Linear Technology LTC2977 Demo Board: Octal Power Supply Manager [Requires DC1613] DC2028A DC2028A Data Sheet

LTC2977

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MFR_STATUS_2
This command returns additional manufacturer specific fault and state information. Bits marked Sticky = Yes are set 

by the appropriate event and not cleared until the user issues a CLEAR_FAULTS command or turns the channel back 

on. Bits marked ALERT = Yes assert ALERTB low when they are set. Bits marked Channel = All are not paged.

b[15:3] Reserved

Read only, always returns 0s.

b[2]

Mfr_status_2_short_cycle_fault 1: This channel was commanded on by user before it finished sequencing off.

0: No short cycle fault has occurred for this channel.

Yes

Yes

Current 

Page

b[1]

Mfr_status_2_vinen_drive

1: VIN_EN pad is being driven low by this chip.
0: VIN_EN pad is not being driven low by this chip.

No

No

All

b[0]

Mfr_status_2_vin_caused_off

1: This channel was turned off due to VIN_SNS dropping below the VIN_OFF 

threshold.
0: VIN_SNS has not caused this channel to turn off.

Yes

No

Current 

Page

Short cycle fault detection is used to prevent out-of-order on sequencing when the user issues an ON command too 

soon after an OFF command. If some channels are still finishing OFF delays when the early ON command is received, 

they might turn back on too late. This fault should be propagated to all channels in the sequence to ensure a clean 

ON sequence. When a channel detects a short cycle fault it sets Mfr_status_2_short_cycle_fault, Status_word_mfr, 

Status_word_high_byte, and pulls ALERTB low. It also faults off, and stays off until the user issues an OFF-THEN-ON 

sequence or resets the part. Fault retries are not supported for short cycle faults.
Mfr_status_2_vinen_drive indicates the current status of this chip’s VIN_EN pad driver. It is not affected by CLEAR_

FAULTS commands, and no other status bits are affected when it is set.
Mfr_status_2_vin_caused_off indicates that this channel was turned off because VIN_SNS dropped below the VIN_OFF 

threshold. Status_word_mfr and Status_word_high_byte are set at the same time, but ALERTB is not asserted. If 

VIN_SNS subsequently rises above VIN_ON, and this channel turns back on, Mfr_status_2_vin_caused_off will remain 

asserted to record the transient event regardless of the value of Mfr_config_all_vin_on_clr_faults_en.