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PowerUp/DownTime(ms)Options
PowerUp/DownTime(ms)Options
ItispossibletoselecttheV
COM
rampup/downtimefromGNDleveltoacommonvoltagelevelor
vice-versabychoosingaV
COM
capacitorvalueandtimebychoosingoneoftheavailablecheckboxes.A
4.7μFV
COM
capacitorischosenasthedefaultsetting(thiscapacitorisalsomountedontheEVM).
The4.7μFV
COM
capacitoristherecommendedvalueforoperatingtheEVM.Thisconfigurationisthe
recommendedpower-onsequencediscussedintheproductdatasheet.
ToselectadifferentV
COM
value,choosetheappropriatevaluefromtheV
COM
capacitordrop-downmenu.
BesuretochangethecapacitorontheEVMtothesamevalue(1.0μF,2.2μFor10μF).
ThecombinationofPTM[1:0]andRES[4:0]determinestheV
COM
rampup/downtime,asdescribedin
Table3-2andTable3-3.
Tosettherampupordowntimewithoutdirectlyaccessingtheregisters,userscanselectaV
COM
capacitorvalueandtimeinthegroupbox.Therampupwaveformwiththedefaultsettingisshownin
Figure3-5,andtherampdownwaveforminFigure3-6,asreferences.
Table3-2.PCM3793A/94AResistor125(7dh)
RES[4:0]:ResistorValueControl
RES[4:0]V
COM
ResistorValue
1000060kΩ
1100024kΩ
1110012kΩ
111106kΩ
OthersReserved
Table3-3.PCM3793A/94AResistor125(7dh)PMT[1:0]:PowerUp/DownTimeControland
RegisterDirectAccess
V
COM
CapacitorPower-UpTimePower-DownTimeRegisterDirect
[μF]RES[4:0]PTM[1:0][ms][ms]Access
1011110004507500x7D1E
111001190015000x7D7C
11000Donotset———
10000Donotset———
4.711110012504000x7D3E
11100004507500x7D1C(default)
110001190015000x7D78
10000Donotset———
2.211110101003000x7D5E
11100012504000x7D3C
11000004507500x7D18
100001190015000x7D70
1.011110Donotset———
11100101003000x7D5C
11000012504000x7D38
10000004507500x7D10
SBAU127–July2007Set-UpGuide25
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