Datasheet

OUTPUT EQUATIONS
IFB = (V
OUT
)/(R1+R2)
DS4424RFS=(7.75)/(I
FB
x margining range)
DS4424fullscale=(0.976x127)/(16xR
FS
)
DS4424 step size = full scale/64
MAX34460 Evaluation Kit
Evaluates: MAX34460
5Maxim Integrated
Sequencing Graph Tab
The Sequencing Graph tab sheet (Figure 2) displays the
timingdiagramsforallthechannels.WhenthePower Up
radio button is selected, the TON Delay
(TON_DELAY
60h) and TON Max (TON_MAX_FAULT_LIMIT 62h) val-
ues are displayed on the graph. To change the TON
Delay, click and drag the green vertical bar; to change
TON Max, click and drag the red vertical bar. The Power
Down graph displays the TOFF Delay
 (TOFF_DELAY
64h) and can be changed by clicking and dragging
the green vertical bar. These values write to the PMBus
command when the mouse is released. The Power
Up graph can be changed to PMBus (time-based) or
Timeslot (event-based) by selecting the option on the
Sequencing tab (Figure 1
). When Timeslot (event-
based) is selected, the power-up graph allows the
Timeslot
 (MFR_SEQ_TIMSLOT D3h) to bechanged by
clicking and dragging the ramp.
Monitoring Tab
The Monitoring tab sheet (Figure 3) displays the fault/
warn limit settings for each channel and for each tem-
perature sensor. To read the settings, click on the
Monitoring tab and all the values are automatically read.
To write to a value, click on the corresponding cell, type in
a valid value, and either click another cell or press Enter
on the keyboard. In the VOLTAGE table, the Sequencer
column shows the status of the channel and is read
only. To turn on or off the sequencer, select a PSEN
or GPO option, respectively, on the Sequencing tab
(Figure 1) under the Output Type column. The Nominal
and Resistive Ratio columns are calculated based on
a nominal ADC level of 1.8V to set the VOUT_SCALE_
MONITOR(2Ah).TheResistive Ratio is found by divid-
ing 1.8V by the Nominal value. The fault/warn limits can
be set by entering the voltage level or the percent of
the nominal in the UV Fault (VOUT_UV_FAULT_LIMIT
44h), UV Warn
(VOUT_UV_WARN_LIMIT43h),OV Warn
(VOUT_OV_WARN_LIMIT 42h), OV Fault (VOUT_OV_
FAULT_LIMIT 40h), PG On
 (POWER_GOOD_ON 5Eh),
and PG Off (POWER_GOOD_OFF 5Fh) columns. The
Fault Response column writes to the OV and UV fault
responsebitsinMFR_FAULT_RESPONSE(D9h).Towrite
totheOTfaultresponsebitsinMFR_FAULT_RESPONSE
(D9h), check the checkbox in the OT Fault column and it
sets the same response selected in the Fault Response
column. To log faults into the NV fault log, check the
checkbox in the Log Faults
 column to write to MFR_
FAULT_REPSPONSE (D9h). In the TEMPERATURE
table, the sensors can be enable/disabled in the Enable
column, which writes to a bit in MFR_TEMP_SENSOR_
CONFIG (F0h). The OT warn/fault limits can be set by
entering a value in the OT Warn
(OT_WARN_LIMIT51h)
or OT Fault (OT_FAULT_LIMIT 4Fh) columns.
The power-good delay can be adjusted with the PG
Delay up/down spin box, which writes to MFR_PG_
DELAY (DBh). The Watchdog Configuration section
sets up the external watchdog and reads/writes to bits in
MFR_WATCHDOG_CONFIG(FDh).
Margining Tab
The Margining tab sheet (Figure 4) includes the margin
configurations, margin fault status, and a DAC calcula-
tor for the DS4424. All values on the tab are read when
the tab is selected. The Margin column turns the margin
on/off by writing to the OPERATION (01h) command.
To force all the channels to the same margin, select
the state in the Margin All Control drop-down list to
the right of the table. The Slope, Open Loop, and DAC
Value columns configure the DS4424 and are read from
bitsintheMFR_MARGIN_CONFIG(DFh)command.The
margining limits can be set by entering the voltage level
or the percent of the nominal in the Margin Low (VOUT_
MARGIN_LOW26h)andMargin High(VOUT_MARGIN_
HIGH 25h) columns. When the margining is turned on,
the fault status is shown in the Status column read from
STATUS_MFR_SPECIFIC(80h).ThePolled column dis-
playsthecurrentchannelvoltagereadfromREAD_VOUT
(8Bh). To read the Status and Polled values, press the
Read Status and Vout button or turn on Auto Polling.
The margin fault can be cleared by pressing the Clear
Faults button on the Status tab (Figure 5).
The Calculator is used to find the DS4424 external resis-
tor(R
FS
), which determines the full-scale and step-size
currentfortheDAC.IfR
FS
is calculated to be outside its
limits (40kI
<R
FS
< 160kI), then the resistor is forced
to the edge of the limit and the DS4424 RFS edit box
turns red. The equations used to calculate the outputs
are given in Table 1.
Table 1. DAC Calculator