Datasheet
LTC2974
39
2974fc
For more information www.linear.com/LTC2974
pMbus coMManD DescripTion
The following example illustrates configuring an LTC2974 with one master channel and three slaves.
Master channel 0
TON_DELAY = Ton_delay_master
TON_RISE = Ton_rise_master
TOFF_DELAY = Toff_delay_master
Mfr_track_en_chan0 = 0
Slave channel n
TON_DELAY = Ton_delay_slave
TON_RISE = Ton_delay_master + Ton_rise_slave
TOFF_DELAY = Toff_delay_master + T_off_delay_slave
Mfr_track_en_chan0 = 1
Where:
Ton_delay_master – Ton_delay_slave > RUN to TRACK setup time
Toff_delay_slave > time for master supply to fall.
The system response to a control pin toggle is illustrated in Figure 18.
The system response to a UV fault on a slave channel is illustrated in Figure 19.
MFR_CONFIG_ALL_LTC2974
This command is used to configure parameters that are common to all channels on the IC. They may be set or reviewed
from any PAGE setting.
MFR_CONFIG_ALL_LTC2974 Data Contents
BIT(S) SYMBOL OPERATION
b[15:12] Reserved Don’t care. Always returns 0.
b[11] Mfr_config_all_pwrgd_off_uses_uv Selects PWRGD de-assertion source for all channels.
0: PWRGD is de-asserted based on V
OUT
being below or equal to POWER_GOOD_OFF. This option
uses the ADC. Response time is approximately 100ms to 200ms.
1: PWRGD is de-asserted based on V
OUT
being below or equal to VOUT_UV_LIMIT. This option uses
the high speed supervisor. Response time is approximately 12µs.
b[10] Mfr_config_all_fast_fault_log Controls number of ADC readings completed before transferring fault log memory to EEPROM.
0: All ADC telemetry values will be updated before transferring fault log to EEPROM. Slower.
1: Telemetry values will be transferred from fault log to EEPROM within 24ms after detecting fault.
Faster.
b[9] Mfr_config_all_control3_pol Selects active polarity of CONTROL3 pin
0: Active low (pull pin low to start unit).
1: Active high (pull pin high to start unit).
b[8] Mfr_config_all_control2_pol Selects active polarity of CONTROL2 pin
0: Active low (pull pin low to start unit).
1: Active high (pull pin high to start unit).