Single-Chip, Half-Duplex Modem Overlays 1200bps FSK Digital Communication on Top of Installed 4mA–20mA Current Loop Infrastructure
Digital Signal Processing Provides Reliable Input Signal Detection in Noisy Conditions
Standard Component 3.6864MHz Crystal Reduces System Cost
Fully Tested and Verified as a HART-Registered Modem IC
Integrated Solution Requires Minimal Power and Space
2.7V to 3.6V Operating Voltage
285µA (max) Current Consumption
Space-Saving, 5mm x 5mm x 0.8mm, 20-Pin TQFN Package
Few External Components Required
DS8500 Applications
4-20mA Loop-Powered Transmitters for Temperature, Pressure, Flow, and Level Measurement
HART Modem Interface Connectivity
HART Multiplexers
DS8500 Description
The DS8500 is a single-chip modem with Highway Addressable Remote Transducer (HART) capabilities. It has been fully tested and verified and has received a HART® Certificate of Registration. 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.
