ltc2978 Linear Technology Corporation, ltc2978 Datasheet - Page 27

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

Input Voltage Related Commands
VIN_ON, VIN_OFF , VIN_OV_FAULT_LIMIT, VIN_OV_
WARN_LIMIT, VIN_UV_WARN_LIMIT and VIN_UV_
FAULT_LIMIT
These commands use the same format and provide voltage
supervising limits for VIN.
Data Contents
Temperature Related Commands
OT_FAULT_LIMIT, OT_WARN_LIMIT, UT_WARN_LIMIT
and UT_FAULT_LIMIT
These commands provide supervising limits for tem-
perature.
Data Contents
Timer Limits
TON_DELAY , TON_RISE, TON_MAX_FAULT_LIMIT and
TOFF_DELAY
These commands share the same format and provide
sequencing and timer fault and warning delays in ms.
operaTion
b[15:0] Vin_on[15:0],
b[15:0] Ot_fault_limit[15:0],
BIT(S) SYMBOL
BIT(S) SYMBOL
Ot_warn_limit[15:0],
Ut_warn_limit[15:0],
Ut_fault_limit[15:0]
Vin_off[15:0],
Vin_ov_fault_limit[15:0],
Vin_ov_warn_limit[15:0],
Vin_uv_warn_limit[15:0],
Vin_uv_fault_limit[15:0]
OPERATION
The data uses the linear format:
T(Symbol) = Y • 2
where N = b[15:11] is a 5-bit two’s
complement integer and
Y = b[10:0] is an 11-bit two’s
complement integer
Units: °C.
OPERATION
These commands relate to input
voltage. The data uses the linear
format:
V(Symbol) = Y • 2
where N = b[15:11] is a 5-bit
two’s complement integer and
Y = b[10:0] is an 11-bit two’s
complement integer
Units: V.
N
N
TON_DELAY is the amount time in ms that elapses after
the channel has been allowed on (usually due to CON-
TROLn pin or OPERATION command) until the channel
enables the power supply. This delay is counted using
SHARE_CLK only.
TON_RISE is the amount of time in ms that elapses after
the power supply has been enabled until the LTC2978’s
voltage buffered current DAC soft connects and servo’s
the output voltage to the desired level if Mfr_dac_mode =
2’b00. This delay is counted using SHARE_CLK only.
TON_MAX_FAULT_LIMIT is the maximum amount of time
that can elapse after the power supply has been enabled
until the LTC2978 unmasks the VOUT_UV_FAULT_LIMIT
threshold. (Note that a value of zero means there is no limit
to how long the power supply can attempt to bring up its
output voltage.) This delay is counted using SHARE_CLK
only.
TOFF_DELAY is the amount of time that elapses after the
CONTROLn pin and/or OPERATION command is deas-
serted until the channel is disabled (soft-off). This delay
is counted using SHARE_CLK if available, otherwise the
internal oscillator is used.
Data Contents
b[15:0] Ton_delay[15:0],
BIT(S) SYMBOL
Ton_rise[15:0],
Ton_max_fault_limit[15:0],
Toff_delay[15:0],
OPERATION
The data uses the linear format:
T(Symbol) = Y • 2
Where N = b[15:11] is a 5-bit
two’s complement integer and
Y = b[10:0] is an 11-bit two’s
complement integer
The internal timers operate
on a 10µs internal clock. The
SHARE_CLK pin may be used to
synchronize the 10µs timer.
Delays are rounded to the nearest
10µs
Units: ms. Max value: 655ms
LTC2978
N

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