JAJSSV1B December 2017 – January 2024 FPC202
PRODUCTION DATA
For this design example, the following guidelines outlined in Table 8-1 apply.
DESIGN PARAMETER | REQUIREMENT |
---|---|
FPC202 physical placement |
The FPC202 package is small enough to fit underneath an SFP or QSFP cage, on the opposite side of the board. For SFP applications, such a placement leaves 4.6 mm of air gap between the FPC202 package edge and the SFP pressfit pins (assuming 14.25 mm pin-to-pin spacing for a stacked SFP cage). For QSFP applications, such a placement leaves 7.2 mm of air gap between the FPC202 package edge and the QSFP pressfit pins (assuming 19.5 mm pin-to-pin spacing for a stacked QSFP cage). |
LED implementation | The FPC202 is designed to drive active-low LEDs which have their anode connected to the port-side 3.3-V supply. Refer to Section 7.3.2. |
Port-side I2C SDA and SCL pull-ups | As per the SFF-8431 and SFF-8436 specification, the port-side (downstream) SCL and SDA nets should be pulled up to 3.3 V using resistors in the 4.7-kΩ to 10-kΩ range. |
QSFP ModSelL | QSFP provides a mechanism to enable or disable the port’s I2C interface. Since the FPC202 has a separate I2C master to communicate with each port, the ModSelL input for every QSFP can be connected to GND, thereby permanently enabling each QSFP port’s I2C bus. |
SFP/QSFP port power supply de-coupling | Follow the SFF-8431 and SFF-8436 recommendations for power supply de-coupling. |