TET2000 Series

13

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BCD.00877_AB

SMB_ALERT_L output

Output low level voltage

0

0.4

V

Output open collector

External pull up VDD

V

Recommended external pull up

resistor on SMB_ALERT_L at

10

k

Ω

Low level output

PSU in warning or failure

condition

High level output

PSU is ok

PRESENT_L output

Output low level voltage

0

0.4

V

N.A

This pin is shorted to SGND in PSU

V

Recommended external pull up

resistor on PRESENT_L at

10

k

Ω

Low level output

PSU is present

High level output

PSU is not present

Table 4. Output signals

8.2.1 PWOK

PWOK is a power OK signal and will be pulled HIGH by the power supply to indicate that all the outputs are within the regulation

limits of the power supply. When any output voltage falls below regulation limits or when AC power has been removed for a time

sufficiently long so that power supply operation is no longer guaranteed, PWOK will be de-asserted to a LOW state.

Figure 27. PWOK circuit in PSU

8.2.2 ACOK

The ACOK is an open collector output that requires an external pull-up to a maximum of 12V indicating whether the input is within

the range the power supply can use and turn on. A 15V zener diode is added on this signal pin versus signal ground SGND to

protect internal circuits from negative and high positive voltage. The ACOK signal is active-high.

PSU 1 PDU

PSU 2

ACOK0

≥1kΩ

3.3V

ACOK1

≥1kΩ

3.3V

Figure 28. ACOK Connection