LTC2978C View Datasheet(PDF) - Linear Technology

Part Name

Description

MFG CO.

LTC2978C

Octal PMBus Power Supply Monitor and Controller with EEPROM

Linear Technology 

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LTC2978

PMBus Command Description

Temperature Related Commands

OT_FAULT_LIMIT, OT_WARN_LIMIT, UT_WARN_LIMIT and UT_FAULT_LIMIT

These commands provide supervising limits for temperature.

Data Contents

BIT(S) SYMBOL

b[15:0] Ot_fault_limit[15:0],

Ot_warn_limit[15:0],

Ut_warn_limit[15:0],

Ut_fault_limit[15:0]

OPERATION

The data uses the L11 format.

Units: °C.

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.

TON_DELAY is the amount time in ms that elapses after the channel has been allowed on (usually due to CONTROLn 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 DAC

soft connects and servos the output voltage to the desired level if Mfr_dac_mode = 00b. This delay is counted using

SHARE_CLK only.

TON_MAX_FAULT_LIMIT is the maximum amount of time that the power supply being controlled by the LTC2978 can

attempt to power up the output without reaching the VOUT_UV_FAULT_LIMIT. If the output reaches VOUT_UV_FAULT_

LIMIT prior to TON_MAX_FAULT_LIMIT, the LTC2978 unmasks the VOUT_UV_FAULT_LIMIT threshold. If it does not,

then a TON_MAX_FAULT is declared. (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 deasserted

until the channel is disabled (soft-off). This delay is counted using SHARE_CLK if available, otherwise the internal

oscillator is used.

Data Contents

BIT(S) SYMBOL

OPERATION

b[15:0] Ton_delay[15:0],

The data uses the L11 format.

Ton_rise[15:0],

Ton_max_fault_limit[15:0],

Toff_delay[15:0],

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

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For more information www.linear.com/LTC2978

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