Ultra Fast USB 2.0 SD/MMC Flash Media Controller
Datasheet
Revision 1.0 (05-27-08)
12
SMSC USB2244/USB2244i
DATASHEET
5.2
Buffer Type Descriptions
TEST Input
TEST
28
I
This signal is used for testing the chip. User
should normally tie this pin low externally if the
test function is not used.
No Connects
NC
No Connect. No trace or signal should be
routed/attached to these pins.
DIGITAL / POWER
+1.8V Core
power
VDD18
13
All VDD18 pins must be connected together on
the circuit board.
+1.8V core power. This pin must have a 1.0
μ
F
(or greater) ±20% (ESR <0.1
Ω
) capacitor to
VSS.
3.3V Power &
Regulator Input.
VDD33
6
14
22
3.3V Power & Regulator Input.
Ground
VSS
SLUG
Ground Reference
Table 5.3 USB2244/USB2244i Buffer Type Descriptions
BUFFER
DESCRIPTION
I
Input.
IS
Input with Schmitt trigger.
I/O12
Input/Output buffer with 12mA sink and 12mA source.
I/O200
Input/Output buffer 12mA with FET disabled, 100/200mA source only when the FET is
enabled.
I/O12PU
Input/Output buffer with 12mA sink and 12mA source with a pull-up resistor.
O12
Output buffer with 12mA source.
ICLKx
XTAL clock input.
OCLKx
XTAL clock output.
I/O-U
Analog Input/Output Defined in USB specification.
I-R
RBIAS.
Table 5.2 USB2244/2244i 36-Pin QFN Pin Descriptions (continued)
NAME
SYMBOL
36-PIN
QFN
BUFFER
TYPE
DESCRIPTION
