Smsc USB3250 Manual de usuario descargar pdf (Pagina 7)

Hi-Speed USB Device Transceiver with UTMI Interface

SMSC USB3250 7 Revision 1.7 (05-11-07)

PRODUCT PREVIEW

Note 2.1 A Ferrite Bead (with DC resistance <.5 Ohms) is recommended for filtering between both

the VDD3.3 and VDDA3.3 supplies and the VDD1.8 and VDDA1.8 Supplies.

Note 2.2 All VSS and VSSA are bonded to the exposed pad under the IC in the package. The

exposed pad must be connected to solid GND plane on printed circuit board.

Table 3 USB I/O Pins

NAME DIRECTION

ACTIVE

LEVEL DESCRIPTION

DP I/O N/A USB Positive Data Pin.

DM I/O N/A USB Negative Data Pin.

Table 4 Biasing and Clock Oscillator Pins

NAME DIRECTION

ACTIVE

LEVEL DESCRIPTION

RBIAS Input N/A External 1% bias resistor. Requires a 12KΩ resistor to ground.

Used for setting HS transmit current level and on-chip termination

impedance.

XI/XO Input N/A External crystal. 12MHz crystal connected from XI to XO.

Table 5 Power and Ground Pins

NAME DIRECTION

ACTIVE

LEVEL DESCRIPTION

VDD3.3 N/A N/A 3.3V Digital Supply. Powers digital pads. See Note 2.1

VDD1.8 N/A N/A 1.8V Digital Supply. Powers digital core.

VSS N/A N/A Digital Ground. See Note 2.2

VDDA3.3 N/A N/A 3.3V Analog Supply. Powers analog I/O and 3.3V analog

circuitry.

VDDA1.8 N/A N/A 1.8V Analog Supply. Powers 1.8V analog circuitry. See Note 2.1

VSSA N/A N/A Analog Ground. See Note 2.2

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Smsc USB3250 Manual de usuario Pagina 7