元器件交易网

SGLS371–JANUARY2007

DEVICEINFORMATION(continued)

TERMINALFUNCTIONS

TERMINALNAMERC

NO.1

I/O

DESCRIPTION

Switchingfrequency-settingRCnetwork.ConnectcapacitorfromRCpintoGNDpinandresistorfromVINpintoRCpin.Thedevicemaybesynchronizedtoanexternalclockbyconnectinganopen-drainoutputtothispinandpullingittoGND.Thepulsewidthforsynchronizationshouldnotbeexcessive.

Soft-startprogrammingpin.ConnectcapacitorfromSStoGNDtoprogramsoft-starttime.Pullingthispinbelow150mVcausestheoutputswitchingtostop,placingthedeviceinashutdownstate.Thepinalsofunctionsasarestarttimerforovercurrentevents.

Compensation.Erroramplifieroutput.Connectcontrol-loopcompensationnetworkfromCOMPtoFB.Feedback.Erroramplifierinvertinginput.Connectfeedbackresistornetworkcentertaptothispin.Deviceground

OII

DriveroutputforexternalP-channelMOSFET

Current-sensecomparatorinput.ConnectacurrentsenseresistorbetweenISNSandVDDinordertosetdesiredovercurrentthreshold.

Systeminputvoltage.ConnectlocalbypasscapacitorfromVDDtoGND.

I

SSCOMPFBGNDGDRVISNSVDD

2345678

IOI

TYPICALCHARACTERISTICS

QUIESCENTCURRENTvsTEMPERATURE

2.523

QUIESCENTCURRENTvsVDD

IDD- mA

IDD

- mA

1.510.50

510152025

Temperature - °C

3035VDD- V

40455055

Figure3.

SOFT-STARTTHRESHOLDvsTEMPERATURE

156.5156

Figure4.

UVLOTURNONANDTURNOFFvsTEMPERATURE

4.34.25

Reset Threshold - mV

UVLO Turnon - V

155.5155154.5154153.5

4.24.154.14.054

Temperature - °C

Temperature - °C

Figure5.

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Figure6.

5