19-2140; Rev 0; 8/01 +2.5V to +5.5V RS-232 Transceivers in UCSP The MAX3228/MAX3229 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 MAX3228/MAX3229 compatibility with multiple logic families. The MAX3229 contains one receiver and one transmitter. The MAX3228 contains two receivers and two transmitters. The MAX3228/MAX3229 are available in tiny chip-scale packaging and are specified across the extended industrial temperature range of -40°C to +85°C. Features ♦ 6 ✕ 5 Chip-Scale Packaging (UCSP) ♦ 1µA Low-Power AutoShutdown ♦ 250kbps Guaranteed Data Rate ♦ Meets EIA/TIA-232 Specifications Down to +3.1V ♦ RS-232 Compatible to +2.5V Allows Operation from Single Li+ Cell ♦ Small 0.1µF Capacitors ♦ Configurable Logic Levels Ordering Information TEMP. RANGE PINPACKAGE MAX3228EBV -40°C to +85°C 6 ✕ 5 UCSP* MAX3229EBV -40°C to +85°C 6 ✕ 5 UCSP* PART *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 Applications Personal Digital Assistants C1 0.1µF A2 C2 0.1µF Cell Phone Data Lump Cables Set-Top Boxes Hand-Held Devices D1 A3 A5 VCC C1+ C1- VL MAX3228 C2+ V- B1 C3 0.1µF A4 C4 0.1µF VL C2- T1OUT A6 T1IN TTL/CMOS INPUTS E3 RS-232 OUTPUTS VL T2OUT E4 B6 T2IN VL Cell Phones R1IN D6 R1OUT Typical Operating Circuits continued at end of data sheet. V+ TTL/CMOS OUTPUTS VL E6 5kΩ RS-232 INPUTS R2IN E5 C6 R2OUT Pin Configurations appear at end of data sheet. 5kΩ VL UCSP is a trademark of Maxim Integrated Products, Inc. AutoShutdown is a trademark of Maxim Integrated Products, Inc. VL INVALID 20µA 20µA 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 MAX3228/MAX3229 General Description The MAX3228/MAX3229 are +2.5V to +5.5V powered EIA/TIA-232 and V.28/V.24 communications interfaces with low power requirements, and high data-rate capabilities, in a chip-scale package (UCSP™). The MAX3228/MAX3229 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. MAX3228/MAX3229 +2.5V to +5.5V RS-232 Transceivers in UCSP ABSOLUTE MAXIMUM RATINGS 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 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 to GND ...........................................-0.3V to (VL + 0.3V) 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 FORCEON, FORCEOFF floating 85 µA 1 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 +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 AUTOSHUTDOWN 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 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 INVALID OUTPUT Output Voltage Low IOUT = 0.8mA Output Voltage High IOUT = -0.5mA 0.4 VCC - 0.4 VCC - 0.1 V V _______________________________________________________________________________________ 3 MAX3228/MAX3229 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 SYMBOL 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 100 ns 50 ns Transmitter Skew | tPHL - tPLH | Receiver Skew | tPHL - tPLH | RL = 3kΩ to 7kΩ, CL = 150pF to 1000pF, TA = +25°C Transition Region Slew Rate TYP MAX UNITS kbps 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 VOL -6 0 1000 1500 2000 LOAD CAPACITANCE (pF) 2500 3000 VCC = 2.5V MAX3228/9 toc03 MAX3228/9 toc02 10 5 500 VCC = 5.5V 15 -4 0 4 20 20 OPERATING SUPPLY CURRENT (mA) 0 -2 25 SLEW RATE (V/µs) VOH 2 30 MAX3228/9 toc01 VCC RISING 4 OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE (MAX3229) SLEW RATE vs. LOAD CAPACITANCE 6 TRANSMITTER OUTPUT VOLTAGE (V) MAX3228/MAX3229 +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 +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 SUPPLY VOLTAGE (V) VOL -4 2 2.5 VOH 2 10 TRANSMITTER OUTPUT VOLTAGE (V) 16 10 MAX3228/9 toc05 18 TRANSMITTER OUTPUT VOLTAGE (V) MAX3228/9 toc04 OPERATING SUPPLY CURRENT (mA) 20 TRANSMITTER OUTPUT VOLTAGE vs. SUPPLY VOLTAGE (VCC FALLING) MAX3228/9 toc06 OPERATING SUPPLY CURRENT vs. SUPPLY VOLTAGE (MAX3229) 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) 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) Pin Description PIN MAX3228 MAX3229 NAME FUNCTION A1 A1 VCC +2.5V to +5.5V Supply Voltage A2 A2 C2+ Positive Terminal of Inverting Charge-Pump Capacitor A3 A3 C2- 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 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 Negative Terminal of Inverting Charge-Pump Capacitor 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. No Connection. These locations are not populated with solder bumps. _______________________________________________________________________________________ 5 MAX3228/MAX3229 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.) MAX3228/MAX3229 +2.5V to +5.5V RS-232 Transceivers in UCSP Pin Description (continued) PIN NAME FUNCTION MAX3228 MAX3229 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 MAX3228/MAX3229 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. 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 The MAX3228/MAX3229 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 0 20ms/div Figure 1. V+ Switchover for Changing VCC 6 _______________________________________________________________________________________ +2.5V to +5.5V RS-232 Transceivers in UCSP R_IN -0.3V 30µs COUNTER R TO MAX322 _ POWER SUPPLY AND TRANSMITTERS R_IN INVALID *TRANSMITTERS ARE DISABLED, REDUCING SUPPLY CURRENT TO 1µA IF ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30µs. TO MAX322 _ POWER SUPPLY 30µs COUNTER R -2.7V 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_ Entering 1µA Supply Mode via AutoShutdown Figure 2b. MAX322_ with Transmitters Enabled Using AutoShutdown 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 MAX3228/MAX3229 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 power is off, the MAX3228/MAX3229 permit the transmitter outputs to be driven up to ±12V. RS-232 Transmitters The transmitters are inverting level translators that convert CMOS-logic levels to RS-232 levels. The MAX3228/MAX3229 will automatically reduce the RS232 compliant levels (±5.5V) to RS-232 compatible levels (±4.0V) when VCC 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-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 will return to RS-232 compliant levels (±5.5V) when VCC rises above approximately +3.5V. The MAX3228/MAX3229 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 transmitter inputs do not have pullup resistors. Connect unused inputs to GND or VL. RS-232 Receivers The MAX3228/MAX3229 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 MAX3228/MAX3229 receivers are in a high-impedance state (Table 3). The MAX3228/MAX3229 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_ AutoShutdown Logic _______________________________________________________________________________________ 7 MAX3228/MAX3229 +2.7V +0.3V +2.5V to +5.5V RS-232 Transceivers in UCSP MAX3228/MAX3229 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 MAX3228/MAX3229 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 MAX3228/ MAX3229 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 MAX3228/MAX3229 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 devices’ 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 60Ω (typ) pullup resistors connected to VL (Table 2). Therefore, if FORCEON and FORCEOFF are not connected, the MAX3228 and MAX3229 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 MAX3228 MAX3229 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 System 8 PIN NAME POWER-ON DEFAULT MECHANISM FORCEON High Internal pullup FORCEOFF High Internal pullup _______________________________________________________________________________________ +2.5V to +5.5V RS-232 Transceivers in UCSP FORCEON FORCEOFF Low X Normal Operation (Forced On) Normal Operation (AutoShutdown) TRANSCEIVER STATUS Shutdown (AutoShutdown) Shutdown (Forced Off) RECEIVER STATUS INVALID High High-Z L Low High-Z † High High Active † Low High Active H X = Don’t care. † = INVALID output state is determined by R_IN input levels. MAX3228/MAX3229 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. Applications Information 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 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. Capacitor Selection The capacitor type used for C1–C4 is not critical for proper operation; either polarized or nonpolarized 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 5V/div FORCEON = FORCEOFF 0 2V/div Table 4. Required Capacitor Values TOUT 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 0 4µs/div Figure 5. Transmitter Outputs Exiting Shutdown or Powering Up _______________________________________________________________________________________ 9 MAX3228/MAX3229 Table 3. Output Control Truth Table MAX3228/MAX3229 +2.5V to +5.5V RS-232 Transceivers in UCSP VCC VL 5V 0.1µF 0.1µF C1+ VCC VL 0 5V V+ T_OUT C3 C1 C1- T_IN 0 -5V MAX3229 C2+ V- C2 5V C4 C2- R_OUT VL 0 T1OUT T1IN Figure 7. Loopback Test Result at 120kbps R1IN R1OUT 4µs/div 1000pF VL 5kΩ 5V INVALID FORCEON GND FORCEOFF TO POWERMANAGEMENT UNIT T_IN 0 VL 5V T_OUT 0 -5V Figure 6. Transmitter Loopback Test Circuit 5V R_OUT Transmitter Outputs when Exiting Shutdown Figure 5 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 The MAX3228/MAX3229 maintain the RS-232 ±5.0V minimum transmitter output voltage even at high data rates. Figure 6 shows a transmitter loopback test cir- 10 0 4µs/div Figure 8. Loopback Test Result at 250kbps cuit. Figure 7 shows a loopback test result at 120kbps, and Figure 8 shows the same test at 250kbps. For Figure 7, the transmitter was driven at 120kbps into an RS-232 load in parallel with 1000pF. For Figure 8, a single transmitter was driven at 250kbps, and loaded with an RS-232 receiver in parallel with 1000pF. ______________________________________________________________________________________ +2.5V to +5.5V RS-232 Transceivers in UCSP 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 -20°C 240hr 0/10 Low-Temperature Operational -10°C 24hr 0/10 Solderability 8hr steam age — 0/15 ESD ±2000V, Human Body Model — 0/5 High-Temperature Operating Life TJ = +150°C 168hr 0/45 Typical Operating Circuits (continued) 2.5V TO 5.5V 1.65V TO 5.5V CBYPASS 0.1µF C1 C1 0.1µF D1 A2 C2 0.1µF 0.1µF A1 A3 A5 VCC C1+ C1- VL V+ MAX3229 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 GND E1 TO POWERMANAGEMENT UNIT VL 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 5 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 TRANSISTOR COUNT: 698 PROCESS TECHNOLOGY: CMOS ______________________________________________________________________________________ 11 MAX3228/MAX3229 Table 5. Reliability Test Data +2.5V to +5.5V RS-232 Transceivers in UCSP MAX3228/MAX3229 Pin Configurations 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 MAX3228 12 6 FON = FORCEON FOFF = FORCEOFF INV = INVALID ______________________________________________________________________________________ +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 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 MAX3229 6 FON = FORCEON FOFF = FORCEOFF INV = INVALID ______________________________________________________________________________________ 13 MAX3228/MAX3229 Pin Configurations (continued) +2.5V to +5.5V RS-232 Transceivers in UCSP 30L, UCSP 6x5 .EPS MAX3228/MAX3229 Package Information 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. 14 ____________________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.