIZONTAL – 0.5V/DIV
Figure 8. Y-Input Feedthrough with X_OS Nulled
Nonlinearity
Multiplier core nonlinearity is the irreducible component of error.
It is the difference between actual performance and “best-straight-
line” theoretical output, for all pairs of input values. It is expressed
as a percentage of full scale with all other dc errors nulled. Typical
X- and Y-input nonlinearities for the MLT04 are shown in Figures
9 through 12. Worst-case X-input nonlinearity measured less than
0.2%, and Y-input nonlinearity measured better than 0.06%. For
modulator/demodulator or mixer applications it is, therefore,
recommended that the carrier be connected to the X-input while
the signal is applied to the Y-input.
100
90
X-INPUT: ±2.5V @ 10Hz
Y-INPUT: +2.5V
10
0%
Y_OS NULLED
T_A = +25°C
HORIZONTAL – 0.5V/DIV
Figure 9. X-Input Nonlinearity @ Y = +2.5 V
100
90
X-INPUT: ±2.5V @ 10Hz
Y-INPUT: –2.5V
10
0%
Y_OS NULLED
T_A = +25°C
HORIZONTAL – 0.5V/DIV
Figure 10. X-Input Nonlinearity @ Y = –2.5 V
Y-INPUT: ±2.5V @ 10Hz
100
X-INPUT: +2.5V
90
X_OS NULLED
T_A = +25°C
10
0%
HORIZONTAL – 0.5V/DIV
Figure 11. Y-Input Nonlinearity @ X = +2.5 V
Y-INPUT: ±2.5V @ 10Hz
100
X-INPUT: –2.5V
90
X_OS NULLED
T_A = +25°C
10
0%
HORIZONTAL – 0.5V/DIV
Figure 12. Y-Input Nonlinearity @ X = –2.5 V
–4–
REV. B