Introduction:
A voltage Translator is used to change the voltage level of signals and an Isolator is a device which isolates one side from another side up to a voltage level . If you want to develop communication between two devices which works on different voltage then you’ll need a voltage translator. We’ll use ADuM7642 IC which can be used for both purpose as voltage translator and Isolator. ADuM7642 works up to 25 Mbps. Other type of Isolator is opto-isolators.
See figure 1 for pin configuration:

Fig1

ADuM7642 as an Isolator:
First of all we will use ADuM7642 as an Isolator. As we are seeing side 1 of IC is isolated from side 2 of IC so it is very simple to use. You will connect this as shown in figure2. We can connect all VCC pins together because we are using this as an Isolator and our devices are working on same voltage. We will explain this with SPI example for better understanding.

FIG2

ADuM7642 as voltage level translator cum Isolator:
As we have seen that side 1 is always isolated from side 2 but next thing comes that how to use this as a voltage level translator. Let’s assume we are using two SPI devices, one is Master and another is Slave. Master is working 3.3V and Slave is working on 5V. For better understanding take Nano 130 as a master and ADE7753 as a Slave. See figure 3 there is only one change in VDD voltages which is red marked. If master is working on 5V and Slave is working on 3.3 then use VDD vice versa. It means at master side, VDD must be 5V and 3.3V at Slave side.

FIG3

Applications:-

  1. SPI
  2. I2C
  3. UART
  4. Serial Communication
  5. Parallel Communication
  6. etc.

Note:-
Figure 1 is taken from the data sheet of ADuM7642 provided by Analog Devices and rest two are edited. Follow circuit standard and precautions suggested by Analog Devices. If still you are not getting desired output then multiple checks your connection otherwise fault is on another end because I have tested this multiple times.