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| AMC1200_15 Datasheet, PDF (16/31 Pages) Texas Instruments – AMC1200/B Fully-Differential Isolation Amplifier | |||
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AMC1200, AMC1200B
SBAS542D â APRIL 2011 â REVISED JULY 2015
www.ti.com
Typical Applications (continued)
8.2.1.1 Design Requirements
For better performance, the differential input signal is filtered using RC filters (components R2, R3, and C2).
Optionally, C3 and C4 can be used to reduce charge dumping from the inputs. In this case, take care when
choosing the quality of these capacitors; mismatch in values of these capacitors leads to a common mode error
at the modulator input. If implemented, TI recommends using NP0 capacitors for C2, C3 and C4.
Phase
Isolation
Barrier
R1
RSHUNT
R2
12 W
R3
12 W
C1(1)
0.1 mF
C2(1)
330 pF
C3
10 pF
(optional)
C4
10 pF
(optional)
Device
1 VDD1 VDD2 14
2
13
VINP VOUTP
3 VINN VOUTN 11
4 GND1 GND2 9
C5(1)
0.1 mF R
R
TMC320
C/F28xxx
C
ADC
Figure 33. Shunt-Based Current Sensing with the AMC1200
Similar to the current measurements, isolated voltage measurements can be performed as described in the .
8.2.1.2 Detailed Design Procedure
The floating ground reference (GND1) is derived from the end of the shunt resistor, which is connected to the
negative input of the AMC1200 (VINN). If a four-terminal shunt is used, the inputs of the AMC1200 are
connected to the inner leads and GND1 is connected to one of the outer shunt leads. The differential input of the
AMC1200 ensures accurate operation even in noisy environments.
TI recommends limiting the value of resistors R2 and R3 to less than 24 Ω to avoid the incomplete settling of the
AMC1200 input circuitry. The section provides more details on the AMC1200 input circuitry.
The differential output of the AMC1200 can either directly drive an analog-to-digital converter (ADC) input or can
be further filtered before being processed by the ADC. For more information on the general procedure to design
the filtering and driving stages for SAR ADCs, consult the TI Precision Designs 18 bit, 1Msps Data Acquisition
Block Optimized for Lowest Distortion and Noise (SLAU515), and 18 bit Data Acquisition Block Optimized for
Lowest Power (SLAU513) available for download at www.ti.com
16
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Copyright © 2011â2015, Texas Instruments Incorporated
Product Folder Links: AMC1200 AMC1200B
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