26

Rev. 1.5

Si8660/61/62/63

3.3. Layout Recommendations

(creepage/clearance). If a component, such as a digital isolator, straddles this isolation barrier, it must meet those

creepage/clearance requirements and also provide a sufficiently large high-voltage breakdown protection rating

(commonly referred to as working voltage protection). Table 5 on page 17 and Table 6 on page 18 detail the

working voltage and creepage/clearance capabilities of the Si86xx. These tables also detail the component

standards (UL1577, IEC60747, CSA 5A), which are readily accepted by certification bodies to provide proof for

end-system specifications requirements. Refer to the end-system specification (61010-1, 60950-1, 60601-1, etc.)

requirements before starting any design that uses a digital isolator.

3.3.1. Supply Bypass

capacitor should be placed as close as possible to the package. To enhance the robustness of a design, the user

may also include resistors (50–300

 ) in series with the inputs and outputs if the system is excessively noisy.

3.3.2. Output Pin Termination

The nominal output impedance of an isolator driver channel is approximately 50

, ±40%, which is a combination

of the value of the on-chip series termination resistor and channel resistance of the output driver FET. When driving

loads where transmission line effects will be a factor, output pins should be appropriately terminated with controlled

impedance PCB traces.

3.4. Fail-Safe Operating Mode

Si86xx devices feature a selectable (by ordering option) mode whereby the default output state (when the input

supply is unpowered) can either be a logic high or logic low when the output supply is powered. See Table 12 on

page 24 and "5. Ordering Guide" on page 30 for more information.