19-3250; Rev 0; 5/04 ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP Features ♦ 6 x 5 Chip-Scale Packaging (UCSP) The MAX3230E/MAX3231E achieve a 1µA supply current with Maxim’s AutoShutdown™ feature. They save power without changing the 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-232compatible 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 MAX3230E/MAX3231E 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 MAX3230E/MAX3231E compatibility with multiple logic families. The MAX3231E contains one receiver and one transmitter. The MAX3230E contains two receivers and two transmitters. The MAX3230E/MAX3231E are available in tiny chip-scale packaging and are specified across the extended industrial (-40°C to +85°C) temperature range. ♦ Meet EIA/TIA-232 Specifications Down to +3.1V Applications ♦ 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 BUMP-PACKAGE MAX3230EEBV-T -40°C to +85°C 6 x 5 UCSP MAX3231EEBV-T -40°C to +85°C 6 x 5 UCSP 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 C2 0.1µF A3 C1+ C1- VL C2- V+ MAX3230E C2+ V- B1 C3 0.1µF A4 C4 0.1µF VL T1OUT A6 T1IN TTL/CMOS INPUTS E3 RS-232 OUTPUTS VL T2OUT E4 B6 T2IN VL Cell-Phone Data Lump Cables Hand-Held Devices A5 VCC Personal Digital Assistants Set-Top Boxes R1IN D6 R1OUT TTL/CMOS OUTPUTS VL E6 5kΩ RS-232 INPUTS R2IN E5 C6 R2OUT Cell Phones 5kΩ Typical Operating Circuits continued at end of data sheet. INVALID E2 Pin Configurations appear at end of data sheet. FORCEOFF C5 B5 FORCEON UCSP is a trademark of Maxim Integrated Products, Inc. AutoShutdown is a trademark of Maxim Integrated Products, Inc. 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 MAX3230E/MAX3231E General Description The MAX3230E/MAX3231E 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. MAX3230E/MAX3231E ±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 +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) 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. 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 2) 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 1.65 VCC + 0.3 V FORCEON = GND FORCEOFF = VL, all RIN open 10 FORCEOFF = GND 10 FORCEON, FORCEOFF = VL 1 mA 1 mA ICC FORCEON = FORCEOFF = VL, no load 0.3 T_IN, IL FORCEON or FORCEOFF = GND or VL, VCC = VL = +5V, no receivers switching 1 µA µA LOGIC INPUTS Input-Logic Low T_IN, FORCEON, FORCEOFF Input-Logic High T_IN, FORCEON, FORCEOFF Transmitter Input Hysteresis Input Leakage Current 0.4 0.66 ✕ VL V 0.5 T_IN, FORCEON, FORCEOFF V ±0.01 V ±1 µA ±10 µA 0.4 V RECEIVER OUTPUTS 2 Output Leakage Currents R_OUT, receivers disabled, FORCEOFF = GND or in AutoShutdown Output-Voltage Low IOUT = 0.8mA 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 2) 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 AUTOMATIC SHUTDOWN Receiver Input Threshold to INVALID Output High Positive threshold Figure 3a 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 3.10 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, TA = +25°C ±5 VCC = +2.5V to +3.1V, VCC rising ±3.7 VCC = V+ = V- = 0, T_OUT = ±2V ±5.4 V 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 MAX3230E/MAX3231E 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 2) 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 Receiver-Output Disable Time VCC = VL = +5V 200 ns SYMBOL TYP MAX UNITS kbps Transmitter Skew | tPHL - tPLH | 100 ns Receiver Skew | tPHL - tPLH | 50 ns RL = 3kΩ to 7kΩ, CL = 150pF to 1000pF, TA = +25°C Transition-Region Slew Rate 6 30 V/µs Note 2: 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 0 VOL -2 10 5 -6 0 500 1000 1500 2000 LOAD CAPACITANCE (pF) 2500 3000 VCC = 5.5V 15 -4 0 4 20 VCC = 2.5V MAX3230/31E toc03 20 OPERATING SUPPLY CURRENT (mA) VOH 2 25 SLEW RATE (V/µs) 4 30 MAX3230/31E toc02 VCC RISING OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE (MAX3231E) SLEW RATE vs. LOAD CAPACITANCE MAX3230/31E toc01 6 TRANSMITTER OUTPUT VOLTAGE (V) MAX3230E/MAX3231E ±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 OPERATING SUPPLY CURRENT vs. SUPPLY VOLTAGE (MAX3231E) TRANSMITTER OUTPUT VOLTAGE vs. SUPPLY VOLTAGE (VCC RISING) 14 12 10 8 6 4 6 4 VOH 2 0 -2 VOL -4 -6 2 2.5 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) 8 6 4 VOH 2 0 -2 VOL -4 -6 -8 0 MAX3230/31E toc06 8 10 TRANSMITTER OUTPUT VOLTAGE (V) 16 10 MAX3230/31E toc05 18 TRANSMITTER OUTPUT VOLTAGE (V) MAX3230/31E toc04 OPERATING SUPPLY CURRENT (mA) 20 TRANSMITTER OUTPUT VOLTAGE vs. SUPPLY VOLTAGE (VCC FALLING) -8 2.5 3.0 3.5 4.0 4.5 5.0 5.5 2.5 3.0 3.5 SUPPLY VOLTAGE (V) 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) Pin Description BUMP MAX3230E MAX3231E NAME FUNCTION A1 A1 VCC +2.5V to +5.5V Supply Voltage A2 A2 C2+ Inverting Charge-Pump Capacitor Positive Terminal A3 A3 C2- Inverting Charge-Pump Capacitor Negative Terminal A4 A4 V- Negative Supply Voltage (-5.5V/-4.0V) Generated by Charge Pump A5 A5 VL Logic Supply Input. 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 B1 B1 V+ B2, B3, B4, C2, C3, C4, D2–D5 B2, B3, B4, C2, C3, C4, D2–D5 N.C. B5 B5 FORCEON C1 C1 C1+ C5 C5 FORCEOFF Transmitter Input(s) Positive Supply Voltage (+5.5V/+4.0V) Generated by Charge Pump. If charge pump is generating +4.0V, the device has switched from RS-232-compliant to RS-232compatible mode. No Connection. These locations are not populated with solder bumps. Active-High FORCEON Input. Drive FORCEON high to override automatic circuitry, keeping transmitters and charge pumps on. Positive Regulated Charge-Pump Capacitor Positive Terminal Active-Low FORCEOFF Input. Drive FORCEOFF low to shut down transmitters, receivers, and on-board charge pump. This overrides all automatic circuitry and FORCEON. _______________________________________________________________________________________ 5 MAX3230E/MAX3231E 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.) MAX3230E/MAX3231E ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP Pin Description (continued) BUMP MAX3230E MAX3231E NAME FUNCTION C6, D6 C6 R_OUT D1 D1 C1- Positive Regulated Charge-Pump Capacitor Negative Terminal Receiver Output(s) E1 E1 GND Ground E2 E2 INVALID E3, E4 E3 T_OUT E5, E6 E5 R_IN RS-232 Receiver Input(s) — B6, D6, E4, E6 N.C. No Connection. These locations are populated with solder bumps, but are electrically isolated. Valid Signal-Detector Output. INVALID is enabled low if no valid RS-232 level is present on any receiver input. RS-232 Transmitter Output(s) Detailed Description Dual Mode™ Regulated Charge-Pump Voltage Converter The MAX3230E/MAX3231E internal power supply consists of a dual-mode regulated charge pump. For supply voltages above +3.7V, the charge pump generates +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 generates +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. Each charge pump requires a flying capacitor (C1, C2) and a reservoir capacitor (C3, C4) to generate the V+ and V- supply voltages. tion until the battery voltage drops below +3.1V. The output regulation points then change to ±4.0V. When VCC is rising, the charge pump generates 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. RS-232 Transmitters The transmitters are inverting level translators that convert CMOS logic levels to RS-232 levels. The MAX3230E/MAX3231E 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 RS- Voltage Generation in the Switchover Region The MAX3230E/MAX3231E 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. VCC 4V 0 V+ 6V For example, a three-cell NiMh battery system starts at VCC = +3.6V, and the charge pump generates an output voltage of ±5.5V. As the battery discharges, the MAX3230E/MAX3231E maintain the outputs in regula- 0 20ms/div Dual Mode is a trademark of Maxim Integrated Products, Inc. 6 Figure 1. V+ Switchover for Changing VCC _______________________________________________________________________________________ ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP MAX3230E/MAX3231E 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 Table 2. Output Control Truth Table FORCEON FORCEOFF RECEIVER STATUS INVALID Low High High impedance Low X Low High impedance † Normal Operation (Forced On) High High Active † Normal Operation (AutoShutdown) Low High Active High TRANSCEIVER STATUS Shutdown (AutoShutdown) Shutdown (Forced Off) X = Don’t care. † = INVALID output state is determined by R_IN input levels. 232 output levels do not change if VCC is noisy or has a sudden current draw causing the supply voltage to drop slightly. The outputs return to RS-232-compliant levels (±5.5V) when VCC rises above approximately +3.5V. The MAX3230E/MAX3231E 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 MAX3230E/MAX3231E permit the transmitter outputs to be driven up to ±12V. The transmitter inputs do not have pullup resistors. Connect unused inputs to GND or VL. RS-232 Receivers The MAX3230E/MAX3231E receivers convert RS-232 signals to logic-output levels. All receivers have inverting tri-state outputs and can be active or inactive. In shutdown (FORCEOFF = low) or in AutoShutdown, the MAX3230E/MAX3231E receivers are in a high-impedance state (Table 2). The MAX3230E/MAX3231E 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). AutoShutdown The MAX3230E/MAX3231E 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 2 and Figure 2c summarize the MAX3230E/ MAX3231E 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 can require 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 MAX3230E/MAX3231E are _______________________________________________________________________________________ 7 MAX3230E/MAX3231E ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP FORCEOFF +0.3V R_IN -0.3V 30µs COUNTER R TO MAX323 _E POWER SUPPLY AND TRANSMITTERS POWER DOWN VCC INVALID FORCEON INVALID TRANSMITTERS ARE DISABLED, REDUCING SUPPLY CURRENT TO 1µA IF ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30µs. Figure 2a. MAX323_E Entering 1µA Supply Mode with AutoShutdown +2.7V R_IN -2.7V POWER DOWN IS ONLY AN INTERNAL SIGNAL. IT CONTROLS THE OPERATIONAL STATUS OF THE TRANSMITTERS AND THE POWER SUPPLIES. Figure 2c. MAX323_E AutoShutdown Logic 30µs COUNTER R TO MAX323 _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 2b. MAX323_E with Transmitters Enabled Using AutoShutdown 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). VL Logic Supply Input Unlike other RS-232 interface devices, where the receiver outputs swing between 0 and VCC, the MAX3230E/ MAX3231E feature a separate logic supply input (VL) that sets VOH for the receiver 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 V L 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 8 INVALID IS AN INTERNALLY GENERATED SIGNAL THAT IS USED BY THE AutoShutdown LOGIC AND APPEARS AS AN OUTPUT OF THE DEVICE. microcontroller (µC) then drives FORCEOFF and FORCEON like a SHDN input. INVALID can be used to alert the µC 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 MAX3230E/MAX3231E 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 power-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 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. 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, _______________________________________________________________________________________ ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP 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 IEC 1000-4-2 The IEC 1000-4-2 standard covers ESD testing and performance of finished equipment. It does not specifically refer to ICs. The MAX3230E/MAX3231E aid in designing 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 a higher peak current in IEC 1000-4-2, because series resistance is lower in the IEC 1000-4-2 model. Hence, the ESD withstands voltage measured to IEC 1000-4-2 and 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. VCC INVALID OUTPUT (V) 0 tINVL tINVH tWU V+ VCC 0 V- 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 b) Capacitor Selection Figure 3. AutoShutdown Trip Levels POWERMANAGEMENT UNIT MASTER SHDN LINE 0.1µF 1MΩ FORCEOFF FORCEON MAX3230E MAX3231E Figure 4. AutoShutdown with Initial Turn-On to Wake Up a Mouse or Another System The capacitor type used for C1–C4 is not critical for proper operation; either polarized or nonpolarized capacitors can 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, see Table 3 for required capacitor values. Do not use values smaller than those listed in Table 3. 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 the vaue of C1. Caution: 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 _______________________________________________________________________________________ 9 MAX3230E/MAX3231E which is then discharged into the test device through a 1.5kΩ resistor. RC 1MΩ I RD 1500Ω 100% DISCHARGE RESISTANCE CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 100pF 90% DEVICE UNDER TEST STORAGE CAPACITOR I PEAK MAX3230E/MAX3231E ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP 10% Figure 5a. Human Body ESD Test Models t r = 0.7ns to 1ns t 30ns 60ns IP 100% 90% Ir PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) Figure 6b. IEC 1000-4-2 ESD Generator Current Waveform Table 3. Required Capacitor Values AMPERES 36.8% 10% 0 0 TIME tRL tDL CURRENT WAVEFORM Figure 5b. Human Body Model Current Waveform RC 50MΩ TO 100MΩ CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 150pF 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 supply noise, use a capacitor of the same value as the charge-pump capacitor C1. Connect bypass capacitors as close to the IC as possible. RD 330Ω Transmitter Outputs when Exiting Shutdown DISCHARGE RESISTANCE STORAGE CAPACITOR DEVICE UNDER TEST 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. High Data Rates Figure 6a. IEC 1000-4-2 ESD Test Model 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 In most circumstances, a 0.1µF VCC bypass capacitor is adequate. In applications that are sensitive to power10 The MAX3230E/MAX3231E 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 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. _____________________________________________________________________________________ ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP FORCEON = FORCEOFF 0 MAX3230E/MAX3231E 5V 5V/div T_IN 0 5V 0 T_OUT -5V 5V 2V/div T_OUT 0 R_OUT 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 VCC C1+ VL 0 V+ 5V C3 C1 C1- T_OUT MAX3231E C2+ 0 V- C2 C4 -5V VL C2- 5V T1OUT T1IN R_OUT R1IN R1OUT 4µs/div 5kΩ INVALID FORCEON GND 0 1000pF VL FORCEOFF Figure 10. Loopback Test Result at 250kbps TO POWERMANAGEMENT UNIT VL Figure 8. Transmitter Loopback Test Circuit UCSP Applications Information For the latest application details on UCSP construction, dimensions, tape carrier information, PC board techniques, bump-pad layout, and recommended reflow temperature profile, as well as the latest information on reliability testing results, refer to the Application Note UCSP—A Wafer-Level Chip-Scale Package available on Maxim’s website at www.maxim-ic.com/ucsp. Chip Information TRANSISTOR COUNT: 698 PROCESS: CMOS ______________________________________________________________________________________ 11 ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP MAX3230E/MAX3231E 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 C1+ VCC C1- VL V+ MAX3231E C2+ C2- 0.1µF A5 V- B1 C3 0.1µF A4 C4 0.1µF VL T1OUT A6 T1IN E3 VL TTL/CMOS RS-232 R1IN E5 C6 R1OUT 5kΩ INVALID E2 FORCEOFF C5 B5 FORCEON TO POWERMANAGEMENT UNIT VL GND E1 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 MAX3230E 6 FON = FORCEON FOFF = FORCEOFF INV = INVALID ______________________________________________________________________________________ 13 MAX3230E/MAX3231E Pin Configurations ±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP MAX3230E/MAX3231E 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 MAX3231E 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 PACKAGE OUTLINE, 6x5 UCSP 21-0123 G 1 1 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 © 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX3230E/MAX3231E Package 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.)