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DS8500 single-chip modem with Highway Addressable Remote Transducer capabilities

The DS8500 is a single-chip modem with Highway Addressable Remote Transducer (HART) capabilities and satisfies the HART physical layer requirements.
The device integrates the modulation and demodulation of the 1200Hz/2200Hz FSK signal, has very low power consumption, and needs only a few external components due to the integrated digital signal processing.
The input signal is sampled by an analog-to-digital converter (ADC), followed by a digital filter/demodulator.
This architecture ensures reliable signal detection in noisy environments. The output digital-to-analog converter (DAC) generates a sine wave and provides a clean signal with phase-continuous switching between 1200Hz and 2200Hz. Low power is achieved by disabling the receive circuits during transmit and vice versa. The DS8500 is ideal for low-power process control transmitters .
Main features of Ds8500 chip are : 1200bps FSK Modulation and Demodulation , Digital Signal Processing Provides Reliable Input Signal Detection in Noisy Conditions , Sinusoidal Output Signal with Lowest Harmonic Distortion , Few External Components Enable a Space-Saving Solution , Standard Component 3.6864MHz Crystal , Complies to HART Physical Layer Requirements , 2.7V to 3.6V Operating Voltage , 285μA (max) Current Consumption
The DS8500 modem chip consists of a demodulator, carrier detect, digital filter, ADC for input signal conversion, a modulator and DAC for output signal generation, and receive and transmit state machine blocks to perform the HART communication.
The input HART signal’s noise interference is attenuated by a one-pole highpass filter that is external to the chip; the attenuated signal is digitized by the ADC and filtered by the receive state machine. The transmit state machine modulates the input to the HART-compliant signal with the help of the modulator and the DAC.
The DS8500 chip can be used in applications like : 4–20mA Loop-Powered Transmitters for Temperature, Pressure, Flow, and Level Measurement ; HART Multiplexers ; HART Modem Interface Connectivity
ds8500 package ds8500 hart modem application

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