LTC2801CDE-PBF资料

LTC2801/LTC2802/ LTC2803/LTC28041.8V to 5.5V RS-232Single and Dual Transceivers FEATURES

1.8V to 5.5V Supply Voltagen Single and Dual Transceiversn High-Speed Operation 1Mbps for 250pF/3kΩ Load (LTC2802, LTC2804) 250kbps for 1nF/3kΩ Load 100kbps for 2.5nF/3kΩ TIA/EIA-232-F Loadn Low-Power 1μA Shutdown and 15μA Receivers- Active Modesn No Damage or Latch-Up to ±10kV ESD on RS-232 Interfacen Logic Supply Pin for Easy Level-Shifting to UART or Microprocessorn Low-Latency Output Enable Allows Line Sharing and Half-Duplex Operationn True RS-232 Compliant Output Levelsn Small Footprint: LTC2801/LTC2802 4mm × 3mm DFN Package LTC2803/LTC2804 Narrow SSOP-16 and 5mm × 3mm DFN PackagesnDESCRIPTION

The LTC®2801/LTC2802/LTC2803/LTC2804 are single and dual RS-232 transceivers in narrow SSOP and chip-scale DFN packages. All operate over a supply range of 1.8V to 5.5V, which permits operation directly from two alkaline, NiCd or NiMH cells. An integrated DC-to-DC converter generates power supplies for driving RS-232 levels. A logic supply pin allows easy interfacing with different logic levels independent of the DC-DC supply.These parts are compatible with the TIA/EIA-232-F stan-dard. Driver outputs are protected from overload and can be shorted to ground or up to ±15V without damage. To extend battery life, receivers can be kept active, operating at reduced speed, with only 15μA current. In shutdown mode, current is further reduced to 1μA. Line sharing and half-duplex operation are also supported.PRODUCT SELECTION GUIDE

PART NUMBERLTC2801LTC2802LTC2803LTC2803-1LTC2804LTC2804-1DRIVERS112222RECEIVERS112222PACKAGE12-Lead DFN12-Lead DFN16-Lead DFN16-Lead Narrow SSOP16-Lead DFN16-Lead Narrow SSOPAPPLICATIONS

Battery-Powered Systemsn Computers and Consumer Electronicsn Diagnostic PortsnL, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.TYPICAL APPLICATION

1.8V TO 5.5VL110μHLTC2802 at 1.8V and 1MbpsC41μFVCCVLPSLTC2802SWC1220nFCAP2V/DIVTINOFF ONMODETINTOUT5V/DIVTOUTROUTRIN2V/DIV

ROUTGNDVDDC21μFVEEC31μF2801 TA01a

VCC = VL = 1.8V400ns/DIVWRAPPING DATA

TOUT LOAD = 250pF + RINROUT LOAD = 150pF

2801 TA01b2801234fc1

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LTC2801/LTC2802/ LTC2803/LTC2804ABSOLUTE MAXIMUM RATINGS

Input Supplies VCC ...........................................................–0.3V to 7V VL..........................................................–0.3V to 6.7VGenerated Supplies VDD ................................................VCC –0.3V to 7.5V VEE ........................................................0.3V to –7.5V VDD – VEE..............................................................14VSW ..................................................–0.3V to VDD + 0.3VCAP ..................................................+0.3V to VEE – 0.3VTIN, T1IN, T2IN, MODE ................................–0.3V to 7V (Note 1)PS, ON/OFF .....................................–0.3V to (VL + 0.3V)RIN, R1IN, R2IN ..........................................–25V to 25VTOUT, T1OUT, T2OUT .................................–15V to 15VROUT, R1OUT, R2OUT ....................–0.3V to (VL + 0.3V)Operating Temperature LTC280XC ................................................0°C to 70°C LTC280XI .............................................–40°C to 85°CStorage Temperature Range ...................–65°C to 125°CLead Temperature (Soldering, 10 sec)GN Package ......................................................300°CPIN CONFIGURATION

1-Driver/1-ReceiverTOP VIEWRINTOUTVCCVDDSWGND123456VEE1312ROUT11TIN10VL987MODEPSCAP2-Driver/2-ReceiverTOP VIEWR1INR2INT1OUTT2OUTVCCVDDSWGND12345678VEE1716R1OUT15R2OUT14T1IN13T2IN12VL11MODE10PS9CAP2-Driver/2-ReceiverTOP VIEWR1INR2INT1OUTT2OUTVCCVDDSWGND1234567816R1OUT15R2OUT14T1IN13T2IN12VL11ON/OFF10CAP9VEEDE PACKAGE12-LEAD (4mm s 3mm) PLASTIC DFNTJMAX = 125°C, θJA = 43°C/W, θJC = 4.3°C/W (4 Layer)EXPOSED PAD (PIN 13) IS VEE, MUST BE SOLDERED TO PCBDHC PACKAGE16-LEAD (5mm s 3mm) PLASTIC DFNTJMAX = 125°C, θJA = 44°C/W, θJC = 4.3°C/W (4 Layer)EXPOSED PAD (PIN 17) IS VEE, MUST BE SOLDERED TO PCBGN PACKAGE16-LEAD (NARROW 0.150) PLASTIC SSOPTJMAX = 125°C, θJA = 110°C/W, θJC = 40°C/W (4 Layer)ORDER INFORMATION

LEAD FREE FINISHLTC2801CDE#PBFLTC2801IDE#PBFLTC2802CDE#PBFLTC2802IDE#PBFLTC2803CDHC#PBFLTC2803IDHC#PBFLTC2804CDHC#PBFLTC2804IDHC#PBFTAPE AND REELLTC2801CDE#TRPBFLTC2801IDE#TRPBFLTC2802CDE#TRPBFLTC2802IDE#TRPBFLTC2803CDHC#TRPBFLTC2803IDHC#TRPBFLTC2804CDHC#TRPBFLTC2804IDHC#TRPBFPART MARKING*28012801280228022803280328042804PACKAGE DESCRIPTION12-Lead (4mm × 3mm) Plastic DFN12-Lead (4mm × 3mm) Plastic DFN12-Lead (4mm × 3mm) Plastic DFN12-Lead (4mm × 3mm) Plastic DFN16-Lead (5mm × 3mm) Plastic DFN16-Lead (5mm × 3mm) Plastic DFN16-Lead (5mm × 3mm) Plastic DFNTEMPERATURE RANGE0°C to 70°C–40°C to 85°C0°C to 70°C–40°C to 85°C0°C to 70°C–40°C to 85°C0°C to 70°C–40°C to 85°C16-Lead (5mm × 3mm) Plastic DFNLTC2803CGN-1#PBFLTC2803CGN-1#TRPBF2803116-Lead (Narrow 0.150) Plastic SSOP0°C to 70°CLTC2803IGN-1#PBFLTC2803IGN-1#TRPBF2803I116-Lead (Narrow 0.150) Plastic SSOP–40°C to 85°CLTC2804CGN-1#PBFLTC2804CGN-1#TRPBF2804116-Lead (Narrow 0.150) Plastic SSOP0°C to 70°CLTC2804IGN-1#PBFLTC2804IGN-1#TRPBF2804I116-Lead (Narrow 0.150) Plastic SSOP–40°C to 85°CConsult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container.Consult LTC Marketing for information on non-standard lead based fi nish parts.For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/2801234fc2

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LTC2801/LTC2802/ LTC2803/LTC2804E LECTRICAL CHARACTERISTICS The l denotes the specifi cations which apply over the full operating SYMBOLPower SuppliesICCVCC Supply CurrentOutputs Unloaded Normal Mode (Note 3) Receivers Active Mode Shutdown ModeOutputs Unloaded Normal Mode (LTC2801, LTC2802) Normal Mode (LTC2803, LTC2804) Receivers Active Mode Shutdown ModeRL = 3kΩ RL = 3kΩ VL = VCC = 5.5V; VTOUT = 0VVL = VCC = VDD = VEE = 0V; VTOUT = ±2VLowHigh2.3110.080.15151–55–5.76.20.6lltemperature range, otherwise specifi cations are at TA = 25°C, VCC = 1.8V to 5.5V, VL = 1.8V to 5.5V, Normal Mode. Typical values are given for VCC = VL = 3.3V and TA = 25°C, unless otherwise noted.PARAMETERCONDITIONSMINTYPMAXUNITSllllllll10100.150.303010mAμAμAmAmAμAμAVVVILVL Supply CurrentDriverVOLDVOHDVHYSDIOSDIPOLDIOLDReceiverVIRVILR VIHRVHYSRVOLRVOHRRINIOSRLogicLogic Input Voltage ThresholdIINVDDLogic Input CurrentRegulated VDD Output VoltageDriver RL = 3kΩ (Note 3)LTC2801, LTC2802: VTIN = VLLTC2803, LTC2804: VT1IN = VL, VT2IN = 0VDriver RL = 3kΩ (Note 3)LTC2801, LTC2802: VTIN = VLLTC2803, LTC2804: VT1IN = VL, VT2IN = 0VPower Supply Generator7VllOutput VoltageOutput VoltageLogic Input HysteresisOutput Short Circuit CurrentPower-Off Output Leakage CurrentOutput Leakage Current±35±0.1±0.1±70±10±10mAµAµAlShutdown or Receivers Active or Drivers Disabled Modes, –15V ≤ VTOUT ≤ 15VInput ThresholdsInput ThresholdsInput ThresholdsInput HysteresisOutput VoltageOutput VoltageInput ResistanceOutput Short Circuit CurrentReceivers Active Mode Normal Mode, Input LowNormal Mode, Input HighNormal ModeOutput Low, IROUT = 1mA (Sinking)Output High, IROUT = –1mA (Sourcing)–15V ≤ VRIN ≤ 15VVL = 5.5V; 0V ≤ VROUT ≤ VLllllllll0.80.80.1VL –0.431.51.31.70.40.2VL –0.25±252.42.51.00.47±500.67 • VL±1VVVVVVkΩmAVμA0.4VEERegulated VEE Output Voltage–6.3V2801234fc3

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LTC2801/LTC2802/ LTC2803/LTC2804SWITCHING CHARACTERISTICS The l denotes the specifi cations which apply over the full operating SYMBOLPARAMETERMaximum Data RateCONDITIONSLTC2801, LTC2803 (Note 3) RL = 3kΩ, CL = 2.5nF RL = 3kΩ, CL = 1nFLTC2802, LTC2804 (Note 3) RL = 3kΩ, CL = 2.5nF RL = 3kΩ, CL = 1nF RL = 3kΩ, CL = 250pFDriverSR(D)Driver Slew RateLTC2801, LTC2803 (Figure 1) VCC = VL = 1.8V, RL = 3kΩ, CL = 2.5nF VCC = VL = 5.5V, RL = 3kΩ, CL = 50pFLTC2802, LTC2804 (Figure 1) VCC = VL = 1.8V, RL = 3kΩ, CL = 2.5nF VCC = VL = 5.5V, RL = 3kΩ, CL = 50pFtPHLD, tPLHDDriver Propagation DelayRL = 3kΩ, CL = 50pF (Figure 2) LTC2801, LTC2803 LTC2802, LTC2804RL = 3kΩ, CL = 50pF (Figure 2) LTC2801, LTC2803 LTC2802, LTC2804PS = VL, MODE = ↑, RL = 3kΩ, CL = 50pF(Figure 4)PS = VL, MODE = ↓, RL = 3kΩ, CL = 50pF(Figure 4)CL = 150pF (Figure 3)CL = 150pF (Figure 3)CL = 150pF (Figure 3)PS = MODE = ↑ or ON/OFF = ↑, RL = 1kΩ, CL = 150pF (Figure 5)PS = MODE = ↓ or ON/OFF = ↓, RL = 1kΩ, CL = 150pF (Figure 5)(Notes 3 and 4)lllllllllllllllltemperature range, otherwise specifi cations are at TA = 25°C, VCC = 1.8V to 5.5V, VL = 1.8V to 5.5V, Normal Mode. Typical values are given for VCC = VL = 3.3V and TA = 25°C, unless otherwise noted.MIN1002501002501000TYPMAXUNITSkbpskbpskbpskbpskbps430415010.2100500.60.32220.5V/μsV/μsV/μsV/μsμsμsnsnsμsμstSKEWDDriver SkewtPZHD, tPZLDtPHZD, tPLZDReceivertPHLR, tPLHRtSKEWRtRR, tFRtPZHR, tPZLRtPHZR, tPLZRDriver Output Enable TimeDriver Output Disable TimeReceiver Propagation DelayReceiver SkewReceiver Rise or Fall TimeShutdown to Receiver Output EnableReceiver Output Disable upon Shutdownl0.2506050.150.4200150.3μsnsnsμsμsPower Supply GeneratorVDD/VEE Supply Rise Timel0.22msNote 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime.Note 2: All currents into pins are positive; all voltages are referenced to GND unless otherwise specifi ed.Note 3: Guaranteed by other measured parameters and not tested directly.Note 4: Time from PS ↑ or ON/OFF ↑ until VDD ≥ 5V and VEE ≤ –5V.2801234fc4

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LTC2801/LTC2802/ LTC2803/LTC2804TEST CIRCUITS

TOUT

RL TIN

tTHL TOUTSR(D) =

6VtTHL or tTLH

3V–3V3V–3VtTLHVL0VVOHDVOLD

2801F02

TINCLTIN tr, tf ≤ 40ns

Figure 1. Driver Slew Rate MeasurementTOUT

TINTINRLCL TOUT1/2 VLtPHLD0VtSKEWD = |tPHLD–tPLHD|

TIN tr, tf ≤ 40ns

1/2 VLtPLHD0VVL0VVOHDVOLD

2801F02

Figure 2. Driver Timing MeasurementROUT

RIN3V

1.5VtPHLR1.5VtPLHR1/2 VLtSKEWR = |tPHLR–tPLHR|

1/2 VL–3VVOHRVOLR

2801F03

RINCL ROUTRIN tr, tf ≤ 40ns

Figure 3. Receiver Timing Measurement MODE1/2 VLtPZHD1/2 VLtPHZD5VtPZLDtPLZD–5VVOLD + 0.5VVOHD – 0.5VVL0VVOHD0V

0 OR VL

MODERLCLTOUT TOUT TOUT

MODE tr, tf ≤ 40ns

0VVOLD

2801F04

Figure 4. Driver Enable/Disable Times2801234fc5

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LTC2801/LTC2802/ LTC2803/LTC2804TEST CIRCUITS

GNDVL

RL–3V OR 3V

ROUT ROUTtPZLR ROUT

PS AND MODE tr, tf ≤ 40ns

1/2 VLPS AND MODE1/2 VLtPZHR1/2 VLtPLZR1/2 VLtPHZRVL0V

V

VOHR – 0.5VOHR

0V

VL

VOLR + 0.5VVOLR

2801F05

PS AND MODECLFigure 5. Receiver Enable/Disable TimesTYPICAL PERFORMANCE CHARACTERISTICS

LTC2803 at 1.8V and 250kbpsT1IN2V/DIV

T1OUTT2OUT10V/DIV

R1OUT2V/DIV

R2OUT2V/DIV10V/DIV

R1OUTR2OUT2V/DIV

T1OUTT2OUTTA = 25°C, VCC = VL = 3.3V unless otherwise noted.LTC2804 at 1.8V and 1Mbps3.0

T1INSUPPLY CURRENT (mA)2.5

Drivers Disabled Mode Supply Current vs Supply VoltageTA = 85°CTA = 25°CTA = –40°CVCC = VL2.01.51.00.50

VCC = VL = 1.8V2μs/DIVWRAPPING DATA

TOUT LOAD = 1nF + RINROUT LOAD = 150pF

2801 G01

VCC = VL = 1.8V400ns/DIVWRAPPING DATA

TOUT LOAD = 250pF + RINROUT LOAD = 150pF

12

534

SUPPLY VOLTAGE (V)

6

2801 G03

2801 G02

Supply Current vs Supply Voltage (Dual Transceiver)6050SUPPLY CURRENT (mA)40

125kbps3020100

ALL DRIVERS SWITCHINGVCC = VLRL = 3k250kbpsCL = 1nF100

Supply Current vs Data RateALL DRIVERS SWITCHINGVCC = VL = 1.8VRL = 3k1nF60

250pF40

250pFLTC2804LTC28020

200

600400

DATA RATE (kbps)

800

1000

2801 G05

Supply Current vs Load Capacitance (Dual Transceiver)100

250kbps80SUPPLY CURRENT (mA)125kbps80SUPPLY CURRENT (mA)1nF60

40

20.8kbps20

VCC = VL = 1.8VLTC2804RL = 3kLTC2803ALL DRIVERS SWITCHING1

324

LOAD CAPACITANCE (nF)

5

2801 G06

20.8kbpsLTC2804LTC28031

2

345SUPPLY VOLTAGE (V)

6

2801 G04

20

0

0

2801234fc6

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LTC2801/LTC2802/ LTC2803/LTC2804TYPICAL PERFORMANCE CHARACTERISTICS

Receiver Input Threshold vs Temperature3.02.5THRESHOLD VOLTAGE (V)2.01.51.00.50

–50–25

INPUT LOWVL = 5.5VVL = 3.3VVL = 1.8VOUTPUT VOLTAGE (V)INPUT HIGH6543210

TA = 25°C, VCC = VL = 3.3V unless otherwise noted.Receiver Output Voltage vs Load CurrentVL = 5.5VVL = 3.3VVL = 1.8VPOSITIVE DUTY CYCLE (%)100

Receiver Output Duty CycleRIN = ±3VCL = 150pFRECEIVERSALIVE MODE60

NORMALMODE80

40

20

5025750

TEMPERATURE (°C)

100125012

3456LOAD CURRENT (mA)

78

0

VL = 5.5VVL = 3.3VVL = 1.8V10

1001000DATA RATE (kbps)

10000

2801 GO9

2801 GO72801 GO8

Driver Slew Rate vs Load Capacitance807060SLEW RATE (V/μs)504030201000

1

43

LOAD CAPACITANCE (nF)

2

5

2801 G10

Driver Short-Circuit Current vs Temperature60SHORT-CIRCUIT CURRENT (mA)5040302010

SINKINGLEAKAGE CURRENT (A)FALLING (LTC2802/04)RISING (LTC2802/04)FALLING (LTC2801/03)RISING (LTC2801/03)10–610–710–810–9

Shutdown or Drivers Disabled Mode Driver Leakage vs TemperatureSOURCINGV(TOUT) = 15V ORV(TOUT) = –15V10–10

REGULATOR CANLIMIT FURTHER5025750

TEMPERATURE (°C)

100

125

10–11

–50–25

0

–50–25

5025750

TEMPERATURE (°C)

100125

2801 G112801 G12

Logic Input Threshold vs VL Supply Voltage3.02.5THRESHOLD VOLTAGE (V)2.01.51.0

INPUT LOW0.50

5V/DIV

TA = 85°CTA = 25°CTA = –40°CINPUT HIGHLTC2804 Driver Outputs Exiting ShutdownLTC2804 Driver Outputs Enable/Disable2V/DIV

MODE AND PS2V/DIV

MODET1OUT5V/DIV

T2OUTT1OUTT2OUT12

345VL SUPPLY VOLTAGE (V)

6

2801 G13

100μs/DIVVCC = 3.3V

VL = 1.8V

LOAD = 3k + 2.5nF

2801 G14

2μs/DIVVCC = 3.3V

VL = 1.8V

LOAD = 3k + 250nF

2801 G15

2801234fc7

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LTC2801/LTC2802/ LTC2803/LTC2804PIN FUNCTIONS

PIN NUMBERPIN NAMEVCCVDDVEESWGNDCAPVLTIN (T1IN, T2IN)TOUT (T1OUT, T2OUT)RIN (R1IN, R2IN)ROUT (R1OUT, R2OUT)PSMODEON/OFF*Backside thermal pad280128023413*56710112112—280328045617*71214, 133, 41, 216, 151011—2803-12804-1COMMENTS56978101214, 133, 41, 216, 15——11Input Supply (1.8V-5.5V). Bypass to GND with a 1μF capacitor.Generated Positive Supply Voltage for RS-232 Driver (7V). Connect a 1μF capacitor between VDD and GND.Generated Negative Supply Voltage for RS-232 Driver (–6.3V). Connect a 1μF capacitor between VEE and GND.Switch Pin. Connect a 10μH inductor between SW and VCC.Ground.Charge Pump Capacitor for Generated Negative Supply Voltage. Connect a 220nF capacitor between CAP and SW.Logic Supply (1.8V-5.5V) for the receiver outputs, driver inputs, and control inputs. This pin should be bypassed to GND with a 220nF capacitor if it’s not tied to VCC.Driver Input(s), referenced to VL.RS-232 Driver Output(s).RS-232 Receiver Input(s). Includes internal 5kΩ termination resistor(s).Receiver Output(s), referenced to VL. Output is short-circuit protected to GND/VCC/VL, and is high impedance in Shutdown mode, allowing data line sharing.Power Supply control pin, referenced to VL. Enables the integrated DC-DC converter.Mode control pin, referenced to VL. See Table 1 for functionality.Transceiver enable pin, referenced to VL. A logic low puts the device in Shutdown mode and places both driver and receiver outputs in a high impedance state.MODE CONTROL

Table 1. LTC2801-LTC2804MODE NAMESHUTDOWNRECEIVERS ACTIVEDRIVERS DISABLEDNORMALPSLLHHMODELHLHRECEIVER OUTPUT(S)HI-ZONONONDC-DCOFFOFFONONDRIVER OUTPUT(S)HI-ZHI-ZHI-ZONIVCC*1μA1μA2.1mA2.3mAIVL*1μA15μA80μA OR 150μA80μA OR 150μATable 2. LTC2803-1, LTC2804-1MODE NAMESHUTDOWNNORMALON/OFFLHRECEIVER OUTPUTS DC-DCHI-ZONOFFONDRIVER OUTPUTS IVCC*HI-ZON1μA2.3mAIVL*1μA150μA*Typical currents for static drivers. Normal mode currents are for unloaded outputs.2801234fc8

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LTC2801/LTC2802/ LTC2803/LTC2804FEATURE SUMMARY

FEATUREDRIVERS and RECEIVERSPACKAGE1.8V - 5.5V OPERATION1.8V - 5.5V LOGIC SUPPLY (VL)SHUTDOWN (1μA)RECEIVER(S) ACTIVE (15μA)DRIVER DISABLE100kb/s for RL = 3kΩ, CL = 2.5nF250kb/s for RL = 3kΩ, CL = 1nF1Mb/s for RL = 3kΩ, CL = 250pF28011 + 1DElllllll28021 + 1DEllllllll28032 + 2DHClllllll2803-12 + 2GNlll28042 + 2DHClllll2804-12 + 2GNlllllllllllBLOCK DIAGRAM

L1

10μH1.8V TO 5.5V

C41μFVCCSWCAPVDD1.8V TO 5.5V

C5220nFVLBOOSTREGULATORVEEC31μFC21μFC1220nFVLT2INT1INVDDT2OUTT1OUTVL******

R2OUTGNDVEER2IN**5kR1OUTVLLTC2801LTC2802LTC2803LTC2804LTC2803-1LTC2804-1

PSMODEON/OFFGNDCONTROL5k**LTC2803LTC2804LTC2803-1LTC2804-1R1IN2801BDGND2801234fc9

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LTC2801/LTC2802/ LTC2803/LTC2804APPLICATIONS INFORMATION

OverviewThe LTC2801 family of RS-232 transceivers operates on a VCC supply of 1.8V to 5.5V, utilizing a switching regula-tor to generate the necessary higher voltage rails for the drivers. The transceivers interface with logic operating on any supply from 1.8V to 5.5V, independent of the VCC voltage. Depending on the device, one or two control pins are available to invoke Shutdown, Receiver Active and Driver Disable features.DC-DC ConverterThe on-chip DC-DC converter operates from the VCC input, generating a 7V VDD supply and a charge pumped – 6.3V VEE supply, as shown in Figure 6. VDD and VEE power the output stage of the drivers and are regulated to levels that guarantee greater than ±5V output swing. The DC-DC converter requires a 10μH inductor (L1) and a bypass capacitor (C4) of at least 1μF. The recommended size for the charge pump capacitor (C1) is 220nF and for the storage capacitors (C2 and C3) is 1μF. Larger storage capacitors up to 4.7μF may be used if C1 is kept at 20% to 50% their size and C4 is also scaled. Locate C1-C4 close to their associated pins.L110μH1.8V TO 5.5VC41μFVCCC1220nFSWCAPVDD1.8V TO 5.5VC5*220nFVLBOOSTREGULATORVEEC31μFC21μFANY VOLTAGE FROM

1.8V TO 5.5VANY VOLTAGE FROM

1.8V TO 5.5VVCCVLEXTERNALDEVICERS-232

2801F07Figure 7. VCC and VL Are IndependentPower-Saving ModesWhen the DC-DC converter and drivers are turned off (PS or ON/OFF = logic low), VCC supply current is reduced to 1μA. Tables 1 and 2 summarize the modes for each device. In Shutdown mode, VL supply current is reduced to 1μA, and both receiver and driver outputs assume a high im-pedance state. In Receivers Active mode, the quiescent VL supply current is reduced to 15μA and the driver outputs assume a high impedance state. The receivers operate at a reduced rate (typically 100 kbps) with hysteresis turned off.Half-Duplex OperationWhen the DC-DC converter is kept on (PS = logic high), MODE serves as a low-latency driver enable for half-duplex operation. Each driver is enabled and disabled in less than 2μs, while each receiver remains continuously active. This mode of operation is illustrated in Figures 15-17.Battery OperationTo maximize battery life, connect VCC (and L1) directly to the unregulated battery voltage and VL to the regulated supply, as shown in Figure 22. This confi guration typically minimizes conversion loss while providing compatibility with system logic levels.Inductor SelectionA 10μH inductor with a saturation current (ISAT) rating of at least 200mA and low DCR (copper wire resistance) is recommended. Some small inductors meeting these requirements are listed in Table 3.2801234fc*OMIT IF VL IS CONNECTED TO VCC2801F06Figure 6. DC/DC Converter and Recommended BypassingVL Logic SupplyA separate logic supply pin VL allows the LTC2801 family to interface with any logic signal from 1.8V to 5.5V, as shown in Figure 7. Simply connect the desired logic supply to VL. There is no interdependency between VCC and VL; they may simultaneously operate at any voltage from 1.8V to 5.5V and sequence in any order. If VL is powered separately from VCC, bypass VL with a 220nF capacitor (C5).10

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LTC2801/LTC2802/ LTC2803/LTC2804APPLICATIONS INFORMATION

Table 3. Recommended InductorsPART NUMBERISATMAX DCR(mA)(Ω)1.20.851.1SIZE(mm)MANUFACTURERLQH2MCN100K02L225LBC2016T100KFSLB2520-100K2452202 × 1.6 × 0.95Muratawww.murata.com2 × 1.6 × 1.6Taiyo Yudenwww.t-yuden.com2.5 × 2 × 1.6Tokowww.tokoam.comfl owing through inductor L1 and capacitors C1, C2. The peak inrush current must not exceed 2A. To avoid this condition, add a 1Ω resistor as shown in Figure 8. This precaution is not relevant for supply voltages below 4.5V or rise times longer than 10μs.Board LayoutThe board layout should minimize the length and area of the SW and CAP traces. Suggested compact layouts for the LTC2801 family are shown in Figure 9 (a) and (b).Capacitor SelectionThe small size of ceramic capacitors makes them ideal for the LTC2801 family. X5R and X7R (preferred) types are recommended because their ESR is low and they retain their capacitance over relatively wide voltage and temperature ranges. Use a voltage rating of at least 10V.Table 4. Recommended Ceramic Capacitor ManufacturersMANUFACTURERMurataTDKTaiyo YudenAVXKemetURLwww.murata.comwww.tdk.comwww.t-yuden.comwww.avxcorp.comwww.kemet.comC1GNDGNDC2VLGNDC5VCCGNDC4L1GNDTOP VIEW= VIAC3Inrush Current and Supply Overshoot PrecautionIn certain applications, such as battery-operated and wall-adapter devices, fast supply slew rates are generated when power is connected. If VCC’s voltage is greater than 4.5V and its rise time is faster than 10μs, the pins VDD and SW can exceed their ABS MAX values during start-up. When supply voltage is applied to VCC, the voltage difference between VCC and VDD generates inrush current 4.5V TO 5.5VINRUSHCURRENTVCCL110μHC1220nFC1GNDGNDC2C5VLVCCGNDC4L1GNDR11Ω1/8WC41μFSWCAPGNDC3C21μFSCALE R1 WITH C1, C2, 1/C4VDDGNDTOP VIEW= VIA2801F082801F09Figure 8. Supply Overshoot Protection for Input Supplies of 4.5V or HigherFigure 9. Recommended Board Layouts for (a) Single and (b) Dual Transceiver Parts2801234fc11

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LTC2801/LTC2802/ LTC2803/LTC2804TYPICAL APPLICATIONS

1.8V TO 5.5V51211RA ON10VCCLTC2803VLMODEPST2OUT4T1OUT3R2IN2R1IN1GND82801F105VCC12VL1.8V TO 5.5VCELL PHONEVBATTRTSTDCTSRD10PS11MODE13T2IN14T1IN15R2OUT16R1OUTGND82801F11LTC2804PERIPHERALT2OUT4T1OUT3R2IN2R1IN1RTSTDCTSRD13T2IN14T1IN15R2OUT16R1OUTFigure 10. Power-Saving Receivers-Active Mode5V1.8V310μP11TINTOUT2VCCLTC2801VLPSMODEμP11TIN5V3V310VCCLTC2802VLPSMODEFigure 11. Cellphone Peripheral Interface1.8V TO 5.5V512VCCLTC2804-1VLOFF ON11ON/OFFT2OUT4T1OUT3R2IN2R1IN1GND13T2INTOUT214T1IN15R2OUT12ROUTGND6RIN112ROUTGNDRIN116R1OUT2801F1262801F1382801F14Figure 12. 1.8V Microprocessor Interface1.8V TO 5.5V3108R T9VCCLTC2802VLPSMODEFigure 13. 5V Microprocessor Interface1.8V TO 5.5V3108R T9VCCLTC2802VLPSMODEFigure 14. Power-Saving Shutdown Mode1.8V TO 5.5V51210R T11VCCLTC2803VLPSMODET2OUT4R2IN2T1OUT3R1IN1GND13T2IN11TINTOUT23.3k12ROUTGND62801F1511TINTOUT23.3k15R2OUT14T1INRIN112ROUTGND6RIN13.3k16R1OUT2801F1682801F17Figure 15. Half-Duplex on Single Line, Separate ROUT, TINFigure 16. Half-Duplex on Single LineFigure 17. Half-Duplex Dual Transceiver2801234fc12

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LTC2801/LTC2802/ LTC2803/LTC2804TYPICAL APPLICATIONS

2.5V TO 5.5VL110μH5134C42μF

12VCCLTC2803VLSWCAP79C1470nF512VCCLTC2803VLSWCAP791433kCL

2801F1813T2IN14T1IN15R2OUT16R1OUTGND8VDD6T2OUT4T1OUT3R2IN2R1IN1VEE1713T2IN14T1IN15R2OUT16R1OUTGND8VDD6T2OUT4T1OUT3R2IN2R1IN1VEE17DATA RATE

CL (nF)LTC2803LTC2804(kbps)

5XX100

2XX250

0.5X1000

Figure 18. Driving Larger Loads2801F19C22μFC32μFANY COMBINATIONLTC2801/LTC2802/LTC2803/LTC2804Figure 19. Quad Transceiver (2.5V < VCC < 5.5V)1.8V TO 5.5VC5220nF12VLLTC28033V TO 25V–25V TO 0V2R2IN1R2INR2OUT15R1OUT16VL0VVSW5V/DIV

VCC = 1.8V

DRIVERS DISABLEDVCC = 1.8V

DRIVERS LOADEDVCC = 5.5V

DRIVERS DISABLED

OFF ON1157MODEVCCSWGND8VDD6PST2INT1INVEE17101314VCC = 5.5V

DRIVERS LOADED

200ns/DIV

2801F21

Figure 21. Typical SW Pin Waveforms2801F20NOTES:1. NO L1 OR C2-C4 NEEDED.

2. RECEIVERS ACTIVE MODE SHOWN HAS NO DC HYSTERESIS.3. SEE DUTY CYCLE GRAPH IN TYPICAL PERFORMANCE SECTION.

Figure 20. 100kbps Dual Inverting Level Translator (IL = 15μA Static)2801234fc13

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LTC2801/LTC2802/ LTC2803/LTC2804TYPICAL APPLICATIONS

DE/UE Package12-Lead Plastic DFN (4mm × 3mm)(Reference LTC DWG # 05-08-1695 Rev D)4.00 ±0.10(2 SIDES)0.70 ±0.053.30 ±0.051.70 ± 0.05PIN 1TOP MARK(NOTE 6)R = 0.05TYP3.00 ±0.10(2 SIDES)3.30 ±0.101.70 ± 0.10PIN 1 NOTCHR = 0.20 OR0.35 × 45°CHAMFER10.50 BSC2.50 REF0.00 – 0.05BOTTOM VIEW—EXPOSED PAD

(UE12/DE12) DFN 0806 REV D 7R = 0.115TYP0.40 ± 0.10123.60 ±0.052.20 ±0.050.25 ± 0.050.50 BSC2.50 REFRECOMMENDED SOLDER PAD PITCH AND DIMENSIONSAPPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED

NOTE:

1. DRAWING PROPOSED TO BE A VARIATION OF VERSION(WGED) IN JEDEC PACKAGE OUTLINE M0-2292.DRAWING NOT TO SCALE

3. ALL DIMENSIONS ARE IN MILLIMETERS

PACKAGE OUTLINE0.200 REF0.75 ±0.0560.25 ± 0.054. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE

MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE5. EXPOSED PAD SHALL BE SOLDER PLATED

6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE

DHC Package16-Lead Plastic DFN (5mm × 3mm)(Reference LTC DWG # 05-08-1706)5.00 ±0.10(2 SIDES)0.65 ±0.05R = 0.20TYPR = 0.115TYP9160.40 ± 0.103.50 ±0.051.65 ±0.052.20 ±0.05(2 SIDES)PIN 1TOP MARK(SEE NOTE 6)PACKAGEOUTLINE3.00 ±0.101.65 ± 0.10(2 SIDES)(2 SIDES)PIN 1NOTCH (DHC16) DFN 110380.25 ± 0.050.50 BSC4.40 ±0.05(2 SIDES)RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

0.200 REF0.75 ±0.054.40 ±0.10(2 SIDES)10.25 ± 0.050.50 BSC0.00 – 0.05NOTE:

1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WJED-1) IN JEDECPACKAGE OUTLINE MO-2292. DRAWING NOT TO SCALE

3. ALL DIMENSIONS ARE IN MILLIMETERS

4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE

MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE5. EXPOSED PAD SHALL BE SOLDER PLATED

6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE

BOTTOM VIEW—EXPOSED PAD

2801234fc14

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LTC2801/LTC2802/ LTC2803/LTC2804PACKAGE DESCRIPTION

GN Package16-Lead Plastic SSOP (Narrow .150 Inch)(Reference LTC DWG # 05-08-11).045 ±.005 .1 – .196*(4.801 – 4.978)161514131211109.254 MIN

.150 – .165.229 – .244(5.817 – 6.198) .150 – .157**(3.810 – 3.988).009(0.229)REF.0165 ±.0015.0250 BSC1 .015 ± .004× 45°

(0.38 ± 0.10).0532 – .0688(1.35 – 1.75)2345678.004 – .0098(0.102 – 0.249)RECOMMENDED SOLDER PAD LAYOUT

.007 – .0098(0.178 – 0.249)0° – 8° TYP.016 – .050(0.406 – 1.270)NOTE:

1. CONTROLLING DIMENSION: INCHES

INCHES

2. DIMENSIONS ARE IN

(MILLIMETERS)

3. DRAWING NOT TO SCALE

*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006\" (0.152mm) PER SIDE

**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010\" (0.254mm) PER SIDE

.008 – .012(0.203 – 0.305)TYP.0250(0.635)BSC

GN16 (SSOP) 02042801234fcInformation furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.15

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LTC2801/LTC2802/ LTC2803/LTC2804TYPICAL APPLICATION

1.8V TO 5.5VL1

10μHC41μF*DC-DC1.8V TO 5.5VC5220nFPPXPPYTXDμPPPZRXD5121011VCCVLPSMODET2OUT4T1OUT3R2IN2R1IN1CTSRXUARTRTSTX7SW9CAPC1220nF+–LTC2804*VCC13T2IN14T1IN15R2OUT16R1OUTGND8VDD6C21μFVEE17C31μF2801F22*ADDITIONAL BYPASS CAPACITOR AS NEEDEDFigure 22. Diagnostic Port Operating Directly Off Unregulated Battery VoltageRELATED PARTS

PART NUMBERLT1780/LT1781LTC1337LTC1338LT1039/LT1039-16LTC1348DESCRIPTION2-Driver/2-Receiver RS232 Transceiver3-Driver/5-Receiver RS232 Transceiver5-Driver/3-Receiver RS232 Transceiver3-Driver/3-Receiver RS232 Transceiver3-Driver/5-Receiver RS232 TransceiverCOMMENTSSingle 5V Supply with 0.1μF Capacitors, 15kV ESDUltralow Power for DTE ApplicationsUltralow Power for DCE Applications30kΩ Input Impedance for Multi-Drop ApplicationsTrue RS232 Levels on 3.3V Supply2801234fc16

Linear Technology CorporationLT 0808 REV C • PRINTED IN USA

1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com© LINEAR TECHNOLOGY CORPORATION 2005