CY28401

Rev 1.0, November 21, 2006

Page 8 of 13

Output Enable Clarification

The OE function may be implemented in two ways, via writing

a ‘0’ to SMBus register bit corresponding to output of interest

or by asserting an OE input pin LOW. In both methods, if

SMBus registered bit has been written LOW or the OE pin is

LOW or both, the output of interest will be three-stated. (The

assertion and deassertion of this signal is absolutely

asynchronous.)

DIFC (Stoppable)

DIFC(Free Running

PWRDWN#

1mS

SRC_STOP#

DIFT (Stoppable)

DIFT(Free Running

Figure 5. SRC_STOP# =Driven, PWRDWN# = Three-state

DIFC (Stoppable)

DIFC(Free Running

DIFT(Free Running

PWRDWN#

1mS

SRC_STOP#

DIFT (Stoppable)

Figure 6. SRC_STOP# =Three-state, PWRDWN# = Driven

DIFC(Free Running

DIFT(Free Running

DIFT (Stoppable)

DIFC (Stoppable)

PWRDWN#

1mS

SRC_STOP#

Figure 7. SRC_STOP# =Three-state, PWRDWN# = Three-state

Table 6. OE Functionality

OE (Pin)#

OE (SMBus Bit)

DIFT

DIFC

1

1

Normal

Normal

1

0

Three-state

Low

0

1

Three-state

Low

0

0

Three-state

Low