ISOM8710: Bias Power For Opto-Emulator

Brian Wang0928

Part Number: ISOM8710
Other Parts Discussed in Thread: ISOM8110

Tool/software:

For the Opto-emulator topology, how the RX side is biased? Is BJT collector current amplitude at Rx side depends on IF amplitude at Tx side? Is there more explanation you can offer? thanks.

1 month ago

0 Andrew J 1 month ago

TI__Mastermind 29665 points

Hello Brian,

ISOM8710 is a digital output style opto-emulator. No biasing is needed for these parts since it is taken care of by the side 2 VCC pin when power is applied.

ISOM8110 is analog output and will have an OOK magnitude based transmission as shown in the above diagram. The output behavior will depend on the output circuits which is commonly a resistor on IC. The ISOM8110 will operate with an analog behavior as long as the output current has enough head room to not hit the maximum current for a given IF*CTR. If the output current is intentionally limited so that IF*CTR >> Ic_max this is saturation mode and ISOM811x will operate as a switch. See the below for more details.

(+) [FAQ] What is Current Transfer Ratio (CTR)? - Isolation forum - Isolation - TI E2E support forums

(+) [FAQ] What are the different output types of TI Opto-emulators? - Isolation forum - Isolation - TI E2E support forums

(+) [FAQ] ISOM8110: How do I design ISOM8110 to have the best timing performance for switching applications? - Isolation forum - Isolation - TI E2E support forums