Dual-port usb 2.0 hubs are handy when a local usb device also has a downstream usb port. Most Systems that try to daisy-chain peripherals utilize two ports of a four-port hub. A four-port hub requires more space and uses more power than SMSC's USB2502 dual-port USB 2.0 hub. Savings can be significant, especially when trying to pack the hub into the tiny confines of portable devices.
The USB 2502 supports high-speed (HS), full-speed (FS), and low-speed (LS) data rates along with bus-powered operation. It has an on-chip 1.8-V regulator to support the 1.8-V low-power core. The external interface is 3.3-V I/O with 5-V input tolerances. The chip can be configured using SMBus with an external processor, EEPROM, or pin-strapping.
The USB2502 is priced at $2 in quantity. It is available in a compact, 6- by 6- by 1-mm, 36-pin QFN package. That's small enough to fit inside a cable or a compact device like an intelligent USB flash drive.