19-1289; Rev 4; 10/08 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus The MAX3224–MAX3227/MAX3244/MAX3245 are 3Vpowered EIA/TIA-232 and V.28/V.24 communications interfaces with automatic shutdown/wakeup features and high data-rate capabilities. All devices achieve a 1µA supply current using Maxim’s revolutionary AutoShutdown Plus™ feature. These devices automatically enter a low-power shutdown mode when the RS-232 cable is disconnected or the transmitters of the connected peripherals are inactive, and the UART driving the transmitter inputs is inactive for more than 30 seconds. They turn on again when they sense a valid transition at any transmitter or receiver input. AutoShutdown Plus saves power without changes to the existing BIOS or operating system. The MAX3225/MAX3227/MAX3245 also feature MegaBaud™ operation, guaranteeing 1Mbps for highspeed applications such as communicating with ISDN modems. The MAX3224/MAX3226/MAX3244 guarantee 250kbps operation. The transceivers have a proprietary low-dropout transmitter output stage enabling true RS232 performance from a +3.0V to +5.5V supply with a dual charge pump. The charge pump requires only four small 0.1µF capacitors for operation from a 3.3V supply. The MAX3224–MAX3227 feature a logic-level output (READY) that asserts when the charge pump is regulating and the device is ready to begin transmitting. All devices are available in a space-saving TQFN, TSSOP, and SSOP packages. ________________________Applications Notebook, Subnotebook, and Palmtop Computers _Next Generation Device Features ♦ For Smaller Packaging: MAX3228/MAX3229: +2.5V to +5.5V RS-232 Transceivers in UCSP™ ♦ For Low-Voltage or Data Cable Applications: MAX3380E/MAX3381E: +2.35V to +5.5V, 1µA, 2 Tx/2 Rx RS-232 Transceivers with ±15kV ESDProtected I/O and Logic Pins ♦ For Integrated ESD Protection: MAX3222E/MAX3232E/MAX3237E/MAX3241E†/ MAX3246E: ±15kV ESD-Protected, Down to 10nA, +3.0V to +5.5V, Up to 1Mbps, True RS-232 Transceivers (MAX3246E Available in UCSP) _______________Ordering Information PART TEMP RANGE PIN-PACKAGE 0°C to +70°C 20 Plastic DIP MAX3224CAP 0°C to +70°C 20 SSOP MAX3224CTP 0°C to +70°C 20 Thin QFN-EP* MAX3224CUP 0°C to +70°C 20 TSSOP MAX3224EPP -40°C to +85°C 20 Plastic DIP MAX3224EAP -40°C to +85°C 20 SSOP MAX3224ETP -40°C to +85°C 20 Thin QFN-EP* 5mm x 5mm MAX3224EUP -40°C to +85°C 20 TSSOP MAX3224CPP Ordering Information continued at end of data sheet. *EP = Exposed paddle. Cellular Phones Battery-Powered Equipment _____________________ Selector Guide Handheld Equipment PART Peripherals Printers NO. OF GUARANTEED AUTOREADY DRIVERS/ DATA RATE SHUTDOWN OUTPUT RECEIVERS PLUS (bps) MAX3224 2/2 250k ✔ ✔ MAX3225 2/2 1M ✔ ✔ ✔ MAX3226 1/1 250k ✔ MAX3227 1/1 1M ✔ ✔ MAX3244 3/5 250k — ✔ MAX3245 3/5 1M — ✔ AutoShutdownPlus, MegaBaud, and UCSP are trademarks of Maxim Integrated Products, Inc. †Covered by U.S. Patent numbers 4,636,930; 4,679,134; 4,777,577; 4,797,899; 4,809,152; 4,897,774; 4,999,761; 5,649,210; and other patents pending. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX3224–MAX3227/MAX3244/MAX3245† ________________General Description MAX3224–MAX3227/MAX3244/MAX3245† 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus ABSOLUTE MAXIMUM RATINGS VCC to GND ..............................................................-0.3V to +6V V+ to GND (Note 1) ..................................................-0.3V to +7V V- to GND (Note 1) ...................................................+0.3V to -7V V+ + ⏐V-⏐(Note 1) ................................................................+13V Input Voltages T_IN, FORCEON, FORCEOFF to GND ................ -0.3V to +6V R_IN to GND ....................................................................±25V Output Voltages T_OUT to GND.............................................................±13.2V R_OUT, INVALID, READY to GND .........-0.3V to (VCC + 0.3V) Short-Circuit Duration T_OUT to GND .......................................................Continuous Continuous Power Dissipation (TA = +70°C) 16-Pin SSOP (derate 7.14mW/°C above +70°C) .........571mW 20-Pin Plastic DIP (derate 11.11mW/°C above +70°C) ...889mW 20-Pin TQFN (derate 21.3mW/°C above +70°C)........1702.1mW 20-Pin SSOP (derate 8.00mW/°C above +70°C) .........640mW 20-Pin TSSOP (derate 7.00mW/°C above +70°C) .......559mW 28-Pin Wide SO (derate 12.5mW/°C above +70°C)........... 1W 28-Pin SSOP (derate 9.52mW/°C above +70°C) .........762mW Operating Temperature Ranges MAX32_ _C_ _....................................................0°C to +70°C MAX32_ _E_ _ ..................................................-40°C to +85°C Storage Temperature Range .............................-65°C to +160°C Lead Temperature (soldering, 10s) .................................+300°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 = +3V to +5.5V, C1–C4 = 0.1µF, tested at 3.3V ±10%; CL = 0.047µF, C2–C4 = 0.33µF, tested at 5.0V ±10%; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DC CHARACTERISTICS (VCC = 3.3V or 5.0V, TA = +25°C) Supply Current, AutoShutdown Plus FORCEON = GND, FORCEOFF = VCC, all R_IN idle, all T_IN idle 1 10 µA Supply Current, Shutdown FORCEOFF = GND 1 10 µA Supply Current, AutoShutdown Plus Disabled FORCEON = FORCEOFF = VCC, no load 0.3 1 mA 0.8 V LOGIC INPUTS AND RECEIVER OUTPUTS Input Logic Threshold Low T_IN, FORCEON, FORCEOFF Input Logic Threshold High T_IN, FORCEON, FORCEOFF VCC = 3.3V 2 VCC = 5.0V 2.4 Transmitter Input Hysteresis V 0.5 V T_IN, FORCEON, FORCEOFF ±0.01 ±1 µA Output Leakage Current R_OUT (MAX3244/MAX3245), receivers disabled ±0.05 ±10 µA Output Voltage Low IOUT = 1.6mA 0.4 V Output Voltage High IOUT = -1.0mA Input Leakage Current VCC - 0.6 VCC - 0.1 V RECEIVER INPUTS Input Voltage Range -25 Input Threshold Low TA = +25°C Input Threshold High TA = +25°C 0.6 1.2 VCC = 5.0V 0.8 1.5 1.5 2.4 VCC = 5.0V 1.8 2.4 2 0.5 TA = +25°C 3 5 _______________________________________________________________________________________ V V VCC = 3.3V Input Hysteresis Input Resistance +25 VCC = 3.3V V V 7 kΩ 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus (VCC = +3V to +5.5V, C1–C4 = 0.1µF, tested at 3.3V ±10%; CL = 0.047µF, C2–C4 = 0.33µF, tested at 5.0V ±10%; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS TRANSMITTER OUTPUTS Output Voltage Swing All transmitter outputs loaded with 3kΩ to ground ±5 ±5.4 V Output Resistance VCC = V+ = V- = 0, transmitter outputs = ±2V 300 10M Ω Output Short-Circuit Current VCC = 0 or 3V to 5.5V, VOUT = ±12V, Transmitters disabled Output Leakage Current ±60 mA ±25 µA MOUSE DRIVEABILITY (MAX3244/MAX3245) T1IN = T2IN = GND, T3IN = VCC, T3OUT loaded with 3kΩ to GND, Transmitter Output Voltage T1OUT and T2OUT loaded with 2.5mA each AUTOSHUTDOWN PLUS (FORCEON = GND, FORCEOFF = VCC) Receiver Input Threshold to INVALID Output High Figure 4a Receiver Input Threshold to INVALID Output Low Figure 4a INVALID, READY (MAX3224–MAX3227) Output Voltage Low IOUT = -1.6mA INVALID, READY (MAX3224–MAX3227) Output Voltage High IOUT = -1.0mA ±5 V Positive threshold Negative threshold 2.7 -2.7 -0.3 V 0.3 V 0.4 V VCC - 0.6 V Receiver Positive or Negative Threshold to INVALID High tINVH VCC = 5V, Figure 4b 1 µs Receiver Positive or Negative Threshold to INVALID Low tINVL VCC = 5V, Figure 4b 30 µs Receiver or Transmitter Edge to Transmitters Enabled tWU VCC = 5V, Figure 5b (Note 2) 100 µs Receiver or Transmitter Edge to tAUTOSHDN VCC = 5V, Figure 5b (Note 2) Transmitters Shutdown 15 30 60 s _______________________________________________________________________________________ 3 MAX3224–MAX3227/MAX3244/MAX3245† ELECTRICAL CHARACTERISTICS (continued) MAX3224–MAX3227/MAX3244/MAX3245† 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus TIMING CHARACTERISTICS—MAX3224/MAX3226/MAX3244 (VCC = +3V to +5.5V, C1–C4 = 0.1µF, tested at 3.3V ±10%; CL = 0.047µF, C2–C4 = 0.33µF, tested at 5.0V ±10%; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL tPHL tPLH Receiver Output Enable Time Receiver Output Disable Time Transmitter Skew Receiver Skew MIN RL = 3kΩ, CL = 1000pF, one transmitter switching Maximum Data Rate Receiver Propagation Delay CONDITIONS ⏐ tPHL - tPLH ⏐ ⏐ tPHL - tPLH ⏐ MAX 250 UNITS kbps 0.15 R_IN to R_OUT, CL = 150pF µs 0.15 Normal operation (MAX3244 only) 200 ns Normal operation (MAX3244 only) 200 ns (Note 3) 100 ns 50 ns VCC = 3.3V, TA = +25°C, RL = 3kΩ to 7kΩ, measured from +3V to -3V or -3V to +3V Transition-Region Slew Rate TYP CL = 150pF to 1000pF 6 30 CL = 150pF to 2500pF 4 30 V/µs TIMING CHARACTERISTICS—MAX3225/MAX3227/MAX3245 (VCC = +3V to +5.5V, C1–C4 = 0.1µF, tested at 3.3V ±10%; CL = 0.047µF, C2–C4 = 0.33µF, tested at 5.0V ±10%; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL Maximum Data Rate Receiver Propagation Delay tPHL tPLH CONDITIONS MIN RL = 3kΩ, CL = 1000pF, one transmitter switching 250 VCC = 3.0V to 4.5V, RL = 3kΩ, CL = 250pF, one transmitter switching 1000 VCC = 4.5V to 5.5V, RL = 3kΩ, CL = 1000pF, one transmitter switching 1000 TYP MAX kbps 0.15 R_IN to R_OUT, CL = 150pF UNITS µs 0.15 Receiver Output Enable Time Normal operation (MAX3245 only) 200 ns Receiver Output Disable Time Normal operation (MAX3245 only) 200 ns (Note 3) 25 ns 50 ns Transmitter Skew Receiver Skew Transition-Region Slew Rate ⏐ tPHL - tPLH ⏐ ⏐ tPHL - tPLH ⏐ VCC = 3.3V, TA = +25°C, RL = 3kΩ to 7kΩ, CL = 150pF to 1000pF, measured from +3V to -3V or -3V to +3V 24 Note 2: A transmitter/receiver edge is defined as a transition through the transmitter/receiver input logic thresholds. Note 3: Transmitter skew is measured at the transmitter zero cross points. 4 _______________________________________________________________________________________ 150 V/µs 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus +SLEW 8 6 3000 4000 5000 0 1000 2000 3000 4000 3000 4000 80 -SLEW 50 +SLEW 40 30 1 TRANSMITTER AT 1Mbps 1 TRANSMITTER AT 62.5kbps (MAX3225) 1000 1500 2000 2500 MAX3225/MAX3227 TRANSMITTER SKEW vs. LOAD CAPACITANCE 500 20 AVERAGE; 10 PARTS 15 1000 1500 2000 LOAD CAPACITANCE (pF) 2500 3000 1000 1500 2000 MAX3224–MAX3227 READY TURN-OFF TIME vs. TEMPERATURE 200 MAX3224-08 26 2500 180 160 140 120 100 80 60 40 20 0 20 500 500 MAX3224–MAX3227 READY TURN-ON TIME vs. TEMPERATURE 28 22 0 LOAD CAPACITANCE (pF) 30 5 1Mbps LOAD CAPACITANCE (pF) 32 24 30 2500 34 10 0 2000 READY TURN-OFF TIME (ns) 25 1500 36 READY TURN-ON TIME (μs) 30 1000 38 MAX3224-07 1 TRANSMITTER AT 512kbps 1 TRANSMITTER AT 30kbps (MAX3225) LOAD = 3kΩ + CL 1.5Mbps 40 0 0 LOAD CAPACITANCE (pF) 50 50 10 0 500 2Mbps 60 20 10 -7.5 70 MAX3224-09 1Mbps 1 TRANSMITTER AT FULL DATA RATE 1 TRANSMITTER AT 1/16 DATA RATE (MAX3225) LOAD = 3kΩ + CL 90 SUPPLY CURRENT (mA) 60 MAX3224-06 70 5000 100 MAX3224-05 MAX3224-04 80 -5.0 0 2000 MAX3225/MAX3227 OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE 20 35 1000 MAX3225/MAX3227 SLEW RATE vs. LOAD CAPACITANCE 1 TRANSMITTER AT FULL DATA RATE 1 TRANSMITTER AT 1/16 DATA RATE (MAX3225) LOAD = 3kΩ + CL 1.5Mbps 1Mbps 2Mbps 40 MAX3224-03 0 5000 MAX3225/MAX3227 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE 1.5Mbps 45 T1 TRANSMITTING AT 250kbps T2 (MAX3224) TRANSMITTING AT 15.6kbps LOAD CAPACITANCE (pF) 2.5 0 20kbps 15 LOAD CAPACITANCE (pF) 2Mbps -2.5 20 LOAD CAPACITANCE (pF) 5.0 0 120kbps 25 0 0 2000 30 5 FOR DATA RATES UP TO 250kbps 1000 250kbps 35 10 2 7.5 TRANSMITTER SKEW (ns) SUPPLY CURRENT (mA) SLEW RATE (Vμ/s) -SLEW 10 40 4 VOUT0 TRANSMITTER OUTPUT VOLTAGE (V) 14 12 T1 TRANSMITTING AT 250kbps T2 (MAX3224) TRANSMITTING AT 15.6kbps 45 MAX3224-02 VOUT+ -2 -3 -4 -5 -6 16 MAX3224-01 6 5 4 3 2 1 0 -1 MAX3224/MAX3226 OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE MAX3224/MAX3226 SLEW RATE vs. LOAD CAPACITANCE SLEW RATE (V/μs) TRANSMITTER OUTPUT VOLTAGE (V) MAX3224/MAX3226 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE -40 -20 0 20 40 60 TEMPERATURE (°C) 80 100 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) _______________________________________________________________________________________ 5 MAX3224–MAX3227/MAX3244/MAX3245† __________________________________________Typical Operating Characteristics (VCC = +3.3V, 250kbps data rate, C1–C4 = 0.1µF, all transmitters loaded with 3kΩ and CL, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = +3.3V, 250kbps data rate, C1–C4 = 0.1µF, all transmitters loaded with 3kΩ and CL, TA = +25°C, unless otherwise noted.) MAX3224-11 12 10 SLEW RATE (V/μs) 1 TRANSMITTER AT 250kbps 2 TRANSMITTERS AT 15.6kbps 8 6 4 1000 2000 3000 4000 1000 2000 3000 4000 20kbps 20 60 SLEW RATE (V/μs) 1Mbps 1 TRANSMITTER AT FULL DATA RATE 2 TRANSMITTERS AT 1/16 DATA RATE 2Mbps 3000 4000 1.5Mbps 1Mbps MAX3224-14 MAX3224-13 50 40 30 20 -5.0 10 1 TRANSMITTER AT 1Mbps 2 TRANSMITTERS AT 62.5kbps 0 0 400 800 1200 1600 0 2000 400 800 1200 1600 LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) MAX3245 OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE MAX3245 TRANSMITTER SKEW vs. LOAD CAPACITANCE 50 MAX3224-15 100 90 45 80 2000 MAX3224-16 TRANSMITTER OUTPUT VOLTAGE (V) 70 2Mbps 1.5Mbps 2000 MAX3245 SLEW RATE vs. LOAD CAPACITANCE 5.0 2.5 1000 LOAD CAPACITANCE (pF) -7.5 40 70 2Mbps 60 1.5Mbps 50 40 30 1Mbps 20 TRANSMITTER SKEW (ns) SUPPLY CURRENT (mA) 0 LOAD CAPACITANCE (pF) 7.5 35 30 25 20 15 10 1 TRANSMITTER AT FULL DATA RATE 2 TRANSMITTERS AT 1/16 DATA RATE 10 5 0 0 0 400 800 1200 1600 LOAD CAPACITANCE (pF) 6 30 5000 MAX3245 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE -2.5 120kbps 0 0 5000 LOAD CAPACITANCE (pF) 0 250kbps 40 0 0 1 TRANSMITTER AT 250kbps 2 TRANSMITTERS AT 15.6kbps 50 10 2 VOUT- 60 SUPPLY CURRENT (mA) VOUT+ 4 3 2 1 0 -1 -2 -3 -4 -5 -6 14 MAX3224-10 6 5 MAX3244 OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE MAX3244 SLEW RATE vs. LOAD CAPACITANCE MAX3224-12 MAX3244 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE TRANSMITTER OUTPUT VOLTAGE (V) MAX3224–MAX3227/MAX3244/MAX3245† 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus 2000 0 1000 2000 LOAD CAPACITANCE (pF) _______________________________________________________________________________________ 3000 5000 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus PIN MAX3224 MAX3225 DIP/ TQFN SSIP/ TSSOP 1 19 MAX3226 MAX3227 MAX3244 MAX3245 NAME 1 — READY FUNCTION Ready to Transmit Output, Active High. READY is enabled high when V- goes below -4V and the device is ready to transmit. 2 1 2 28 C1+ 3 20 3 27 V+ +5.5V Generated By the Charge Pump 4 2 4 24 C1- Negative Terminal of Voltage-Doubler Charge-Pump Capacitor 5 3 5 1 C2+ Positive Terminal of Inverting Charge-Pump Capacitor 6 4 6 2 C2- Negative Terminal of Inverting Charge-Pump Capacitor 7 5 7 3 V- 8, 17 6, 15 13 9, 10, 11 T_OUT 9, 16 7, 14 8 4–8 R_IN 10, 15 8, 13 9 15–19 R_OUT Positive Terminal of Voltage-Doubler Charge-Pump Capacitor -5.5V Generated By the Charge Pump RS-232 Transmitter Outputs RS-232 Receiver Inputs TTL/CMOS Transmitter Outputs Valid Signal Detector Output, Active Low. A logic-high indicates that a valid RS-232 level is present on a receiver input. 11 9 10 21 INVALID 12, 13 10, 11 11 12, 13, 14 T_IN 14 12 12 23 FORCEON 18 16 14 25 GND Ground 19 17 15 26 VCC +3.0V to +5.5V Single Supply Voltage 20 18 16 22 — — — 20 R2OUTB TTL/CMOS Noninverting Complementary Receiver Outputs. Always active. — EP — — EP Exposed Paddle. Solder the exposed paddle to the ground, or leave unconnected. TTL/CMOS Transmitter Inputs Force-On Input, Active High. Drive high to override AutoShutdown Plus, keeping transmitters and receivers on (FORCEOFF must be high) (Table 1). Force-Off Input, Active Low. Drive low to shut down transmitters, FORCEOFF receivers (except R2OUTB), and charge pump. This overrides AutoShutdown Plus and FORCEON (Table 1). _______________Detailed Description Dual Charge-Pump Voltage Converter The MAX3224–MAX3227/MAX3244/MAX3245’s internal power supply consists of a regulated dual charge pump that provides output voltages of +5.5V (doubling charge pump) and -5.5V (inverting charge pump), over the +3.0V to +5.5V range. The charge pump operates in discontinuous mode: if the output voltages are less than 5.5V, the charge pump is enabled; if the output voltages exceed 5.5V, the charge-pump is disabled. Each charge pump requires a flying capacitor (C1, C2) and a reservoir capacitor (C3, C4) to generate the V+ and V- supplies. The READY output (MAX3224–MAX3227) is low when the charge pumps are disabled in shutdown mode. The READY signal asserts high when V- goes below -4V. LapLink is a trademark of Traveling Software. _______________________________________________________________________________________ 7 MAX3224–MAX3227/MAX3244/MAX3245† Pin Description MAX3224–MAX3227/MAX3244/MAX3245† 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus POWERMANAGEMENT UNIT OR KEYBOARD CONTROLLER VCC FORCEOFF FORCEON INVALID PROTECTION DIODE MAX3244 MAX3245 PREVIOUS RS-232 VCC I Rx 5kΩ UART Tx GND CPU I/O CHIP WITH UART SHDN = GND RS-232 a) OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM ACTIVE RECEIVER OUTPUT IN SHUTDOWN. VCC TO μP LOGIC TRANSITION DETECTOR Figure 1. Interface Under Control of PMU I PROTECTION DIODE RS-232 Transmitters The transmitters are inverting level translators that convert CMOS-logic levels to 5.0V EIA/TIA-232 levels. The MAX3224/MAX3226/MAX3244 guarantee a 250kbps data rate (1Mbps for the MAX3225/MAX3227/ MAX3245) with worst-case loads of 3kΩ in parallel with 1000pF, providing compatibility with PC-to-PC communication software (such as LapLink™). Transmitters can be paralleled to drive multiple receivers. Figure 1 shows a complete system connection. When FORCEOFF is driven to ground or when the AutoShutdown Plus circuitry senses that all receiver and transmitter inputs are inactive for more than 30sec, the transmitters are disabled and the outputs go into a highimpedance state. When powered off or shut down, the outputs can be driven to ±12V. The transmitter inputs do not have pull-up resistors. Connect unused inputs to GND or VCC. 8 MAX3244 MAX3245 R2OUTB VCC Rx UART 5kΩ Tx GND b) R2IN R2OUT THREE-STATED T1IN T1OUT FORCEOFF = GND NEW MAX3244/MAX3245: IN SHUTDOWN, R2OUTB IS USED TO MONITOR EXTERNAL DEVICES AND R2OUT IS THREE STATED, ELIMINATING A CURRENT PATH THROUGH THE UART’S PROTECTION DIODE. Figure 2. The MAX3244/MAX3245 detect RS-232 activity when the UART and interface are shut down. _______________________________________________________________________________________ 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus RECEIVER OR TRANSMITTER EDGE WITHIN 30sec T_OUT R_OUT (MAX3224/ MAX3225/ MAX3226/ MAX3227) R_OUT (MAX3244/ MAX3245) R2OUTB (MAX3244/ MAX3245) FORCEON FORCEOFF VALID RECEIVER LEVEL Shutdown (Forced Off) X 0 X X High-Z Active High-Z Active Normal Operation (Forced On) 1 1 X X Active Active Active Active Normal Operation (AutoShutdown Plus) 0 1 X Yes Active Active Active Active Shutdown (AutoShutdown Plus) 0 1 X No High-Z Active Active Active Normal Operation INVALID* 1 Yes X Active Active Active Active Normal Operation INVALID* 1 X Yes Active Active Active Active Shutdown INVALID* 1 No No High-Z Active Active Active Normal Operation (AutoShutdown) INVALID* INVALID** Yes X Active Active Active Active Shutdown (AutoShutdown) INVALID* INVALID** No X High-Z Active High-Z Active OPERATION STATUS X = Don’t care *INVALID connected to FORCEON **INVALID connected to FORCEON and FORCEOFF RS-232 Receivers The receivers convert RS-232 signals to CMOS-logic output levels. The MAX3224–MAX3227 feature inverting outputs that always remain active (Table 1). The MAX3244/MAX3245 have inverting three-state outputs that are high impedance when shut down (FORCEOFF = GND) (Table 1). The MAX3244/MAX3245 feature an extra, always active, noninverting output, R2OUTB. R2OUTB output monitors receiver activity while the other receivers are high impedance, allowing Ring Indicator applications to be monitored without forward biasing other devices connected to the receiver outputs. This is ideal for systems where V CC is set to ground in shutdown to accommodate peripherals such as UARTs (Figure 2). The MAX3224–MAX3227/MAX3244/MAX3245 feature an INVALID output that is enabled low when no valid RS-232 voltage levels have been detected on all receiver inputs. Because INVALID indicates the receiver input’s condition, it is independent of FORCEON and FORCEOFF states (Figures 3 and 4). AutoShutdown Plus Mode The MAX3224–MAX3227/MAX3244/MAX3245 achieve a 1µA supply current with Maxim’s AutoShutdown Plusfeature, which operates when FORCEOFF is high and a FORCEON is low. When these devices do not sense a valid signal transition on any receiver and transmitter input for 30sec, the on-board charge pumps are shut down, reducing supply current to 1µA. This occurs if the RS-232 cable is disconnected or if the connected _______________________________________________________________________________________ 9 MAX3224–MAX3227/MAX3244/MAX3245† Table 1. Output Control Truth Table +0.3V T_IN R_IN 30µs TIMER R -0.3V INVALID R_IN EDGE DETECT Figure 3a. INVALID Functional Diagram, INVALID Low FORCEOFF S 30sec TIMER EDGE DETECT INVALID ASSERTED IF ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30μs. AUTOSHDN R FORCEON Figure 3c. AutoShutdown Plus Logic +2.7V FORCEOFF POWERDOWN* FORCEON R_IN 30µs TIMER R -2.7V AUTOSHDN INVALID INVALID DEASSERTED IF ANY RECEIVER INPUT HAS BEEN BETWEEN +2.7V AND -2.7V FOR LESS THAN 30μs. Figure 3b. INVALID Functional Diagram, INVALID High * POWERDOWN IS ONLY AN INTERNAL SIGNAL. IT CONTROLS THE OPERATIONAL STATUS OF THE TRANSMITTERS AND THE POWER SUPPLIES. Figure 3d. Power-Down Logic Table 2. INVALID Truth Table INVALID HIGH RS-232 SIGNAL PRESENT AT ANY RECEIVER INPUT INVALID OUTPUT Yes High No Low peripheral transmitters are turned off, and the UART driving the transmitter inputs is inactive. The system turns on again when a valid transition is applied to any RS-232 receiver or transmitter input. As a result, the system saves power without changes to the existing BIOS or operating system. Figures 3a and 3b depict valid and invalid RS-232 receiver voltage levels. INVALID indicates the receiver input’s condition, and is independent of FORCEON and FORCEOFF states. Figure 3 and Tables 1 and 2 summarize the operating modes of the MAX3224– MAX3227/MAX3244/MAX3245 devices. FORCEON and FORCEOFF override AutoShutdown Plus circuitry. When neither control is asserted, the IC selects 10 +2.7V RECEIVER INPUT LEVELS MAX3224–MAX3227/MAX3244/MAX3245† 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus INDETERMINATE +0.3V 0 INVALID LOW -0.3V INDETERMINATE -2.7V INVALID HIGH Figure 4a. Receiver Positive/Negative Thresholds for INVALID between these states automatically based on the last receiver or transmitter input edge received. When shut down, the device’s charge pumps turn off, V+ is pulled to VCC, V- is pulled to ground, the transmitter outputs are high impedance, and READY (MAX3224–MAX3227) is driven low. The time required to exit shutdown is typically 100µs (Figure 8). ______________________________________________________________________________________ 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus MAX3224–MAX3227/MAX3244/MAX3245† RECEIVER INPUTS INVALID } REGION TRANSMITTER INPUTS TRANSMITTER OUTPUTS INVALID OUTPUT VCC tINVL 0 tINVH tAUTOSHDN tAUTOSHDN tWU tWU *VCC OUTPUT 0 V+ VCC 0 V- *MAX3224–MAX3227 Figure 4b. AutoShutdown Plus, INVALID, and READY Timing Diagram By connecting FORCEON to INVALID, the MAX3224– MAX3227/MAX3244/MAX3245 shut down when no valid receiver level and no receiver or transmitter edge is detected for 30sec, and wake up when a valid receiver level or receiver or transmitter edge is detected. By connecting FORCEON and FORCEOFF to INVALID, the MAX3224–MAX3227/MAX3244/MAX3245 shutdown when no valid receiver level is detected and wake up when a valid receiver level is detected (same functionality as AutoShutdown feature on MAX3221/MAX3223/ MAX3243). A mouse or other system with AutoShutdown Plus may need time to wake up. Figure 5 shows a circuit that forces the transmitters on for 100ms, allowing enough time for the other system to realize that the MAX3244/ MAX3245 is awake. If the other system outputs valid RS-232 signal transitions within that time, the RS-232 ports on both systems remain enabled. POWERMANAGEMENT UNIT MASTER SHDN LINE 0.1μF 1MΩ FORCEOFF FORCEON MAX3224 MAX3225 MAX3226 MAX3227 MAX3244 MAX3245 Figure 5. AutoShutdown Plus Initial Turn-On to Wake Up a Mouse or Another System ______________________________________________________________________________________ 11 MAX3224–MAX3227/MAX3244/MAX3245† 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus Software-Controlled Shutdown If direct software control is desired, use INVALID to indicate DTR or Ring Indicator signal. Tie FORCEOFF and FORCEON together to bypass the AutoShutdown Plus so the line acts like a SHDN input. transmitter is loaded with 3kΩ in parallel with 1000pF. The transmitter outputs display no ringing or undesirable transients as they come out of shutdown. Note that the transmitters are enabled only when the magnitude of V- exceeds approximately -3V. __________Applications Information Capacitor Selection The capacitor type used for C1–C4 is not critical for proper operation; polarized or nonpolarized capacitors can be used. 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 C1’s value. However, do not increase C1 without also increasing the values of C2, C3, C4, and CBYPASS, to maintain the proper ratios (C1 to the other capacitors). When using the minimum required capacitor values, make sure the capacitor value does not degrade excessively with temperature. If in doubt, use capacitors with a larger nominal value. The capacitor’s equivalent series resistance (ESR), which usually rises at low temperatures, influences the amount of ripple on V+ and V-. FORCEON = FORCEOFF 5V/div 0 T1OUT 2V/div 0 Figure 6. Transmitter Outputs when Exiting Shutdown or Powering Up VCC CBYPASS 12 C1, CBYPASS (µF) C2, C3, C4 (µF) 3.0 to 3.6 0.1 0.1 4.5 to 5.5 0.047 0.33 3.0 to 5.5 0.22 1 V+ C3* C1 C1C2+ C2 C2- MAX3224 MAX3225 MAX3226 MAX3227 MAX3244 MAX3245 5kΩ FORCEON FORCEOFF C4 R_ IN R_ OUT VCC V- T_ OUT T_ IN Figure 6 shows two transmitter outputs when exiting shutdown mode. As they become active, the two transmitter outputs are shown going to opposite RS-232 levels (one transmitter input is high; the other is low). Each VCC (V) VCC C1+ Transmitter Outputs when Exiting Shutdown Table 3. Required Minimum Capacitance Values READY 5μs/div Power-Supply Decoupling In most circumstances, a 0.1µF VCC bypass capacitor is adequate. In applications that are sensitive to powersupply noise, use a capacitor of the same value as charge-pump capacitor C1. Connect bypass capacitors as close to the IC as possible. T2OUT VCC = 3.3V C1–C4 = 0.1μF 5V/div 0 GND *C3 CAN BE RETURNED TO VCC OR GND. Figure 7. Loopback Test Circuit ______________________________________________________________________________________ 1000pF 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus T1IN The MAX3225/MAX3227/MAX3245 maintain the RS-232 ±5.0V minimum transmitter output voltage at data rates up to 1Mbps (MegaBaud). Figure 10 shows a loopback test result with a single transmitter driven at 1Mbps and all transmitters loaded with an RS-232 receiver in parallel with 250pF. Mouse Driveability The MAX3244/MAX3245 are specifically designed to power serial mice while operating from low-voltage power supplies. They have been tested with leading mouse brands from manufacturers such as Microsoft and Logitech. The MAX3244/MAX3245 successfully 5V/div T1IN 5V/div 5V/div T1OUT 5V/div 5V/div R1OUT T1OUT R1OUT 5V/div VCC = 3.3V VCC = 3.3V 200ns/div 2μs/div 5V/div T1IN 5V/div T1OUT 5V/div R1OUT VCC = 3.3V 2μs/div Figure 9. MAX3224/MAX3226/MAX3244 Loopback Test Result at 250kbps Figure 10. MAX3225/MAX3227/MAX3245 Loopback Test Result at 1Mbps TRANSMITTER OUTPUT VOLTAGE (V) Figure 8. MAX3224/MAX3226/MAX3244 Loopback Test Result at 120kbps 6 5 4 3 VOUT+ VCC = 3.0V 2 1 0 VOUT+ -1 -2 VCC -3 -4 -5 -6 VOUTVOUT- 0 1 2 3 4 5 6 7 8 9 10 LOAD CURRENT PER TRANSMITTER (mA) Figure 11a. MAX324_ Transmitter Output Voltage vs. Load Current per Transmitter ______________________________________________________________________________________ 13 MAX3224–MAX3227/MAX3244/MAX3245† High Data Rates The MAX3224/MAX3226/MAX3244 maintain the RS-232 ±5.0V minimum transmitter output voltage even at high data rates. Figure 7 shows a transmitter loopback test circuit. Figure 8 shows a loopback test result at 120kbps, and Figure 9 shows the same test at 250kbps. For Figure 8, all transmitters were driven simultaneously at 120kbps into RS-232 loads in parallel with 1000pF. For Figure 9, a single transmitter was driven at 250kbps, and all transmitters were loaded with an RS-232 receiver in parallel with 250pF. MAX3224–MAX3227/MAX3244/MAX3245† 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus +3.3V 26 0.1μF 28 C1 0.1μF 24 1 C2 0.1μF 2 LOGIC INPUTS VCC 27 C1+ V+ C3 0.1μF C1C2+ MAX3244 MAX3245 COMPUTER SERIAL PORT 3 V- C4 0.1μF C2- 14 T1IN T1OUT 9 +V 13 T2IN T2OUT 10 +V 12 T3IN T3OUT 11 -V 20 R2OUTB 19 R1OUT GND R1IN 4 R2IN 5 Tx 5kΩ 18 R2OUT 5kΩ LOGIC OUTPUTS 17 R3OUT R3IN 6 R4IN 7 R5IN 8 RS-232 INPUTS 5kΩ 16 R4OUT 5kΩ 15 23 VCC TO POWERMANAGEMENT UNIT 22 21 R5OUT SERIAL MOUSE 5kΩ FORCEON FORCEOFF INVALID GND 25 Figure 11b. Mouse Driver Test Circuit 14 ______________________________________________________________________________________ 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus Interconnection with 3V and 5V Logic The MAX3224–MAX3227/MAX3244/MAX3245 can directly interface with various 5V logic families, including ACT and HCT CMOS. See Table 4 for more information on possible combinations of interconnections. Table 5 lists other Maxim 3.0V to 5.5V powered transceivers. Table 4. Logic Family Compatibility with Various Supply Voltages SYSTEM POWER-SUPPLY VOLTAGE (V) VCC SUPPLY VOLTAGE (V) 3.3 3.3 5 5 5 3.3 COMPATIBILITY Compatible with all CMOS families Compatible with all TTL and CMOS families Compatible with ACT and HCT CMOS, and with AC, HC, or CD4000 CMOS Table 5. 3.0V to 5.5V Powered RS-232 Transceivers from Maxim PART SUPPLY VOLTAGE RANGE (V) NO. OF Tx/Rx SUPPLY CURRENT (µA) AUTOSHUTDOWN PLUS AUTOSHUTDOWN GUARANTEED DATA RATE (bps) MAX3241 +3.0 to +5.5 3/5 300 — — 120k MAX3243 +3.0 to +5.5 3/5 1 — Yes 120k MAX3244 +3.0 to +5.5 3/5 1 Yes — 250k MAX3245 +3.0 to +5.5 3/5 1 Yes — 1M MAX3232 +3.0 to +5.5 2/2 300 — — 120k MAX3222 +3.0 to +5.5 2/2 300 — — 120k MAX3223 +3.0 to +5.5 2/2 1 — Yes 120k MAX3224 +3.0 to +5.5 2/2 1 Yes — 250k MAX3225 +3.0 to +5.5 2/2 1 Yes — 1M MAX3221 +3.0 to +5.5 1/1 1 — Yes 120k MAX3226 +3.0 to +5.5 1/1 1 Yes — 250k MAX3227 +3.0 to +5.5 1/1 1 Yes — 1M ______________________________________________________________________________________ 15 MAX3224–MAX3227/MAX3244/MAX3245† drove all serial mice tested and met their respective current and voltage requirements. The MAX3244/ MAX3245 dual charge pump ensures the transmitters will supply at least ±5V during worst-case conditions. Figure 11a shows the transmitter output voltages under increasing load current. Figure 11b shows a typical mouse connection. MAX3224–MAX3227/MAX3244/MAX3245† 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus ___________________________________________________Typical Operating Circuits +3.3V +3.3V 15 0.1μF CBYPASS 2 C1+ C1 0.1μF 4 C15 C2 0.1μF 6 C2+ 3 V+ MAX3226 MAX3227 V- 9 R1OUT C3 0.1μF C1 0.1μF C4 0.1μF C2 0.1μF 7 C2- 11 T1IN 12 24 1 2 27 V+ C3 0.1μF C1C2+ MAX3244 MAX3245 V- R1IN 8 13 T2IN T2OUT 10 12 T3IN T3OUT 11 FORCEOFF 16 TO POWERMANAGEMENT UNIT VCC 22 FORCEOFF 23 FORCEON AUTOSHUTDOWN PLUS INVALID 21 20 R2OUTB 14 19 R1OUT R1IN 4 +3.3V C1 0.1μF 2 C1+ 4 C15 C2 0.1μF 6 C2+ VCC MAX3224* MAX3225* V- C3 0.1μF R3IN 6 C4 0.1μF 5kΩ 16 R4OUT T1OUT 17 R4IN 7 5kΩ RS-232 OUTPUTS T2OUT 8 5 5kΩ 17 R3OUT 7 C2- 12 T2IN R2IN 18 R2OUT 3 V+ 13 T1IN TTL/CMOS INPUTS 5kΩ 19 0.1μF C4 0.1μF C2T1OUT 9 GND CBYPASS 3 14 T1IN AUTOSHUTDOWN INVALID 10 PLUS FORCEON 28 C1+ VCC T1OUT 13 5kΩ 1 READY 26 CBYPASS 0.1μF VCC 15 R5OUT R5IN 8 5kΩ R1IN 16 15 R1OUT TTL/CMOS OUTPUTS RS-232 INPUTS 5kΩ R2IN 10 R2OUT 9 GND 25 5kΩ 1 READY 14 AUTOSHUTDOWN PLUS INVALID 11 FORCEOFF 20 FORCEON GND TO POWERMANAGEMENT UNIT VCC *MAX3224/MAX3225 PINOUT REFERS TO DIP/SSOP/TSSOP PACKAGES. 18 16 ______________________________________________________________________________________ 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus 20 FORCEOFF READY 1 16 FORCEOFF READY 1 C1+ 2 19 VCC C1+ 2 15 VCC V+ 3 18 GND V+ 3 14 GND C1- 4 MAX3224 MAX3225 C2+ 5 C2- 6 V- 7 T2OUT 17 T1OUT C1- 4 16 R1IN C2+ 5 15 R1OUT C2- 6 14 FORCEON 8 13 T1IN R2IN 9 12 T2IN R2OUT 10 MAX3226 MAX3227 13 T1OUT 12 FORCEON 11 T1IN V- 7 10 INVALID 9 R1OUT R1IN 8 SSOP 11 INVALID 15 14 13 12 T1IN FORCEON R1OUT R1IN T1OUT DIP/SSOP/TSSOP 11 C2+ 1 28 C1+ C2- 2 27 V+ V- 3 26 VCC R1IN 4 25 GND R2IN 5 10 T2IN R3IN 6 24 C123 FORCEON R4IN 7 22 FORCEOFF VCC 17 9 INVALID R5IN 8 21 INVALID FORCEOFF 18 8 R2OUT T1OUT 9 20 R2OUTB 7 R2IN T2OUT 10 19 R1OUT 6 T2OUT T3OUT 11 18 R2OUT T3IN 12 17 R3OUT 5 T2IN 13 16 R4OUT V- GND 16 MAX3244 MAX3245 T1IN 14 15 R5OUT MAX3244 MAX3225 READY 19 EXPOSED PADDLE 3 TQFN 4 C2-. 2 C2+ C1+ 1 C1- V+ 20 SO/SSOP ______________________________________________________________________________________ 17 MAX3224–MAX3227/MAX3244/MAX3245† ___________________________________________________________ Pin Configurations MAX3224–MAX3227/MAX3244/MAX3245† 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus _ Ordering Information (continued) ___________________Chip Information MAX3225CPP 0°C to +70°C MAX3225CAP 0°C to +70°C 20 SSOP MAX3225CTP 0°C to +70°C 20 Thin QFN-EP* MAX3225CUP 0°C to +70°C 20 TSSOP MAX3224 TRANSISTOR COUNT: 1129 MAX3225 TRANSISTOR COUNT: 1129 MAX3226 TRANSISTOR COUNT: 1129 MAX3227 TRANSISTOR COUNT: 1129 MAX3244/MAX3245 TRANSISTOR COUNT: 1335 MAX3225EPP -40°C to +85°C 20 Plastic DIP PROCESS: BiCMOS MAX3225EAP -40°C to +85°C 20 SSOP MAX3225ETP -40°C to +85°C 20 Thin QFN-EP* MAX3225EUP -40°C to +85°C 20 TSSOP MAX3225EUP/V -40°C to +85°C 20 TSSOP PART TEMP RANGE PIN-PACKAGE 20 Plastic DIP MAX3226CAE 0°C to +70°C MAX3226EAE -40°C to +85°C 16 SSOP 16 SSOP MAX3227CAE 0°C to +70°C 16 SSOP MAX3227EAE -40°C to +85°C MAX3244CWI 0°C to +70°C 28 Wide SO MAX3244CAI 0°C to +70°C 28 SSOP MAX3244EWI -40°C to +85°C 28 Wide SO MAX3244EAI -40°C to +85°C 28 SSOP 16 SSOP MAX3245CWI 0°C to +70°C 28 Wide SO MAX3245CAI 0°C to +70°C 28 SSOP MAX3245EWI -40°C to +85°C MAX3245EAI -40°C to +85°C *EP = Exposed paddle. /V denotes an automotive qualified part. 18 28 Wide SO 28 SSOP ______________________________________________________________________________________ 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 16 SSOP — 21-0056 20 SSOP T4477-3 21-0056 20 Thin QFN-EP T2055-5 21-0140 20 TSSOP — 21-0108 20 Plastic DIP — 21-0043 28 Wide SO — 21-0042 28 SSOP — 21-0056 ______________________________________________________________________________________ 19 MAX3224–MAX3227/MAX3244/MAX3245† Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. MAX3224–MAX3227/MAX3244/MAX3245† 1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus Revision History REVISION NUMBER REVISION DATE 2 5/05 Added new packaging types 3 10/08 Added automotive qualified product information DESCRIPTION PAGES CHANGED ⎯ 1, 18 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. 20 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.