ISOW7721

The ISOW7721 device is a galvanically-isolated dual-channel digital isolator with an integrated high-efficiency power converter with low emissions. The integrated DC-DC converter provides up to 550mW of isolated power, eliminating the need for a separate isolated power supply in space-constrained isolation designs. If additional power is needed, the ISOW7721 supports multi-device chaining, increasing the integrated power output to > 1W using two devices in a system.

The high-efficiency of the power converter allows for operation at a wide operating ambient temperature range of –40°C to +125°C. This device provides improved emissions performance, allowing for simplified board design and has provisions for ferrite beads to further attenuate emissions. The ISOW7721 has been designed with enhanced protection features in mind, including soft-start to limit inrush current, over-voltage and under-voltage lock out, overload and short-circuit protection, and thermal shutdown.

The ISOW7721 provide high electromagnetic immunity while isolating CMOS or LVCMOS digital I/Os. The signal-isolation channel has a logic input and output buffer separated by a double capacitive silicon dioxide (SiO2) insulation barrier, whereas, power isolation uses on-chip transformers separated by thin film polymer as insulating material. The ISOW7721 has 1 forward channel and 1 reverse channel. If the input signal is lost, the default output is high for the ISOW7721 device without the F suffix and low for the ISOW7721F with the F suffix. The ISOW7721 can operate from a single supply voltage of 3V to 5.5V by connecting VIO and VDD together on a PCB. If lower logic levels are required, these devices support 1.71V to 5.5V logic supply (VIO) that can be independent from the power converter supply (VDD) of 3V to 5.5V. VISOIN and VISOOUT need to be connected on board with either a ferrite bead or fed through a LDO.

These devices help prevent noise currents on data buses, such as UART, RS-485, RS-232, and CAN, or other circuits from entering the local ground and interfering with or damaging sensitive circuitry. Through remarkable chip design and layout techniques, electromagnetic compatibility of the device has been significantly enhanced to ease system-level ESD, EFT, surge and emissions compliance. The device is available in a 20-pin SOIC wide-body (SOIC-WB) DFM package.