ltc2978 Linear Technology Corporation, ltc2978 Datasheet - Page 54

• Manufacturer Part Number: ltc2978
• Description: Octal Pmbus Power Supply Monitor And Controller With Eeprom
• Manufacturer: Linear Technology Corporation

Interconnect Between Multiple LTC2978s
Figure 14 shows how to interconnect the pins in a typical
multi-LTC2978 array.
• All V
• Connecting all V
LTC2978
applicaTions inForMaTion

connection at the point where V
This will minimize timing errors for the case where the
ON_OFF_CONFIG is configured to start the LTC2978
based on V
OPERATION command. In multi-part applications that
are sensitive to timing errors, it is recommended that
the Vin_share_enable bit of the MFR_CONFIG_ALL
register be set high in order to allow SHARE_CLK to
synchronize on/off sequencing in response to the V
and V
overvoltage (OV) fault on any DC/DC converter’s output
in the array to shut off a common input switch.
IN_SNS
IN_OFF
IN
lines should be tied together in a star type
thresholds.
and ignore the CONTROLn line and the
IN_EN
lines together will allow an
LTC2978 1
Figure 14. Typical Connections Between Multiple LTC2978s
SHARE_CLK
WDI/RESET
CONTROL0
CONTROL1
GND
FAULTB00
FAULTB01
FAULTB10
FAULTB11
VIN_SNS
ALERTB
PWRGD
IN
VIN_EN
SDA
SCL
is to be sensed.
TO OTHER LTC2978s–10k EQUIV PULL-UP RECOMMENDED
TO V
ON EACH LINE EXCEPT SHARE_CLK (USE 5.49k)
DC/DCs
IN
OF
TO HOST CONTROLLER
IN_ON
• ALERTB is typically one line in an array of PMBus
• WDI/RESET can be used to put the LTC2978 in the
• The FAULTBzn lines can be connected together to create
• PWRGD reflects the status of the outputs that are
converters. The LTC2978 allows a rich combination of
faults and warnings to be propagated to the ALERTB
pin.
power-on reset state. Pull WDI/RESET low for at least
t
fault dependencies. Figure 14 shows a configuration
where a fault on any FAULTBzn will pull all others low.
This is useful for arrays where it is desired to abort a
startup sequence in the event any channel does not
come up (see Figure 15).
mapped to it by the MFR_PWRGD_EN command. Fig-
ure 14 shows all the PWRGD pins connected together,
but any combination may be used.
RESETB
TO INPUT
SWITCH
to enter this state.
VIN_SNS
VIN_EN
SDA
SCL
ALERTB
CONTROL0
CONTROL1
WDI/RESET
FAULTB00
FAULTB01
FAULTB10
FAULTB11
SHARE_CLK
PWRGD
LTC2978 #n
GND
2978 F14
2978fa