Datasheet

LTC2974
62
2974fc
For more information www.linear.com/LTC2974
STATUS_WORD
The STATUS_WORD command returns two bytes of information with a summary of the unit’s fault condition. Based on
the information in these bytes, the host can get more information by reading the appropriate detailed status register.
The low byte of the STATUS_WORD is the same register as the STATUS_BYTE command.
STATUS_WORD Data Contents
BIT(S) SYMBOL OPERATION
b[15] Status_word_vout An output voltage fault or warning has occurred. See STATUS_VOUT.
b[14] Status_word_iout An output current fault or warning has occurred. See STATUS_IOUT.
b[13] Status_word_input An input voltage fault or warning has occurred. See STATUS_INPUT.
b[12] Status_word_mfr A manufacturer specific fault has occurred. See STATUS_MFR._SPECIFIC.
b[11] Status_word_power_not_good The PWRGD pin, if enabled, is negated. Power is not good.
b[10] Status_word_fans Not supported. Always
returns 0.
b[9] Status_word_other Not supported. Always
returns 0.
b[8] Status_word_unknown Not supported. Always
returns 0.
b[7] Status_word_busy Device busy when PMBus command received. See OPERATION: Processing Commands.
b[6] Status_word_off This bit is asserted if the unit is not providing power to the output, regardless of the reason, including simply
not being enabled. The off-bit is clear if unit is allowed to provide power to the output.
b[5] Status_word_vout_ov
An output overvoltage fault has occurred.
b[4] Status_word_iout_oc An output overcurrent fault has occurred.
b[3] Status_word_vin_uv A V
IN
undervoltage fault has occurred.
b[2] Status_word_temp A temperature fault or warning has occurred. See STATUS_TEMPERATURE.
b[1] Status_word_cml A communication, memory or logic fault has occurred. See STATUS_CML.
b[0] Status_word_high_byte A fault/warning not listed in b[7:1] has occurred.
STATUS_VOUT
The STATUS_VOUT command returns the summary of the output voltage faults or warnings which have occurred, as
shown in the following table:
STATUS_VOUT Data Contents
BIT(S) SYMBOL OPERATION
b[7] Status_vout_ov_fault Overvoltage fault.
b[6] Status_vout_ov_warn Overvoltage warning.
b[5] Status_vout_uv_warn Undervoltage warning
b[4] Status_vout_uv_fault Undervoltage fault.
b[3] Status_vout_max_fault VOUT_MAX fault. An attempt has been made to set the output voltage to a value higher than allowed by the
VOUT_MAX command. After being cleared, Status_vout_max_fault will not report additional faults until a channel
state transition (off-then-on) has been performed or a valid output voltage, lower than allowed by VOUT_MAX, has
been set.
b[2] Status_vout_ton_max_fault TON_MAX_FAULT sequencing fault.
b[1] Status_vout_toff_max_warn Not supported. Always returns 0.
b[0] Status_vout_tracking_error Not supported. Always returns 0.
pMbus coMManD DescripTion