20H04 Datasheet, PDF (14/38 Pages) SMSC Corporation – 4-PORT USB2.0 HUB CONTROLLER

NAME
RBIAS
XTAL1/CLKIN
XTAL2
CLKIN_EN
4-Port USB2.0 Hub Controller
Datasheet
Table 4.4 - Biasing and Clock Oscillator Signals
BUFFER
TYPE
I-R
ICLKx
OCLKx
I
ACTIVE
LEVEL
DESCRIPTION
N/A External 1% bias resistor. Requires a 12KΩ resistor to ground. Used for
setting HS transmit current level and on-chip termination impedance.
N/A External crystal. 24MHz crystal or external clock input when a crystal is not
used.
Connect a 5M ohm resistor from this pin to XTAL2 when a crystal is used.
N/A External crystal. 24MHz crystal. Not connected when using an external clock.
High Clock Input Enable. When high, an external CMOS clock drives XTAL1.
NAME
VDD3.3
VDD1.8
VSS
VDDA3.3
VDDA1.8
Table 4.5 - Power and Ground Signals
BUFFER
TYPE
N/A
N/A
N/A
N/A
N/A
ACTIVE
LEVEL
DESCRIPTION
N/A 3.3V Digital Supply. Powers digital pads.
N/A 1.8V Digital Supply. Powers digital core.
N/A Signal Ground.
N/A 3.3V Analog Supply. Powers analog I/O and 3.3V analog circuitry.
N/A 1.8V Analog Supply. Powers 1.8V analog circuitry.
4.2 Buffer Type Descriptions
Table 4.6 – USB20H04 Buffer Type Descriptions
BUFFER
I
IPU
IPD
IS
IO8
IOSD12
O8
OD8
ICLKx
OCLKx
IO-U
AO
I-R
DESCRIPTION
Input
Input with weak internal pull-up resistor.
Input with weak internal pull-down resistor
Input with Schmitt trigger
Input/Output with 8mA drive
Open drain with 12mA sink with Schmitt
trigger. Meets I2C-Bus Spec Version 2.1
Output with 8mA drive
Open drain with 8mA sink
XTAL clock input
XTAL clock output
Defined in USB specification
Analog Output
3.3V Tolerant Analog Pin
Revision 1.63 (10-14-04)
Page 14
DATASHEET
SMSC USB20H04