AMC1305L25-Q1 Datasheet, PDF (20/38 Pages) Texas Instruments – High-Precision, Reinforced Isolated Delta-Sigma Modulators

AMC1305L25-Q1, AMC1305M05-Q1, AMC1305M25-Q1
SBAS797 – FEBRUARY 2017
8 Detailed Description
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8.1 Overview
The differential analog input (AINP and AINN) of the AMC1305-Q1 is a fully-differential amplifier feeding the
switched-capacitor input of a second-order delta-sigma (ΔΣ) modulator stage that digitizes the input signal into a
1-bit output stream. The isolated data output (DOUT) of the converter provides a stream of digital ones and zeros
synchronous to the externally-provided clock source at the CLKIN pin with a frequency in the range of 5 MHz to
20.1 MHz. The time average of this serial bit-stream output is proportional to the analog input voltage.
The Functional Block Diagram section shows a detailed block diagram of the AMC1305-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 the
system level. The extended frequency range of up to 20.1 MHz supports higher performance levels compared to
other solutions available on the market.
8.2 Functional Block Diagram
AVDD
DVDD
AINP
AINN
BUF
TX
-
û -Modulator
+
TX
BUF
1.25-V
Reference
BUF
AMC1305-Q1
AGND
DOUT
DOUT_N
(AMC1305L25-Q1 only)
TX
CLKIN
CLKIN_N
(AMC1305L25-Q1 only)
TX
DGND
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