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19-0306; Rev 8; 10/03
1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown
_______________General Description
The MAX3221/MAX3223/MAX3243 achieve 1A supply current with Maxim's revolutionary AutoShutdownTM feature. When the MAX3221/MAX3223/MAX3243 do not sense a valid signal level on their receiver inputs, the on-board power supply and drivers shut down. This occurs if the RS-232 cable is disconnected or if the transmitters of the connected peripheral are turned off. The system 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. The MAX3221/MAX3223/MAX3243 transceivers are 3Vpowered EIA/TIA-232 and V.28/V.24 communications interfaces intended for notebook computer applications. A proprietary, high-efficiency, dual charge-pump power supply and a low-dropout transmitter combine to deliver true RS-232 performance from a single +3.0V to +5.5V supply. A guaranteed data rate of 120kbps provides compatibility with popular software for communicating with personal computers. The MAX3221/MAX3223/MAX3243 require only 0.1F capacitors in 3.3V operation, and can operate from input voltages ranging from +3.0V to +5.5V. They are ideal for 3.3V-only systems, mixed 3.3V and 5.0V systems, or 5.0V-only systems that require true RS-232 performance. The MAX3221 is a 1-driver/1-receiver 16-pin SSOP version of the 20-pin MAX3223 (2-driver/2-receiver). The MAX3243 3-driver/5-receiver, complete serial port is ideal for notebook or subnotebook computers. The MAX3243 includes one complementary always-active receiver. This receiver can monitor an external device (such as a modem) in shutdown, without forward biasing the protection diodes in a UART that may have VCC completely removed.
Next Generation Device Features
For Space-Constrained Applications: MAX3228/MAX3229: +2.5V to +5.5V RS-232 Transceivers in UCSPTM 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 Package) For Low-Voltage or Data Cable Applications: MAX3380E/MAX3381E: +2.5V to +5.5V, 1A, 2 Tx/2 Rx RS-232 Transceivers with 15kV ESDProtected I/O and Logic Pins
MAX3221/MAX3223/MAX3243*
________________________Applications
Notebook, Subnotebook, and Palmtop Computers Battery-Powered Equipment Hand-Held Equipment Peripherals Printers
______________Ordering Information
PART MAX3221CAE MAX3221CUE MAX3221EAE MAX3221EUE MAX3223CPP MAX3223CAP MAX3223CUP MAX3223EPP MAX3223EAP MAX3223EUP MAX3243CWI MAX3243CAI MAX3243CUI MAX3243EWI MAX3243EAI MAX3243EUI TEMP RANGE 0C to +70C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C -40C to +85C PIN-PACKAGE 16 SSOP 16 TSSOP 16 SSOP 16 TSSOP 20 Plastic DIP 20 SSOP 20 TSSOP 20 Plastic DIP 20 SSOP 20 TSSOP 28 Wide SO 28 SSOP 28 TSSOP 28 Wide SO 28 SSOP 28 TSSOP
_____________________Selector Guide
PART MAX3221 MAX3223 MAX3243 Tx 1 2 3 Rx 1 2 5 VCC RANGE (V) AutoShutdown 3.0 to 5.5 3.0 to 5.5 3.0 to 5.5 Yes Yes Yes
Pin Configurations appear at end of data sheet. Typical Operating Circuits appear at end of data sheet. Future product--contact factory for availability. AutoShutdown 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; and other patents pending. ________________________________________________________________ Maxim Integrated Products 1
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.
1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown MAX3221/MAX3223/MAX3243
ABSOLUTE MAXIMUM RATINGS
VCC ...........................................................................-0.3V to +6V V+ (Note 1) ...............................................................-0.3V to +7V V- (Note 1) ...............................................................+0.3V to -7V V+ + |V-| (Note 1).................................................................+13V Input Voltages T_IN, FORCEOFF, FORCEON, EN (MAX3223) ......-0.3V to +6V R_IN ...................................................................................25V Output Voltages T_OUT.............................................................................13.2V R_OUT, INVALID ......................................-0.3V to (VCC + 0.3V) Short-Circuit Duration T_OUT ......................................................................Continuous Continuous Power Dissipation (TA = +70C) 16-Pin SSOP (derate 7.14mW/C above +70C) ...........571mW 16-Pin TSSOP (derate 6.70mW/C above +70C) .........533mW 20-Pin Plastic DIP (derate 11.11mW/C above +70C)....889mW 20-Pin SSOP (derate 8.00mW/C above +70C) ...........640mW 20-Pin TSSOP DIP (derate 7.00mW/C above +70C).....559mW 28-Pin Wide SO (derate 12.50mW/C above +70C) ............1W 28-Pin SSOP (derate 9.52mW/C above +70C) ...........762mW 28-Pin TSSOP (derate 8.70mW/C above +70C) .........696mW Operating Temperature Ranges MAX32_ _C_ _.......................................................0C to +70C MAX32_ _E_ _ ....................................................-40C to +85C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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 = +3.0V to +5.5V, C1-C4 = 0.1F (Note 2), TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER DC CHARACTERISTICS Supply Current, AutoShutdown Supply Current, Shutdown Supply Current, AutoShutdown Disabled Input Logic Threshold Low Input Logic Threshold High Input Leakage Current Output Leakage Current Output Voltage Low Output Voltage High All R_IN open, FORCEON = GND, VCC = 3.3V FORCEOFF = VCC or 5.0V, FORCEOFF = GND TA = +25C FORCEON = FORCEOFF = V , CC no load T_IN, FORCEON, FORCEOFF, EN (MAX3223) T_IN, EN, FORCEON, FORCEOFF T_IN, EN, FORCEON, FORCEOFF Receivers disabled IOUT = 1.6mA IOUT = -1.0mA Positive threshold Negative threshold -2.7 -0.3 0.3 0.4 VCC - 0.6 250 1 30 VCC - 0.6 VCC - 0.1 2.7 VCC = 3.3V VCC = 5.0V 2.0 2.4 0.01 0.05 1.0 10 0.4 1.0 1.0 0.3 10 10 1.0 A A mA CONDITIONS MIN TYP MAX UNITS
LOGIC INPUTS AND RECEIVER OUTPUTS 0.8 V V A A V V
AUTOSHUTDOWN (FORCEON = GND, FORCEOFF = VCC) Receiver Input Thresholds to Transmitters Enabled Receiver Input Thresholds to Transmitters Disabled INVALID Output Voltage Low INVALID Output Voltage High Receiver Threshold to Transmitters Enabled (tWU) Receiver Positive or Negative Threshold to INVALID High (tINVH) Receiver Positive or Negative Threshold to INVALID Low (tINVL) 2 Figure 5 V V V V s s s
1A supply current, Figure 5 IOUT = 1.6mA IOUT = -1.0mA Figure 5 Figure 5 Figure 5
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1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +5.5V, C1-C4 = 0.1F (Note 2), TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER RECEIVER INPUTS Input Voltage Range Input Threshold Low Input Threshold High Input Hysteresis Input Resistance TRANSMITTER OUTPUTS Output Voltage Swing Output Resistance Output Short-Circuit Current Output Leakage Current VOUT = 12V, VCC = 0V or 3.0V to 5.5V, transmitters disabled All transmitter outputs loaded with 3k to ground VCC = V+ = V- = 0V, transmitter output = 2V 5.0 300 5.4 10M 35 60 25 V mA A TA = +25C 3 TA = +25C TA = +25C VCC = 3.3V VCC = 5.0V VCC = 3.3V VCC = 5.0V -25 0.6 0.8 1.2 1.5 1.5 1.8 0.3 5 7 2.4 2.4 25 V V V V k CONDITIONS MIN TYP MAX UNITS
MAX3221/MAX3223/MAX3243
MOUSE DRIVEABILITY (MAX3243) Transmitter Output Voltage TIMING CHARACTERISTICS Maximum Data Rate Receiver Propagation Delay Receiver Output Enable Time Receiver Output Disable Time Transmitter Skew Receiver Skew RL = 3k, CL = 1000pF, one transmitter switching Receiver input to receiver output, CL = 150pF Normal operation Normal operation tPHL - tPLH tPHL - tPLH VCC = 3.3V, RL = 3k to 7k, TA = +25C, measured from +3V to -3V or -3V to +3V MAX3221/MAX3223 MAX3243 MAX3221/MAX3223 MAX3243 CL = 200pF to 2500pF 4 tPHL tPLH 120 235 0.3 0.3 200 200 200 200 100 100 8.0 500 30 V/s CL = 200pF to 1000pF 6 30 1000 kbps s ns ns ns ns T1IN = T2IN = GND, T3IN = VCC, T3OUT loaded with 3k to GND, T1OUT and T2OUT loaded with 2.5mA each 5 V
Transition-Region Slew Rate
Note 2: C1-C4 = 0.1F, tested at 3.3V 10%. C1 = 0.047F, C2-C4 = 0.33F, tested at 5.0V 10%.
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3
1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown MAX3221/MAX3223/MAX3243
__________________________________________Typical Operating Characteristics
(VCC = +3.3V, 235kbps data rate, 0.1F capacitors, all transmitters loaded with 3k, TA = +25C, unless otherwise noted.)
MAX3221/MAX3223 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE
MAX3221/3223-01
MAX3221/MAX3223 SLEW RATE vs. LOAD CAPACITANCE
MAX3223 SUPPLY CURRENT (mA) 20 18 SLEW RATE (V/s) 16 14 12 10 8 6 4 2 +SLEW -SLEW
MAX3221/3223-02
MAX3221/MAX3223 SUPPLY CURRENT vs. LOAD CAPACITANCE WHEN TRANSMITTING DATA
40 35 235kbps 30 25 20 15 10 5 20kbps 120kbps 25 20 15 10 5 0 0 1000 2000 3000 4000 5000 LOAD CAPACITANCE (pF)
MAX3221/3223-03
4 3 2 1 0 -1 -2 -3 -4 -5 -6 0 1000 2000 3000 4000 VOUT-
30
FOR DATA RATES UP TO 235kbps
5000
0 150 500 1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
MAX3243 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE
MAX3221/3223-04
MAX3243 SLEW RATE vs. LOAD CAPACITANCE
MAX3221/3223-05
MAX3243 SUPPLY CURRENT vs. LOAD CAPACITANCE WHEN TRANSMITTING DATA
40 SUPPLY CURRENT (mA) 35 30 25 20 15 10 5 0 5000 0 1000 2000 3000 4000 5000 LOAD CAPACITANCE (pF) 20kbps 120kbps 235kbps
MAX3221/3223-06
7.5 TRANSMITTER OUTPUT VOLTAGE (V) VOUT+ 5.0 2.5 0 -2.5 -5.0 -7.5 0 1000 2000 3000 4000 VOUT-
24 22 20 SLEW RATE (V/s) 18 16 14 12 10 8 6 4 +SLEW ALL OUTPUTS LOADED WITH 3k +CL 0.1F CHARGE-PUMP CAPACITORS FOR ALL DATA RATES UP TO 235kbps 0 1000 2000 3000 4000 -SLEW
45
1 TRANSMITTER AT 235kbps 2 TRANSMITTERS AT 30kbps
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
4
_______________________________________________________________________________________
MAX3221 SUPPLY CURRENT (mA)
6 5 TRANSMITTER OUTPUT VOLTAGE (V)
22
35
VOUT+
1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown
______________________________________________________________Pin Description
PIN MAX3221 1 5 6 7 8 13 11 9 -- 10 16 12 4 14 15 3 2 MAX3223 1 5 6 7 9, 16 8, 17 12, 13 10, 15 -- 11 20 14 4 18 19 3 2 MAX3243 -- 1 2 3 4-8 9, 10, 11 12, 13, 14 15-19 20 21 22 23 24 25 26 27 28 NAME EN C2+ C2VR_IN T_OUT T_IN R_OUT R2OUTB INVALID FORCEOFF FORCEON C1GND VCC V+ C1+ FUNCTION Receiver Enable Control. Drive low for normal operation. Drive high to force the receiver outputs into a high-Z state. Positive terminal of inverting charge-pump capacitor Negative terminal of inverting charge-pump capacitor -5.5V generated by the charge pump RS-232 Receiver Inputs RS-232 Transmitter Outputs TTL/CMOS Transmitter Inputs TTL/CMOS Receiver Outputs Noninverting Receiver Output--active in shutdown Output of the valid signal detector. Indicates if a valid RS-232 level is present on receiver inputs logic "1". Drive low to shut down transmitters and on-board power supply. This overrides all automatic circuitry and FORCEON (Table 1). Drive high to override automatic circuitry keeping transmitters on (FORCEOFF must be high) (Table 1). Negative terminal of the voltage doubler charge-pump capacitor Ground +3.0V to +5.5V Supply Voltage +5.5V generated by the charge pump Positive terminal of the voltage doubler charge-pump capacitor
MAX3221/MAX3223/MAX3243
_______________Detailed Description
Dual Charge-Pump Voltage Converter
The MAX3221/MAX3223/MAX3243'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), regardless of the input voltage (V CC) over the +3.0V to +5.5V range. 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. Each charge pump requires a flying capacitor (C1, C2) and a reservoir capacitor (C3, C4) to generate the V+ and V- supplies.
RS-232 Transmitters
The transmitters are inverting level translators that convert CMOS-logic levels to 5.0V EIA/TIA-232 levels. They guarantee a 120kbps data rate with worst-case loads of 3k in parallel with 1000pF, providing compatibility with PC-to-PC communication software (such as LaplinkTM). Typically, the MAX3221/MAX3223/MAX3243 can operate at data rates of 235kbps. Transmitters can be paralleled to drive multiple receivers or mice (MAX3243). Figure 1 shows a complete system connection. When FORCEOFF is driven to ground, or the AutoShutdown circuitry senses invalid voltage levels at all receiver inputs, the transmitters are disabled and the outputs are forced into a high-impedance state.
LapLink is a trademark of Traveling Software.
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5
1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown MAX3221/MAX3223/MAX3243
POWER MANAGEMENT UNIT OR KEYBOARD CONTROLLER FORCEOFF FORCEON INVALID PROTECTION DIODE VCC
MAX3243
VCC Rx UART Tx I
PREVIOUS RS-232
5k
CPU
I/O CHIP WITH UART
GND RS-232
SHDN = GND
(a)
OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM ACTIVE RECEIVER OUTPUT IN SHUTDOWN.
VCC TO P LOGIC TRANSITION DETECTOR
Figure 1. Interface Under Control of PMU
PROTECTION DIODE
I
MAX3243
R2OUTB
RS-232 Receivers
The MAX3221/MAX3223/MAX3243's receivers convert RS-232 signals to CMOS-logic output levels. All receivers have one inverting three-state output. In shutdown (FORCEOFF = low) or in AutoShutdown, the MAX3221/MAX3223's receivers are active (Table 1). Driving EN high places the receiver(s) in a high-impedance state. The MAX3243's receivers are high impedance when the part is shut down. The MAX3243 has an always-active complementary output (R2OUTB). R2OUTB is an extra output that monitors receiver activity while the other receivers are high impedance. This allows Ring Indicator to be monitored without forward biasing other devices connected to the receiver outputs. This is ideal for systems where VCC is set to 0V in shutdown to accommodate peripherals, such as UARTs (Figure 2).
VCC Rx UART R2OUT THREE-STATED 5k T1IN FORCEOFF = GND T1OUT R2IN
Tx GND
(b)
NEW MAX3243: 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 MAX3243 detects RS-232 activity when the UART and interface are shut down.
6
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1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown MAX3221/MAX3223/MAX3243
Table 1a. MAX3221/MAX3223 FORCEOFF and Enable Control Truth Table
FORCEOFF 0 0 1 1 EN 0 1 0 1 T_OUT High-Z High-Z Active* Active* R_OUT Active High-Z Active High-Z
-0.3V +0.3V TO MAX32_ _ POWER SUPPLY AND TRANSMITTERS INVALID
R_IN
30s COUNTER R
* TRANSMITTERS ARE DISABLED, REDUCING SUPPLY CURRENT TO 1A IF ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30s.
Figure 3a. MAX32_ _ Entering 1A Supply Mode via AutoShutdown
Table 1b. MAX3243 FORCEOFF Control Truth Table
FORCEOFF 0 1 T_OUT High-Z Active* R_OUT High-Z Active* R2OUTB Active Active
+2.7V TO MAX32_ _ POWER SUPPLY INVALID
R_IN
-2.7V
30s COUNTER R
*Note: If the part is in AutoShutdown mode (FORCEOFF = VCC, FORCEON = GND), it is shut down if no valid RS-232 levels are present on all receiver inputs.
* 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 30s.
AutoShutdown
A 1A supply current is achieved with Maxim's new AutoShutdown feature, which operates when FORCEON is low and FORCEOFF is high. When the MAX3221/MAX3223/MAX3243 sense no valid signal levels on all receiver inputs for 30s, the on-board power supply and drivers are shut off, reducing supply current to 1A. This occurs if the RS-232 cable is disconnected or the connected peripheral transmitters are turned off. The system 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. When using AutoShutdown, the INVALID output is high when the device is on and low when the device is shut down. Because INVALID indicates the receiver inputs' condition, it can be used in any mode (Figure 3). Table 2 and Figure 3c summarize the MAX3221/ MAX3223/MAX3243 operating modes. FORCEON and FORCEOFF override the automatic circuitry and force the transceiver into its normal operating state or into its low-power standby state. When neither control is asserted, the IC selects between these states automatically based on receiver input levels. Figures 3a, 3b, and 5a depict valid and invalid RS-232 receiver levels. A mouse or other 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
Figure 3b. MAX32_ _ with Transmitters Enabled Using AutoShutdown
FORCEOFF 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. POWER DOWN
Figure 3c. AutoShutdown Logic
POWER MANAGEMENT UNIT
MASTER SHDN LINE 0.1F 1M
FORCEOFF FORCEON
MAX3221 MAX3223 MAX3243
Figure 4. AutoShutdown with Initial Turn-On to Wake Up a Mouse or Another System
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7
1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown MAX3221/MAX3223/MAX3243
Table 2. AutoShutdown Logic
RS-232 SIGNAL PRESENT AT RECEIVER INPUT Yes No No Yes No FORCEOFF INPUT H H H L L FORCEON INPUT X H L X X INVALID OUTPUT H L L H L TRANSCEIVER STATUS Normal Operation Normal Operation (Forced On) Shutdown (AutoShutdown) Shutdown (Forced Off) Shutdown (Forced Off)
RECEIVER INPUT LEVELS
other system to realize that the MAX3221/MAX3223/ MAX3243 is awake. If the other system outputs 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 turned off, V+ decays to VCC, V- decays to ground, and the transmitter outputs are disabled (high impedance). The time required to exit shutdown is typically 100s (Figure 5b).
TRANSMITTERS ENABLED, INVALID HIGH +2.7V INDETERMINATE +0.3V 0V -0.3V INDETERMINATE -2.7V TRANSMITTERS ENABLED, INVALID HIGH AUTOSHUTDOWN, TRANSMITTERS DISABLED, 1A SUPPLY CURRENT, INVALID LOW
Software-Controlled Shutdown
If direct software control is desired, INVALID can be used to indicate DTR or Ring Indicator signal. Tie FORCEOFF and FORCEON together to bypass AutoShutdown so the line acts like a SHDN input. (a)
___________Applications Information
Capacitor Selection
The capacitor type used for C1-C4 is not critical for proper operation; either polarized or nonpolarized capacitors may be used. The charge pump requires 0.1F capacitors for 3.3V operation. For other supply voltages, refer to 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, 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-.
8
RECEIVER INPUT VOLTAGE (V) INVALID REGION
VCC INVALID OUTPUT (V) 0
tINVL
tINVH tWU
V+ VCC 0 V-
(b)
Figure 5. AutoShutdown Trip Levels
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1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown MAX3221/MAX3223/MAX3243
5V/div
T2
TRANSMITTER OUTPUT VOLTAGE (V)
4 3 2 1 0 -1 -2 -3 -4 -5 -6 0
VCC = 3.0V
T1
VOUT+
2V/div
VOUT+
T2
T1
VCC
T3
VOUTVOUT-
50s/div VCC = +3.3V C1-C4 = 0.1F
1
2
3
4
5
6
7
LOAD CURRENT PER TRANSMITTER (mA)
Figure 6. Transmitter Outputs when Exiting Shutdown or Powering Up
Figure 7a. MAX3243 Transmitter Output Voltage vs. Load Current per Transmitter
Power-Supply Decoupling
In most circumstances a 0.1F bypass capacitor is adequate. In applications that are sensitive to powersupply noise, decouple VCC to ground with a capacitor of the same value as the charge-pump capacitor C1. Connect bypass capacitors as close to the IC as possible.
Transmitter Outputs when Exiting Shutdown
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. Each transmitter is loaded with 3k in parallel with 2500pF. The transmitter outputs display no ringing or undesirable transients as they come out of shutdown. Note that the transmitters are enabled only when the magnitude of V- exceeds approximately 3V. Figure 7a shows the MAX3243's transmitter output voltage vs. current per transmitter. Figure 7b is a mouse driver test circuit.
Microsoft. The MAX3243 successfully drove all serial mice and met their respective current and voltage requirements. Figure 7a shows the transmitter outputs under increasing load current. The MAX3243's switching regulator ensures the transmitters will supply at least 5V during worst-case conditions. The AutoShutdown feature does not work with a mouse, so FORCEOFF and FORCEON should be connected to VCC.
High Data Rates
The MAX3221/MAX3223/MAX3243 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 235kbps. For Figure 9, all three transmitters were driven simultaneously at 120kbps into RS-232 loads in parallel with 1000pF. For Figure 10, a single transmitter was driven at 235kbps, but all three transmitters were loaded with an RS-232 receiver in parallel with 1000pF.
Mouse Driveability (MAX3243)
The MAX3243 has been specifically designed to power serial mice while operating from low-voltage power supplies. It has been tested with samples of ten major mouse models from six manufacturers including the leading three: Logitech (5 models), Mouse Systems, and
Interconnection with 3V and 5V Logic
The MAX3221/MAX3223/MAX3243 can directly interface with various 5V logic families, including ACT and HCT CMOS. See Table 4 for more information on possible combinations of interconnections.
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MAX3222-04
6 5
9
1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown MAX3221/MAX3223/MAX3243
+3.3V 0.1F 28 C1 0.1F 24 1 C2 0.1F 2 14 C1+ C1C2+ C2T1IN T1OUT 9 +V 26 VCC V+ 27 C3 0.1F 3 VC4 0.1F
COMPUTER SERIAL PORT
MAX3243
LOGIC INPUTS
13
T2IN
T2OUT
10
+V
12
T3IN
T3OUT
11
-V
20
R2OUTB
GND
19
R1OUT 5k
R1IN
4
Tx
18 LOGIC OUTPUTS 17
R2OUT 5k R3OUT 5k
R2IN
5
R3IN
6
RS-232 INPUTS
16
R4OUT 5k
R4IN
7
15 23 22
R5OUT 5k
R5IN
8
SERIAL MOUSE
FORCEON FORCEOFF INVALID
VCC TO POWER MANAGEMENT UNIT
21
GND 25
Figure 7b. Mouse Driver Test Circuit 10 ______________________________________________________________________________________
1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown
Table 3. Required Capacitor Values
VCC 0.1F
MAX3221/MAX3223/MAX3243
VCC (V) 3.0 to 3.6
VCC
C1 (F) 0.1 0.047 0.1
C2, C3, C4 (F) 0.1 0.33 0.47
C1+ C1 C1C2+ C2 C2-
V+ C3
4.5 to 5.5 3.0 to 5.5
MAX3221 MAX3223 MAX3243
VC4
Table 4. Logic Family Compatibility with Various Supply Voltages
SYSTEM POWERSUPPLY VOLTAGE (V) 3.3 VCC SUPPLY VOLTAGE (V)
T_ IN
T_ OUT
COMPATIBILITY
R_ OUT 0V VCC EN (MAX3221/3)
R_ IN 5k
3.3 5
1000pF
Compatible with all CMOS families. Compatible with all TTL and CMOS-logic families. Compatible with ACT and HCT CMOS, and with TTL. Incompatible with AC, HC, or CD4000 CMOS.
5
FORCEOFF GND
5
3.3
Figure 8. Loopback Test Circuit
T1IN
5V/div
T1IN
5V/div
T1OUT
5V/div
T1OUT
5V/div
R1OUT
5V/div
R1OUT
5V/div
5s/div VCC = +3.3V, 120kbps C1-C4 = 0.1F VCC = +3.3V, 235kbps C1-C4 = 0.1F
2s/div
Figure 9. Loopback Test Result at 120kbps
Figure 10. Loopback Test Result at 235kbps
______________________________________________________________________________________
11
1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown MAX3221/MAX3223/MAX3243
__________________________________________________Typical Operating Circuits
+3.3V C5 C1 0.1F 0.1F 2 C1+ 4 C15 C2 0.1F 6 C2+ C2T1OUT 13 C2 0.1F 15 VCC V+ 3 C3 0.1F 7 C4 0.1F C1 0.1F +3.3V 0.1F 28 C1+ 24 C11 9 R1OUT R1IN 8 5k LOGIC INPUTS 2 C2+ C2T1OUT 9 T2OUT 10 T3OUT 11 RS-232 OUTPUTS 26 VCC V+ 27 C3 0.1F 3 C4 0.1F
MAX3221
V-
11 T1IN
MAX3243
V-
14 T1IN 13 T2IN 12 T3IN 20 R2OUTB 19 R1OUT
1 EN
INVALID 10
TO POWER MANAGEMENT UNIT VCC
12
FORCEON GND 14
FORCEOFF 16
R1IN 4 5k
+3.3V C5 C1 0.1F 0.1F 2 C1+ 4 C15 C2 0.1F 6 C2+ C2T1OUT 17 RS-232 OUTPUTS 15 R5OUT 23 15 R1OUT TTL/CMOS OUTPUTS 10 R2OUT R1IN 16 5k R2IN 5k 9 RS-232 INPUTS VCC TO POWER MANAGEMENT UNIT 22 FORCEON FORCEOFF GND 25 19 VCC V+ 3 C3 0.1F 7 C4 0.1F 16 R4OUT LOGIC OUTPUTS 18 R2OUT
R2IN 5k
5
17 R3OUT
R3IN 6 5k R4IN 7 5k R5IN 8 5k
MAX3223
V-
RS-232 INPUTS
13 T1IN TTL/CMOS INPUTS
12 T2IN
T2OUT 8
21 INVALID
1 EN
INVALID 11
TO POWER MANAGEMENT UNIT VCC
14
FORCEON GND 18
FORCEOFF 20
12
______________________________________________________________________________________
1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown MAX3221/MAX3223/MAX3243
______3V-Powered EIA/TIA-232 and EIA/TIA-562 Transceivers from Maxim
POWERSUPPLY VOLTAGE (V) 3.0 to 3.6 1.8 to 4.25 2.7 to 5.25 3.0 to 3.6 2.7 to 3.6 3.0 to 5.5 3.0 to 5.5 3.0 to 5.5 3.0 to 5.5 3.0 to 5.5 No. OF TRANSMITTERS/ RECEIVERS 3/5 2/2 3/5 2/2 3/5 1/1 2/2 2/2 2/2 3/5 No. OF RECEIVERS ACTIVE IN SHUTDOWN 5 2 5 2 5 1 2 2 N/A 5 GUARANTEED DATA RATE (kbps) 120 120 230 120 235 120 120 120 120 120 EIA/TIA232 OR 562 232 232 562 562 232 232 232 232 232 232
PART
FEATURES
MAX212 MAX218 MAX562 MAX563 MAX3212 MAX3221 MAX3222 MAX3223 MAX3232 MAX3241
Drives mice Operates directly from batteries without a voltage regulator 230kbps guaranteed data rate 0.1F capacitors AutoShutdown, complementary receiver, drives mice, transient detection 0.1F capacitors, 16-pin SSOP 0.1F capacitors, MAX242 pinout 0.1F capacitors, AutoShutdown 0.1F capacitors, MAX232 pinout 0.1F capacitors, 2 complementary receivers, drives mice 0.1F capacitors, AutoShutdown complementary receiver, drives mice
MAX3243
3.0 to 5.5
3/5
1
120
232
______________________________________________________________________________________
13
1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown MAX3221/MAX3223/MAX3243
__________________________________________________________Pin Configurations
TOP VIEW
EN 1 EN 1 C1+ 2 V+ 3 C1- 4 C2+ 5 C2- 6 V- 7 R1IN 8 16 FORCEOFF 15 VCC 14 GND C1+ 2 V+ 3 C1- 4 C2+ 5 C2- 6 V- 7 T2OUT 8 R2IN 9 R2OUT 10 20 FORCEOFF 19 VCC 18 GND 17 T1OUT
MAX3221
13 T1OUT 12 FORCEON 11 T1IN 10 INVALID 9 R1OUT
MAX3223
16 R1IN 15 R1OUT 14 FORCEON 13 T1IN 12 T2IN 11 INVALID
SSOP/TSSOP
C2+ 1 C2- 2 V- 3 R1IN 4 R2IN 5 R3IN 6 R4IN 7 R5IN 8 T1OUT 9 T2OUT 10 T3OUT 11 T3IN 12 T2IN 13 T1IN 14 28 C1+ 27 V+ 26 VCC 25 GND
DIP/SSOP/TSSOP
MAX3243
24 C123 FORCEON 22 FORCEOFF 21 INVALID 20 R2OUTB 19 R1OUT 18 R2OUT 17 R3OUT 16 R4OUT 15 R5OUT
SO/SSOP/TSSOP
___________________Chip Information
MAX3221 TRANSISTOR COUNT: 269 MAX3223 TRANSISTOR COUNT: 339 MAX3243 TRANSISTOR COUNT: 476
14
______________________________________________________________________________________
1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown
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.)
2 1
SSOP.EPS
MAX3221/MAX3223/MAX3243
INCHES DIM A A1 B C E H D E e H L MIN 0.068 0.002 0.010 MAX 0.078 0.008 0.015
MILLIMETERS MIN 1.73 0.05 0.25 MAX 1.99 0.21 0.38 D D D D D INCHES MIN 0.239 0.239 0.278 0.317 0.397 MAX 0.249 0.249 0.289 0.328 0.407 MILLIMETERS MIN 6.07 6.07 7.07 8.07 10.07 MAX 6.33 6.33 7.33 8.33 10.33 N 14L 16L 20L 24L 28L
0.09 0.20 0.004 0.008 SEE VARIATIONS 0.205 0.301 0.025 0 0.212 0.311 0.037 8 5.20 7.65 0.63 0 5.38 7.90 0.95 8 0.0256 BSC 0.65 BSC
N
A C e D B A1 L
NOTES: 1. D&E DO NOT INCLUDE MOLD FLASH. 2. MOLD FLASH OR PROTRUSIONS NOT TO EXCEED .15 MM (.006"). 3. CONTROLLING DIMENSION: MILLIMETERS. 4. MEETS JEDEC MO150. 5. LEADS TO BE COPLANAR WITHIN 0.10 MM.
PROPRIETARY INFORMATION TITLE:
PACKAGE OUTLINE, SSOP, 5.3 MM
APPROVAL DOCUMENT CONTROL NO. REV.
21-0056
C
1 1
______________________________________________________________________________________
TSSOP4.40mm.EPS
15
1A Supply-Current, True +3V to +5.5V RS-232 Transceivers with AutoShutdown MAX3221/MAX3223/MAX3243
Package Information (continued)
(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.)
SOICW.EPS
INCHES
N
MILLIMETERS MIN 2.35 0.10 0.35 0.23 MAX 2.65 0.30 0.49 0.32
E
H
DIM A A1 B C e E H L
MAX MIN 0.104 0.093 0.012 0.004 0.019 0.014 0.009 0.013 0.050 0.291 0.299 0.394 0.419 0.050 0.016
1.27 7.40 7.60 10.00 10.65 0.40 1.27
1
VARIATIONS: INCHES MILLIMETERS MIN 10.10 11.35 12.60 15.20 17.70 MAX 10.50 11.75 13.00 15.60 18.10 N MS013 16 AA 18 AB 20 AC 24 AD 28 AE
TOP VIEW
D
DIM D D D D D
MIN 0.398 0.447 0.496 0.598 0.697
MAX 0.413 0.463 0.512 0.614 0.713
A e B A1
C 0-8 L
FRONT VIEW
SIDE VIEW
PROPRIETARY INFORMATION TITLE:
PACKAGE OUTLINE, .300" SOIC
APPROVAL DOCUMENT CONTROL NO. REV.
21-0042
B
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.
16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
PDIPN.EPS

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