MAX34446_12 Datasheet, PDF (33/36 Pages) Maxim Integrated Products – PMBus Power-Supply Data Logger

MAX34446
PMBus Power-Supply Data Logger
MFR_TIME_COUNT (DDh)
The MFR_TIME_COUNT command returns the number of seconds of device lifetime operation. Once every hour, the
device automatically stores this counter in flash memory. Also, the falling edge of the ENABLE input causes the device
to attempt to store MFR_TIME_COUNT into flash memory as long as V_DD is above 2.9V. The counter is a 32-bit value
that rolls over. The latest stored value is automatically recalled from flash memory upon device power cycle, RST action,
or a soft reset. This count can be reset to zero by writing a sequence of all zeros (00000000h), followed by all ones
(FFFFFFFFh), followed by all zeros (00000000h) within 8ms.
MFR_POUT_PEAK (E0h)
The MFR_POUT_PEAK command returns the maximum calculated power. To reset this value to zero, write to this com-
mand with a data value of zero. The 2 data bytes are in DIRECT format. When the ENABLE pin goes low or the channel
is disabled, this command resets to 0000h.
MFR_POUT_AVG (E1h)
The MFR_POUT_AVG command returns the calculated average power. To reset the average, write to this command
with a data value of zero. Any other values written by this command are ignored. The 2 data bytes are in DIRECT format.
When the ENABLE pin goes low or the channel is disabled, this command resets to 0000h.
MFR_IOUT_AVG (E2h)
The MFR_IOUT_AVG command returns the calculated average current. To reset the average, write to this command
with a data value of zero. Any other values written by this command are ignored. The 2 data bytes are in DIRECT format.
When the ENABLE pin goes low or the channel is disabled, this command resets to 0000h.
MFR_TEMPERATURE_AVG (E3h)
The MFR_TEMPERATURE_AVG command returns the calculated average temperature. To reset the average, write to
this command with a data value of zero. Any other values written by this command are ignored. The 2 data bytes are in
DIRECT format. When the ENABLE pin goes low or the channel is disabled, this command resets to 0000h.
MFR_SYNC_CONFIG (EFh)
The MFR_SYNC_CONFIG command determines the action of the SYNC output. The SYNC output can be programmed
with the MFR_SYNC_CONFIG command to switch between two frequencies depending on the power-good state.
MFR_SYNC_CONFIG is a 2-byte command. The MSB contains the SYNC frequency when all voltage channels have
reached a power-good state. The LSB contains the SYNC frequency when any of the voltage channels is not in a power-
good state. The format for the LSB and MSB to set the SYNC frequency is an integer between 8 and 200 (inclusive). The
programmed integer is divided into the 4MHz on-board system oscillator to create the SYNC frequency.
As shown in Table 20, if MFR_SYNC_CONFIG was programmed as 19C8h, then the SYNC output would be 160kHz
in a power-good state and 20kHz when any of the voltage channels are not in a power-good state. If either byte of
MFR_SYNC_CONFIG is set to 00h, the SYNC output is forced to high impedance during the respective power-good
state. It is acceptable to have both the MSB and the LSB programmed to the same frequency, which eliminates the
frequency dependency on the state of power good. See Figure 3 for more timing details.
Table 20. MFR_SYNC_CONFIG Examples
MFR_SYNC_CONFIG
MSB OR LSB VALUE (HEX)
08h
19h
7Dh
C8h
SYSTEM OSCILLATOR
(MHz)
4
4
4
4
DIVIDE INTEGER
(DECIMAL)
8
25
125
200
SYNC FREQUENCY
(SYSTEM OSCILLATOR/INTEGER)
(kHz)
500
160
32
20
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