USB 2.0 High-Speed 2-Port Hub Controller

Datasheet

SMSC USB2512

8

Revision 1.92 (11-28-07)

DATASHEET

Chapter 3 Pin Descriptions

3.1

PIN Descriptions

This section provides a detailed description of each signal. The signals are arranged in functional

groups according to their associated interface.

The “N” symbol in the signal name indicates that the active, or asserted, state occurs when the signal

is at a low voltage level. When “N” is not present before the signal name, the signal is asserted when

at the high voltage level.

The terms assertion and negation are used exclusively. This is done to avoid confusion when working

with a mixture of “active low” and “active high” signals. The term assert, or assertion, indicates that a

signal is active, independent of whether that level is represented by a high or low voltage. The term

negate, or negation, indicates that a signal is inactive.

Table 3.1 USB2512 Pin Descriptions

SYMBOL

QFN-36

EMB

BUFFER

TYPE

DESCRIPTION

UPSTREAM USB INTERFACES

USBUP_DP

USBUP_DM

31

30

IO-U

USB Bus Data

These pins connect to the upstream USB bus data signals

(Host port, or upstream hub).

VBUS_DET

27

I/O12

Detect Upstream VBUS Power

Detects state of Upstream VBUS power. The SMSC Hub

monitors VBUS_DET to determine when to assert the internal

D+ pull-up resistor (signaling a connect event).

When designing a detachable hub, this pin must be connected

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 must be connected to 3.3V (typically VDD33).

DOWNSTREAM 2-PORT USB 2.0 INTERFACE

USBDN_DP[2:1]/

&

USBDN_DM[2:1]/

4

2

IO-U

High-Speed USB Data

These pins connect to the downstream USB peripheral devices

attached to the hub’s port.

3

1

PRTPWR[2:1]

16

12

O12

USB Power Enable

Enables power to USB peripheral devices downstream.

Note: The hub supports active high power controllers only!

OCS[2:1]_N

17

13

IPU

Over Current Sense

Input from external current monitor indicating an over-current

condition.

{Note: Contains internal pull-up to 3.3V supply}

RBIAS

35

I-R

USB Transceiver Bias

A 12.0k

to set the transceiver’s internal bias settings.