19-2218; Rev 1; 5/02
3.3V, High-Speed, RS-485/RS-422 Transceiver in
SOT Package
General Description
FeaturesThe MAX3362 low-power, high-speed transceiver forRS-485/RS-422 communication operates from a singleoSpace-Saving 8-Pin SOT Package+3.3V power supply. The device contains one differen-tial transceiver consisting of a line driver and receiver.oGuaranteed 20Mbps Data Rate The transceiver operates at data rates up to 20Mbps,oOperates from a Single +3.3V Supplywith an output skew of less than 6ns. Driver and receiv-er propagation delays are guaranteed below 50ns. Thiso6ns (max) Transmitter and Receiver Skewfast switching and low skew make the MAX3362 idealoHot-Swap Feature
for multidrop clock/data distribution applications.
The output level is guaranteed at +1.5V with a standardoInteroperable with +5V Logic
54oAllows up to 256 Transceivers on the Bustransceiver draws 1.7mA supply current whenΩload, compliant with RS-485 specifications. Theunloaded or fully loaded with the drivers disabled.o1µA Low-Power Shutdown ModeAdditionally, the MAX3362 has a low-power shutdownmode, reducing the supply current to 1µA.
o1.7mA Operating Supply CurrentThe MAX3362 has a 1/8-unit-load receiver input imped-o-7V to +12V Common-Mode Rangeance, allowing up to 256 transceivers on the bus. TheoCurrent Limiting and Thermal Shutdown MAX3362 is designed for half-duplex communication.The device has a hot-swap feature that eliminates falseoHalf-Duplex Operation
transitions on the data cable during circuit initialization.The drivers are short-circuit current limited, and a ther-oAutomotive Temperature Range Variants
mal shutdown circuit protects against excessive powerdissipation.
The MAX3362 is available in an 8-pin SOT packageand specified over industrial and automotive tempera-Ordering Informationture ranges.
Applications
PARTTEMP RANGEPIN-PACKAGETOP MARKClock/Data Distribution MAX3362EKA-40°C to +85°C8 SOT23AAJLTelecom EquipmentMAX3362AKA-40°C to +125°C8 SOT23AALLSecurity Equipment
Point-of-Sale EquipmentIndustrial Controls
Pin Configuration and Functional Diagram appear at end ofdata sheet.
Typical Operating Circuit120Ω120ΩDIBBDEDDDEABABAADIRORRRORERERRMAX3362DDDIDEROREDIDERORE________________________________________________________________Maxim Integrated Products1
For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
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3.3V, High-Speed, RS-485/RS-422 Transceiver inSOT PackageMAX3362ABSOLUTE MAXIMUM RATINGS
All voltages with respect to GND.
VCC, RE, DE, DI ......................................................-0.3V to +6VReceiver Input Voltages, Driver Output
Voltages (A, B).......................................................-8V to +13VReceiver Input Current, Driver Output
Current (A, B).................................................................250mA|VA - VB|..................................................................................+8VReceiver Output Voltage (RO)....................-0.3V to (VCC+ 0.3V)
Continuous Power Dissipation (TA= +70°C)
8-Pin SOT (derate 9.7mW/°C above +70°C) ...............777mWOperating Temperature Range
MAX3362E__ ..................................................-40°C to +85°CMAX3362A__ ................................................-40°C to +125°CStorage Temperature Range.............................-65°C to +150°CJunction Temperature......................................................+150°CLead Temperature (soldering, 10s).................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS
(VCC= +3.3V ±5%, TA= TMINto TMAX, unless otherwise noted. Typical values are at VCC= +3.3V and TA= +25°C.) (Notes 1, 2)
PARAMETERDRIVERFigure 1, RL = 100Ω (RS-422)(extended temperature range)Differential Driver OutputVODFigure 1, RL = 100Ω(automotive temperature range)Figure 1, RL = 54Ω (RS-485)(extended temperature range)Change in Magnitude ofDifferential Output VoltageDriver Common-Mode OutputVoltageChange In Magnitude ofCommon-Mode VoltageInput High VoltageInput Low VoltageInput HysteresisInput Current (DE, DI, RE)Driver Short-Circuit OutputCurrentDriver Short-Circuit FoldbackOutput Current∆VODVOC∆VOCVIHVILVHYSIINIOSDIOSDFFigure 1, RL = 54Ω or 100Ω(Note 3)Figure 1, RL = 54Ω or 100ΩFigure 1, RL = 54Ω or 100Ω(Note 3)DE, DI, REDE, DI, REDE, DI, RE0 < V IN 5V< 0 < V OUT < 12V (Note 4) -7V < V OUT < V CC (Note 4)(VCC - 1V) < V OUT < 12V (Note 4) -7V < V OUT < 1V (Note 4) -250+25-2550±1+2502.00.82.01.51.50.230.2VVVVVmVµAmAmAVSYMBOLCONDITIONSMINTYPMAXUNITS2_______________________________________________________________________________________
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3.3V, High-Speed, RS-485/RS-422 Transceiver in
SOT Package
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC= +3.3V ±5%, TA= TMINto TMAX, unless otherwise noted. Typical values are at VCC= +3.3V and TA= +25°C.) (Notes 1, 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSThermal Shutdown ThresholdVTS150°CThermal Shutdown HysteresisVTSH10°CRECEIVERReceiver Differential ThresholdVoltageVTH-7V < V CM < 12V -2000+200mVReceiver Input Hysteresis∆VTHVA + VB = 025mVReceiver Output High VoltageVOHIO = -1mA, VA - VB = VTHVCC - 0.4VReceiver Output Low VoltageVOLIO = 1mA, VA - VB = -VTH0.4VThree-State Output Current atReceiverIOZR0 < V O < V CC±1µAReceiver Input ResistanceRINVCM = 12V96kΩReceiver Input CurrentIINDE = GND,VIN = +12V125VCC = GND or 3.465VVµAIN = -7V-100Receiver Output Short-CircuitCurrentIOSR0 < V RO < V CC±150mAPOWER SUPPLYSupply VoltageVCC3.1353.3003.465VSupply Current in NormalOperation (Static Condition)IQNo load, DI = VCC or GND1.73mASupply Current in ShutdownModeISHDNDE = GND, RE = VCC110µASWITCHING CHARACTERISTICS (MAX3362E_ _ only)
(VCC= +3.3V ±5%, TA= TMINto TMAX, unless otherwise noted. Typical values are at VCC= +3.3V and TA= +25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSDriver Propagation DelaytPDLHFigures 2 and 3,50tPDHLRL = 54Ω, CL = 50pF50nsDriver Differential OutputtDRFigures 2 and 3,12.5Rise or Fall TimetDFRL = 54Ω, CL = 50pF12.5nsFigures 2 and 3,Driver Output SkewtDSKEWRL = 54Ω, CL = 50pF6nstDSKEW = |tPDLH - tPDHL|Maximum Data RatefMAX20MbpsDriver Enable to Output LowtPDZLFigure 4,RL = 500Ω, CL = 50pF100nsDriver Disable Time from LowtPDLZFigure 4,RL = 500Ω, CL = 50pF100nsDriver Disable Time from HightPDHZFigure 5,RL = 500Ω, CL = 50pF100ns_______________________________________________________________________________________3MAX3362元器件交易网www.cecb2b.com
3.3V, High-Speed, RS-485/RS-422 Transceiver inSOT PackageMAX3362SWITCHING CHARACTERISTICS (MAX3362E_ _ only)(continued)
(VCC= +3.3V ±5%, TA= TMINto TMAX, unless otherwise noted. Typical values are at VCC= +3.3V and TA= +25°C.) (Note 1)
PARAMETERDriver Enable to Output HighReceiver Propagation DelayReceiver Output SkewReceiver Enable to Output LowReceiver Enable to Output HighReceiver Disable Time from LowReceiver Disable Time fromHighTime to ShutdownDriver Enable from Output Highto ShutdownDriver Enable from Output Lowto ShutdownReceiver Enable from OutputHigh to ShutdownReceiver Enable from OutputLow to ShutdownTime to Normal OperationDriver Enable from Shutdown toOutput HighDriver Enable from Shutdown toOutput LowReceiver Enable from Shutdownto Output HighReceiver Enable from Shutdownto Output LowSYMBOLtPDZHtPRLHtPRHLtRSKEWtPRZLtPRZHtPRLZtPRHZtSDtPDHStPDLStPRHStPRLStNOtPDSHtPDSLtPRSHtPRSL(Note 6)Figure 5RL = 500Ω, CL = 50pFFigure 4RL = 500Ω, CL = 50pFFigure 7RL = 1kΩ, CL = 15pFFigure 7RL = 1kΩ, CL = 15pFCONDITIONSFigure 5,RL = 500Ω, CL = 50pFFigure 6, CL = 15pFFigure 6, CL = 15pFtRSKEW = |tPRLH - tPRHL|Figure 7, RL = 1kΩ, CL = 15pFFigure 7, RL = 1kΩ, CL = 15pFFigure 7, RL = 1kΩ, CL = 15pFFigure 7, RL = 1kΩ, CL = 15pF(Note 5)505050505015001500150015001500MINTYPMAX1005050610010010010060060060060060030003000300030003000UNITSnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsnsNote 1:Devices production tested at +25°C. Over-temperature limits are guaranteed by design.Note 2:All currents into the device are positive; all currents out of the device are negative. All voltages are referenced to device
ground, unless otherwise noted.
Note 3:∆VODand ∆VOCare the changes in VODand VOC, respectively, when the DI input changes state.
Note 4:The short-circuit output current applies to peak current just prior to foldback-current limiting; the short-circuit foldback out-put current applies during current limiting to allow a recovery from bus contention.
Note 5:Shutdown is enabled by bringing REhigh and DE low. If the enable inputs are in this state for less than 50ns, the device is
guaranteed not to enter shutdown. If the enable inputs are in this state for at least 600ns, the device is guaranteed to haveentered shutdown.
Note 6:Transition time from shutdown mode to normal operation.
4_______________________________________________________________________________________
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3.3V, High-Speed, RS-485/RS-422 Transceiver in
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Typical Operating Characteristics
(VCC= +3.3V, TA = +25°C, unless otherwise noted.)
OUTPUT CURRENT vs. RECEIVER OUTPUT
OUTPUT CURRENT vs. RECEIVER OUTPUT
RECEIVER OUTPUT HIGH VOLTAGE
LOW VOLTAGE
HIGH VOLTAGE
vs. TEMPERATURE
401023.26
3000cccooottt 2223566)63333V33X-5X(AA XAMMEGM))AA30AT3.25
mmL((-10O TV N25 TNHEERGIRRHU-15 TC20RUCU3.24
TTPUTPUT15UPT-20OUU OR10OEVIE3.23
-25CE5R0-30
3.22
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
-40-25-105203550658095110125
RECEIVER OUTPUT LOW VOLTAGE (V)
RECEIVER OUTPUT HIGH VOLTAGE (V)
TEMPERATURE (°C)
RECEIVER OUTPUT LOW VOLTAGE
DRIVER OUTPUT CURRENT
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
vs. DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
0.0547553.06000)cccooVottt ( 22 2)66V33E6333(XXG3 A)EAAXAGMMTMLA0.04A60
2.5m(OT LTV ONTVEU R2.0W0.03RPTOU45
ULCO TTLUUA1.5PPITTU0.02TUNO30
EO R RRE1.0EEFVVFIIIED0.01R CD15
REERV0.5
IRDRL = 54Ω0
00
-40-25-105203550658095110125
2.2
2.4
2.6
2.8
3.0
3.2
3.4
-40-25-105203550658095110125
TEMPERATURE (°C)
DIFFERENTIAL OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
DRIVER OUTPUT CURRENTDRIVER OUTPUT CURRENTvs. DRIVER OUTPUT LOW VOLTAGE
vs. DRIVER OUTPUT HIGH VOLTAGE
SUPPLY CURRENT vs. TEMPERATURE
1307108001.76
90ccc120o0oottt 222666333110333X-10X1.75X)A)AMAAAMMm100m-20(( T90T-301.74NNEER80R-40RRUU-50)1.73C70C-60A mTT(U60U -70C1.72PPCTTIU50UOO-80 1.71R40REE-90VVI30IRR-1001.70DD20-110-120101.69-1300
-140
1.68
012
3
4
5
67
8
9101112-7-6-5-4-3-2-1012345-40-25-105203550658095110125
DRIVER OUTPUT LOW VOLTAGE (V)
DRIVER OUTPUT HIGH VOLTAGE (V)
TEMPERATURE (°C)
_______________________________________________________________________________________5
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3.3V, High-Speed, RS-485/RS-422 Transceiver inSOT PackageMAX3362Typical Operating Characteristics (continued)(VCC= +3.3V, TA = +25°C, unless otherwise noted.)
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX3362 toc10DRIVER OUTPUT SKEW vs. TEMPERATURE
0.260.240.220.200.180.160.140.120.100.080.060.040.020
TEMPERATURE (°C)
MAX3362 toc11RECEIVER PROPAGATION DELAY
vs. TEMPERATURE
RECEIVER PROPAGATION DELAY (ns)MAX3362 toc121.41.21.0ISHDN (µA)0.80.60.40.20
35
DRIVER OUTPUT SKEW (ns)33
31
29
27
25
-40-25-105203550658095110125
-40-25-105203550658095110125
TEMPERATURE (°C)
-40-25-105203550658095110125
TEMPERATURE (°C)
UNLOADED DRIVER OUTPUT
WAVEFORM
MAX3362 toc13LOADED DRIVER OUTPUT
WAVEFORM
MAX3362 toc14A
3.3V
A
2V
B
B
0
0
fDIN = 16Mbps
20ns/div
fDIN = 16MbpsRL = 54Ω
20ns/div
DRIVER PROPAGATION DELAY
MAX3362 toc15RECEIVER PROPAGATION DELAY
MAX3362 toc163.3V
DIN
0
A
2V/div
B
A
2V/div
B
RO
2V/div
fDIN = 16Mbps
20ns/div
fDIN = 16Mbps
20ns/div
6_______________________________________________________________________________________
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3.3V, High-Speed, RS-485/RS-422 Transceiver in
SOT Package
Pin DescriptionPINNAMEDESCRIPTION1ROReceiver Output. RO is high if the receiver input differential (A-B) ≥ 200mV and the receiver is enabled(RE is low). RO is low if the receiver input differential (A-B) ≤ -200mV and the receiver is enabled.2REReceiver Output Enable. Driving RE low enables RO. RO is high impedance when RE is high. Drive REhigh and DE low (disable both receiver and driver outputs) to enter low-power shutdown mode.Driver Output Enable. Driving DE high enables driver outputs. These outputs are high impedance3DEwhen DE is low. Drive RE high and DE low (disable both receiver and driver outputs) to enter low-power shutdown mode.4DID ri v er Inp ut. D ri v i ng D I l ow for ces the noni nver ti ng outp ut l ow and i nver ti ng outp ut hi gh , w hen the d ri v er i senab le d ( DE i s hi gh ) . D ri v i ng D I hi gh for ces the noni nver ti ng outp ut hi gh and i nver ti ng outp ut l ow .5GNDGround6ANoninverting Receiver Input and Noninverting Driver Output7BInverting Receiver Input and Inverting Driver Output8VCCSupply Voltage. VCC = 3.3V ±5%. Bypass VCC to GND with a 0.1µF capacitor.RL/2DVODDCLRLOUTRL/2VOCVCCVCCCL = 50pFRL = 54ΩFigure 1. Driver DC Test LoadFigure 2. Driver Timing Test Circuit
VCCVtritfiCCtri = 5nstDIVfi = 5nsRL = 500ΩCC /2S100 or 3VDOUTtPDLHtPDHLCL = 50pFB(A+B)/2AGENERATOR50Ω90%A - B10%tDRtDFVCCVCC/2INtPDSL, tPDZL0Figure 3. Driver Propagation Delay
OUTtPDLZVCCVOM = (VOL + VCC) /2VOL0.25VFigure 4. Driver Enable and Disable Times (tPDSL, ttPDZL, tPDLS,PDLZ)
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7
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3.3V, High-Speed, RS-485/RS-422 Transceiver inSOT PackageMAX3362S10 or 3VDCL = 50pFOUTRL = 500ΩGENERATOR50ΩVCCVCC/2INtPDSH, tPDZHVOM = (VOH) /2OUTVOL tPDHZ00.25VVCCFigure 5. Driver Enable and Disable Times (tPDSH, tPDZH, tPDHS, tPDHZ)
VIDGENERATOR50ΩROUTCL = 15pF1.5V0VOM = VCC23.0VIN1.5VtPRLHOUTVOLVOM1.5VtPRHLVOM00VCCFigure 6. Receiver Propagation Delays
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3.3V, High-Speed, RS-485/RS-422 Transceiver in
SOT Package
1.5VS3RS1L = 1kΩVCC-1.5VVIDRCLS2GENERATOR50Ω3V3V1.5V1.5VIN0INtPRZHt0tPRSHVtPRZLOHPRSLVOUTOCOUT1.5VS1 OPEN0S1 CLOSEDVOLS2 CLOSEDS2 OPENS3 = 1.5VS3 = -1.5V3V3V1.5V1.5VININtPRHZ0tPRLZ00.25VVOHVOHOUTOUT00.25V0S1 OPENS1 CLOSEDS2 CLOSEDS2 OPENS3 = 1.5VS3 = -1.5VFigure 7. Receiver Enable and Disable Times
Detailed Description
distribution applications, such as cellular base stations.The MAX3362 low-power, high-speed transceiver forDriver and receiver propagation delays are below 50ns.RS-485/RS-422 communication operates from a singleThe output level is guaranteed at 1.5V on a standard+3.3V power supply. The device contains one differen-54Ωload.
tial line driver and one differential line receiver. The dri-The device has a hot-swap feature that eliminates falsever and receiver may be independently enabled. Whentransitions on the data cable during circuit initialization.disabled, outputs enter a high-impedance state.Also, drivers are short-circuit current limited and areThe transceiver guarantees data rates up to 20Mbps,protected against excessive power dissipation by ther-with an output skew of less than 6ns. This low skewmal shutdown circuitry.
time makes the MAX3362 ideal for multidrop clock/data
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3.3V, High-Speed, RS-485/RS-422 Transceiver inSOT PackageMAX3362Table 1. Transmitter Functional TableTRANSMITTINGINPUTSREXX01DE1100DI10XXA10High ZShutdownOUTPUTSB01High ZDrive REhigh and DE low (disable both receiver anddriver outputs) to enter low-power shutdown mode.
Hot-Swap Capability
Hot-Swap Input
When circuit boards are inserted into a hot or poweredbackplane, disturbances to the enable and differentialreceiver inputs can lead to data errors. Upon initial cir-cuit board insertion, the processor undergoes itspower-up sequence. During this period, the output dri-vers are high impedance and are unable to drive theDE input of the MAX3362 to a defined logic level.Leakage currents up to 10µA from the high-impedanceoutput could cause DE to drift to an incorrect logicstate. Additionally, parasitic circuit board capacitancecould cause coupling of VCCor GND to DE. These fac-tors could improperly enable the driver.
When VCCrises, an internal pulldown circuit holds DElow for at least 10µs and until the current into DEexceeds 200µA. After the initial power-up sequence,the pulldown circuit becomes transparent, resetting thehot-swap tolerable input.
Hot-Swap Input Circuitry
The MAX3362 enable inputs feature hot-swap capability.At the input there are two NMOS devices, M1 and M2(Figure 8). When VCCramps from 0, an internal 10µstimer turns on M2 and sets the SR latch, which also turnson M1. Transistors M2, a 300µA current sink, and M1, a30µA current sink, pull DE to GND through an 8kΩresis-tor. M2 is designed to pull DE to the disabled stateagainst an external parasitic capacitance up to 100pFthat may drive DE high. After 10µs, the timer deactivatesM2 while M1 remains on, holding DE low against three-state leakages that may drive DE high. M1 remains onuntil an external source overcomes the required inputcurrent. At this time, the SR latch resets and M1 turns off.When M1 turns off, DE reverts to a standard, high-impedance CMOS input. Whenever VCCdrops below1V, the hot-swap input is reset.
For REthere is a complimentary circuit employing twoPMOS devices pulling REto VCC.
Hot-Swap Line Transient
The circuit of Figure 9 shows a typical offset terminationused to guarantee a greater than 200mV offset when aline is not driven (the 50pF represents the minimumparasitic capacitance that would exist in a typical appli-cation). During a hot-swap event when the driver is
Table 2. Receiver Functional TableRECEIVINGINPUTSRE0011DEXX10A –B ≥ 200mV≤ -200mVXXOUTPUTRO10High-ZShutdownThe MAX3362 has a 1/8-unit-load receiver input imped-ance, allowing up to 256 transceivers to be connectedsimultaneously on a bus. The MAX3362 is designed forhalf-duplex communication.
Driver
The driver transfers single-ended input (DI) to differen-tial outputs (A, B). The driver enable (DE) input controlsthe driver. When DE is high, driver outputs are enabled.These outputs are high impedance when DE is low. When the driver is enabled, setting DI low forces thenoninverting output (A) low and inverting output (B)high. Conversely, drive DI high to force noninvertingoutput high and inverting output low (Table 1).
Drive REhigh and DE low (disable both receiver anddriver outputs) to enter low-power shutdown mode.
Receiver
The receiver reads differential inputs from the bus lines(A, B) and transfers this data as a single-ended output(RO). The receiver enable (RE) input controls thereceiver. Drive RElow to enable the receiver. DrivingREhigh places RO into a high-impedance state. When the receiver is enabled, RO is high if (A-B) ≥200mV. RO is low if (A-B) ≤-200mV.
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3.3V, High-Speed, RS-485/RS-422 Transceiver in
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VCC10µsTIMERTIMER8kΩDEDE(HOT SWAP)30µA300µAM1M2Figure 8. Simplified Structure of the Driver Enable Input (DE)
3.3V3.3VVCC1kΩVCC0YA10mV/divTIN0.1kΩ50pFAC-COUPLEDVCC OR GNDZB10mV/div1kΩAC-COUPLEDA-B10mV/div10µs/divFigure 9. Differential Power-Up Glitch (Hot Swap)Figure 10. Differential Power-Up Glitch (0.1V/µs)
______________________________________________________________________________________11
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3.3V, High-Speed, RS-485/RS-422 Transceiver inSOT PackageMAX33623.3VVCCAVCCA3.3V010mV/divAC-COUPLED050mV/divAC-COUPLEDB10mV/divAC-COUPLED10mV/div1µs/divB50mV/divAC-COUPLED10mV/div200ns/divA-BA-BFigure 11. Differential Power-Up Glitch (1V/µs)
Figure 12. Differential Power-Up Glitch (10V/µs)
connected to the line and is powered up the drivermust not cause the differential signal to drop below200mV. Figures 10, 11, and 12 show the results of theMAX3362 during power-up for three different VCCramprates (0.1V/µs, 1V/µs, and 10V/µs). The photos showthe VCCramp, the single-ended signal on each side ofthe 100Ωtermination, as well as the differential signalacross the termination.
256 Transceivers on the Bus
The standard RS-485 receiver input impedance is 12kΩ(one-unit load), and a standard driver can drive up to32 unit loads. The MAX3362 transceiver has a 1/8-unit-load receiver input impedance (96kΩ), allowing up to256 transceivers to be connected in parallel on onecommunication line. Any combination of these devicesand/or other RS-485 transceivers with a total of 32 unitloads or less can be connected to the line.
Low-Power Shutdown Mode
Low-power shutdown mode is initiated by bringing bothREhigh and DE low. In shutdown, the MAX3362 typi-cally draws only 1µA supply current.
REand DE may be driven simultaneously; the device isguaranteed not to enter shutdown if REis high and DEis low for less than 50ns. If the inputs are in this statefor at least 600ns, the device will enter shutdown.Enable times tPDZH, tPDZL, tPRZHand tPRZLin theSwitching Characteristics table assume the device wasnot in a low-power shutdown state. Enable times tPDSH,tPDSL, tPRSH,and tPRSL assume the device was shutdown. Drivers and receivers take longer to becomeenabled from low-power shutdown mode than from driver/receiver disable mode.
Driver Output Protection
Two mechanisms prevent excessive output current andpower dissipation caused by faults or by bus con-tention. The first, a foldback current limit on the outputstage, provides immediate protection against short cir-cuits over the whole common-mode voltage range (seeTypical Operating Characteristics). The second, a ther-mal shutdown circuit, forces the driver outputs into ahigh-impedance state if the die temperature becomesexcessive.
Typical Applications
The MAX3362 transceiver is designed for bidirectionaldata communications on multipoint bus transmissionlines. The Typical Operating Circuit shows a typical net-work applications circuit. To minimize reflections, theline should be terminated at both ends in its character-istic impedance, and stub lengths off the main lineshould be kept as short as possible.
Applications Information
Propagation Delays
Figures 5 and 6 show the typical propagation delays.Skew time is simply the difference between the low-to-high and high-to-low propagation delay. Smalldriver/receiver skew times help maintain a symmetricalmark-space ratio (50% duty cycle). Both the receiverskew time and driver skew time are under 6ns.
12______________________________________________________________________________________
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3.3V, High-Speed, RS-485/RS-422 Transceiver in
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Pin Configuration
Functional Diagram
TOP VIEWVCCDERO18VMAX3362CCDIDRE27BMAX3362ADE36ABDI45GNDRDRRESOT23GNDChip InformationTRANSISTOR COUNT: 708PROCESS: BiCMOS
______________________________________________________________________________________13
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3.3V, High-Speed, RS-485/RS-422 Transceiver inSOT PackageMAX3362Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,go to www.maxim-ic.com/packages.)
SOT23, 8L.EPSMaxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses areimplied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
14____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600©2002 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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