SMSC USB2250 User Manual

Ultra Fast USB 2.0 Multi-Slot Flash Media Controller

SMSC USB2250/50i/51/51i

29

Revision 1.1 (05-29-08)

When powering the device, the maximum power supply ramp time should be set at a rate
faster than 400

μs. This speed is important to ensure that the device resets properly.

Measure rise time at 10% and 90%.

A 3.3V regulator with an output tolerance of 1% must be used if the output of the internal
power FET’s must support a 5% tolerance.

Commercial Part 

Industrial Part

T

A

T

A

0

-40

70

85

°C

°C

3.3V supply voltage

V

DD33, 

V

DDA33

3.0

3.6

V

(

3.3V supply rise time

t

RT

0

400

μs (See 

 and 

)

Voltage on 
USB+ and USB- pins

-0.3

5.5

V

If any 3.3V supply voltage drops 
below 3.0V, then the MAX 
becomes:

(3.3V supply voltage) + 0.5 

≤ 5.5

Voltage on any signal 
pin

-0.3

V

DD33

V

Voltage on XTAL1 

-0.3

V

DDA33

V

Voltage on XTAL2

-0.3

V

DD18

V

t

10%

10%

90%

Voltage

t

RT

t

90%

Time

100%

3.3V

VSS

VDD33