SMSC USB2502 Manuel D’Utilisation

2-Port USB 2.0 Hub Controller

Revision 2.3 (08-27-07)

14

SMSC USB2502

Analog Test

&

Internal 1.8V 

voltage 

regulator 

enable

ATEST/

REG_EN

AIO

This signal is used for testing the analog section of the 
chip, and to enable or disable the internal 1.8v regulator. 

This pin must be connected to VDDA33 to enable the 
internal 1.8V regulator, or to VSS to disable the internal 
regulator.

When the internal regulator is enabled, the 1.8V power 
pins must be left unconnected, except for the required 
bypass capacitors.When the PHY is in test mode, the 
internal regulator is disabled and the ATEST pin 
functions as a test pin.

VDDCORE3P3

VDD33CR

+3.3V I/O Power.

If the internal core 1.8V regulator is enabled, then this pin 
acts as the regulator input

VDD1P8

VDD18

+1.8V core power.

If the internal regulator is enabled, then VDD18 pin 27 
must have a 4.7

μ

F (or greater) ±20% (ESR <0.1

Ω) 

capacitor to VSS

VDDAPLL3P3

VDDA33PLL

+3.3V Filtered analog power for the internal PLL

If the internal PLL 1.8V regulator is enabled, then this pin 
acts as the regulator input

VDDAPLL1P8

VDDA18PLL

+1.8V Filtered analog power for internal PLL.

If the internal regulator is enabled, then this pin must 
have a 4.7

μ

F (or greater) ±20% (ESR <0.1

Ω) 

capacitor 

to VSS

VDDA3P3

VDDA33

+3.3V Filtered analog power.

VSS

VSS

Ground.

I

Input.

IPD

Input, with a weak Internal pull-down.

IPU

Input, with a weak Internal pull-up.

IS

Input with Schmitt trigger.

I/O8

Input/Output 8mA

O8

Output 8mA