Introduce a method of measuring current using a 16-bit ADC. This ADC has an input noise floor of 1.45µVRMS and an input range from 100mV to VCC, which makes it suitable for a wide range of applications.
The document presents Design Note 341 by Mark Thoren from Linear Technology Corporation. It details the use of the LTC2433-1, a high-performance 16-bit Delta-Sigma ADC, specifically for DC current measurement applications such as telecom supply monitoring.
A key focus is on simplifying data transfer in isolated environments where level shifting is required. The note explains how to configure the device's flexible SPI interface for self-clocking and describes an asynchronous reception method using XOR logic to decode serial data without a crystal-controlled clock, tolerating significant timing errors.
The device clocks out its data at a serial data rate of 17.5kHz.
While converting, the ADC draws 200uA.
The series resistor must be chosen so the LT1029 current is at least 3mA.