USB2512 datasheet(21/63 Pages) MICROCHIP

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USB 2.0 Hi-Speed Hub Controller

Datasheet

SMSC USB251xB/xBi

Revision 2.2 (02-17-12)

DATASHEET

SUSP_IND/

I/O

Active/Suspend Status LED: indicates USB state of the hub.

Negated = unconfigured; or configured and in USB suspend

Asserted = hub is configured and is active (i.e., not in suspend)

LOCAL_PWR/

Local Power: detects availability of local self-power source.

Low = self/local power source is NOT available (i.e., the hub gets all power from

the upstream USB VBus)

High = self/local power source is available

NON_REM0

Non-Removable 0 Strap Option: when enabled by package and configuration

settings (see Table 5.1 on page 26), this pin will be sampled (in conjunction with

NON_REM[1]) at RESET_N negation to determine if ports [x:1] contain

permanently attached (non-removable) devices:

Note:

When implementing an external LED on this pin, the active state is

outlined below and detailed in Section 3.3.1.3, on page 23.

NON_REM[1:0] = 00 : all ports are removable; LED is active high

NON_REM[1:0] = 01 : port 1 is non-removable; LED is active low

NON_REM[1:0] = 10 : ports 1 and 2 are non-removable; LED is active high

NON_REM[1:0] = 11 : (when available) ports 1, 2, and 3 are non-removable;

LED is active low

TEST

IPD

Test Pin: treat as a no connect pin or connect to ground. No trace or signal

should be routed or attached to this pin.

POWER, GROUND, and NO CONNECTS

CRFILT

VDD Core Regulator Filter Capacitor: this pin can have up to a 0.1

μF low-ESR

capacitor to VSS, or be left unconnected.

VDD33

3.3 V Power

PLLFILT

PLL Regulator Filter Capacitor: this pin can have up to a 0.1

μF low-ESR

capacitor to VSS, or be left unconnected.

VSS

Ground Pad/ePad: the package slug is the only VSS for the device and must be

tied to ground with multiple vias.

No Connect: no signal or trace should be routed or attached to all NC pins.

Table 3.3 USB251xB/xBi Pin Descriptions (continued)

SYMBOL

BUFFER

TYPE

DESCRIPTION

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