General Description
The Microchip USB251xB/xBi hub is a family of lowpower,
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, while the B indicates battery
charging support. The Microchip hub supports lowspeed,
full-speed, and hi-speed (if operating as a hispeed
hub) downstream devices on all of the enabled
downstream ports.

Features
• USB251xB/xBi products are fully footprint compatible
with USB251x/xi/xA/xAi products as direct
drop-in replacements
— Cost savings include using the same PCB
components and application of USB-IF Compliance
by Similarity
• Full power management with individual or ganged
power control of each downstream port
• Fully integrated USB termination and pull-up/pulldown
resistors
• Supports a single external 3.3 V supply source;
internal regulators provide 1.2 V internal core voltage
• Onboard 24 MHz crystal driver or external
24 MHz clock input
• Customizable vendor ID, product ID, and device
ID
• 4 kilovolts of HBM JESD22-A114F ESD protection
(powered and unpowered)
• Supports self- or bus-powered operation
• Supports the USB Battery Charging specification
Rev. 1.1 for Charging Downstream Ports (CDP)
• The USB251xB/xBi offers the following packages:
- 36-pin SQFN (6x6 mm) (Preferred)
- 36-pin QFN (6x6 mm) (Legacy)
• USB251xBi products support the industrial temperature
range of -40ºC to +85ºC
• USB251xB products support the extended commercial
temperature range of 0ºC to +85ºC

Applications
• LCD monitors and TVs
• Multi-function USB peripherals
• PC motherboards
• Set-top boxes, DVD players, DVR/PVR
• Printers and scanners
• PC media drive bay
• Portable hub boxes
• Mobile PC docking
• Embedded systems