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19-1298; Rev 3a; 1/00
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers
________________General Description
The MAX3222E/MAX3232E/MAX3237E/MAX3241E are 3V-powered EIA/TIA-232 and V.28/V.24 communications interfaces with low power requirements, high datarate capabilities, and enhanced electrostatic discharge (ESD) protection. All transmitter outputs and receiver inputs are protected to 15kV using IEC 1000-4-2 AirGap Discharge, 8kV using IEC 1000-4-2 Contact Discharge, and 15kV using the Human Body Model. The MAX3237E's logic and receiver I/O pins are protected to the above standards, while the transmitter output pins are protected to 15kV using the Human Body Model. The transceivers have a proprietary low-dropout transmitter output stage, delivering true RS-232 performance from a +3.0V to +5.5V supply with a dual charge pump. The charge pump requires only four small 0.1F capacitors for operation from a +3.3V supply. Each device is guaranteed to run at data rates of 250kbps while maintaining RS232 output levels. The MAX3237E is guaranteed to run at data rates of 250kbps in the normal operating mode and 1Mbps in the MegaBaudTM operating mode while maintaining RS-232-compliant output levels. The MAX3222E/MAX3232E have two receivers and two drivers. The MAX3222E features a 1A shutdown mode that reduces power consumption and extends battery life in portable systems. Its receivers can remain active in shutdown mode, allowing external devices such as modems to be monitored using only 1A supply current. Both the MAX3222E and MAX3232E are pin, package, and functionally compatible with the industry-standard MAX242 and MAX232, respectively. The MAX3241E is a complete serial port (three drivers/five receivers) designed for notebook and subnotebook computers. The MAX3237E (five drivers/three receivers) is ideal for peripheral applications that require fast data transfer. Both devices feature a shutdown mode in which all receivers can remain active while using a supply current of only 1A (MAX3241E) or 10nA (MAX3237E). The MAX3237E/MAX3241E have additional receiver outputs that always remain active. The MAX3222E and MAX3232E are available in spacesaving SO, SSOP, and TSSOP packages. The MAX3241E is available in SO and SSOP packages. The MAX3237E is available in an SSOP package.
____________________________Features
o ESD Protection for RS-232 I/O Pins (MAX3222E/MAX3232E/MAX3241E) 15kV--Human Body Model 8kV--IEC 1000-4-2, Contact Discharge 15kV--IEC 1000-4-2, Air-Gap Discharge o ESD Protection for All Logic and Receiver I/O Pins (MAX3237E) 15kV--Human Body Model 8kV--IEC 1000-4-2, Contact Discharge 15kV--IEC 1000-4-2, Air-Gap Discharge o ESD Protection for Transmitter Output Pins (MAX3237E) 15kV--Human Body Model o Guaranteed Data Rate 250kbps (MAX3222E/MAX3232E/MAX3241E and MAX3237E, normal operation) 1Mbps (MAX3237E, MegaBaud operation) o Latchup Free o Low-Power Shutdown with Receivers Active 1A (MAX3222E/MAX3241E) 10nA (MAX3237E) o Flow-Through Pinout (MAX3237E) o Guaranteed Mouse Driveability (MAX3241E) o Meets EIA/TIA-232 Specifications Down to 3.0V
MAX3222E/MAX3232E/MAX3237E/MAX3241E
_______________Ordering Information
PART MAX3222ECUP TEMP. RANGE 0C to +70C PIN-PACKAGE 20 TSSOP
MAX3222ECAP 0C to +70C 20 SSOP Ordering Information continued at end of data sheet.
___________________________Selector Guide
PART MAX3222E MAX3232E MAX3237E (Normal) MAX3237E (MegaBaud) MAX3241E NO. OF DRIVERS/ RECEIVERS 2/2 2/2 5/3 5/3 3/5 LOWPOWER SHUTDOWN -- GUARANTEED DATA RATE (kbps) 250 250 250 1M 250
________________________Applications
Notebooks, Subnotebooks, and Palmtop Computers Battery-Powered Equipment Cell-Phone Data Cables Smart Phones XDSL Modems Printers Cell Phones
Pin Configurations appear at end of data sheet. Typical Operating Circuits appear at end of data sheet.
MegaBaud is a trademark of Maxim Integrated Products.
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 free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800. For small orders, phone 1-800-835-8769.
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers MAX3222E/MAX3232E/MAX3237E/MAX3241E
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, EN, SHDN, MBAUD to GND ........................-0.3V to +6V R_IN to GND .....................................................................25V Output Voltages T_OUT to GND...............................................................13.2V R_OUT, R_OUTB (MAX3241E)................-0.3V to (VCC + 0.3V) Short-Circuit Duration, T_OUT to GND.......................Continuous Continuous Power Dissipation (TA = +70C) 16-Pin SSOP (derate 7.14mW/C above +70C) ..........571mW 16-Pin Wide SO (derate 9.52mW/C above +70C) .....762mW 18-Pin Wide SO (derate 9.52mW/C above +70C) .....762mW 18-Pin PDIP (derate 11.11mW/C above +70C)..........889mW 20-Pin TSSOP (derate 7.0mW/C above +70C) ..........559mW 20-Pin SSOP (derate 8.00mW/C above +70C) ..........640mW 28-Pin SSOP (derate 9.52mW/C above +70C) ..........762mW 28-Pin Wide SO (derate 12.50mW/C above +70C) .............1W Operating Temperature Ranges MAX32_ _EC_ _ ...................................................0C to +70C MAX32_ _EE_ _.................................................-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, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2) PARAMETER CONDITIONS MAX3222E, MAX3232E, MAX3241E MAX3237E Shutdown Supply Current LOGIC INPUTS Input Logic Low Input Logic High Transmitter Input Hysteresis Input Leakage Current RECEIVER OUTPUTS Output Leakage Current Output Voltage Low Output Voltage High RECEIVER INPUTS Input Voltage Range Input Threshold Low TA = +25C VCC = 3.3V VCC = 5.0V -25 0.6 0.8 1.1 1.5 +25 V V R_OUT (MAX3222E/MAX3237E/MAX3241E), EN = VCC, receivers disabled IOUT = 1.6mA (MAX3222E/MAX3232E/MAX3241E) IOUT = 1.0mA (MAX3237E) IOUT = -1.0mA VCC 0.6 VCC 0.1 0.05 10 0.4 0.4 A V V T_IN, EN, SHDN T_IN, SHDN, MBAUD MAX3222E, MAX3232E, MAX3241E MAX3237E (Note 3) T_IN, EN, SHDN, MBAUD T_IN, EN, SHDN, MBAUD VCC = 3.3V VCC = 5.0V 2.0 2.4 0.5 0.01 9 1 18 0.8 V V V A SHDN = GND SHDN = R_IN = GND, T_IN = GND or VCC (MAX3237E) MIN TYP MAX UNITS
DC CHARACTERISTICS (VCC = +3.3V or +5.0V, TA = +25C) Supply Current SHDN = VCC, no load 0.3 0.5 1 10 1 2.0 10 300 A nA mA
2
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15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +5.5V, C1-C4 = 0.1F, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2) PARAMETER RECEIVER INPUTS Input Threshold High Input Hysteresis Input Resistance TRANSMITTER OUTPUTS Output Voltage Swing Output Resistance Output Short-Circuit Current Output Leakage Current VCC = 0 or 3V to 5.5V, VOUT = 12V, transmitters disabled (MAX3222E/MAX3232E/MAX3241E) All transmitter outputs loaded with 3k to ground VCC = 0, transmitter output = 2V 5 300 5.4 50k 60 25 V mA A TA = +25C 3 TA = +25C VCC = 3.3V VCC = 5.0V 1.5 2.0 0.5 5 7 2.4 2.4 V V k CONDITIONS MIN TYP MAX UNITS
MAX3222E/MAX3232E/MAX3237E/MAX3241E
MOUSE DRIVEABILITY (MAX3241E) Transmitter Output Voltage ESD PROTECTION Human Body Model R_IN, T_OUT IEC 1000-4-2 Air-Gap Discharge (except MAX3237E) IEC 1000-4-2 Contact Discharge (except MAX3237E) T_IN, R_IN, R_OUT, EN, SHDN, MBAUD Human Body Model MAX3237E IEC 1000-4-2 Air-Gap Discharge IEC 1000-4-2 Contact Discharge 15 15 8 15 15 8 kV kV T1IN = T2IN = GND, T3IN = VCC, T3OUT loaded with 3k to GND, T1OUT and T2OUT loaded with 2.5mA each 5 V
TIMING CHARACTERISTICS--MAX3222E/MAX3232E/MAX3241E
(VCC = +3.0V to +5.5V, C1-C4 = 0.1F, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Maximum Data Rate Receiver Propagation Delay Receiver Output Enable Time Receiver Output Disable Time Transmitter Skew Receiver Skew tPHL - tPLH tPHL - tPLH VCC = 3.3V, TA = +25C, RL = 3k to 7k, measured from +3V to -3V or -3V to +3V CL = 150pF to 1000pF CL = 150pF to 2500pF 6 4 tPHL tPLH RL = 3k, CL = 1000pF, one transmitter switching Receiver input to receiver output, CL = 150pF Normal operation (except MAX3232E) Normal operation (except MAX3232E) (Note 4) 250 0.15 0.15 200 200 100 50 30 V/s 30 kbps s ns ns ns ns
Transition-Region Slew Rate
Note 2: MAX3222E/MAX3232E/MAX3241E: C1-C4 = 0.1F tested at 3.3V 10%; C1 = 0.047F, C2-C4 = 0.33F tested at 5.0V 10%. MAX3237E: C1-C4 = 0.1F, tested at 3.3V 5%; C1-C4 = 0.22F tested at 3.3V 10%; C1 = 0.047F, C2-C4 = 0.33F tested at 5.0V 10%. Note 3: The MAX3237E logic inputs have an active positive feedback resistor. The input current goes to zero when the inputs are at the supply rails. Note 4: Transmitter skew is measured at the transmitter zero crosspoints. _______________________________________________________________________________________ 3
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers MAX3222E/MAX3232E/MAX3237E/MAX3241E
TIMING CHARACTERISTICS--MAX3237E
(VCC = +3.0V to +5.5V, C1-C4 = 0.1F, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2) PARAMETER CONDITIONS RL = 3k, CL = 1000pF, one transmitter switching, MBAUD = GND Maximum Data Rate VCC = 3.0V to 4.5V, RL = 3k, CL = 250pF, one transmitter switching, MBAUD = VCC VCC = 4.5V to 5.5V, RL = 3k, CL = 1000pF, one transmitter switching, MBAUD = VCC Receiver Propagation Delay Receiver Output Enable Time Receiver Output Disable Time Transmitter Skew Receiver Skew R_IN to R_OUT, CL = 150pF Normal operation Normal operation tPHL tPLH MIN 250 1000 1000 0.15 0.15 2.6 2.4 100 100 50 CL = 150pF to 1000pF MBAUD = GND MBAUD = VCC 6 24 4 30 150 30 V/s s s s ns ns ns kbps TYP MAX UNITS
| tPHL - tPLH |, MBAUD = GND | tPHL - tPLH |, MBAUD = VCC | tPHL - tPLH |
Transition-Region Slew Rate
VCC = 3.3V, RL = 3k to 7k, +3V to -3V or -3V to +3V, TA = +25C
CL = 150pF to 2500pF, MBAUD = GND
__________________________________________Typical Operating Characteristics
(VCC = +3.3V, 250kbps data rate, 0.1F capacitors, all transmitters loaded with 3k and CL, TA = +25C, unless otherwise noted.)
MAX3222E/MAX3232E TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE
MAX3237E toc01
MAX3222E/MAX3232E SLEW RATE vs. LOAD CAPACITANCE
MAX3237E toc02
MAX3222E/MAX3232E OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE
40 SUPPLY CURRENT (mA) 35 250kbps 30 25 20 15 10 20kbps 120kbps T1 TRANSMITTING AT 250kbps T2 TRANSMITTING AT 15.6kbps
MAX3237E toc03
TRANSMITTER OUTPUT VOLTAGE (V)
6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 0 1000 2000
16 14 12 SLEW RATE (V/s) 10 8 6 4 +SLEW -SLEW
45
VOUT+ T1 TRANSMITTING AT 250kbps T2 TRANSMITTING AT 15.6kbps
VOUT-
2 FOR DATA RATES UP TO 250kbps 0
5 0 4000 5000 0 1000 2000 3000 4000 5000
3000
4000
5000
0
1000
2000
3000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
4
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15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers
Typical Operating Characteristics (continued)
(VCC = +3.3V, 250kbps data rate, 0.1F capacitors, all transmitters loaded with 3k and CL, TA = +25C, unless otherwise noted.)
MAX3241E TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE
MAX3237E to04
MAX3222E/MAX3232E/MAX3237E/MAX3241E
MAX3241E SLEW RATE vs. LOAD CAPACITANCE
MAX3237E toc05
MAX3241E OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE
1 TRANSMITTER AT 250kbps 2 TRANSMITTERS AT 15.6kbps 250kbps 40 30 20kbps 20 10 0 120kbps
MAX3237E toc06
TRANSMITTER OUTPUT VOLTAGE (V)
6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 0
14 12 SLEW RATE (V/s) 10 8 6 4
60 50 SUPPLY CURRENT (mA)
VOUT+ 1 TRANSMITTER AT 250kbps 2 TRANSMITTERS AT 15.6kbps
VOUT1000 2000 3000 4000 5000
2 0 0 1000 2000 3000 4000 5000
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE
6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 0
MAX3238E toc01
MAX3237E TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE (MBAUD = VCC)
MAX3237E toc08
MAX3237E SLEW RATE vs. LOAD CAPACITANCE (MBAUD = GND)
MAX3237E toc09
7.5 1Mbps TRANSMITTER OUTPUT VOLTAGE (V) 5.0 2.5 0 -2.5 -5.0 -7.5 2Mbps 1.5Mbps 1Mbps 0 500 1000 1500 1 TRANSMITTER AT FULL DATA RATE 4 TRANSMITTERS AT 1/16 DATA RATE 3k + CL LOAD, EACH OUTPUT 2Mbps 1.5Mbps
12 10 SRSLEW RATE (V/s) 8 SR+ 6 4 2 0 1 TRANSMITTER AT 250kbps 4 TRANSMITTERS 15.6kbps ALL TRANSMITTERS LOADED WITH 3k + CL 0 500 1000 1500 2000 2500
TRANSMITTER OUTPUT VOLTAGE (V)
VOUT+
FOR DATA RATES UP TO 250kbps 1 TRANSMITTER 250kbps 4 TRANSMITTERS 15.6kbps ALL TRANSMITTERS LOADED WITH 3k + CL
VOUT500 1000 1500 2000 2500 300
2000
3000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
MAX3237E SLEW RATE vs. LOAD CAPACITANCE (MBAUD = VCC)
MAX3237E toc10
MAX3237E SUPPLY CURRENT vs. LOAD CAPACITANCE WHEN TRANSMITTING DATA (MBAUD = GND)
MAX3237E toc11
MAX3237E TRANSMITTER SKEW vs. LOAD CAPACITANCE (MBAUD = VCC)
MAX3237E toc12
70 60 SLEW RATE (V/s) 50 40 30 20 10 0 0 500 1000 1500 -SLEW, 1Mbps +SLEW, 1Mbps -SLEW, 2Mbps +SLEW, 2Mbps
50 250kbps 40 SUPPLY CURRENT (mA) 120kbps 20kbps 30
100
80 TRANSMITTER SKEW (ns)
60
20 1 TRANSMITTER AT 20kbps, 120kbps, 250kbps 4 TRANSMITTERS AT 15.6kbps ALL TRANSMITTERS LOADED WITH 3k + CL 0 500 1000 1500 2000 2500 3000
40 |tPLH - tPHL| 1 TRANSMITTER AT 500kbps 4 TRANSMITTERS AT 1/16 DATA RATE ALL TRANSMITTERS LOADED WITH 3k + CL 0 500 1000 1500 2000 LOAD CAPACITANCE (pF)
1 TRANSMITTER AT FULL DATA RATE 4 TRANSMITTERS AT 1/16 DATA RATE 3k + CL LOAD EACH OUTPUT 2000
10
20
0 LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF)
0
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15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers MAX3222E/MAX3232E/MAX3237E/MAX3241E
Typical Operating Characteristics (continued)
(VCC = +3.3V, 250kbps data rate, 0.1F capacitors, all transmitters loaded with 3k and CL, TA = +25C, unless otherwise noted.)
MAX3237E TRANSMITTER OUTPUT VOLTAGE vs. SUPPLY VOLTAGE (MBAUD = GND)
6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 2.0 TRANSMITTER OUTPUT VOLTAGE (V) VOUT+
MAX3237E toc13
MAX3237E SUPPLY CURRENT vs. SUPPLY VOLTAGE (MBAUD = GND)
MAX3237E toc14
50
40 SUPPLY CURRENT (mA)
1 TRANSMITTER 250kbps 4 TRANSMITTERS 15.6kbps ALL TRANSMITTERS LOADED WITH 3k +1000pF
30
20 1 TRANSMITTER AT 250kbps 4 TRANSMITTERS AT 15.6kbps ALL TRANSMITTERS LOADED WITH 3k AND 1000pF 2.0 2.5 3.0 3.5 4.0 4.5 5.0
VOUT-
10 0
2.5
3.0
3.5
4.0
4.5
5.0
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
______________________________________________________________Pin Description
PIN MAX3222E SO/DIP 1 2 3 4 5 6 7 8, 15 9, 14 10, 13 11, 12 16 6 TSSOP/ SSOP 1 2 3 4 5 6 7 8, 17 9, 16 10, 15 12, 13 18 MAX3232E SO/DIP -- 1 2 3 4 5 6 7, 14 8, 13 9, 12 10, 11 15 TSSOP/ SSOP -- 2 3 4 5 6 7 8, 17 9, 16 12, 15 13, 14 18 MAX3237E MAX3241E EN C1+ V+ C1C2+ C2VT_OUT R_IN R_OUT T_IN GND NAME FUNCTION
13* 28 27 25 1 3 4 5, 6, 7, 10, 12 8, 9, 11 18, 20, 21 17*, 19*, 22*, 23*, 24* 2
23 28 27 24 1 2 3 9, 10, 11 4-8 15-19 12, 13, 14 25
Receiver Enable. Active low. Positive Terminal of Voltage-Doubler Charge-Pump Capacitor +5.5V Generated by the Charge Pump Negative Terminal of Voltage-Doubler Charge-Pump Capacitor Positive Terminal of Inverting ChargePump Capacitor Negative Terminal of Inverting Charge-Pump Capacitor -5.5V Generated by the Charge Pump RS-232 Transmitter Outputs RS-232 Receiver Inputs TTL/CMOS Receiver Outputs TTL/CMOS Transmitter Inputs Ground
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15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers
_________________________________________________Pin Description (continued)
PIN MAX3222E SO/DIP 17 18 -- TSSOP/ SSOP 19 20 11, 14 MAX3232E SO/DIP 16 -- -- TSSOP/ SSOP 19 -- 1, 10, 11, 20 -- MAX3237E MAX3241E NAME FUNCTION
MAX3222E/MAX3232E/MAX3237E/MAX3241E
26 14* --
26 22 --
VCC SHDN N.C.
+3.0V to +5.5V Supply Voltage Shutdown Control. Active low. No Connection MegaBaud Control Input. Connect to GND for normal operation; connect to VCC for 1Mbps transmission rates. Noninverting Complementary Receiver Outputs. Always active.
--
--
--
15*
--
MBAUD
--
--
--
--
16
20, 21
R_OUTB
*These pins have an active positive feedback resistor internal to the MAX3237E, allowing unused inputs to be left unconnected.
_______________Detailed Description
Dual Charge-Pump Voltage Converter
The MAX3222E/MAX3232E/MAX3237E/MAX3241E'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 VCC range. The charge pump operates in discontinuous mode; if the output voltages are less than 5.5V, the charge pump is enabled, and 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 (Figure 1).
ance state when the device is in shutdown mode (SHDN = GND). The MAX3222E/MAX3232E/MAX3237E/MAX3241E permit the outputs to be driven up to 12V in shutdown. The MAX3222E/MAX3232E/MAX3241E transmitter inputs do not have pull-up resistors. Connect unused inputs to GND or VCC. The MAX3237E transmitter inputs have a 400k active positive feedback resistor, allowing unused inputs to be left unconnected.
MAX3237E MegaBaud Operation
For higher-speed serial communications, the MAX3237E features MegaBaud operation. In MegaBaud operating mode (MBAUD = V CC), the MAX3237E transmitters guarantee a 1Mbps data rate with worst-case loads of 3k in parallel with 250pF for 3.0V < VCC < 4.5V. For 5V 10% operation, the MAX3237E transmitters guarantee a 1Mbps data rate into worst-case loads of 3k in parallel with 1000pF.
RS-232 Transmitters
The transmitters are inverting level translators that convert TTL/CMOS-logic levels to 5.0V EIA/TIA-232-compliant levels. The MAX3222E/MAX3232E/MAX3237E/MAX3241E transmitters guarantee a 250kbps data rate with worstcase loads of 3k in parallel with 1000pF, providing compatibility with PC-to-PC communication software (such as LapLinkTM). Transmitters can be paralleled to drive multiple receivers or mice. The MAX3222E/MAX3237E/MAX3241E's transmitters are disabled and the outputs are forced into a high-imped-
RS-232 Receivers
The receivers convert RS-232 signals to CMOS-logic output levels. The MAX3222E/MAX3237E/MAX3241E receivers have inverting three-state outputs. Drive EN high to place the receiver(s) into a high-impedance state. Receivers can be either active or inactive in shutdown (Table 1).
LapLink is a trademark of Traveling Software. _______________________________________________________________________________________ 7
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers MAX3222E/MAX3232E/MAX3237E/MAX3241E
VCC 0.1F VCC
VCC 0.1F VCC
C1+ C1 C1C2+ C2 C2T_ IN
V+ C3 C1
C1+ C1-
V+ C3
MAX3222E MAX3232E MAX3237E MAX3241E
VC4 T_ OUT C2
C2+ C2T_ IN
MAX3222E MAX3232E MAX3237E MAX3241E
VC4 T_ OUT
R_ OUT
R_ IN
R_ OUT
R_ IN
5k GND 3k 2500pF GND
5k 7k 150pF
MINIMUM SLEW-RATE TEST CIRCUIT
MAXIMUM SLEW-RATE TEST CIRCUIT
Figure 1. Slew-Rate Test Circuits
The complementary outputs on the MAX3237E/MAX3241E (R_OUTB) are always active, regardless of the state of EN or SHDN. This allows the device to be used for ring indicator applications without forward biasing other devices connected to the receiver outputs. This is ideal for systems where VCC drops to 0 in shutdown to accommodate peripherals such as UARTs (Figure 2).
down mode is not used. SHDN has no effect on R_OUT or R_OUTB (MAX3237E/MAX3241E).
15kV ESD Protection
As with all Maxim devices, ESD-protection structures are incorporated to protect against electrostatic discharges encountered during handling and assembly. The driver outputs and receiver inputs of the
MAX3222E/MAX3237E/MAX3241E Shutdown Mode
Supply current falls to less than 1A in shutdown mode (SHDN = low). The MAX3237E's supply current falls to 10nA (typ) when all receiver inputs are in the invalid range (-0.3V < R_IN < +0.3). When shut down, the device's charge pumps are shut off, V+ is pulled down to V CC , V- is pulled to ground, and the transmitter outputs are disabled (high impedance). The time required to recover from shutdown is typically 100s, as shown in Figure 3. Connect SHDN to VCC if the shut-
Table 1. MAX3222E/MAX3237E/MAX3241E Shutdown and Enable Control Truth Table
SHDN 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 R_OUTB (MAX3237E/ MAX3241E) Active Active Active Active
8
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15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers
MAX3222E/MAX3232E/MAX3237E/MAX3241E have extra protection against static electricity. Maxim's engineers have developed state-of-the-art structures to protect these pins against ESD of 15kV without damage. The ESD structures withstand high ESD in all states: normal operation, shutdown, and powered down. After an ESD event, Maxim's E versions keep working without
VCC
latchup, whereas competing RS-232 products can latch and must be powered down to remove latchup. Furthermore, the MAX3237E logic I/O pins also have 15kV ESD protection. Protecting the logic I/O pins to 15kV makes the MAX3237E ideal for data cable applications. ESD protection can be tested in various ways; the transmitter outputs and receiver inputs for the MAX3222E/MAX3232E/MAX3241E are characterized for protection to the following limits: * 15kV using the Human Body Model * 8kV using the Contact Discharge method specified in IEC 1000-4-2 * 15kV using IEC 1000-4-2's Air-Gap Discharge method
MAX3222E/MAX3232E/MAX3237E/MAX3241E
VCC
PROTECTION DIODE Rx
PREVIOUS RS-232
5k UART Tx GND SHDN = GND
For the MAX3237E, all logic and RS-232 I/O pins are characterized for protection to 15kV per the Human Body Model. ESD Test Conditions ESD performance depends on a variety of conditions. Contact Maxim for a reliability report that documents test setup, test methodology, and test results. Human Body Model Figure 4a shows the Human Body Model, and Figure 4b shows the current waveform it generates when discharged into a low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of interest, which is then discharged into the test device through a 1.5k resistor.
a) OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM ACTIVE RECEIVER OUTPUT IN SHUTDOWN. VCC TO P LOGIC TRANSITION DETECTOR
MAX3237E/MAX3241E
R1OUTB VCC PROTECTION DIODE Rx
R1OUT THREE-STATED EN = VCC 5k
R1IN
5V/div 0
SHDN T2OUT
UART Tx GND T1IN SHDN = GND
T1OUT
2V/div 0
b) NEW MAX3237E/MAX3241E: EN SHUTS DOWN RECEIVER OUTPUTS (EXCEPT FOR B OUTPUTS), SO NO CURRENT FLOWS TO UART IN SHUTDOWN. B OUTPUTS INDICATE RECEIVER ACTIVITY DURING SHUTDOWN WITH EN HIGH.
VCC = 3.3V C1-C4 = 0.1F 40s/div
T1OUT
Figure 2. Detection of RS-232 Activity when the UART and Interface are Shut Down; Comparison of MAX3237E/ MAX3241E (b) with Previous Transceivers (a)
Figure 3. Transmitter Outputs Recovering from Shutdown or Powering Up
_______________________________________________________________________________________
9
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers MAX3222E/MAX3232E/MAX3237E/MAX3241E
IEC 1000-4-2 The IEC 1000-4-2 standard covers ESD testing and performance of finished equipment; it does not specifically refer to integrated circuits. The MAX3222E/MAX3232E/ MAX3237E/MAX3241E help you design equipment that meets Level 4 (the highest level) of IEC 1000-4-2, without the need for additional ESD-protection components. The major difference between tests done using the Human Body Model and IEC 1000-4-2 is higher peak current in IEC 1000-4-2 because series resistance is lower in the IEC 1000-4-2 model. Hence, the ESD withstand voltage measured to IEC 1000-4-2 is generally lower than that measured using the Human Body Model. Figure 5a shows the IEC 1000-4-2 model, and Figure 5b shows the current waveform for the 8kV IEC 1000-4-2 Level 4 ESD Contact Discharge test.
RC 1M CHARGE-CURRENT LIMIT RESISTOR HIGHVOLTAGE DC SOURCE RD 1500 DISCHARGE RESISTANCE DEVICE UNDER TEST IP 100% 90% AMPERES Cs 100pF STORAGE CAPACITOR 36.8% 10% 0 0 tRL TIME tDL CURRENT WAVEFORM Ir PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE)
The Air-Gap Discharge test involves approaching the device with a charged probe. The Contact Discharge method connects the probe to the device before the probe is energized. Machine Model The Machine Model for ESD tests all pins using a 200pF storage capacitor and zero discharge resistance. Its objective is to emulate the stress caused by contact that occurs with handling and assembly during manufacturing. All pins require this protection during manufacturing, not just RS-232 inputs and outputs. Therefore, after PC board assembly, the Machine Model is less relevant to I/O ports.
Figure 4a. Human Body ESD Test Model
Figure 4b. Human Body Model Current Waveform
I 100% RC 50M to 100M CHARGE-CURRENT LIMIT RESISTOR HIGHVOLTAGE DC SOURCE RD 330 DISCHARGE RESISTANCE DEVICE UNDER TEST 90%
Cs 150pF
STORAGE CAPACITOR
I PEAK
10% t r = 0.7ns to 1ns t 30ns 60ns
Figure 5a. IEC 1000-4-2 ESD Test Model 10
Figure 5b. IEC 1000-4-2 ESD Generator Current Waveform
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15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers MAX3222E/MAX3232E/MAX3237E/MAX3241E
TRANSMITTER OUTPUT VOLTAGE (V) 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 0 1 2 3 4 5 6 7 8 9 10 LOAD CURRENT PER TRANSMITTER (mA) VCC VOUTVOUTVCC = 3.0V VOUT+ VOUT+
MAX3222E-fig06a
Table 2. Required Minimum Capacitor Values
VCC (V) C1 (F) C2, C3, C4 (F)
6
MAX3222E/MAX3232E/MAX3241E 3.0 to 3.6 4.5 to 5.5 3.0 to 5.5 MAX3237E 3.0 to 3.6 3.15 to 3.6 4.5 to 5.5 3.0 to 5.5 0.22 0.1 0.047 0.22 0.22 0.1 0.33 1.0 0.1 0.047 0.1 0.1 0.33 0.47
Figure 6a. MAX3241E Transmitter Output Voltage vs. Load Current per Transmitter
___________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 0.1F capacitors for 3.3V operation. For other supply voltages, see Table 2 for required capacitor values. Do not use values smaller than those listed in Table 2. 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-.
Transmitter Outputs when Recovering from Shutdown
Figure 3 shows two transmitter outputs when recovering from 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 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.
Mouse Driveability
The MAX3241E has been specifically designed to power serial mice while operating from low-voltage power supplies. It has been tested with leading mouse brands from manufacturers such as Microsoft and Logitech. The MAX3241E successfully drove all serial mice tested and met their respective current and voltage requirements. Figure 6a shows the transmitter output voltages under increasing load current at 3.0V. Figure 6b shows a typical mouse connection using the MAX3241E.
Power-Supply Decoupling
In most circumstances, a 0.1F 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.
High Data Rates
The MAX3222E/MAX3232E/MAX3237E/MAX3241E 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 1000pF.
Operation Down to 2.7V
Transmitter outputs will meet EIA/TIA-562 levels of 3.7V with supply voltages as low as 2.7V.
______________________________________________________________________________________
11
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers MAX3222E/MAX3232E/MAX3237E/MAX3241E
VCC = 3V to 5.5V
CBYPASS 26 VCC 27 C3 COMPUTER SERIAL PORT 3 C4 9 +V 10 +V 11 -V GND R1IN 4 5k 5k 5k 5k 5k SHDN GND 25 R2IN 5 R3IN R4IN 6 7 MOUSE Tx
28 C1 24 1 C2 2 14 13 VCC 12 21 20 19 18 17 16 15 23
C1+ C1C2+ C2T1IN T2IN T3IN R1OUTB R2OUTB R1OUT R2OUT R3OUT R4OUT R5OUT EN
V+
MAX3241E
VT1OUT T2OUT T3OUT
R5IN 8 22
VCC
Figure 6b. Mouse Driver Test Circuit
The MAX3237E maintains the RS-232 5.0V minimum transmitter output voltage at data rates up to 1Mbps. Figure 10 shows a loopback test result at 1Mbps with MBAUD = VCC. For Figure 10, all transmitters were loaded with an RS-232 receiver in parallel with 250pF.
Interconnection with 3V and 5V Logic
The MAX3222E/MAX3232E/MAX3237E/MAX3241E can directly interface with various 5V logic families, including ACT and HCT CMOS. See Table 3 for more information on possible combinations of interconnections.
12
______________________________________________________________________________________
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers MAX3222E/MAX3232E/MAX3237E/MAX3241E
Table 3. Logic-Family Compatibility with Various Supply Voltages
SYSTEM POWER-SUPPLY VOLTAGE (V) 3.3 VCC SUPPLY VOLTAGE (V) 3.3
T1IN 5V/div
COMPATIBILITY
5V/div
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
T1OUT
5
5
R1OUT
VCC = 3.3V C1-C4 = 0.1F 2s/div
5V/div
5
3.3
Figure 8. MAX3241E Loopback Test Result at 120kbps
T1IN
5V/div
VCC 0.1F
T1OUT 5V/div
VCC C1+ C1 C1C2+ C2 C2V+ C3
R1OUT
5V/div VCC = 3.3V, C1-C4 = 0.1F
MAX3222E MAX3232E MAX3237E MAX3241E
VC4
2s/div
Figure 9. MAX3241E Loopback Test Result at 250kbps
T_ OUT
T_ IN
R_ OUT
R_ IN 5k
+5V T_IN
1000pF
0 +5V
GND
0 -5V +5V VCC = 3.3V C1-C4 = 0.1F
T_OUT 5k + 250pF
R_OUT
Figure 7. Loopback Test Circuit
0
400ns/div
Figure 10. MAX3237E Loopback Test Result at 1000kbps (MBAUD = VCC) ______________________________________________________________________________________ 13
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers MAX3222E/MAX3232E/MAX3237E/MAX3241E
Pin Configurations
TOP VIEW
EN 1 C1+ 2 V+ 3 C1- 4 C2+ 5 C2VT2OUT R2IN 6 7 8 9
18 SHDN 17 VCC 16 GND 15 T1OUT
EN 1 C1+ 2 V+ 3 C1- 4 C2+ 5 C2- 6 V- 7 T2OUT 8 R2IN 9 R2OUT 10
20 SHDN 19 VCC 18 GND 17 T1OUT
N.C. 1 C1+ 2 V+ 3 C1- 4 C2+ 5 C2- 6 V- 7 T2OUT 8 R2IN 9 N.C. 10
20 N.C. 19 VCC 18 GND 17 T1OUT
MAX3222E
14 R1IN 13 R1OUT 12 T1IN 11 T2IN 10 R2OUT
MAX3222E
16 R1IN 15 R1OUT 14 N.C. 13 T1IN 12 T2IN 11 N.C.
MAX3232E
16 R1IN 15 R1OUT 14 T1IN 13 T2IN 12 R2OUT 11 N.C.
SO/DIP TSSOP/SSOP TSSOP
C1+ 1 V+ 2 C1- 3 C2+ 4 C2- 5 V- 6 T2OUT 7 R2IN 8
16 VCC 15 GND 14 T1OUT
C2+ GND C2VT1OUT T2OUT T3OUT R1IN R2IN
1 2 3 4 5 6 7 8 9
28 C1+ 27 V+ 26 VCC 25 C124 T1IN
C2+ C2VR1IN R2IN R3IN R4IN R5IN T1OUT
1 2 3 4 5 6 7 8 9
28 C1+ 27 V+ 26 VCC 25 GND 24 C1-
MAX3232E
13 R1IN 12 R1OUT 11 T1IN 10 T2IN 9 R2OUT
MAX3237E
23 T2IN 22 T3IN 21 R1OUT 20 R2OUT 19 T4IN 18 R3OUT 17 T5IN 16 R1OUTB 15 MBAUD
MAX3241E
23 EN 22 SHDN 21 R1OUTB 20 R2OUTB 19 R1OUT 18 R2OUT 17 R3OUT 16 R4OUT 15 R5OUT
SSOP/SO/DIP
T4OUT 10 R3IN 11 T5OUT 12 EN 13 SHDN 14
T2OUT 10 T3OUT 11 T3IN 12 T2IN 13 T1IN 14
SSOP
SSOP/SO
14
______________________________________________________________________________________
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers
__________________________________________________Typical Operating Circuits
MAX3222E/MAX3232E/MAX3237E/MAX3241E
+3.3V CBYPASS C1 0.1F 2 C1+ 4 5 C2 0.1F 6 C117 VCC V+ 3 C3* 0.1F
+3.3V CBYPASS C1 0.1F 1 C1+ 3 4 C4 0.1F C2 0.1F 5 C1C2+ C2T1OUT 14 RS-232 OUTPUTS 10 T2IN T2OUT 7 16 VCC V+ 2 C3* 0.1F 6 C4 0.1F
MAX3222E
C2+ C2V-
7
MAX3232E
V-
12 T1IN TTL/CMOS INPUTS 11 T2IN
T1OUT 15 RS-232 OUTPUTS T2OUT 8 TTL/CMOS INPUTS
11 T1IN
13 R1OUT TTL/CMOS OUTPUTS 10 R2OUT 1 EN GND 16
R1IN 14 5k R2IN 9 5k SHDN 18 RS-232 INPUTS TTL/CMOS OUTPUTS
12 R1OUT
R1IN 13 5k RS-232 INPUTS
9 R2OUT
R2IN 8 5k
GND 15
*C3 CAN BE RETURNED TO EITHER VCC OR GROUND.
NOTE: PIN NUMBERS REFER TO SO/DIP PACKAGES. SEE TABLE 2 FOR CAPACITOR SELECTION.
______________________________________________________________________________________
15
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers MAX3222E/MAX3232E/MAX3237E/MAX3241E
_____________________________________Typical Operating Circuits (continued)
+3.3V CBYPASS 28 C1+ 24 C11 C2 0.1F 2 C2+ C2T1OUT 9 T2OUT 10 T3OUT 11 26 VCC V+ C3* 0.1F 27 0.1F 25 C11 C4 0.1F 0.1F 3 C2+ C2T1 T2 T1OUT 5 T2OUT 6 T3OUT 7 RS-232 OUTPUTS +3.3V CBYPASS 28 C1+ 26 VCC V+ 27 C3* 0.1F 4 0.1F
C1 0.1F
MAX3241E
V-
3
MAX3237E
V-
14 T1IN 13 T2IN 12 T3IN 21 R1OUTB 20 R2OUTB
24 T1IN 23 T2IN LOGIC INPUTS 22 T3IN 19 T4IN 17 T5IN
TTL/CMOS INPUTS
RS-232 OUTPUTS
T3 T4 T5
T4OUT 10 T5OUT 12
19 R1OUT 5k 18 R2OUT TTL/CMOS OUTPUTS 5k 17 R3OUT 5k 16 R4OUT 5k 15 R5OUT 5k 23 EN GND 25
R1IN 4 16 R1OUTB R2IN 5 21 R1OUT R1
R1IN 8 5k
R3IN 6
RS-232 INPUTS
LOGIC OUTPUTS
20 R2OUT
R2 5k
R2IN
9
RS-232 INPUTS
R4IN 7
18 R3OUT
R3 5k
R3IN 11
R5IN 8 MBAUD GND 2 SHDN 15 14
13 EN SHDN 22
*C3 CAN BE RETURNED TO EITHER VCC OR GROUND.
16
______________________________________________________________________________________
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers
__Ordering Information (continued)
PART MAX3222ECWN MAX3222ECPN MAX3222EC/D MAX3222EEUP MAX3222EEAP MAX3222EEWN MAX3222EEPN MAX3232ECUP MAX3232ECAE MAX3232ECWE MAX3232ECPE MAX3232EEUP MAX3232EEAE MAX3232EEWE MAX3232EEPE MAX3237ECAI MAX3237EEAI MAX3241ECAI MAX3241ECWI MAX3241EEAI MAX3241EEWI TEMP. RANGE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -0C to +70C -40C to +85C 0C to +70C 0C to +70C -40C to +85C -40C to +85C PIN-PACKAGE 18 Wide SO 18 Plastic DIP Dice* 20 TSSOP 20 SSOP 18 Wide SO 18 Plastic DIP 20 TSSOP 16 SSOP 16 Wide SO 16 Plastic DIP 20 TSSOP 16 SSOP 16 Wide SO 16 Plastic DIP 28 SSOP 28 SSOP 28 SSOP 28 Wide SO 28 SSOP 28 Wide SO
___________________ Chip Information
TRANSISTOR COUNTS: MAX3222E/MAX3232E: 1129 MAX3237E: 2110 MAX3241E: 1335
MAX3222E/MAX3232E/MAX3237E/MAX3241E
*Dice are tested at TA = +25C, DC parameters only.
______________________________________________________________________________________
17
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers MAX3222E/MAX3232E/MAX3237E/MAX3241E
________________________________________________________Package Information
TSSOP.EPS
18
______________________________________________________________________________________
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers
___________________________________________Package Information (continued)
SSOP.EPS
MAX3222E/MAX3232E/MAX3237E/MAX3241E
______________________________________________________________________________________
19
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers MAX3222E/MAX3232E/MAX3237E/MAX3241E
NOTES
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 (c) 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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