SLLU339 July   2021 ISOW7740 , ISOW7741 , ISOW7742 , ISOW7743 , ISOW7744

 

  1.   Trademarks
  2. 1Introduction
  3. 2Overview
  4. 3Pin Configurations of the ISOW7841 and ISOW7741
  5. 4EVM Setup and Operation
  6. 5EVM Schematic
  7. 6PCB Layout and 3D Diagram
  8. 7Bill of Materials

2 Overview

The ISOW774x, where 'x' can be any number from 0 to 4 based on the number of channels in reverse, is a galvanically-isolated quad- channel digital isolator with an integrated high-efficiency, low emissions power converter. The integrated DC-DC converter provides up to 550 mW of isolated power, eliminating the need for a separate isolated power supply in space-constrained isolated designs. 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 ISOW774x has been designed with enhanced protection features in mind, including soft-start to limit inrush current, over-voltage and under-voltage lock out, fault detection on the EN/FLT pin, overload and short-circuit protection, and thermal shutdown.

The ISOW774x device provides 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 ISOW774x can operate from a single supply voltage of 3 V to 5.5 V by connecting VIO and VDD together on PCB. If lower logic levels are required, these devices support 1.71 V to 5.5 V logic supply (VIO) that can be independent from the power converter supply (VDD) of 3 V to 5.5 V. VISOIN and VISOOUT needs to be connected on board with either a ferrite bead or fed through a LDO.

ISOW784x is a first-generation family of quad-channel digital isoaltors with integrated DC-DC converter and ISOW774x is the second-generation family of quad-channel digital isoaltors with integrated DC-DC converter. One of the major improvements done in ISOW774x family compared to ISOW784x is the radiated emissions performance. Other improvements include, lower output ripple voltage, separate logic and DC-DC converter supply, wider supply voltage option for data channels and many other smaller additional features. Unfortunately, ISOW774x isn't pin-compatible to ISOW784x and hence, ISOW774x cannot be directly evaluated on an existing customer PCB that is built with ISOW784x.

The ISOW-ADAPTOR-EVM is and adaptor PCB that enables customers to mount ISOW774x device on their existing PCBs with ISOW784x footprint. By facilitating mounting of ISOW774x on ISOW784x customer PCB, the adaptor PCB enables evaluation of existing ISOW784x customer PCB with ISOW774x to verify the overall improvements that can be achieved with the upgrade to ISOW774x. This is especially useful for verifying the improvement that can be achieved in radiated emissions perfromance by using ISOW774x in their existing PCB without needing any PCB redesign and saving significant development time.