LTC2413 LINER [Linear Technology], LTC2413 Datasheet - Page 35

• Manufacturer Part Number: LTC2413
• Description: 24-Bit No Latency ADC, with Simultaneous 50Hz/60Hz Rejection
• Manufacturer: LINER [Linear Technology]

APPLICATIO S I FOR ATIO
range of 5V peak-to-peak. Figure 42 shows measurement
results for the LTC2413 normal mode rejection ratio with
a 7.5V peak-to-peak (150% of full scale) input signal su-
perimposed over the more traditional normal mode rejec-
tion ratio results obtained with a 5V peak-to-peak (full
scale) input signal. It is clear that the LTC2413 rejection
performance is maintained with no compromises in this
extreme situation. When operating with large input signal
levels, the user must observe that such signals do not
violate the device’s absolute maximum ratings.
BRIDGE APPLICATIONS
Typical strain gauge based bridges deliver only 2mV/Volt
of excitation. As the maximum reference voltage of the
LTC2413 is 5V, remote sensing of applied excitation
without additional circuitry requires that excitation be
U
U
–100
–120
– 60
–20
–40
–80
0
0
Figure 42. Measured Input Normal Mode Rejection vs Input
Frequency with Input Perturbation of 150% of Full Scale
20
W
40
60
U
80
INPUT FREQUENCY (Hz)
100
V
V
(150% OF FULL SCALE)
limited to 5V. This gives only 10mV full scale, which can
be resolved to 1 part in 10000 without averaging. For many
solid state sensors, this is still better than the sensor. For
example, averaging 64 samples however reduces the
noise level by a factor of eight, bringing the resolving
power to 1 part in 80000, comparable to better weighing
systems. Hysteresis and creep effects in the load cells are
typically much greater than this. Most applications that
require strain measurements to this level of accuracy are
measuring slowly changing phenomena, hence the time
required to average a large number of readings is usually
not an issue. For those systems that require accurate
measurement of a small incremental change on a signifi-
cant tare weight, the lack of history effects in the LTC2400
family is of great benefit.
IN(P-P)
IN(P-P)
120
= 5V
= 7.5V
140
160
180
V
REF
REF
V
T
A
CC
INCM
= 25 C
+
–
= 5V
= 5V
200
= GND
= 2.5V
2413 F42
220
LTC2413
sn2413 2413fs
35