USB2640I Standard Microsystems Corp., USB2640I Datasheet - Page 20

• Manufacturer Part Number: USB2640I
• Description: Industrial Temperature Usb 2.0 Flash Media Controller And Usb Hub Combo
• Manufacturer: Standard Microsystems Corp.

Revision 2.0 (10-03-08)
USB Power
Enable
Detect Upstream
VBUS Power
USB Transceiver
Bias
Crystal
Input/External
Clock Input
Crystal
Output
1.8V PLL Power
Bypass
3.3V Analog
Power
SPI Chip Enable
NAME
PRTCTL[3:2]
VBUS_DET
VDD18PLL
SPI_CE_N
SYMBOL
VDDA33
(CLKIN)
RBIAS
XTAL1
XTAL2
Table 6.1 USB2640i/USB2641i Pin Descriptions (continued)
48-PIN
QFN
39
47
45
44
46
41
48
7
6
5
8
Industrial Temperature USB 2.0 Flash Media Controller and USB Hub Combo
DATASHEET
SPI INTERFACE
I/OD12PU
BUFFER
OCLKx
ICLKx
TYPE
O12
I-R
I
20
DESCRIPTION
As an output, these pins enables power
downstream USB peripheral devices. See
6.3, "Port Power Control"
instructions.
As an input, when the power is enabled, these
pins monitor the over-current condition. When an
over-current condition is detected, the pins turn the
power off.
Detects the state of upstream VBUS power. The
Hub monitors VBUS_DET to determine when to
assert the internal D+ pull-up resistor (signaling a
connect event).
When designing a detachable hub, connect this
pin to the VBUS power pin of the USB port that is
upstream of the Hub.
For self-powered applications with a permanently
attached host, this pin should be pulled up,
typically to VDD33.
VBUS is a 3.3V input. A resistor divider must be
used when connecting to 5V USB power.
A 12.0 k
to this pin in order to set the transceiver's internal
bias currents.
24 MHz Crystal or external clock input.
This pin can be connected to one terminal of the
crystal or it can be connected to an external
24MHz clock when a crystal is not used.
24 MHz Crystal.
This is the other terminal of the crystal, or it is left
open when an external clock source is used to
drive XTAL1(CLKIN).
Note:
This pin is the 1.8V Power bypass for the PLL.
This requires an external bypass capacitor of 1.0
μF minimum.
3.3V Analog Power
This is the active low chip enable output.
If the SPI interface is enabled, this pin must be
driven high in power down states.
Ω
Do not use it to drive any external
circuitry other than the crystal circuit.
,
±
1.0% resistor is attached from VSSA
for diagram and usage
SMSC USB2640i/USB2641i
Section