Dual Delta-Sigma Modulator and Encoder

The DS8102 is a stand-alone, dual-channel, delta-sigma modulator that converts measurements from two differential analog input pairs into a Manchester-encoded output bit stream that can be processed by a companion microcontroller such as the MAXQ3108. One channel operates at a fixed 1x gain, while the other operates at a pin-selectable gain of 1x, 4x, 16x, or 32x. The DS8102 includes an internal power-supply monitor, on-board voltage reference, and low-power oscillator to reduce the number of external components required for data acquisition.

The Manchester-encoded output from the DS8102 combines pulse-density-modulated measurement values from both differential input channels with a synchronization bit stream and is transmitted over a single pin. This transmission scheme is ideal for split voltage domain applications where the DS8102 and other "hot"-side components must be electrically isolated from "cold" low-voltage components such as a companion microcontroller. In this type of application, the DS8102 can be capacitively coupled to a companion microcontroller with only two connection points required (MNOUT and DGND).

The MAXQ3108 dual-core microcontroller, which includes specialized Manchester bit-stream decoding inputs and sinc3 filters, is specifically designed to act as a companion microcontroller for up to three DS8102 devices. This configuration, which supports up to six differential analog input channels, is well suited for three-phase electricity-metering applications.

* Dual Delta-Sigma 2nd-Order Modulators

* Channel 0: Pin-Selectable Gain of 1x, 4x, 16x, or 32x

* Channel 1: Fixed Gain of 1x

* Selectable Internal or External Voltage Reference

* Manchester-Encoded Bit Stream Output

* Includes Synchronization Bits to Allow Clock Recovery

* Single-Pin Transmission Scheme Simplifies Electrical Isolation Using Capacitive Coupling

* Selectable Internal or External Clock Source

* Integrated Low-Power 8MHz Oscillator

* Operating Mode

* Active Mode (8MHz, VDD = 3.6V): 3.5mA