AMC1204-Q1_15 Datasheet, PDF (15/33 Pages) Texas Instruments – 20 MHz, Second-Order, Isolated Delta-Sigma Modulator for Current-Shunt Measurement

AMC1204-Q1
www.ti.com
GENERAL DESCRIPTION
SLAS886B – JULY 2012 – REVISED JANUARY 2013
The AMC1204-Q1 is a single-channel, second-order, delta-sigma (ΔΣ) modulators designed for medium- to high-
resolution analog-to-digital conversions. The isolated output of the converter (DATA) provides a stream of digital
ones and zeros. The time average of this serial output is proportional to the analog input voltage.
Figure 41 shows a detailed block diagram of the AMC1204-Q1. The analog input range is tailored to directly
accommodate a voltage drop across a shunt resistor used for current sensing. The SiO₂-based capacitive
isolation barrier supports a high level of magnetic field immunity as described in the application report ISO72x
Digital Isolator Magnetic-Field Immunity (SLLA181A, available for download at www.ti.com). The external clock
input simplifies the synchronization of multiple current sense channels on system level. The extended frequency
range of up to 20 MHz supports higher performance levels compared to the other solutions available on the
market.
Isolation Barrier
VINP
VINN
2nd-Order
DS Modulator
+
-
V_REF
+
-
3-State
Output
Buffer
DATA
POR
Buffer
2.5V
V_REF
V_REF
CLKIN
Figure 41. Detailed Block Diagram
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