SMSC USB2512B, USB2513B, USB2514B, USB2517 5.3Buffer Type Descriptions, TYPE, BUFFER, SYMBOL, BUFFER, DATASHEET, DESCRIPTION, DESCRIPTION, POWER, GROUND, and NO CONNECTS

USB 2.0 Hi-Speed Hub Controller

Datasheet

Table 5.2 USB251x Pin Descriptions (continued)

	BUFFER
SYMBOL	TYPE	DESCRIPTION
SEL48	I	48 MHz Clock Input Selection
		48 MHz external input clock select. When the hub is clocked from an external
		clock source, this pin selects either 24 MHz or 48 MHz mode.
		‘0’ = 24 MHz
		‘1’ = 48 MHz
		POWER, GROUND, and NO CONNECTS
CRFILT		VDD Core Regulator Filter Capacitor
		This pin must have a 1.0 μF (or greater) ±20% (ESR <0.1 Ω) capacitor to
		VSS.
VDD33		3.3 V Power
PLLFILT		PLL Regulator Filter Capacitor
		This pin must have a 1.0 μF (or greater) ±20% (ESR <0.1 Ω) capacitor to
		VSS.
VSS		Ground Pad / ePad
		The package slug is the only VSS for the device and must be tied to ground
		with multiple vias.
NC		No Connect
		No signal or trace should be routed or attached to these pins.

5.3Buffer Type Descriptions

	Table 5.3 Buffer Type Descriptions
BUFFER	DESCRIPTION
I	Input.
I/O	Input/Output.
IPD	Input with internal weak pull-down resistor.
IPU	Input with internal weak pull-up resistor.
IS	Input with Schmitt trigger.
O12	Output 12 mA.

SMSC USB251x 27 Revision 1.0 (3-11-09)

DATASHEET