MAXIM MAX3385E handbook(1)
Contents
1. SLEW RATE vs LOAD CAPACITANCE Vcc 3 3V 250kbps data rate 0 1uF capacitors all transmitters loaded with 3kQ and CL TA 25 C unless otherwise noted OPERATING SUPPLY CURRENT vs LOAD CAPACITANCE V 2 B T1 TRANSMITTING AT 250kbps a 8 4 E 40 F 12 TRANSMITTING AT 15 6kbps 2 S oA C35 5 SMITTING AT 250kbps gt ie E 250kbps SMITTING AT 15 6kbps 10 gt S N 120kbps E Es gt 20 E 6 gt 20kb 2 85 15 ps B 4 e lt 10 FOR DATA RATES UP TO 250kbps 0 0 1000 2000 3000 4000 5000 0 1000 42000 3000 4000 5000 0 1000 2000 3000 4000 5000 LOAD CAPACITANCE pF LOAD CAPACITANCE pF LOAD CAPACITANCE pF Pin Description PIN NAME FUNCTION 50 SSOP il 1 10 11 N C o Connection Not internally connected 2 2 C1 Positive terminal of the voltage doubler charge pump capacitor 3 3 V 5 5V generated by the charge pump 4 4 C1 egative terminal of the voltage doubler charge pump capacitor 5 5 C2 Positive terminal of inverting charge pump capacitor 6 6 C2 egative terminal of inverting charge pump capacitor 7 7 V 5 5V generated by the charge pump 8 15 8 17 T OUT RS 232 Transmitter Outputs 9 14 9 16 R_IN RS 232 Receiver Inputs 10 13 12 15 R OU TTL CMOS Receiver Outputs 11 12 13 14 T IN T2. MAX3385E 15kV ESD Protected 3 0V to 5 5V Low Power up to 250kbps True RS 232 Transceiver NOTES Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product No circuit patent licenses are implied Maxim reserves the right to change the circuitry and specifications without notice at any time 12 Maxim Integrated Products 120 San Gabriel Drive Sunnyvale CA 94086 408 737 7600 1999 Maxim Integrated Products Printed USA MAXIM is a registered trademark of Maxim Integrated Products
3. MAXIM MAX3385E C2 MAXIMUM SLEW RATE TEST CIRCUIT The MAX3385E s transmitters are disabled and the out puts are forced into a high impedance state when the device is in shutdown SHDN gt GND The MAX3385E permits the outputs to be driven up to 12V in shut down The transmitter inputs do not have pull up resistors Connect unused inputs to GND or Vcc RS 232 Receivers The receivers convert RS 232 signals to CMOS logic output levels Table 1 Shutdown Mode Supply current falls to less than 10A in shutdown mode SHDN low When shut down the devices charge pumps are shut off V is pulled down to Vcc V is pulled to ground and the transmitter outputs are dis abled high impedance The time required to exit shut Table 1 Shutdown Truth Table SHDN T OUT R OUT 0 High Z Active 1 Active Active J3658 XVIN MAX3385E 15kV ESD Protected 3 0V to 5 5V Low Power up to 250kbps True RS 232 Transceiver 40us div Figure 2 Transmitter Outputs Exiting Shutdown or Powering Up down is typically 100us as shown in Figure 2 Connect SHDN to Vcc if the shutdown mode is not used 15kV ESD Protection As with all Maxim devices ESD protection structures are incorporated on all pins to protect against electro static discharges encountered during handling and assembly The driver outputs and receiver inputs of the MAX3385E have extra protection against static
4. TIME FS tb CURRENT WAVEFORM 1096 lr 0 7ns to Ins Figure 4b IEC 10000 4 2 ESD Generator Current Waveform Power Supply Decoupling In most circumstances a 0 1uF Vcc bypass capacitor is adequate In applications that are sensitive to power supply noise use a capacitor of the same value as charge pump capacitor C1 Connect bypass capaci tors as close to the IC as possible Operation Down to 2 7V Transmitter outputs will meet EIA TIA 562 levels of 3 7V with supply voltages as low as 2 7V Transmitter Outputs when Exiting Shutdown Figure 2 shows two transmitter outputs when exiting shutdown mode As they become active the two trans mitter outputs are shown going to opposite RS 232 lev 7 J3658 XVIN MAX3385E 15kV ESD Protected 3 0V to 5 5V Low Power up to 250kbps True RS 232 Transceiver els one transmitter input is high the other is low Each transmitter is loaded with 3kQ in parallel with 2500pF The transmitter outputs display no ringing or undesir able transients as they come out of shutdown Note that the transmitters are enabled only when the magnitude of V exceeds approximately 3V High Data Rates The MAX3385E maintains the RS 232 5 0V minimum transmitter output voltage even at high data rates Figure 6 shows a transmitter loopback test circuit Figure 7 shows a loopback test result at 120kbps and MAXUM MAX3385E 1000pF Figure 6 Loopback
5. V Output Resistance Voc V V 0 transmitter output 2V 300 10M Q Output Short Circuit Current 60 mA Output Leakage Current Vcc 0 or 3V to 5 5V VOUT 12V transmitters disabled 25 UA ESD PROTECTION Human Body Model EC1000 4 2 Air Discharge 15 kV EC1000 4 2 Contact Discharge 8 R_IN T OUT TIMING CHARACTERISTICS Vcc 8V to 5 5V C1 C4 O 1uF tested at 3 3V 1096 C1 0 047uF C2 C4 0 33uF tested at 5 0V 10 TA gt TMIN to TMAX unless otherwise noted Typical values are at TA gt 25 C PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Maximum Data Rate RL Ske cr 250 kbps one transmitter switching tPHL Receiver input to receiver output 0 15 Receiver Propagation Dela k S Time to Exit Shutdown VouT 2 3 7V RLOAD at V 3kQ 250 US Transmitter Skew tPLH Note 2 100 ns Receiver Skew ItPHL tPLH 50 ns Vcc 3 3V CL 150pF to 6 30 TA 25 C 1000pF Transition Region Slew Rate RL 3kQ to 7kQ Vius measured from 3V CL 150pF to 4 30 to 3V or 3V to 3V 2500pF Note 2 Transmitter skew is measured at the transmitter zero cross points AVLAZCLAVI 3 J3658 XVIN MAX3385E 15kV ESD Protected 3 0V to 5 5V Low Power up to 250kbps True RS 232 Transceiver Typical Operating Characteristics TRANSMITTER OUTPUT VOLTAGE vs LOAD CAPACITANCE
6. VIEW Pin Configurations continued at end of data sheet MAXIM Features ESD Protection for RS 232 I O Pins 15kV Human Body Model 8kV IEC 1000 4 2 Contact Discharge 15kV IEC 1000 4 2 Air Gap Discharge Latchup Free 300pA Supply Current 1pA Low Power Shutdown with Receivers Active 250kbps Guaranteed Data Rate 250us Time to Exit Shutdown with 3kQ Load on V 6V yus Guaranteed Slew Rate Meets EIA TIA 232 Specifications Down to 3 0V Ordering Information 9 9 9 9 9 PART TEMP RANGE PIN PACKAGE MAX3385ECAP 0 C to 70 C 20 SSOP MAX3385ECWN 0 C to 70 C 18 SO MAX3385EEAP 40 C to 85 C 20 SSOP Typical Operating Circuit 43 3V dt BYPASS T Vcc MAXIM T iE MAX3385E C4 0 1uF TTL CMOS RS 232 INPUTS OUTPUTS TTL CMOS RS 232 OUTPUTS INPUTS C3 CAN BE RETURNED TO EITHER Vcc OR GROUND NOTE SEE TABLE 2 FOR CAPACITOR SELECTION Maxim Integrated Products 1 For free samples amp the latest literature http www maxim ic com or phone 1 800 998 8800 For small orders phone 1 800 835 8769 J3658 XVIN MAX3385E 15kV ESD Protected 3 0V to 5 5V Low Power up to 250kbps True RS 232 Transceiver ABSOLUTE MAXIMUM RATINGS 6640 GND ence Haro tet te ue eec es bee te a d 0 3V to 6V V T0 GND Not lt 1 ee bite tet iie he ethene del 0 3V to 7V N lt TONI Note 1 xau et
7. 047uF C2 C4 0 33uF tested at 5 0V 410 TA TMIN to TMAX unless otherwise noted Typical values are at TA 25 C PARAMETER CONDITIONS MIN TYP MAX UNITS DC CHARACTERISTICS Vcc 3 3V or 5V TA 25 C Supply Current SHDN Vcc no load 0 3 1 mA Shutdown Supply Current SHDN GND 1 10 UA LOGIC INPUTS Input Logic Threshold Low T_IN SHDN 0 8 V m Voc 3 3V 2 0 Input Logic Threshold High _IN SHDN V Voc 5 0V 2 4 Transmitter Input Hysteresis 0 5 V Input Leakage Current T IN SHDN x0 01 UA RECEIVER OUTPUTS Output Leakage Current R_OUT receivers disabled 0 05 10 UA Output Voltage Low loUT 1 6mA 4 V Output Voltage High IOUT 1 0mA Vec Vec V 0 6 0 1 RECEIVER INPUTS Input Voltage Range 25 25 V E i Voc 3 3V 0 6 1 2 Input Threshold Low A 25 C V Voc 5 0V 0 8 1 5 i Voc 3 3V 1 5 2 4 Input Threshold High A 25 C V Vcc 5 0V 1 8 2 4 Input Hysteresis 0 5 V Input Resistance TA 25 C 3 5 7 kQ MAXIM 15kV ESD Protected 3 0 5 5V Low Power up to 250kbps True RS 232 Transceiver ELECTRICAL CHARACTERISTICS continued Vcc 8V to 5 5V C1 C4 O 1uF tested at 3 3V 1096 C1 0 047uF C2 C4 0 33uF tested at 5 0V 1096 TA TMIN to TMAX unless otherwise noted Typical values are at TA 25 C PARAMETER CONDITIONS MIN TYP MAX UNITS TRANSMITTER OUTPUTS Output Voltage Swing All transmitter outputs loaded with 3kQ to ground 5 5 4
8. 19 1437 Rev 1 10 99 AVLAZXLAMI 15kV ESD Protected 3 0V to 5 5V Low Power up to 250kbps True RS 232 Transceiver General Description The MAX3385E is a 3V powered EIA TIA 232 and V 28 V 24 communications interface with low power requirements high data rate capabilities and en hanced electrostatic discharge ESD protection All transmitter outputs and receiver inputs are protected to 15kV using IEC 1000 4 2 Air Gap Discharge 8kV using IEC 1000 4 2 Contact Discharge and 15kV using the Human Body Model The transceiver has a proprietary low dropout transmit ter output stage delivering true RS 232 performance from a 3 0V to 5 5V supply with a dual charge pump The charge pump requires only four small 0 1uF capac itors for operation from a 3 3V supply Each device is guaranteed to run at data rates of 250kbps while main taining RS 232 output levels The MAX3385E has two receivers and two drivers It features a 1A shutdown mode that reduces power con sumption and extends battery life in portable systems Its receivers can remain active in shutdown mode allowing external devices such as modems to be moni tored using only 10A supply current The MAX3385E is available in a space saving SSOP package in either the commercial 0 C to 70 C or extended industrial 40 C to 85 C temperature range Applications Hand Held Equipment Battery Powered Peripherals Equipment Printers Pin Configurations TOP
9. 2 without the need for additional ESD pro tection components The major difference between tests done using the Human Body Model and IEC 1000 4 2 is higher peak current in IEC 1000 4 2 because series resistance is lower in the IEC 1000 4 2 model Hence the ESD with stand voltage measured to IEC 1000 4 2 is generally lower than that measured using the Human Body Model Figure 4a shows the IEC 1000 4 2 model and Figure 4b shows the current waveform for the 8kV IEC 1000 4 2 Level 4 ESD contact discharge test The air gap test involves approaching the device with a charged probe The contact discharge method con nects the probe to the device before the probe is ener gized Machine Model The Machine Model for ESD tests all pins using a 200pF storage capacitor and zero discharge resis tance Its objective is to emulate the stress caused by contact that occurs with handling and assembly during manufacturing Of course all pins require this protec tion during manufacturing not just RS 232 inputs and outputs Therefore after PC board assembly the Machine Model is less relevant to I O ports Applications Information Capacitor Selection The capacitor type used for C1 CA is not critical for proper operation polarized or nonpolarized capacitors can be used The charge pump requires 0 1uF capaci tors for 3 3V operation For other supply voltages refer to Table 2 for required capacitor values Do not use val Table 2 Required Mini
10. S 232 Transceiver Package Information continued c h i 8 i x Ett qued s e B lt n l en LL INCHES MILLIMETERS INCHES MILLIMETERS MIN AX MIN MAX MIN AX MIN MAX N MS013 0 093 0104 8 35 2 65 D 10 398 0 413 10 10 110 50116 AA 1 0 004 0 012 0 10 0 30 D 0 447 0 463 1135117518 AB B 0 014 0 019 0 35 0 49 D 10 496 0 512 112 60 13 00 80 AC C 0 009 0 013 0 23 032 D 0 598 0 614 15 20115 60 24 AD e 0 050 Lc D 10 697 10 713 17 7011810188 AE EX 0 291 0 29 99 740 15 60 MES H 0 3941 0 419 10 00 10 63 1 D amp E DO NOT INCLUDE MOLD FLASH h 0 010 0 030 0 2e5 0 75 MOLD FLASH OR PROTRUSIONS NOT oe eecbad eet ME 102mm 004 4 CONTROLLING DIMENSION MILLIMETER 5 MEETS JEDEC MS013 XX AS SHOWN N ABOVE TABLE 6 N NUMBER OF PINS LAAK 1 AVA IE FAMILY DUTLINE SOIC 001 21 0042 A PROPRIETARY INFORMATION DOCUMENT CONTROL NUMBER REV 7 MAXIM 11 JG8EEXVN
11. TL CMOS Transmitter Inputs 16 18 GND Ground 17 19 Vcc 3 0V to 5 5V Supply Voltage 18 20 SHDN Active Low Shutdown Control Input Drive low to shut down transmitters and charge AVLAZCLAVI 15kV ESD Protected 3 0V 5 5V Low Power up to 250kbps True RS 232 Transceiver MAXIM MAX3385E C2 2500pF MINIMUM SLEW RATE TEST CIRCUIT Figure 1 Slew Rate Test Circuits Detailed Description Dual Charge Pump Voltage Converter The MAX3385E s internal power supply consists of a regulated dual charge pump that provides output volt ages of 5 5V doubling charge pump and 5 5V inverting charge pump over the 3 0V to 5 5V Vcc range The charge pump operates in discontinuous mode if the output voltages are less than 5 5V the charge pump is enabled and if the output voltages exceed 5 5V the charge pump is disabled Each charge pump requires a flying capacitor C1 C2 anda reservoir capacitor C3 C4 to generate the V and V supplies Figure 1 RS 232 Transmitters The transmitters are inverting level translators that con vert CMOS logic levels to 5 0V EIA TIA 232 levels The MAX3385E transmitters guarantee a 250kbps data rate with worst case loads of 3kQ in parallel with 1000pF providing compatibility with PC to PC communication software such as LapLink Transmitters can be paral leled to drive multiple receivers or mice Laplink is a trademark of Traveling Software MAXIM
12. Test Circuit Figure 8 shows the same test at 250kbps For Figure 7 all transmitters were driven simultaneously at 120kbps into RS 232 loads in parallel with 1000pF For Figure 8 a single transmitter was driven at 250kbps and all transmitters were loaded with an RS 232 receiver in parallel with 1000pF Interconnection with 3V and 5V Logic The MAX3385E can directly interface with various 5V logic families including ACT and HCT CMOS See Table 3 for more information on possible combinations of interconnections sVidiv 5V div 5vjdiv CI C4 0dgF 1 xiii E sear 2us div Figure 7 MAX3385E Loopback Test Result at 120kbps l 5V div 5V div 1 5V div H Vec 3 3V 01 04 01 i 2us div Figure 8 MAX3385E Loopback Test Result at 250kbps MAXIM 15kV ESD Protected 3 0 5 5V Low Power up to 250kbps True RS 232 Transceiver Table 3 Logic Family Compatibility with Various Supply Voltages SYSTEM Vcc SUPPLY POWER SUPPLY VOLTAGE is COMPATIBILITY V 3 3 33 Compatible with all CMOS families Compatible with all TTL and CMOS families 3 3 Compatible with ACT and HCT CMOS and with AC HC or CD4000 CMOS MAXIM Pin Configurations continued TOP VIEW Chip Information TRANSISTOR COUNT 1129 J3658 XVIN MAX3385E 15kV ESD Protected 3 0V to 5 5V Low Power up to 250kbps
13. True RS 232 Transceiver Package Information SSOP EPS INCHES MILLIMETERS MIN MAX MIN MAX 0 239 0249 6 07 633 14L D 0 239 0249 6 07 633 16L Di 0 27910 2991 7 07 7 33 20L D 0 317 0 328 8 07 8 33 24L DJ0 397 0 407 10 07 10 33 28L INCHES ILLIMETERS DIM MIN MAX MIN MAX A 0 068 0 078 1 73 1 99 1 0 002 0 008 0 05 0 21 B 0 010 0 015 0 25 10 38 C 0 004 0 008 0 09 0 20 D SEE VARIATIONS E 0 205 0 209 5 20 5 38 e 0 0256 BSC 0 65 BSC H 0 301 0 311 7 65 7 90 L 0 025 0037 0 63 0 95 a 0 8 0 8 D A NOTES 1 D amp E DO NOT INCLUDE LD FLASH 2 MOLD FLASH OR PROTRUSIONS N T EXCEED 15mm 006 3 CONTROLLING DIMENSION MILLIMETER M AXI SVI PROPRIETARY INFORMATION DILE PACKAGE OUTLINE SSOP 5 3X 65mm ICUMENT CONTROL ND REV APPROVAL Dot 1 21 0056 A A MAXIM 15kV ESD Protected 3 0V 5 5V Low Power up to 250kbps True R
14. electric ity Maxim s engineers have developed state of the art structures to protect these pins against ESD of 15kV without damage The ESD structures withstand high ESD in all states normal operation shutdown and powered down After an ESD event Maxim s E ver sions keep working without latchup whereas compet ing RS 232 products can latch and must be powered down to remove latchup ESD protection can be tested in various ways the transmitter outputs and receiver inputs of this product family are characterized for protection to the following limits 1 15kV using the Human Body Model 2 8kV using the contact discharge method specified in IEC 1000 4 2 3 15kV using IEC 1000 4 2 s air gap method ESD Test Conditions ESD performance depends on a variety of conditions Contact Maxim for a reliability report that documents test setup test methodology and test results Human Body Model Figure 3a shows the Human Body Model and Figure 3b shows the current waveform it generates when dis charged into a low impedance This model consists of a 100pF capacitor charged to the ESD voltage of interest which is then discharged into the test device through a 1 5kQ resistor IEC 1000 4 2 The IEC 1000 4 2 standard covers ESD testing and per formance of finished equipment it does not specifically refer to integrated circuits The MAX3385E helps you design equipment that meets Level 4 the highest level of IEC 1000 4
15. mum Capacitance Values Vcc C1 CByPASS C2 C3 C4 V HF HF 3 0 to 3 6 0 1 0 1 4 5 to 5 5 0 047 0 33 3 0 to 5 5 0 1 0 47 MAXIM 15kV ESD Protected 3 0V 5 5V Low Power up to 250kbps True RS 232 Transceiver gh g CURRENT ies LIMIT RESISTOR RESISTANCE HIGH Lp DEVICE VOLTAGE STORAGE UNDER DC CAPACITOR TEST SOURCE Figure 3a Human Body ESD Test Model Rc 50M to 100M DISCHARGE RESISTANCE CHARGE CURRENT LIMIT RESISTOR HIGH DEVICE VOLTAGE STORAGE UNDER DC CAPACITOR TEST SOURCE Figure 4a IEC 1000 4 2 ESD Test Model ues smaller than those listed in Table 2 Increasing the capacitor values e g by a factor of 2 reduces ripple on the transmitter outputs and slightly reduces power consumption C2 C3 and C4 can be increased without changing C1 s value However do not increase C1 without also increasing the values of C2 C3 CA and CByPAss to maintain the proper ratios C1 to the other capacitors When using the minimum required capacitor values make sure the capacitor value does not degrade excessively with temperature If in doubt use capaci tors with a larger nominal value The capacitor s equiva lent series resistance ESR which usually rises at low temperatures influences the amount of ripple on V and V MAXIM _ Ip 100 PEAK TO PEAK RINGING 90 NOT DRAWN TO SCALE AMPERES 36 8 10
16. te tee a othe as 0 3V to 7V EL NOTE D e Nt tee ese ette 13V Input Voltages TIN SHIDN tO GND dorn egt 0 3V to 6V REIN TOSGINBD 2 5 sete seat 25V Output Voltages TOU TO GND 13 2V ROUT itte 0 3V to Vcc 0 3V Short Circuit Duration T OUT to GND Continuous Continuous Power Dissipation TA 70 C 20 Pin SSOP derate 8 00mW C above 70 C 640mW 18 Pin SO derate 9 52mW C above 707 762mW Operating Temperature Ranges MAXSS8BEQRAP ta st ope oet ttt 0 C to 70 C MAX3385ECWN MAX3385EEAP Storage Temperature Range Lead Temperature soldering 10sec 300 C 0 C to 70 C Note 1 V and V can have maximum magnitudes of 7V but their absolute difference cannot exceed 13V Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied Exposure to absolute maximum rating conditions for extended periods may affect device reliability ELECTRICAL CHARACTERISTICS Vcc 8V to 5 5V C1 C4 O 1uF tested at 3 3V 10 C1 0
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