General Description
The SMSC USB251x hub is a family of low-power, OEM configurable, MTT (multi transaction translator) hub controller IC products for embedded USB solutions. The “x” in the part number indicates the number of downstream ports available. The SMSC hub supports low-speed, full-speed, and hi-speed (if operating as a hi speed hub) downstream devices on all of the enabled downstream ports.

Features
Full power management with individual or ganged power control of each downstream port
Fully integrated USB termination and pull-up/pull down resistors
Supports a single external 3.3 V supply source;
  internal regulators provide 1.2 V or 1.8 V internal core voltage
On-chip driver for 24 MHz crystal resonator or external 24/48 MHz clock input
Customizable vendor ID, product ID, and device ID
ESD protection up to 4 kilovolts on all USB pins
Supports self- or bus-powered operation
USB251xB2 and USB251xBi products support the USB Battery Charging specification
Lead-free RoHS compliant packages:
— 36-pin QFN (6x6 mm)
— 48-pin QFN (7x7 mm)
— 64-pin QFN (9x9 mm)
USB251xi, USB2512Ai, and USB251xBi products support the industrial temperature range of -40ºC
to +85ºC