Rev. 1.00 1 December 09, 2016 Rev. 1.00 PB December 09, 2016

HT42B534-xUSB to UART Bridge IC

Features• OperatingVoltage(VDD):3.3V~5.5V• UARTpinVoltage(VDDIO):1.8V~VDD (Less thanVDDvoltage)

• Powerdownandwake-up functions to reducepowerconsumption

• Fully integrated12MHzoscillatorwith0.25%accuracy for allUSBmodeswhich requiresnoexternalcomponents

• USBinterface♦ USB2.0FullSpeedcompatible♦ ImplementsUSBprotocolcompositedevice:– CommunicationDeviceClass(CDC)forcommunicationsandconfiguration– HumanInterfaceDevice(HID)foruserconfigureUSBVID,PIDanddevicedescriptionstrings

♦ Internal1.5kΩpull-highresistoronD+pin

• Fully-duplexUniversalAsynchronousReceiverandTransmitterInterface–UART♦ SupportsBaudRateupto3Mbps♦ Supportsmaximum128bytestransmitbufferand128bytesreceivebuffer

♦ UARTDataformatssupported:– Databits:8– Stopbits:1and2– Parity:odd,even,noparity

♦ SupportsRTS/CTSpinsforautoflowcontrol♦ SupportsRXpinresumesignaltorequestaremotewake-up

♦ SupportsVDDIOpinforUARTpinspowersupply

• SupportsstandardWindows®driversforVirtualComPort(VCP):WindowsXP(SP2),Vista,Widows7&Windows8(onlyanINFfileisrequired),Windows10

• SupportsAndroid4.0orlaterversionandMacOSX• Integrated256bytestrue EEPROMforusermemory• Packagetypes:8-pinSOP,10-pinSOP/MSOP,16-pinNSOP

General DescriptionTheHT42B534-xdeviceisahighperformanceUSBtoUARTbridge controllerwith fully integratedUSBandUART interface functions, designed forapplications that communicatewithvarious typesofUART.The device includes aUSB 2.0 fullspeed compatible interfacewhich is used forPCcommunication.Thedevice also includes a fullyintegratedhighspeedoscillatorwhichisusedasclocksourcefor theUSBandUARTbaudrategenerator.Thebaudrategeneratorcansupportupto3MbpsofbaudratefortheUARTinterface.

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USB Bridge IC Naming Rules

HT42B 5 3 4 - xProduct Family

HT42B = Holtek Bridge IC

Bridge Series of Host

5 = USB

USB Class type

Version

1 = First Version

Bridge Series of Device

2 = I2C3 = SPI 4 = UART

3 = CDC Class6 = HID Class

Selection Table

Part No. Description VDD USB VirtualCOM HID FIFO/Buffer Interface

Data RateI/O

VDD Package

HT42B532-x USB to I2C Bridge

3.3V~ 5.5V Full-Speed

√ — TX: 62 bytesRX: 62 bytes Up to 400kHz √ 8SOP

10MSOP

HT42B533-x USB to SPI Bridge √ — TX: 128 bytesRX: 128 bytes Up to 8MHz √ 10MSOP

16NSOP

HT42B534-x USB to UART Bridge √ — TX: 128 bytesRX: 128 bytes

Up to 3Mbps Baud √

8SOP10SOP/MSOP

16NSOP

HT42B564-x USB (HID) to UART Bridge — √ TX: 32 bytes

RX: 32 bytesUp to 115.2kbps

Baud √ 10SOP

Block Diagram

3.3V Regulator

Baud Rate Generator

UART

VIDPID

Configure

128BRX

Buffer

USB PHY

InternalOscillator

TXRXCTSRTS

D+

D-

VDD

GND

V33OVDDIO

128BTX

BufferUSB

Controller DTRDSR

RIDSD

LEDUDET

ExternalRS-232

TRansceiveror

UART Circuitry

DevicePower

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Pin Assignment

GND

VDDIO D-VDDV33O

TX

RX D+

1234

8765

V33OGND

CTSTX VDDIO

RXRTSD-D+VDD

HT42B534-x8 SOP-A

109876

12345

HT42B534-x10 MSOP-A

D+D-

V33OGNDCTSTX

UDETLED DTR

VDDIORXDSRRTSDCDRIVDD16

1514131211109

12345678

HT42B534-x16 NSOP-A

VDDV33O

TXLED UDET

VDDIORXGNDD-D+ 10

9876

12345

HT42B534-x10 SOP-A

Package Type Marking8SOP HT42B534-x10SOP HT42B534-x10MSOP B534-x16NSOP HT42B534-x

Note:x=1forversionnumber.

Pin DescriptionAsthePinDescriptiontableappliestothepackagetypewiththemostpins,notallofthelistedpinsmaybepresentonpackagetypeswithsmallernumbersofpins.

Pin Name Type DescriptionD+ I/O USB D+ LineD- I/O USB D- LineTX O Asynchronous data output (UART Transmit)RX I Asynchronous data input (UART Receive)CTS I Clear To Send control input, active lowRTS O Ready to Send control output, active lowDSR I Data Set Ready control input, active lowDTR O Data Terminal Ready control output, active lowDCD I Data Carrier Detect control input, active lowRI I Ring Indicator control input, active lowLED O TX/RX signal LED indication, active lowUDET I USB plug in/out detect pin, only for 10-pin SOP packageV33O O 3.3V regulator outputVDDIO PWR Positive power supply for TX/RX/CTS/RTS/DSR/DTR/DCD/RI pinsVDD PWR Positive power supply, USB bus powerGND PWR Negative power supply, ground

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Absolute Maximum RatingsSupplyVoltage........................VSS−0.3VtoVSS+6.0V

InputVoltage..........................VSS−0.3VtoVDD+0.3V

StorageTemperature...........................-50˚Cto125˚C

OperatingTemperature.........................-40˚Cto85˚C

IOHTotal............................................................ -80mA

IOLTotal............................................................. 80mA

TotalPowerDissipation................................. 500mW

Note:Thesearestressratingsonly.Stressesexceedingtherangespecifiedunder“AbsoluteMaximumRatings”maycausesubstantialdamagetothisdevice.Functionaloperationofthisdeviceatotherconditionsbeyondthoselistedinthespecificationisnotimpliedandprolongedexposuretoextremeconditionsmayaffectdevicesreliability.

D.C CharacteristicsTa=25°C

Symbol ParameterTest Conditions

Min. Typ. Max. UnitVDD Conditions

VDD Operating Voltage — — 3.3 — 5.5 VVDDIO UART Pins VDDIO Input Voltage — — 1.8 — VDD VIDD Operating Current 5V No load — 11 16 mA

ISUS Suspend Current (USB) 5V Suspend mode, No load, USB on, other peripherals off — 360 450 μA

ISTBStandby Current (Non-USB) for 10-pin SOP package only 3V

Standby mode, No load, USB Plug-out, other peripherals off, VDD power is from VDDIO

– 0.1 1.0 μA

VIL Input Pins Input Low Voltage — — 0 — 0.2VDDIO VVIH Input Pins Input High Voltage — — 0.8VDDIO — VDDIO V

IOL I/O Pins Sink Current3V

VOL = 0.1VDDIO4 8 — mA

5V 10 20 — mA

IOH I/O Pins Source Current 3V

VOH = 0.9VDDIO-2 -4 — mA

5V -5 -10 — mA

RPH I/O Pins Pull-high Resistance 3V — 20 60 100 kΩ5V — 10 30 50 kΩ

ILEAK Input Leakage Current3V

VIN = VDD or VIN = VSS— — ±1 μA

5V — — ±1 μAVV33O 3.3V Regulator Output Voltage 5V IV33O = 70mA 3.0 3.3 3.6 V

RUDP1Pull-high Resistance between D+ and V33O 3.3V — -5% 1.5 +5% kΩ

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A.C CharacteristicsTa=25°C

Symbol ParameterTest Condition

Min. Typ. Max. UnitVDD Condition

fHIRC High Speed Internal RC Oscillator 3.3V~5.5V USB mode -0.25% 12 +0.25% MHz

tSST System Start-up Timer Period — RX pin Wake-up from power down mode 16 — — tHIRC

tRSTD System Reset Delay Time — Power-on reset 25 50 100 ms

Power-on Reset CharacteristicsTa=25°C

Symbol ParameterTest Conditions

Min. Typ. Max. UnitVDD Conditions

VPOR VDD Start Voltage to Ensure Power-on Reset — — — — 100 mVRRPOR VDD Rising Rate to Ensure Power-on Reset — — 0.035 — — V/ms

tPORMinimum Time for VDD Stays at VPOR to Ensure Power-on Reset — — 1 — — ms

VDD

tPOR RRPOR

VPOR

Time

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USB InterfaceTheUSB interface, beingUSB 2.0 full-speedcompatible, is a 4-wire serial bus that allowscommunicationbetweenahostdeviceandupto127maxperipheraldeviceson the samebus.A tokenbasedprotocolmethodisusedbythehostdeviceforcommunicationcontrol.OtheradvantagesoftheUSBbusincludelivepluggingandunplugginganddynamicdevice configuration.As the complexity ofUSBdataprotocoldoesnotpermitcomprehensiveUSBoperationinformationtobeprovidedinthisdatasheet,the reader should thereforeconsultotherexternalinformationforadetailedUSBunderstanding.

Power PlanesThereare twopowerplanesfor thedeviceandtheyare theUSB bus power input (VDD) and 3.3Vregulatoroutput(V33O).

FortheUSBSIEVDDwillsupplyallcircuitsrelatedtoUSBSIEandbesourcedfrompin“VDD”.OncetheUSBis removedfromtheUSBand there isnopower in theUSBBUS, theUSBSIEcircuit isnolongeroperational.

USB Interface OperationTocommunicatewith an externalUSBhost, theinternalUSBmodulehas externalpinsknownasD+andD- alongwith the3.3V regulator outputV33O.ASerial InterfaceEngine(SIE)decodes theincomingUSBdata streamand transfers it to thecorrectendpointbuffermemoryknownastheFIFO.TheUSBmodulehas4endpoints,EP0~EP3.Theendpoint0 supports theControl transferwhile theendpoint 1~ endpoint 3 support the Interrupt orBulk transfer.TheHT42B534-xBridgeICsupportstheUSBCommunicationDeviceClass (CDC) forcommunicationsandconfiguration.

Endpoint Transfer Type0 Control1 Interrupt2 Bulk Out3 Bulk In

USB Endpoint Transfer Type

IfthereisnosignalontheUSBbusforover3ms,theUSBdevicewillenterthesuspendmode.Thedeviceenters thesuspendstatetomeet therequirementsoftheUSBsuspendcurrent specification.When theresumesignalisassertedbytheUSBhost,thedevicewillbewokenupandleavethesuspendmode.

AstheUSBdevicehasaremotewake-upfunction,theUSBdevicecanwakeuptheUSBhostbysendingaremotewake-uppulse.OncetheUSBhostreceivesa remotewake-upsignal fromtheUSBdevice, thehostwillsendaresumesignaltodevice.

USB VID and PID ConfigurationThedevicehas configured thedefaultVendor ID(VID:0x04D9),ProductID(PID:0xB534)andproductdescriptionstringsof“USBtoUARTBridge”.Theusercanupdate theVendorID,ProductID,productdescriptionstringsandremotewake-upsettingusingtheirapplicationprogram.

ThisdevicehasbeenconfiguredtothedefaultUSBconfigurationdataasshowninthefollowingtable.

Parameter Value (hex)USB Vendor ID (VID) 0x04D9USB Product ID (PID) 0xB534Remote wake-up Default disableManufacturer Name HoltekProduct Description USB to UART BridgeSerial Number 0000

UART InterfaceTheHT42B534-xcontainsanintegratedfull-duplexasynchronousserialcommunicationsUARTinterfacethatenablescommunicationwithexternaldevicesthatcontainaserial interface.TheUARTfunctionhasmanyfeaturesandcantransmitandreceivedataseriallybytransferringaframeofdatawitheightdatabitsper transmissionaswellasbeingable todetecterrorswhen thedata isoverwrittenor incorrectlyframed.TheUART function possesses its owninternalinterruptwhichcanbeusedtoindicatewhenareceptionoccursorwhenatransmissionterminates.

TheintegratedUARTfunctioncontainsthefollowingfeatures:

• Full-duplex,asynchronouscommunication• 8bitscharacterlength• Even,oddornoparityoptions• Oneortwostopbits• Baudrategeneratorwithprescaler• 128-byteDeepFIFOTransmitDataBuffer• 128-byteDeepFIFOReceiveDataBuffer• RXpinwake-upfunction• UARTpinspowersupplybyVDDIOpin

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UART External PinTocommunicatewithanexternal serial interface,the internalUARThas twoexternalpinsknownasTXandRX.TheTXandRXpins are theUARTtransmitterandreceiverpinsrespectively.

UART Data Transfer SchemeThedatawillbe transferred to theTransmitShiftRegisterfromwhereitwillbeshiftedout,LSBfirst,onto theTXpin at a rate controlledby theBaudRateGenerator.Data tobe receivedby theUARTisacceptedontheexternalRXpin,fromwhereit isshifted in,LSBfirst, to theReceiverShiftRegisterat a rate controlledby theBaudRateGenerator.TheUARTinterfaceprovidesa128bytedeepFIFOtransmitdatabufferanda128bytedeepFIFOreceivedatabufferforapplications.

Fordata transfer, theUARTfunctionutilisesanon-return-to-zero,more commonly known asNRZ,format.Thisiscomposedofonestartbit,eightdatabitsandoneor twostopbits.ParityissupportedbytheUARThardwareandcanbesetuptobeeven,oddornoparity.Forthemostcommondataformat,8databitsalongwithnoparityandonestopbit,denotedas8,N,1,isusedasthedefaultsetting,whichisthesettingatpower-on.

Thefollowingdiagramshowsthetransmitandreceivewaveformsforan8-bitdataformat.

Bit 0

8-bit Data Format

Bit 1 Stop Bit

Next StartBit

StartBit

Parity BitBit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7

Baud Rate GeneratorTosetupthespeedoftheserialdatacommunication,theUARTfunctioncontains itsowndedicatedbaudrategenerator.ThedefaultUARTbaudrateis9600bpsanditcanbecontrolledbytheapplicationprogram.

Thebaudrateandmissratetable:

Baud Rate Real Rate Miss Rate (%)2400 2403.846154 0.164800 4807.692308 0.169600 9603.841537 0.0419200 19207.68307 0.0438400 38461.53846 0.1657600 57692.30769 0.16115200 115384.6154 0.16230400 230769.2308 0.16460800 457142.8571 0.79

1700000 1714285.714 0.842300000 2285714.286 0.623400000 3428571.429 0.84

UART Power Down and Wake-upIf theUSB host sends a suspend signal to theHT42B534-xUSBdevice, itwillenter thesuspendmode. It is recommended toensure that theUARTdata transmissionor receptionhas been finishedbeforethedeviceentersthesuspendmode.

TheUARTfunctioncontainsareceiverRXpinwake-upfunction.AfallingedgeontheRXpinwillwakeupthedevicefromthesuspendmode.

Application Program Demo

Holtek USB Bridge ProgramHoltekprovides an applicationprogram to setuptheHT42B534-xBridgeICforUSBtoUARTdatacommunication.Theapplicationprogramcarriesthename“HoltekUSBBridgeProgram”.Theapplicationprogramfunctioncontainstwoblocks,thefirstblockisforthecustomervendorID,productIDandproductinformationupgrate,thesecondblockisfortheUSBtoUARTapplicationsettings.TheUSB toUARTsettingblockcanbeusedtoconfigurethebaudrate,data,stopbits,parity,flowcontrolanddatatransmit/receivedemo.

Themainfigurefortheprogramupdateisasfollows:

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HT42B534-x

Program Update BlockOn theprogramupdateblockpage, firstopen theHoltekVID/PIDBridge IC. If theUSBhasbeenplugged into thehostPC,anewwindowwillpopupshowingUSBopensuccess.TheusercanupdatethecustomerVID,PID,manufacturername,productdescription, serial number and256bytesof usermemory aswell as set theUARTbridge devicehardwareflowcontrolandremotewake-upfunctions.Ausermemoryarea,wherenospecialdatahasbeenstored,canbeusedbytheuserforself-definition.

The following table shows the configurationdescriptorlength.

Parameter LengthUSB Vendor ID(VID) 1 Word (hex)USB Product ID(PID) 1 Word (hex)Manufacturer Name Max. support 16 charactersProduct Description Max. support 32 charactersSerial Number Max. support 4 words

Themainfigureof theprogramupdateblock isasfollows:

Configurationoperatingsteps:

• Step1:OpentheHoltekBridgeVID/PIDdevice.• Step2:ChangecustomdeviceorgotoUSBtoUARTpage.

• Setp3:InputVID/PIDandproductstrings(Iftheuserneedstochangecustomdevice).

• Step4:Hardwareflowcontrolandremotewakeupsetting.

• Step5:Importusermemory(useroptional).• Step6:Saveoropenusermemorydata(useroptional).

• Step7:DownloadoruploadVID/PID/Productstringsandtheusermemorydata.

USB to UART BlockTheUSBtoUARTsettingblockisusedtoconfigurethebaudrate,data,stopbits,parity,flowcontrolanddatatransmit/receivedemo.ThispagecanalsocontroltheoutputRTSandDTRtogglepins,CTS,RI,DSRandDCDpinsinputstatus.

ThefigurefortheUSBtoUARTisasfollows:

USBtoUARTBridgeoperatingsteps:

• Step1:SelectUSBtoUARTpage.• Step2:CheckthatdeviceisHT42B534-x.• Setp3:SelectCOMportnumber.• Step4:Selectbaudrate.• Step5:Selectoneortwostopbits.• Step6:Selectparity.• Step7:Selectflowcontrolfunction.• Step8:Opentheselections.• Step9:Inputthedatatobetransmitted.• Step10:Senddata.• Step11:Receivedata.• Step12:ToggleRTS/DTRpins.• Step13:InputCTS/RI/DSR/DCDpinsstatus.

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Application Circuits

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Dual Power Product Application Circuits

VDD

GND

V33O

D-D+

VDDIO

1µF

VBUSD-D+

VSS

0.1µF10µF

47pF47pF

33Ω

33Ω

0.1µF

HT42B534-x10SOP

USB Connector

Battery3.3V

TX

RX

UDET

LED

VCC

1N58175V or 3.3V

3.3V

0.1µF

VDD

330Ω

LED

TX

RXUART

VDD

MCUApplication

Circuit

Note:1.Designnote:10-SOPpackageonlyfortwopowerapplication,theVCCpowermustbebelowVDDpower.(TheVCCpowercanbefromtheLi-battery).

2.TheUDETpincanusedfordetecttheUSBplug-infortransferdata,detecttheUSBplug-outforentryenergysavingmode.

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Package Information

Notethat thepackageinformationprovidedhereisforconsultationpurposesonly.Asthis informationmaybeupdatedatregularintervalsusersareremindedtoconsulttheHoltekwebsiteforthelatestversionofthePackage/CartonInformation.

Additionalsupplementaryinformationwithregardtopackagingislistedbelow.Clickontherelevantsectiontobetransferredtotherelevantwebsitepage.

• PackageInformation(includeOutlineDimensions,ProductTapeandReelSpecifications)

• TheOperationInstructionofPackingMaterials

• Cartoninformation

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8-pin SOP (150mil) Outline Dimensions

SymbolDimensions in inch

Min. Nom. Max.A — 0.236 BSC —B — 0.154 BSC —C 0.012 — 0.020C′ — 0.193 BSC —D — — 0.069E — 0.050 BSC —F 0.004 — 0.010G 0.016 — 0.050H 0.004 — 0.010α 0° — 8°

SymbolDimensions in mm

Min. Nom. Max.A — 6.00 BSC —B — 3.90 BSC —C 0.31 — 0.51C′ — 4.90 BSC —D — — 1.75E — 1.27 BSC —F 0.10 — 0.25G 0.40 — 1.27H 0.10 — 0.25α 0° — 8°

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10-pin SOP (150mil) Outline Dimensions

SymbolDimensions in inch

Min. Nom. Max.A — 0.236 BSC —B — 0.154 BSC —C 0.012 — 0.018C′ — 0.193 BSC —D — — 0.069E — 0.039 BSC —F 0.004 — 0.010G 0.016 — 0.050H 0.004 — 0.010α 0° — 8°

SymbolDimensions in mm

Min. Nom. Max.A —F 6.00 BSC —B — 3.90 BSC —C 0.30 — 0.45C′ — 4.90 BSC —D — — 1.75E — 1.00 BSC —F 0.10 — 0.25G 0.40 — 1.27H 0.10 — 0.25α 0° — 8°

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HT42B534-x

10-pin MSOP Outline Dimensions

SymbolDimensions in inch

Min. Nom. Max.A — — 0.043

A1 0.000 — 0.006A2 0.030 0.033 0.037B 0.007 — 0.013C 0.003 — 0.009D — 0.118 BSC —E — 0.193 BSC —E1 — 0.118 BSC —e — 0.020 BSC —L 0.016 0.024 0.031

L1 — 0.037 BSC —y — 0.004 —θ 0° — 8°

SymbolDimensions in mm

Min. Nom. Max.A — — 1.10

A1 0.00 — 0.15A2 0.75 0.85 0.95B 0.17 — 0.33C 0.08 — 0.23D — 3.00 BSC —E — 4.90 BSC —E1 — 3.00 BSC —e — 0.50 BSC —L 0.40 0.60 0.80

L1 — 0.95 BSC —y — 0.10 —θ 0° — 8°

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HT42B534-x

16-pin NSOP (150mil) Outline Dimensions

SymbolDimensions in inch

Min. Nom. Max.A — 0.236 BSC —B — 0.154 BSC —C 0.012 — 0.020C’ — 0.390 BSC —D — — 0.069E — 0.050 BSC —F 0.004 — 0.010G 0.016 — 0.050H 0.004 — 0.010α 0° — 8°

SymbolDimensions in mm

Min. Nom. Max.A — 6.0 BSC —B — 3.9 BSC —C 0.31 — 0.51C’ — 9.9 BSC —D — — 1.75E — 1.27 BSC —F 0.10 — 0.25G 0.40 — 1.27H 0.10 — 0.25α 0° — 8°

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Copyright© 2016 by HOLTEK SEMICONDUCTOR INC.

The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. Holtek's products are not authorized for use as critical components in life support devices or systems. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information, please visit our web site at http://www.holtek.com/en/.