19-2139; Rev 0; 8/01 ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP Features ♦ 6 ✕ 5 Chip-Scale Packaging (UCSP) The MAX3228E/MAX3229E achieve a 1µA supply current with Maxim’s AutoShutdown™ feature. They save power without changes to existing BIOS or operating systems by entering low-power shutdown mode when the RS-232 cable is disconnected, or when the transmitters of the connected peripherals are off. The transceivers have a proprietary low-dropout transmitter output stage, delivering RS-232 compliant performance from a +3.1V to +5.5V supply, and RS-232 compatible performance with a supply voltage as low as +2.5V. The dual charge pump requires only four small 0.1µF capacitors for operation from a +3.0V supply. Each device is guaranteed to run at data rates of 250kbps while maintaining RS-232 output levels. The MAX3228E/MAX3229E offer a separate power-supply input for the logic interface, allowing configurable logic levels on the receiver outputs and transmitter inputs. Operating over a +1.65V to VCC range, VL provides the MAX3228E/MAX3229E compatibility with multiple logic families. The MAX3229E contains one receiver and one transmitter. The MAX3228E contains two receivers and two transmitters. The MAX3228E/MAX3229E are available in tiny chip-scale packaging and are specified across the extended industrial temperature range of -40°C to +85°C. ♦ Meets EIA/TIA-232 Specifications Down to +3.1V ♦ ESD Protection for RS-232 I/O Pins: ±15kV—IEC 1000-4-2 Air-Gap Discharge ±8kV—IEC 1000-4-2 Contact Discharge ±15kV—Human Body Model ♦ 1µA Low-Power AutoShutdown ♦ 250kbps Guaranteed Data Rate ♦ RS-232 Compatible to +2.5V Allows Operation from Single Li+ Cell ♦ Small 0.1µF Capacitors ♦ Configurable Logic Levels Ordering Information PART TEMP. RANGE PINPACKAGE MAX3228EEBV -40°C to +85°C 6 ✕ 5 UCSP* MAX3229EEBV -40°C to +85°C 6 ✕ 5 UCSP* *Requires solder temperature profile described in the Absolute Maximum Ratings section. *UCSP reliability is integrally linked to the user’s assembly methods, circuit board material, and environment. Refer to the UCSP Reliabilitly Notice in the UCSP Reliability section of this data sheet for more information. Typical Operating Circuits 2.5V TO 5.5V 1.65V TO 5.5V 0.1µF CBYPASS 0.1µF A1 C1 C1 0.1µF D1 A2 Applications Personal Digital Assistants Cell Phone Data Lump Cables C2 0.1µF Cell Phones C1- VL C2+ V- T1OUT A6 T1IN C3 0.1µF A4 C4 0.1µF E3 RS-232 OUTPUTS VL T2OUT E4 B6 T2IN VL R1IN D6 R1OUT TTL/CMOS OUTPUTS VL E6 5kΩ RS-232 INPUTS R2IN E5 C6 R2OUT 5kΩ VL VL Pin Configurations appear at end of data sheet. INVALID 20µA 20µA AutoShutdown is a trademark of Maxim Integrated Products, Inc. B1 VL C2- Typical Operating Circuits continued at end of data sheet. UCSP is a trademark of Maxim Integrated Products, Inc. V+ MAX3228E TTL/CMOS INPUTS Set-Top Boxes Hand-Held Devices A3 A5 VCC C1+ E2 FORCEOFF C5 B5 FORCEON TO POWERMANAGEMENT UNIT VL GND E1 ________________________________________________________________ Maxim Integrated Products 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. 1 MAX3228E/MAX3229E General Description The MAX3228E/MAX3229E are +2.5V to +5.5V powered EIA/TIA-232 and V.28/V.24 communications interfaces with low power requirements, high data-rate capabilities, and enhanced electrostatic discharge (ESD) protection, in a chip-scale package (UCSP™). 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. MAX3228E/MAX3229E ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP ABSOLUTE MAXIMUM RATINGS VCC to GND ...........................................................-0.3V to +6.0V V+ to GND .............................................................-0.3V to +7.0V V- to GND ..............................................................+0.3V to -7.0V V+ to |V-| (Note 1) ................................................................+13V VL to GND..............................................................-0.3V to +6.0V Input Voltages T_IN_, FORCEON, FORCEOFF to GND .....-0.3V to (VL + 0.3V) R_IN_ to GND ...................................................................±25V Output Voltages T_OUT to GND ...............................................................±13.2V R_OUT INVALID to GND ............................-0.3V to (VL + 0.3V) INVALID to GND..........................................-0.3V to (VCC +0.3V) Short-Circuit Duration T_OUT to GND........................Continuous Continuous Power Dissipation (TA = +70°C) 6 ✕ 5 UCSP (derate 10.1mW/°C above TA = +70°C) ...805mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Bump Temperature (Soldering) (Note 2) Infrared (15s) ...............................................................+200°C Vapor Phase (20s) .......................................................+215°C Note 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V. Note 2: This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device can be exposed to during board level solder attach and rework. This limit permits only the use of the solder profiles recommended in the industry-standard specification, JEDEC 020A, paragraph 7.6, Table 3 for IR/VPR and convection reflow. Preheating is required. Hand or wave soldering is not allowed. 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 = +2.5V to +5.5V, VL = +1.65V to +5.5V, C1–C4 = 0.1µF, tested at +3.3V ±10%, TA = TMIN to TMAX. Typical values are at TA = +25°C, unless otherwise noted.) (Note 3) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DC CHARACTERISTICS VL Input Voltage Range VCC Supply Current, AutoShutdown VCC Supply Current, AutoShutdown Disabled VL Supply Current VL ICC ICC IL 1.65 VCC + 0.3 V FORCEON = GND FORCEOFF = VL, all RIN open 10 µA FORCEOFF = GND 10 µA FORCEON, FORCEOFF floating 1 mA 1 mA FORCEON = FORCEOFF = VL no load 0.3 FORCEON or FORCEOFF = GND, VCC = VL = +5V 85 FORCEON, FORCEOFF floating 1 µA LOGIC INPUTS Pullup Currents FORCEON, FORCEOFF to VL Input Logic Low T_IN, FORCEON, FORCEOFF Input Logic High T_IN, FORCEON, FORCEOFF Transmitter Input Hysteresis Input Leakage Current 20 µA 0.4 0.66 ✕ VL 0.5 T_IN V V ±0.01 V ±1 µA RECEIVER OUTPUTS 2 Output Leakage Currents R_OUT, receivers disabled, FORCEOFF = GND or in AutoShutdown ±10 µA Output Voltage Low IOUT = 0.8mA 0.4 V Output Voltage High IOUT = -0.5mA VL - 0.4 VL - 0.1 _______________________________________________________________________________________ V ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP (VCC = +2.5V to +5.5V, VL = +1.65V to +5.5V, C1–C4 = 0.1µF, tested at +3.3V ±10%, TA = TMIN to TMAX. Typical values are at TA = +25°C, unless otherwise noted.) (Note 3) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS +25 V RECEIVER INPUTS Input Voltage Range -25 Input Threshold Low TA = +25°C Input Threshold High TA = +25°C VCC = +3.3V 0.6 1.2 VCC = +5.0V 0.8 1.7 V VCC = +3.3V 1.3 2.4 VCC = +5.0V 1.8 2.4 Input Hysteresis 0.5 Input Resistance 3 5 V V 7 kΩ AUTO SHUTDOWN Receiver Input Threshold to INVALID Output High Figure 3a Positive threshold Negative threshold Receiver Input Threshold to INVALID Output Low 2.7 -2.7 -0.3 0.3 V V Receiver Positive or Negative Threshold to INVALID High tINVH VCC = +5.0V, Figure 3b 1 µs Receiver Positive or Negative Threshold to INVALID Low tINVL VCC = +5.0V, Figure 3b 30 µs Receiver Edge to Transmitters Enabled tWU VCC = +5.0V, Figure 3b 100 µs INVALID OUTPUT Output Voltage Low IOUT = 0.8mA Output Voltage High IOUT = -0.5mA 0.4 VCC - 0.4 VCC - 0.1 V V TRANSMITTER OUTPUTS VCC Mode Switch Point (VCC Falling) T_OUT = ±5.0V to ±3.7V 2.85 3.1 V VCC Mode Switch Point (VCC Rising) T_OUT = ±3.7V to ±5.0V 3.3 3.7 V VCC Mode Switch Point Hysteresis Output Voltage Swing Output Resistance 400 All transmitter outputs loaded with 3kΩ to ground. VCC = +3.1V to +5.5V, VCC falling VCC = +2.5V to +2.9V VCC = V+ = V- = 0, T_OUT = ±2V ±5 ±5.4 V ±3.7 300 Ω 10M Output Short-Circuit Current Output Leakage Current mV T_OUT = ±12V, transmitters disabled ±60 mA ±25 µA ESD PROTECTION R_IN, T_OUT Human Body Model ±15 IEC 1000-4-2 Air-Gap Discharge ±15 IEC 1000-4-2 Contact Discharge ±8 kV _______________________________________________________________________________________ 3 MAX3228E/MAX3229E ELECTRICAL CHARACTERISTICS (continued) TIMING CHARACTERISTICS (VCC = +2.5V to +5.5V, VL = +1.65V to +5.5V, C1–C4 = 0.1µF, tested at +3.3V ±10%, TA = TMIN to TMAX. Typical values are at TA = +25°C, unless otherwise noted.) (Note 3) PARAMETER CONDITIONS MIN Maximum Data Rate RL = 3kΩ, CL = 1000pF, one transmitter switching 250 Receiver Propagation Delay Receiver input to receiver output, CL = 150pF 0.15 µs Receiver Output Enable-Time VCC = VL = +5V 200 ns SYMBOL Receiver Output Disable-Time TYP MAX UNITS kbps 200 ns Transmitter Skew | tPHL - tPLH | 100 ns Receiver Skew | tPHL - tPLH | 50 ns VCC = VL = +5V RL = 3kΩ to 7kΩ, CL = 150pF to 1000pF, TA = +25°C Transition Region Slew Rate 6 30 V/µs Note 3: VCC must be greater than VL. 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.) TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE SLEW RATE (V/µs) VOH 2 0 VOL -2 20 10 5 -6 0 500 1000 1500 2000 LOAD CAPACITANCE (pF) 2500 3000 VCC = 5.5V 15 -4 0 4 VCC = 2.5V MAX3228E/9E toc03 25 20 OPERATING SUPPLY CURRENT (mA) 4 30 OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE (MAX3229E) MAX3228E/9E toc02 VCC RISING SLEW RATE vs. LOAD CAPACITANCE MAX3228E/9E toc01 6 TRANSMITTER OUTPUT VOLTAGE (V) MAX3228E/MAX3229E ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP 18 16 14 250kbps 12 10 8 6 4 2 20kbps 0 0 500 1000 1500 2000 LOAD CAPACITANCE (pF) 2500 3000 0 500 1000 1500 2000 LOAD CAPACITANCE (pF) _______________________________________________________________________________________ 2500 3000 ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP TRANSMITTER OUTPUT VOLTAGE vs. SUPPLY VOLTAGE (VCC RISING) 14 12 10 8 6 4 8 6 4 0 -2 -6 0 -8 3.0 3.5 4.0 4.5 5.0 5.5 VOL -4 2 2.5 VOH 2 10 MAX3228E/9E toc06 16 10 MAX3228E/9E toc05 18 TRANSMITTER OUTPUT VOLTAGE (V) MAX3228E/9E toc04 OPERATING SUPPLY CURRENT (mA) 20 TRANSMITTER OUTPUT VOLTAGE vs. SUPPLY VOLTAGE (VCC FALLING) TRANSMITTER OUTPUT VOLTAGE (V) OPERATING SUPPLY CURRENT vs. SUPPLY VOLTAGE (MAX3229E) 8 6 4 VOH 2 0 -2 VOL -4 -6 -8 2.5 3.0 3.5 4.0 4.5 5.0 5.5 2.5 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) Pin Description PIN MAX3228E MAX3229E NAME FUNCTION A1 A1 VCC A2 A2 C2+ +2.5V to +5.5V Supply Voltage Positive Terminal of Inverting Charge-Pump Capacitor A3 A3 C2- Negative Terminal of Inverting Charge-Pump Capacitor A4 A4 V- -5.5V/-4.0V Generated by Charge Pump A5 A5 VL Logic-Level Input for Receiver Outputs and Transmitter Inputs. Connect VL to the system logic supply voltage or VCC if no logic supply is required. A6, B6 A6 T_IN Transmitter Input(s) +5.5V/+4.0V Generated by Charge Pump. If charge pump is generating +4.0V, the part has switched from RS-232 compliant to RS-232 compatible mode. B1 B1 V+ B2, B3, B4, C2, C3, C4, D2, D3, D4, D5 B2, B3, B4, C2, C3, C4, D2, D3, D4, D5 N.C. B5 B5 FORCEON FORCEON Input, Active-High. Drive FORCEON high to override automatic circuitry, keeping transmitters and charge pumps on. Pulls itself high internally if not connected. — B6, D6, E4, E6 N.C. No Connection. These locations are populated with solder bumps, but are electrically isolated. C1 C1 C1+ Positive Terminal of Positive Regulated Charge-Pump Capacitor No Connection. These locations are not populated with solder bumps. _______________________________________________________________________________________ 5 MAX3228E/MAX3229E Typical Operating Characteristics (continued) (VCC = +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ and CL, TA = +25°C, unless otherwise noted.) MAX3228E/MAX3229E ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP Pin Description (continued) PIN NAME FUNCTION MAX3228E MAX3229E C5 C5 FORCEOFF C6, D6 C6 R_OUT D1 D1 C1- Negative Terminal of Positive Regulated Charge-Pump Capacitor E1 E1 GND Ground E2 E2 INVALID E3, E4 E3 T_OUT E5, E6 E5 R_IN FORCEOFF Input, Active-Low. Drive FORCEOFF low to shut down transmitters, receivers, and on-board charge pump. This overrides all automatic circuitry and FORCEON. Pulls itself high internally if not connected. Receiver Output(s) Output of Valid Signal Detector. INVALID is enabled low if no valid RS-232 level is present on any receiver input. RS-232 Transmitter Output(s) RS-232 Receiver Input(s) Table 1. Operating Supply Options SYSTEM SUPPLY (V) VCC (V) VL (V) RS-232 MODE 1 Li+ Cell +2.4 to +4.2 Regulated System Voltage Compliant/Compatible 3 NiCad/NiMh Cells +2.4 to +3.8 Regulated System Voltage Compliant/Compatible Regulated Voltage Only (VCC falling) +3.0 to +5.5 +3.0 to +5.5 Compliant Regulated Voltage Only (VCC falling) +2.5 to +3.0 +2.5 to +3.0 Compatible Detailed Description Dual-Mode Regulated Charge-Pump Voltage Converter The MAX3228E/MAX3229E internal power supply consists of a dual-mode regulated charge pump. For supply voltages above +3.7V, the charge pump will generate +5.5V at V+ and -5.5V at V-. The charge pumps operate in a discontinuous mode. If the output voltages are less than ±5.5V, the charge pumps are enabled, if the output voltages exceed ±5.5V, the charge pumps are disabled. For supply voltages below +2.85V, the charge pump will generate +4.0V at V+ and -4.0V at V-. The charge pumps operate in a discontinuous mode. If the output voltages are less than ±4.0V, the charge pumps are enabled, if the output voltages exceed ±4.0V, the charge pumps are disabled. The MAX3228E/MAX3229E include a switchover circuit between these two modes that have approximately 400mV of hysteresis around the switchover point. The hysteresis is shown in Figure 1. This large hysteresis eliminates mode changes due to power-supply bounce. For example, a three-cell NiMh battery system starts at VCC = +3.6V, and the charge pump will generate an output voltage of ±5.5V. As the battery discharges, the VCC 4V 0 V+ 6V Each charge pump requires a flying capacitor (C1, C2) and a reservoir capacitor (C3, C4) to generate the V+ and V- supply voltages. Voltage Generation in the Switchover Region 6 0 20ms/div Figure 1. V+ Switchover for Changing VCC _______________________________________________________________________________________ ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP R_IN -0.3V 30µs COUNTER R TO MAX322 _E POWER SUPPLY AND TRANSMITTERS R_IN 30µs COUNTER R INVALID *TRANSMITTERS ARE DISABLED, REDUCING SUPPLY CURRENT TO 1µA IF ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30µs. -2.7V TO MAX322 _E POWER SUPPLY INVALID *TRANSMITTERS ARE ENABLED IF: ANY RECEIVER INPUT IS GREATER THAN +2.7V OR LESS THAN -2.7V. ANY RECEIVER INPUT HAS BEEN BETWEEN +0.3V AND -0.3V FOR LESS THAN 30µs. Figure 2a. MAX322_E Entering 1µA Supply Mode via AutoShutdown Figure 2b. MAX322_E with Transmitters Enabled Using AutoShutdown MAX3228E/MAX3229E maintain the outputs in regulation until the battery voltage drops below +3.1V. Then the output regulation points change to ±4.0V When VCC is rising, the charge pump will generate an output voltage of ±4.0V, while VCC is between +2.5V and +3.5V. When VCC rises above the switchover voltage of +3.5V, the charge pump switches modes to generate an output of ±5.5V. Table 1 shows different supply schemes and their operating voltage ranges. The transmitter inputs do not have pullup resistors. Connect unused inputs to GND or VL. RS-232 Transmitters The transmitters are inverting level translators that convert CMOS-logic levels to RS-232 levels. The MAX3228E/MAX3229E will automatically reduce the RS-232 compliant levels (±5.5V) to RS-232 compatible levels (±4.0V) when V CC falls below approximately +3.1V. The reduced levels also reduce supply current requirements, extending battery life. Built-in hysteresis of approximately 400mV for VCC ensures that the RS232 output levels do not change if VCC is noisy or has a sudden current draw causing the supply voltage to drop slightly. The outputs will return to RS-232 compliant levels (±5.5V) when VCC rises above approximately +3.5V. The MAX3228E/MAX3229E transmitters guarantee a 250kbps data rate with worst-case loads of 3kΩ in parallel with 1000pF. When FORCEOFF is driven to ground, the transmitters and receivers are disabled and the outputs become high impedance. When the AutoShutdown circuitry senses that all receiver and transmitter inputs are inactive for more than 30µs, the transmitters are disabled and the outputs go to a high-impedance state. When the power is off, the MAX3228E/MAX3229E permit the transmitter outputs to be driven up to ±12V. RS-232 Receivers The MAX3228E/MAX3229E receivers convert RS-232 signals to logic output levels. All receivers have inverting three-state outputs and can be active or inactive. In shutdown (FORCEOFF = low) or in AutoShutdown, the MAX3228E/MAX3229E receivers are in a high-impedance state (Table 3). The MAX3228E/MAX3229E feature an INVALID output that is enabled low when no valid RS-232 signal levels have been detected on any receiver inputs. INVALID is functional in any mode (Figures 2 and 3). VL FORCEOFF POWER DOWN VL VCC FORCEON INVALID INVALID IS AN INTERNALLY GENERATED SIGNAL THAT IS USED BY THE AUTOSHUTDOWN LOGIC AND APPEARS AS AN OUTPUT OF THE DEVICE. POWER DOWN IS ONLY AN INTERNAL SIGNAL. IT CONTROLS THE OPERATIONAL STATUS OF THE TRANSMITTERS AND THE POWER SUPPLIES. Figure 2c. MAX322_E AutoShutdown Logic _______________________________________________________________________________________ 7 MAX3228E/MAX3229E +2.7V +0.3V ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP MAX3228E/MAX3229E AutoShutdown RECEIVER INPUT LEVELS TRANSMITTERS ENABLED, INVALID HIGH +2.7V INDETERMINATE +0.3V 0 AUTOSHUTDOWN, TRANSMITTERS DISABLED, 1µA SUPPLY CURRENT, INVALID LOW -0.3V INDETERMINATE -2.7V TRANSMITTERS ENABLED, INVALID HIGH a) RECEIVER INPUT VOLTAGE (V) INVALID REGION VCC INVALID OUTPUT (V) 0 tINVL tINVH tWU V+ VCC 0 The MAX3228E/MAX3229E achieve a 1µA supply current with Maxim’s AutoShutdown feature, which operates when FORCEON is low and FORCEOFF is high. When these devices sense no valid signal levels on all receiver inputs for 30µs, the on-board charge pump and drivers are shut off, reducing VCC supply current to 1µA. This occurs if the RS-232 cable is disconnected or the connected peripheral transmitters are turned off. The device turns on again when a valid level is applied to any RS-232 receiver input. As a result, the system saves power without changes to the existing BIOS or operating system. Table 3 and Figure 2c summarize the MAX3228E/ MAX3229E operating modes. FORCEON and FORCEOFF override AutoShutdown. When neither control is asserted, the IC selects between these states automatically, based on receiver input levels. Figures 2a, 2b, and 3a depict valid and invalid RS-232 receiver levels. Figures 3a and 3b show the input levels and timing diagram for AutoShutdown operation. A system with AutoShutdown may need time to wake up. Figure 4 shows a circuit that forces the transmitters on for 100ms, allowing enough time for the other system to realize that the MAX3228E/MAX3229E are active. If the other system transmits valid RS-232 signals within that time, the RS-232 ports on both systems remain enabled. When shut down, the device’s charge pumps are off, V+ is pulled to VCC, V- is pulled to ground, and the transmitter outputs are high-impedance. The time required to exit shutdown is typically 100µs (Figure 3b). V- FORCEON and FORCEOFF b) Figure 3. AutoShutdown Trip Levels POWERMANAGEMENT UNIT MASTER SHDN LINE 0.1µF 1MΩ In case FORCEON and FORCEOFF are inaccessible, these pins have 60kΩ (typ) pullup resistors connected to VL (Table 2). Therefore, if FORCEON and FORCEOFF are not connected, the MAX3228E and MAX3229E will always be active. Pulling these pins to ground will draw current from the VL supply. This current can be calculated from the voltage supplied at VL and the 60kΩ (typ) pullup resistor. FORCEOFF FORCEON MAX3228E MAX3229E VL Logic Supply Input Unlike other RS-232 interface devices, where the receiver outputs swing between 0 and V CC , the Table 2. Power-On Default States Figure 4. AutoShutdown with Initial Turn-On to Wake Up a Mouse or Another System 8 PIN NAME POWER-ON DEFAULT FORCEON High Internal pullup FORCEOFF High Internal pullup _______________________________________________________________________________________ MECHANISM ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP TRANSCEIVER STATUS Shutdown (AutoShutdown) Shutdown (Forced Off) FORCEON FORCEOFF RECEIVER STATUS INVALID Low High High-Z L † X Low High-Z Normal Operation (Forced On) High High Active † Normal Operation (AutoShutdown) Low High Active H MAX3228E/MAX3229E Table 3. Output Control Truth Table X = Don’t care. † = INVALID output state is determined by R_IN input levels. MAX3228E/MAX3229E feature a separate logic supply input (VL) that sets VOH for the receiver and INVALID outputs. The transmitter inputs (T_IN), FORCEON and FORCEOFF, are also referred to VL. This feature allows maximum flexibility in interfacing to different systems and logic levels. Connect VL to the system’s logic supply voltage (+1.65V to +5.5V), and bypass it with a 0.1µF capacitor to GND. If the logic supply is the same as VCC, connect VL to VCC. Always enable VCC before enabling the VL supply. VCC must be greater than or equal to the VL supply. Software-Controlled Shutdown If direct software control is desired, connect FORCEOFF and FORCEON together to disable AutoShutdown. The microcontroller then drives FORCEOFF and FORCEON like a SHDN input, INVALID can be used to alert the microcontroller to indicate serial data activity. ±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 MAX3228E/MAX3229E 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 the IEC 1000-4-2 Air-Gap method. RC 1MΩ CHARGE-CURRENT LIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 100pF RD 1500Ω DISCHARGE RESISTANCE DEVICE UNDER TEST STORAGE CAPACITOR Figure 5a. Human Body ESD Test Models IP 100% 90% Ir PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) AMPERES 36.8% 10% 0 0 tRL TIME tDL CURRENT WAVEFORM Figure 5b. Human Body Model Current Waveform 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 5a shows the Human Body Model, and Figure 5b 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. _______________________________________________________________________________________ 9 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 MAX3228E/MAX3229E help you design equipment that meets Level 4 (the highest level) of IED 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 a 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 6a shows the IEC 1000-4-2 model, and Figure 6b 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. RC 50MΩ to 100MΩ CHARGE-CURRENT LIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 150pF RD 330Ω DISCHARGE RESISTANCE STORAGE CAPACITOR DEVICE UNDER TEST Figure 6a. IEC 1000-4-2 ESD Test Model 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; either polarized or non polarized capacitors may be used. However, ceramic chip capacitors with an X7R or X5R dielectric work best. The charge pump requires 0.1µF capacitors for 3.3V operation. For other supply voltages, refer to Table 4 for required capacitor values. Do not use values smaller than those listed in Table 4. 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, and C4 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 equivalent series resistance (ESR) usually rises at low temperatures and influences the amount of ripple on V+ and V-. Power-Supply Decoupling I 100% 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 the charge-pump capacitor C1. Connect bypass capacitors as close to the IC as possible. 90% I PEAK MAX3228E/MAX3229E ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP Table 4. Required Capacitor Values 10% t r = 0.7ns to 1ns t 30ns 60ns VCC (V) C1, CBYPASS (µF) C2, C3, C4 (µF) 2.5 to 3.0 0.22 0.22 3.0 to 3.6 0.1 0.1 4.5 to 5.5 0.047 0.33 3.0 to 5.5 0.22 1 Figure 6b. IEC 1000-4-2 ESD Generator Current Waveform 10 _____________________________________________________________________________________ ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP Figure 7 shows a transmitter output when exiting shutdown mode. The transmitter is loaded with 3kΩ in parallel with 1000pF. The transmitter output displays no ringing or undesirable transients as it comes out of shutdown, and is enabled only when the magnitude of V- exceeds approximately -3V. Figure 9, the transmitter was driven at 120kbps into an RS-232 load in parallel with 1000pF. For Figure 10, a single transmitter was driven at 250kbps, and loaded with an RS-232 receiver in parallel with 1000pF. High Data Rates The MAX3228E/MAX3229E maintain the RS-232 ±5.0V minimum transmitter output voltage even at high data rates. Figure 8 shows a transmitter loopback test circuit. Figure 9 shows a loopback test result at 120kbps, and Figure 10 shows the same test at 250kbps. For 5V/div FORCEON = FORCEOFF 0 5V T_IN 0 5V 0 T_OUT -5V 5V 2V/div TOUT R_OUT 0 4µs/div 4µs/div Figure 7. Transmitter Outputs Exiting Shutdown or Powering Up VCC 0 Figure 9. Loopback Test Result at 120kbps VL 5V 0.1µF 0.1µF T_IN C1+ VCC VL 0 V+ 5V C3 C1 C1- T_OUT MAX3229E C2+ 0 V- C2 -5V C4 VL C2- 5V T1OUT T1IN R_OUT 4µs/div R1IN R1OUT Figure 10. Loopback Test Result at 250kbps 5kΩ INVALID FORCEON GND 0 1000pF VL FORCEOFF TO POWERMANAGEMENT UNIT VL Figure 8. Transmitter Loopback Test Circuit ______________________________________________________________________________________ 11 MAX3228E/MAX3229E Transmitter Outputs when Exiting Shutdown ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP MAX3228E/MAX3229E Typical Operating Circuits (continued) 2.5V TO 5.5V 1.65V TO 5.5V CBYPASS 0.1µF A1 C1 C1 0.1µF D1 A2 C2 0.1µF A3 VCC C1+ C1- 0.1µF A5 VL V+ MAX3229E C2+ V- B1 C3 0.1µF A4 C4 0.1µF VL C2- T1OUT A6 T1IN E3 VL TTL/CMOS RS-232 R1IN E5 C6 R1OUT 5kΩ VL VL INVALID 20µA E2 20µA FORCEOFF C5 B5 FORCEON TO POWERMANAGEMENT UNIT UCSP Reliability The UCSP represents a unique packaging form factor that may not perform equally to a packaged product through traditional mechanical reliability tests. CSP reliability is integrally linked to the user’s assembly methods, circuit board material, and usage environment. The user should closely review these areas when considering use of a CSP package. Performance through Operating Life Test and Moisture Resistance remains uncompromised as it is primarily determined by the wafer-fabrication process. Mechanical stress performance is a greater consideration for a CSP package. CSPs are attached through direct solder contact to the user’s PC board, foregoing the inherent stress relief of a packaged product lead frame. Solder joint contact integrity must be considered. Table 2 shows the testing done to characterize the CSP reliability performance. In conclusion, the UCSP is capable of performing reliably through environmental stresses as indicated by the results in the table. Additional usage data and recommendations are detailed in the UCSP application note, which can be found on Maxim’s website at www.maxim-ic.com. Chip Information VL TRANSISTOR COUNT: 698 PROCESS TECHNOLOGY: CMOS GND E1 Table 2. Reliability Test Data TEST CONDITIONS DURATION NO. OF FAILURES PER SAMPLE SIZE 150 cycles, 900 cycles 0/10, 0/200 Temperature Cycle -35°C to +85°C, -40°C to +100°C Operating Life TA = +70°C 240hr 0/10 Moisture Resistance +20°C to +60°C, 90% RH 240hr 0/10 Low-Temperature Storage Low-Temperature Operational Solderability -20°C 240hr 0/10 -10°C 24hr 0/10 8hr steam age — 0/15 ESD ±2000V, Human Body Model — 0/5 High-Temperature Operating Life TJ = +150°C 168hr 0/45 12 ______________________________________________________________________________________ ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP TOP VIEW A VCC C2+ C2- V- VL T1IN B V+ N.C. N.C. N.C. FON T2IN C C1+ N.C. N.C. N.C. FOFF R2OUT D C1- N.C. N.C. N.C. N.C. R1OUT E GND INV T1OUT T2OUT R2IN R1IN 1 2 3 4 5 MAX3228E 6 FON = FORCEON FOFF = FORCEOFF INV = INVALID ______________________________________________________________________________________ 13 MAX3228E/MAX3229E Pin Configurations ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP MAX3228E/MAX3229E Pin Configurations (continued) TOP VIEW A VCC C2+ C2- V- VL T1IN B V+ N.C. N.C. N.C. FON N.C. C C1+ N.C. N.C. N.C. FOFF R1OUT D C1- N.C. N.C. N.C. N.C. N.C. E GND INV T1OUT N.C. R1IN N.C. 1 2 3 4 5 MAX3229E 14 6 FON = FORCEON FOFF = FORCEOFF INV = INVALID ______________________________________________________________________________________ ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP 30L, UCSP 6x5 .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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 15 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX3228E/MAX3229E Package Information