19-1949; Rev 0; 1/01 ±15kV ESD-Protected, 3.0V to 5.5V, Low-Power, up to 250kbps, True RS-232 Transceiver ____________________________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 ♦ 300µA Supply Current ♦ 1µA Low-Power Shutdown ♦ 250kbps Guaranteed Data Rate ♦ 250µs Time to Exit Shutdown with 3kΩ Load on V+ ♦ 6V/µs Guaranteed Slew Rate ♦ Transmitter and Receiver Outputs High Impedance in Shutdown ♦ Meets EIA/TIA-232 Specifications Down to 3.0V The MAX3384E is available in a space-saving SSOP package in either the commercial (0°C to +70°C) or extended temperature (-40°C to +85°C) range. Ordering Information PART TEMP. RANGE MAX3384ECAP 0°C to +70°C 20 SSOP MAX3384ECWN 0°C to +70°C 18 SO MAX3384EEAP ________________________Applications Hand-Held Equipment Peripherals Printers Battery-Powered Equipment PDAs CBYPASS 20 SHDN 19 VCC V+ 3 18 GND C2- 6 VCC V+ C1- C3* 0.1µF C2+ V- C2- C4 0.1µF T1OUT T1IN RS-232 OUTPUTS TTL/CMOS INPUTS T2IN T2OUT 17 T1OUT C1- 4 C2+ 5 C1+ MAX3384E C2 0.1µF C1+ 2 20 SSOP +3.3V Pin Configurations N.C. 1 -40°C to +85°C Typical Operating Circuit C1 0.1µF TOP VIEW PIN-PACKAGE MAX3384E 16 R1IN R1OUT R1IN 15 R1OUT V- 7 14 T1IN T2OUT 8 13 T2IN R2IN 9 12 R2OUT N.C. 10 11 N.C. SSOP Pin Configurations continued at end of data sheet. TTL/CMOS OUTPUTS 5k R2OUT RS-232 INPUTS R2IN 5k GND SHDN * C3 CAN BE RETURNED TO EITHER VCC OR GROUND. NOTE: SEE TABLE 2 FOR CAPACITOR SELECTION †Covered by U.S. Patent numbers 4,636,930; 4,679,134; 4,777,577; 4,797,899; 4,809,152; 4,897,774; 4,999,761; and other patents pending. ________________________________________________________________ Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX3384E † ________________General Description The MAX3384E is a 3V-powered EIA/TIA-232 and V.28/V.24 communications interface with low power requirements, high data-rate capabilities, and enhanced 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 transmitter 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 0.1µF capacitors for operation from a +3.3V supply. Each device is guaranteed to run at data rates of 250kbps while maintaining RS-232 output levels. The MAX3384E has two receivers and two drivers. It features a 1µA shutdown mode that reduces power consumption and extends battery life in portable systems. MAX3384E ±15kV ESD-Protected, 3.0V to 5.5V, Low-Power, up to 250kbps, True RS-232 Transceiver ABSOLUTE MAXIMUM RATINGS VCC to GND ..............................................................-0.3V to +6V Continuous Power Dissipation (TA = +70°C) V+ to GND (Note 1) ..................................................-0.3V to +7V 20-Pin SSOP (derate 8.00mW/°C above +70°C) ..........640mW V- to GND (Note 1) ...................................................+0.3V to -7V 18-Pin SO (derate 9.52mW/°C above +70°C)...............762mW V+ + |V-| (Note 1) .................................................................+13V Operating Temperature Ranges Input Voltages MAX3384ECAP ....................................................0°C to +70°C T_IN, SHDN to GND ..............................................-0.3V to +6V MAX3384ECWN ...................................................0°C to +70°C R_IN to GND .....................................................................±25V MAX3384EEAP .................................................-40°C to +85°C Output Voltages Junction Temperature ........................................................150°C T_OUT to GND...............................................................±13.2V Storage Temperature Range .............................-65°C to +150°C R_OUT .....................................................-0.3V to (VCC + 0.3V) Lead Temperature (soldering, 10s) .................................+300°C Maximum Current into T_OUT ........................................±100mA Short-Circuit Duration, T_OUT to GND.......................Continuous 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 (V CC = +3V to +5.5V, for tests at 3.3V ±10%, C1–C4 = 0.1µF; for tests at +5V ±10%, C1 = 0.047µF, C2–C4 = 0.33µF; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER CONDITIONS MIN TYP MAX UNITS 0.3 1 mA 1 10 µA 0.8 V DC CHARACTERISTICS (VCC = +3.3V or +5V, TA = +25°C) Supply Current SHDN = VCC, no load Shutdown Supply Current SHDN = GND LOGIC INPUTS Input Logic Threshold Low Input Logic Threshold High T_IN, SHDN T_IN, SHDN VCC = +3.3V 2.0 VCC = +5V 2.4 Transmitter Input Hysteresis V 0.5 V T_IN, SHDN ±0.01 ±1 µA Output Leakage Current R_OUT, receivers disabled ±0.05 ±10 µA Output Voltage Low IOUT = 1.6mA 0.4 V Input Leakage Current RECEIVER OUTPUTS Output Voltage High VCC 0.6 IOUT = -1.0mA VCC 0.1 V RECEIVER INPUTS Input Voltage Range -25 Input Threshold Low TA = +25°C Input Threshold High TA = +25°C 0.6 1.2 VCC = +5V 0.8 1.5 1.5 2.4 VCC = +5V 1.8 2.4 2 0.5 TA = +25°C 3 5 _______________________________________________________________________________________ V V VCC = +3.3V Input Hysteresis Input Resistance +25 VCC = +3.3V V V 7 kΩ ±15kV ESD-Protected, 3.0V to 5.5V, Low-Power, up to 250kbps, True RS-232 Transceiver (V CC = +3V to +5.5V, for tests at 3.3V ±10%, C1–C4 = 0.1µF; for tests at +5V ±10%, C1 = 0.047µF, C2–C4 = 0.33µF; 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 3kΩ to ground ±5 ±5.4 V Output Resistance VCC = 0, transmitter output = ±2V 300 10M Ω Output Short-Circuit Current Output Leakage Current VCC = 0 or +3V to +5.5V, VOUT = ±12V, transmitters dis- ±60 mA ±25 µA ESD PROTECTION R_IN, T_OUT Human Body Model ±15 IEC1000-4-2 Air Discharge ±15 IEC1000-4-2 Contact Discharge ±8 kV TIMING CHARACTERISTICS (VCC = +3V to +5.5V, for tests at 3.3V ±10%, C1–C4 = 0.1µF; for tests at +5V ±10%, C1 = 0.047µF, C2–C4 = 0.33µF; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS RL = 3kΩ, CL = 1000pF, one transmitter switching Maximum Data Rate TYP MAX 250 UNITS kbps Receiver input to receiver output, CL = 150pF 0.15 Receiver Output Enable Time SHDN from GND to VCC 200 ns Receiver Output Disable Time SHDN from VCC to GND 200 ns VOUT ≥ +3.7V, RLOAD at V+ = 3kΩ 250 µs (Note 2) 100 ns 50 ns Receiver Propagation Delay tPHL MIN tPLH Time to Exit Shutdown Transmitter Skew tPHL - tPLH| Receiver Skew tPHL - tPLH| Transition-Region Slew Rate VCC = +3.3V, TA = +25°C, RL = 3kΩ to 7kΩ, measured from +3V to -3V or -3V to +3V µs 0.15 CL = 150pF to 1000pF 6 30 CL = 150pF to 2500pF 4 30 V/µs Note 2: Transmitter skew is measured at the transmitter zero cross points. _______________________________________________________________________________________ 3 MAX3384E ELECTRICAL CHARACTERISTICS (continued) __________________________________________Typical Operating Characteristics (VCC = +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ and CL, TA = +25°C, unless otherwise noted.) -SLEW 12 SLEW RATE (V/µs) T1 TRANSMITTING AT 250kbps T2 TRANSMITTING AT 15.6kbps 0 -1 -2 -3 -4 -5 -6 14 45 10 +SLEW 8 6 4 VOUT- 2000 3000 4000 5000 120kbps 25 20 20kbps 15 0 0 LOAD CAPACITANCE (pF) 250kbps 30 5 FOR DATA RATES UP TO 250kbps 1000 35 10 2 0 0 T1 TRANSMITTING AT 250kbps T2 TRANSMITTING AT 15.6kbps 40 SUPPLY CURRENT (mA) 4 3 2 1 16 MAX3884E-02 VOUT+ MAX3384E-01 6 5 OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE SLEW RATE vs. LOAD CAPACITANCE MAX3884E-03 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE TRANSMITTER OUTPUT VOLTAGE (V) MAX3384E ±15kV ESD-Protected, 3.0V to 5.5V, Low-Power, up to 250kbps, True RS-232 Transceiver 1000 2000 3000 4000 5000 0 1000 2000 3000 4000 5000 LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) ______________________________________________________________ Pin Description PIN 4 NAME FUNCTION SO SSOP 1 1, 10, 11 N.C. No 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- Negative terminal of the voltage-doubler charge-pump capacitor. 5 5 C2+ Positive terminal of inverting charge-pump capacitor. 6 6 C2- Negative terminal of inverting charge-pump capacitor. 7 7 V- 8, 15 8, 17 T_OUT 9, 14 9, 16 R_IN 10, 13 12, 15 R_OUT 11, 12 13, 14 T_IN TTL/CMOS Transmitter Inputs 16 18 GND Ground 17 19 VCC +3.0V to +5.5V Supply Voltage. Connect a 0.1µF capacitor to GND. 18 20 SHDN -5.5V generated by the charge pump. RS-232 Transmitter Outputs. High Z when SHDN is low. RS-232 Receiver Inputs TTL/CMOS Receiver Outputs. High Z when SHDN is low. Active-Low Shutdown-Control Input. Drive low to shut down transmitters, receivers and charge pumps. _______________________________________________________________________________________ ±15kV ESD-Protected, 3.0V to 5.5V, Low-Power, up to 250kbps, True RS-232 Transceiver VCC 0.1µF C1+ 0.1µF VCC C1+ V+ C1 C3 C1C2+ 3kΩ C3 C1C2+ V- VC4 C2T_ OUT T_ IN T_ OUT T_ IN R_ IN R_ OUT R_ IN R_ OUT 5kΩ SHDN 3kΩ MAX3384E C2 C4 C2- VCC V+ C1 MAX3384E C2 VCC 5kΩ 3kΩ GND 2500pF VCC SHDN MINIMUM SLEW-RATE TEST CIRCUIT GND 150pF 7kΩ MAXIMUM SLEW-RATE TEST CIRCUIT Figure 1. Slew-Rate Test Circuits _______________Detailed Description Dual Charge-Pump Voltage Converter The MAX3384E’s internal power supply consists of a regulated dual charge pump that provides output voltages 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) and a reservoir capacitor (C3, C4) to generate the V+ and Vsupplies (Figure 1). The MAX3384E’s transmitters are disabled and the outputs are forced into a high-impedance state when the device is in shutdown (SHDN = GND). The MAX3384E permits the outputs to be driven up to ±12V in shutdown. The transmitter inputs do not have pullup resistors. Connect unused inputs to GND or VCC. RS-232 Receivers The receivers convert RS-232 signals to CMOS-logic output levels (Table 1). The receiver outputs are forced into a high-impedance state when the device is in shutdown (SHDN = GND). This allows a single UART to multiplex between different protocols. RS-232 Transmitters Shutdown Mode The transmitters are inverting level translators that convert CMOS-logic levels to ±5.0V EIA/TIA-232 levels. The MAX3384E transmitters guarantee a 250kbps data rate with worst-case loads of 3kΩ in parallel with 1000pF, providing compatibility with PC-to-PC communication software (such as LapLink™). Transmitters can be paralleled to drive multiple receivers or mice. Supply current falls to less than 1µA in shutdown mode (SHDN = low). When shut down, the device’s charge Laplink is a trademark of Traveling Software. Table 1. Shutdown Truth Table SHDN T_OUT R_OUT 0 High-Z High-Z 1 Active Active _______________________________________________________________________________________ 5 MAX3384E VCC MAX3384E ±15kV ESD-Protected, 3.0V to 5.5V, Low-Power, up to 250kbps, True RS-232 Transceiver 5V/div 0 SHDN T2OUT 2V/div 0 T1OUT VCC = 3.3V C1–C4 = 0.1µF 40µs/div Figure 2. Transmitter Outputs Exiting Shutdown or Powering Up pumps are shut off, V+ is pulled down to VCC, V- is pulled to ground, and the transmitter and receiver outputs are disabled (high impedance). The time required to exit shutdown is typically 100µs, 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 electrostatic discharges encountered during handling and assembly. The driver outputs and receiver inputs of the MAX3384E have extra protection against static electricity. 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” versions keep working without latchup, whereas competing 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. 6 Human Body Model Figure 3a shows the Human Body Model, and Figure 3b shows the current waveform it generates when discharged 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 1.5kΩ resistor. IEC 1000-4-2 The IEC 1000-4-2 standard covers ESD testing and performance of finished equipment; it does not specifically refer to integrated circuits. The MAX3384E helps you design equipment that meets Level 4 (the highest level) of IEC 1000-4-2, without the need for additional ESD-protection 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 withstand 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 connects the probe to the device before the probe is energized. Machine Model The Machine Model for ESD tests all pins using a 200pF storage capacitor and zero discharge resistance. Its objective is to emulate the stress caused by contact that occurs with handling and assembly during manufacturing. Of course, all pins require this protection 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–C4 is not critical for proper operation; polarized or nonpolarized capacitors Table 2. Required Minimum Capacitance Values VCC (V) C1, CBYPASS (µF) C2, C3, C4 (µF) 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 _______________________________________________________________________________________ ±15kV ESD-Protected, 3.0V to 5.5V, Low-Power, up to 250kbps, True RS-232 Transceiver RD 1500Ω CHARGE-CURRENT LIMIT RESISTOR HIGHVOLTAGE DC SOURCE MAX3384E RC 1M Cs 100pF IP 100% 90% DISCHARGE RESISTANCE STORAGE CAPACITOR DEVICE UNDER TEST Ir PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) AMPERES 36.8% 10% 0 0 Figure 3a. Human Body ESD Test Model TIME tRL tDL CURRENT WAVEFORM Figure 3b. Human Body Model Current Waveform I 100% CHARGE-CURRENT LIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 150pF RD 330Ω 90% DISCHARGE RESISTANCE STORAGE CAPACITOR I PEAK RC 50M to 100M DEVICE UNDER TEST 10% t r = 0.7ns to 1ns t 30ns 60ns Figure 4a. IEC 1000-4-2 ESD Test Model Figure 4b. IEC 1000-4-2 ESD Generator Current Waveform can be used. The charge pump requires 0.1µF capacitors for 3.3V operation. For other supply voltages, refer to Table 2 for required capacitor values. Do not use values 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, C4, 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 capacitors 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-. Power-Supply Decoupling In most circumstances, a 0.1µF VCC bypass capacitor is adequate. In applications that are sensitive to powersupply noise, use a capacitor of the same value as charge-pump capacitor C1. Connect bypass capacitors 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. _______________________________________________________________________________________ 7 MAX3384E ±15kV ESD-Protected, 3.0V to 5.5V, Low-Power, up to 250kbps, True RS-232 Transceiver Transmitter Outputs when Exiting Shutdown Figure 2 shows two transmitter outputs when exiting shutdown mode. As they become active, the two transmitter outputs are shown going to opposite RS-232 levels (one transmitter input is high, the other is low). Each transmitter is loaded with 3kΩ in parallel with 2500pF. The transmitter outputs display no ringing or undesirable 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 MAX3384E 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 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. VCC 0.1µF C1+ 5V/div T1IN VCC V+ C3 C1 C1C2+ 5V/div MAX3384E T1OUT VC4 C2 C2- R1OUT T_ OUT T_ IN 5V/div VCC = 3.3V C1–C4 = 0.1µF 2µs/div R_ IN R_ OUT Figure 7. MAX3384E Loopback Test Result at 120kbps 5kΩ VCC SHDN 1000pF GND T1IN 5V/div T1OUT 5V/div Figure 6. Loopback Test Circuit R1OUT 5V/div VCC = 3.3V C1–C4 = 0.1µF 2µs/div Figure 8. MAX3384E Loopback Test Result at 250kbps 8 _______________________________________________________________________________________ ±15kV ESD-Protected, 3.0V to 5.5V, Low-Power, up to 250kbps, True RS-232 Transceiver TOP VIEW SYSTEM POWER-SUPPLY VOLTAGE (V) VCC SUPPLY VOLTAGE (V) 3.3 3.3 5 5 Pin Configurations (continued) COMPATIBILITY Compatible with all CMOS families 5 Compatible with all TTL and CMOS families 3.3 Compatible with ACT and HCT CMOS, and with AC, HC, or CD4000 CMOS N.C. 1 18 SHDN C1+ 2 17 VCC V+ 3 16 GND 15 T1OUT C1- 4 C2+ 5 MAX3384E 14 R1IN 13 R1OUT C2- 6 V- 7 12 T1IN T2OUT 8 11 T2IN 10 R2OUT R2IN 9 SO Interconnection with 3V and 5V Logic The MAX3384E can directly interface with various 5V logic families, including ACT and HCT CMOS. See Table 3 for more information on possible combinations of interconnections. ___________________Chip Information TRANSISTOR COUNT: 1129 Process: BiCMOS _______________________________________________________________________________________ 9 MAX3384E Table 3. Logic-Family Compatibility with Various Supply Voltages ________________________________________________________Package Information SSOP.EPS MAX3384E ±15kV ESD-Protected, 3.0V to 5.5V, Low-Power, up to 250kbps, True RS-232 Transceiver 10 ______________________________________________________________________________________ ±15kV ESD-Protected, 3.0V to 5.5V, Low-Power, up to 250kbps, True RS-232 Transceiver SOICW.EPS 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. 11 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX3384E Package Information (continued)