ZHCSK04B july 2019 – august 2020 ISO7021
PRODUCTION DATA
The ISO7021 device uses edge encoding of data with an ON-OFF keying (OOK) modulation scheme to transmit the digital data across a silicon dioxide isolation barrier. The transmitter uses a high frequency carrier signal to pass data across the barrier representing a signal edge transition. Using this method achieves very low power consumption and high immunity. The receiver demodulates the carrier signal after advanced signal conditioning and produces the output through a buffer stage. For low data rates, a refresh logic option is available to make sure the output state matches the input state. Advanced circuit techniques are used to maximize the CMTI performance and minimize the radiated emissions due to the high frequency carrier and IO buffer switching. The conceptual block diagram of a digital capacitive isolator, Figure 8-2, shows a functional block diagram of a typical channel.