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

(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