MAX3241EUI+T中文资料

________________General Description

The MAX3222/MAX3232/MAX3237/MAX3241 trans-ceivers have a proprietary low-dropout transmitter out-put stage enabling true RS-232 performance from a 3.0V to 5.5V supply with a dual charge pump. The devices require only four small 0.1μF external charge-pump capacitors. The MAX3222, MAX3232, and MAX3241 are guaranteed to run at data rates of 120kbps while maintaining RS-232 output levels. The MAX3237 is guaranteed to run at data rates of 250kbps in the normal operating mode and 1Mbps in the MegaBaud? operating mode, while maintaining RS-232output levels.

The MAX3222/MAX3232 have 2 receivers and 2 drivers. The MAX3222 features a 1μA shutdown mode that reduces power consumption and extends battery life in portable systems. Its receivers remain active in shutdown mode, allowing external devices such as modems to be monitored using only 1μA supply cur-rent. The MAX3222 and MAX3232 are pin, package,and functionally compatible with the industry-standard MAX242 and MAX232, respectively.

The MAX3241 is a complete serial port (3 drivers/5 receivers) designed for notebook and subnotebook computers. The MAX3237 (5 drivers/3 receivers) is ideal for fast modem applications. Both these devices feature a shutdown mode in which all receivers can remain active while using only 1μA supply current. Receivers R1(MAX3237/MAX3241) and R2 (MAX3241) have extra out-puts in addition to their standard outputs. These extra outputs are always active, allowing external devices such as a modem to be monitored without forward bias-ing the protection diodes in circuitry that may have V CC completely removed.

The MAX3222, MAX3237, and MAX3241 are available in space-saving TSSOP and SSOP packages.

________________________Applications

Notebook, Subnotebook, and Palmtop Computers High-Speed Modems Battery-Powered Equipment Hand-Held Equipment Peripherals Printers

__Next Generation Device Features

?For Smaller Packaging:

MAX3228E/MAX3229E: +2.5V to +5.5V RS-232Transceivers in UCSP?

?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-232Transceivers

?For Low-Voltage or Data Cable Applications:MAX3380E/MAX3381E: +2.35V to +5.5V, 1μA, 2 Tx/2 Rx RS-232 Transceivers with ±15kV ESD-Protected I/O and Logic Pins

MAX3222/MAX3232/MAX3237/MAX3241*

3.0V to 5.5V , Low-Power , up to 1Mbps, T rue RS-232Transceivers Using Four 0.1μF External Capacitors

________________________________________________________________Maxim Integrated Products

1

19-0273; Rev 7; 1/07

*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.

Typical Operating Circuits appear at end of data sheet.

Ordering Information continued at end of data sheet.

For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at https://www.sodocs.net/doc/394950439.html,.

+Denotes lead-free package.

M A X 3222/M A X 3232/M A X 3237/M A X 3241

Transceivers Using Four 0.1μF External Capacitors

2_______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(V CC = +3.0V to +5.5V, C1–C4 = 0.1μF (Note 2), T A = T MIN to T MAX , unless otherwise noted. Typical values are at T A = +25°C.)

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.

Note 1:V+ and V- can have a maximum magnitude of 7V, but their absolute difference cannot exceed 13V.

V CC ...........................................................................-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, SHDN , EN ...................................................-0.3V to +6V MBAUD...................................................-0.3V to (V CC + 0.3V)R_IN.................................................................................±25V Output Voltages

T_OUT...........................................................................±13.2V R_OUT....................................................-0.3V to (V CC + 0.3V)Short-Circuit Duration

T_OUT....................................................................Continuous

Continuous Power Dissipation (T A = +70°C)

16-Pin TSSOP (derate 6.7mW/°C above +70°C).............533mW 16-Pin Narrow SO (derate 8.70mW/°C above +70°C)....696mW 16-Pin Wide SO (derate 9.52mW/°C above +70°C)........762mW 16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)...842mW 18-Pin SO (derate 9.52mW/°C above +70°C)..............762mW 18-Pin Plastic DIP (derate 11.11mW/°C above +70°C)..889mW 20-Pin SSOP (derate 7.00mW/°C above +70°C).........559mW 20-Pin TSSOP (derate 8.0mW/°C above +70°C).............640mW 28-Pin TSSOP (derate 8.7mW/°C above +70°C).............696mW 28-Pin SSOP (derate 9.52mW/°C above +70°C).........762mW 28-Pin SO (derate 12.50mW/°C above +70°C).....................1W Operating Temperature Ranges

MAX32_ _C_ _.....................................................0°C to +70°C MAX32_ _E_ _ .................................................-40°C to +85°C Storage Temperature Range.............................-65°C to +150°C Lead Temperature (soldering, 10s).................................+300°C

MAX3222/MAX3232/MAX3237/MAX3241

Transceivers Using Four 0.1μF External Capacitors

_______________________________________________________________________________________3

TIMING CHARACTERISTICS—MAX3222/MAX3232/MAX3241

(V CC = +3.0V to +5.5V, C1–C4 = 0.1μF (Note 2), T A = T MIN to T MAX , unless otherwise noted. Typical values are at T A = +25°C.)

ELECTRICAL CHARACTERISTICS (continued)

(V CC = +3.0V to +5.5V, C1–C4 = 0.1μF (Note 2), T A = T MIN to T MAX , unless otherwise noted. Typical values are at T A = +25°C.)

M A X 3222/M A X 3232/M A X 3237/M A X 3241

Transceivers Using Four 0.1μF External Capacitors

4_______________________________________________________________________________________

__________________________________________Typical Operating Characteristics

(V CC = +3.3V, 235kbps data rate, 0.1μF capacitors, all transmitters loaded with 3k ?, T A = +25°C, unless otherwise noted.)

-6

-5-4-3-2-101234560

MAX3222/MAX3232

TRANSMITTER OUTPUT VOLTAGE

vs. LOAD CAPACITANCE

LOAD CAPACITANCE (pF)T R A N S M I T T E R O U T P U T V O L T A G E (V )

2000

3000

1000

4000

5000

246

810121416182022150

MAX3222/MAX3232

SLEW RATE

vs. LOAD CAPACITANCE

LOAD CAPACITANCE (pF)S L E W R A T E (V /μs )

2000

3000

1000

4000

5000

510

15

2025

303540

MAX3222/MAX3232

SUPPLY CURRENT vs. LOAD CAPACITANCE

WHEN TRANSMITTING DATA

LOAD CAPACITANCE (pF)

S U P P L Y C U R R E N T (m A )

2000

3000

1000

4000

5000

TIMING CHARACTERISTICS—MAX3237

(V CC = +3.0V to +5.5V, C1–C4 = 0.1μF (Note 2), T A = T MIN to T MAX , unless otherwise noted. Typical values are at T A = +25°C.)

Note 2:MAX3222/MAX3232/MAX3241: C1–C4 = 0.1μF tested at 3.3V ±10%; C1 = 0.047μF, C2–C4 = 0.33μF tested at 5.0V ±10%.

MAX3237: C1–C4 = 0.1μF tested at 3.3V ±5%; C1–C4 = 0.22μF tested at 3.3V ±10%; C1 = 0.047μF, C2–C4 = 0.33μF tested at 5.0V ±10%.

Note 3:Transmitter input hysteresis is typically 250mV.

MAX3222/MAX3232/MAX3237/MAX3241

Transceivers Using Four 0.1μF External Capacitors

_______________________________________________________________________________________5

-7.5

-5.0-2.502.55.07.50

MAX3241

TRANSMITTER OUTPUT VOLTAGE

vs. LOAD CAPACITANCE

LOAD CAPACITANCE (pF)

T R A N S M I T T E R O U T P U T V O L T A G E (V )

2000

3000

1000

40005000

4

6810121416182022240

MAX3241SLEW RATE

vs. LOAD CAPACITANCE

LOAD CAPACITANCE (pF)

S L E W R A T E (V /μs )

2000

3000

1000

4000

5000

510152025303545

400

MAX3241

SUPPLY CURRENT vs. LOAD

CAPACITANCE WHEN TRANSMITTING DATA

LOAD CAPACITANCE (pF)

S U P P L Y C U R R E N T (m A )

2000

3000

1000

4000

5000

-7.5

-5.0-2.502.55.07.50

MAX3237

TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE (MBAUD = GND)

LOAD CAPACITANCE (pF)T R A N S M I T T E R O U T P U T V O L T A G E (V )

2000

3000

1000

4000

50000102030504060700

MAX3237

SLEW RATE vs. LOAD CAPACITANCE

(MBAUD = V CC )

LOAD CAPACITANCE (pF)S L E W R A T E (V /μs )

500

1000

1500

2000-7.5

-5.0-2.502.55.07.50

MAX3237

TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE (MBAUD = V CC )

LOAD CAPACITANCE (pF)

T R A N S M I T T E R O U T P U T V O L T A G E (V )

500

1000

1500

2000

102030

4050600

MAX3237

SUPPLY CURRENT vs.

LOAD CAPACITANCE (MBAUD = GND)

LOAD CAPACITANCE (pF)

S U P P L Y C U R R E N T (

m A )

2000

3000

1000

4000

5000

024

6810120

MAX3237

SLEW RATE vs. LOAD CAPACITANCE

(MBAUD = GND)

LOAD CAPACITANCE (pF)

S L E W R A T E (V /μs )

2000

3000

1000

4000

5000

10302040

506070

MAX3237

SKEW vs. LOAD CAPACITANCE

(t PLH - t PHL )

LOAD CAPACITANCE (pF)

1000

1500

500

2000

2500

_____________________________Typical Operating Characteristics (continued)

(V CC = +3.3V, 235kbps data rate, 0.1μF capacitors, all transmitters loaded with 3k ?, T A = +25°C, unless otherwise noted.)

M A X 3222/M A X 3232/M A X 3237/M A X 3241

Transceivers Using Four 0.1μF External Capacitors

6_______________________________________________________________________________________

______________________________________________________________Pin Description

MAX3222/MAX3232/MAX3237/MAX3241

Transceivers Using Four 0.1μF External Capacitors

_______________________________________________________________________________________

7

_______________Detailed Description

Dual Charge-Pump Voltage Converter

The MAX3222/MAX3232/MAX3237/MAX3241’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, and 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 con-vert CMOS-logic levels to 5.0V EIA/TIA-232 levels.

The MAX3222/MAX3232/MAX3241 transmitters guaran-tee a 120kbps data rate with worst-case loads of 3k ?in parallel with 1000pF, providing compatibility with PC-to-PC communication software (such as LapLink?).Typically, these three devices can operate at data rates of 235kbps. Transmitters can be paralleled to drive multi-ple receivers or mice.

The MAX3222/MAX3237/MAX3241’s output stage is turned off (high impedance) when the device is in shut-down mode. When the power is off, the MAX3222/MAX3232/MAX3237/MAX3241 permit the outputs to be driven up to ±12V.

The transmitter inputs do not have pullup resistors.Connect unused inputs to GND or V CC .

MAX3237 MegaBaud Operation

In normal operating mode (MBAUD = G ND), the MAX3237 transmitters guarantee a 250kbps data rate with worst-case loads of 3k ?in parallel with 1000pF.This provides compatibility with PC-to-PC communica-tion software, such as Laplink.

For higher speed serial communications, the MAX3237features MegaBaud operation. In MegaBaud operating mode (MBAUD = V CC ), the MAX3237 transmitters guar-antee a 1Mbps data rate with worst-case loads of 3k ?in parallel with 250pF for 3.0V < V CC < 4.5V. For 5V ±10%operation, the MAX3237 transmitters guarantee a 1Mbps data rate into worst-case loads of 3k ?in parallel with 1000pF.

Figure 1. Slew-Rate Test Circuits

LapLink is a trademark of Traveling Software, Inc.

M A X 3222/M A X 3232/M A X 3237/M A X 3241

Transceivers Using Four 0.1μF External Capacitors

8

_______________________________________________________________________________________

RS-232 Receivers

The receivers convert RS-232 signals to CMOS-logic out-put levels. The MAX3222/MAX3237/MAX3241 receivers have inverting three-state outputs. In shutdown, the receivers can be active or inactive (Table 1).

The complementary outputs on the MAX3237 (R1OUTB)and the MAX3241 (R1OUTB, R2OUTB) are always active,regardless of the state of EN or SHDN . This allows for Ring Indicator applications without forward biasing other devices connected to the receiver outputs. This is ideal for systems where V CC is set to 0V in shutdown to accommodate peripherals, such as UARTs (Figure 2).

MAX3222/MAX3237/MAX3241

Shutdown Mode

Supply current falls to less than 1μA in shutdown mode (SHDN = low). When shut down, the device’s charge pumps are turned off, V+ is pulled down to V CC , V- is pulled to ground, and the transmitter outputs are dis-abled (high impedance). The time required to exit shut-down is typically 100μs, as shown in Figure 3. Connect SHDN to V CC if the shutdown mode is not used. SHDN has no effect on R_OUT or R_OUTB.

MAX3222/MAX3237/MAX3241

Enable Control

The inverting receiver outputs (R_OUT) are put into a high-impedance state when EN is high. The complemen-tary outputs R1OUTB and R2OUTB are always active,regardless of the state of EN and SHDN (Table 1). EN has no effect on T_OUT.

__________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 capaci-tors for 3.3V operation. For other supply voltages, refer to Table 2 for required capacitor values. Do not use values lower than those listed in Table 2. Increasing the capaci-tor values (e.g., by a factor of 2) reduces ripple on the transmitter outputs and slightly reduces power consump-tion. 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 exces-sively with temperature. If in doubt, use capacitors with a higher nominal value. The capacitor’s equivalent series resistance (ESR), which usually rises at low tempera-tures, influences the amount of ripple on V+ and V-.

Figure 2. Detection of RS-232 Activity when the UART and Interface are Shut Down; Comparison of MAX3237/MAX3241(b) with Previous Transceivers (a).

MAX3222/MAX3232/MAX3237/MAX3241

Transceivers Using Four 0.1μF External Capacitors

_______________________________________________________________________________________

9

Power-Supply Decoupling

In most circumstances, a 0.1μF bypass capacitor is adequate. In applications that are sensitive to power-supply noise, decouple V CC to ground with a capacitor of the same value as charge-pump capacitor C1. Connect bypass capacitors as close to the IC as possible.

Operation Down to 2.7V

Transmitter outputs will meet EIA/TIA-562 levels of ±3.7V with supply voltages as low as 2.7V.

Transmitter Outputs when

Exiting Shutdown

Figure 3 shows two transmitter outputs when exiting shutdown mode. As they become active, the two trans-mitter outputs are shown going to opposite RS-232 lev-els (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 MAX3241 has been specifically designed to power serial mice while operating from low-voltage power sup-plies. It has been tested with leading mouse brands from manufacturers such as Microsoft and Logitech. The MAX3241 successfully drove all serial mice tested and met their respective current and voltage requirements.Figure 4a shows the transmitter output voltages under increasing load current at 3.0V. Figure 4b shows a typical mouse connection using the MAX3241.

CC = 3.3V C1–C4 = 0.1μF

50μs/div

Figure 3. Transmitter Outputs when Exiting Shutdown or Powering Up

M A X 3222/M A X 3232/M A X 3237/M A X 3241

Transceivers Using Four 0.1μF External Capacitors

10

______________________________________________________________________________________

Figure 4b. Mouse Driver Test Circuit Figure 4a. MAX3241 Transmitter Output Voltage vs. Load Current per Transmitter

MAX3222/MAX3232/MAX3237/MAX3241

Transceivers Using Four 0.1μF External Capacitors

______________________________________________________________________________________

11

High Data Rates

The MAX3222/MAX3232/MAX3241 maintain the RS-232±5.0V minimum transmitter output voltage even at high data rates. Figure 5 shows a transmitter loopback test circuit. Figure 6 shows a loopback test result at 120kbps, and Figure 7 shows the same test at 235kbps.For Figure 6, all transmitters were driven simultaneously at 120kbps into RS-232 loads in parallel with 1000pF.For Figure 7, a single transmitter was driven at 235kbps,and all transmitters were loaded with an RS-232 receiver in parallel with 1000pF.

The MAX3237 maintains the RS-232 ±5.0V minimum transmitter output voltage at data rates up to 1Mbps.Figure 8 shows a loopback test result at 1Mbps with MBAUD = V CC . For Figure 8, all transmitters were loaded with an RS-232 receiver in parallel with 250pF.

CC = 3.3V

5μs/div

Figure 5. Loopback Test Circuit

Figure 6. MAX3241 Loopback Test Result at 120kbps

CC = 3.3V

2μs/div

Figure 7. MAX3241 Loopback Test Result at 235kbps

0V +5V 0V -5V +5V 0V

T_IN

T_OUT = R_IN 5k R_OUT 150pF

200ns/div

CC = 3.3V

Figure 8. MAX3237 Loopback Test Result at 1000kbps (MBAUD = V CC )

M A X 3222/M A X 3232/M A X 3237/M A X 3241

Transceivers Using Four 0.1μF External Capacitors

__________________________________________________Typical Operating Circuits

Interconnection with 3V and 5V Logic

The MAX3222/MAX3232/MAX3237/MAX3241 can directly interface with various 5V logic families, includ-ing ACT and HCT CMOS. See Table 3 for more informa-tion on possible combinations of interconnections.

Table 3. Logic-Family Compatibility with Various Supply Voltages

MAX3222/MAX3232/MAX3237/MAX3241

Transceivers Using Four 0.1μF External Capacitors

______________________________________________________________________________________13

_____________________________________Typical Operating Circuits (continued)

M A X 3222/M A X 3232/M A X 3237/M A X 3241

Transceivers Using Four 0.1μF External Capacitors

14______________________________________________________________________________________

_____________________________________________Pin Configurations (continued)

MAX3222/MAX3232/MAX3237/MAX3241

Transceivers Using Four 0.1μF External Capacitors

______________________________________________________________________________________15

______3V-Powered EIA/TIA-232 and EIA/TIA-562 Transceivers from Maxim

Ordering Information (continued)

*Dice are tested at T A = +25°C, DC parameters only.+Denotes lead-free package.

M A X 3222/M A X 3232/M A X 3237/M A X 3241

Transceivers Using Four 0.1μF External Capacitors

16______________________________________________________________________________________

___________________Chip Topography

___________________Chip Information

T1IN

T2IN 0.127"(3.225mm)

0.087"(2.209mm)

R2OUT

R2IN T2OUT

V CC

V+

C1+

SHDN

EN

C1- C2+

C2-

V-

MAX3222

TRANSISTOR COUNT: 339

SUBSTRATE CONNECTED TO GND

Transceivers Using Four 0.1μF External Capacitors

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 https://www.sodocs.net/doc/394950439.html,/packages.)

Revision History

Pages changed at Rev 7: 1, 15, 16, 17

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.

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