XR22404CG28EVB MaxLinear

LED LED XR22404-EVB Evaluation Board Users Manual Introduction The XR22404 evaluation board is for the Exar USB 2.0 4-Port hub in both the 28 pin SSOP and 24 pin QFN packages. This manual is intended to guide users to use various functions and configurations of the hub device. Either the 28 pin SSOP package or 24 pin QFN package EVB can be ordered as shown in Table 1. Note that there are two revisions of the PCB, Rev. 1.0 and Rev. 1.1. The Rev. 1.0 requires rework to add a 10k pull-up resistor to be added on the EXT RST signal as 2 noted in the schematic. The Rev. 1.1 PCB also added I C programming headers such that the optional EEPROM can be programmed directly on the PCB as well as an in-rush current limiting circuit on VBUS power. Table 1: Ordering Information Device Ordering Part Number Evaluation Board Ordering Part Number Device Package Device Location XR22404CG28-F XR22404CG28EVB SSOP 28 U1 XR22404CL24-F XR22404CL24EVB QFN 24 U2 Board Layout and Outline Evaluation Board outline Figure 1 shows the topography of the evaluation board. Either U1 or U2 will be installed depending upon the version of the evaluation board. DS Port DS Port DS Port DS Port 1 2 3 4 LED LED LED LED CAP P T C JUMP C M U S U1 B U2 J11 QFN JUMP 24 PWR EE PROM J11: 1-2 Self Power 2-3 Bus Power Figure 1: XR22404 PCB Outline 2016 Exar Corporation 1 / 8 www.exar.com XR22404 Rev 1A 15 14 SOP 28 28 1XR22404 EVB Users Manual Evaluation Board Layout Evaluation Board Picture Figure 2: XR22404 PCB Hardware Configuration This section describes the default board settings, when shipped from the factory, and jumper settings that may be used to reconfigure operation. Differences between XR22404CG28EVB and XR22404CL24EVB The XR22404 is available in two packages, a 28 pin SSOP and a 24 pin QFN. The two versions of the evaluation board may use the same bare PCB, but with different components assembled, which includes either the 28 or 24 pin package. In order to avoid trace stubs on high speed USB (480 MHz) nets, 0 ohm resistors are installed from the upstream and all four downstream USB ports to connect to the QFN24 device for the XR22404CL24EVB. These resistors are not installed for the SSOP28 EVB. Power Configurations The XR22404 EVB may operate in either bus powered or self-powered modes. The power mode must be selected by jumper J11. If self-powered, the device uses the 5V supplied by the external 5V DC input to J11 power jack. When bus pow- ered, the XR22404 may not be capable of providing sufficient power to all downstream ports. By USB specification each downstream port may draw 100 mA maximum and the hub itself may draw an additional 100 mA when bus powered. 2016 Exar Corporation 2 / 8 www.exar.com XR22404 Rev 1A