MAX3222/MAX3232/MAX3237/MAX3241

3.0V至5.5V、低功耗、1Mbps、真RS-232收发器，

使用四只0.1µF外部电容

________________________________________________________________Maxim Integrated Products

1

19-0273; Rev 7; 1/07

MegaBaud和UCSP是Maxim Integrated Products, Inc.的商标。

本文是英文数据资料的译文，文中可能存在翻译上的不准确或错误。如需进一步确认，请在您的设计中参考英文资料。

有关价格、供货及订购信息，请联络Maxim亚洲销售中心：10800 852 1249 (北中国区)，10800 152 1249 (南中国区)，或访问Maxim的中文网站：china.maxim-ic.com。

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

3.0V至5.5V、低功耗、1Mbps、真RS-232收发器，使用四只0.1µF外部电容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)..8mW 20-Pin SSOP (derate 7.00mW/°C above +70°C).........559mW 20-Pin TSSOP (derate 8.0mW/°C above +70°C).............0mW 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

3.0V至5.5V、低功耗、1Mbps、真RS-232收发器，

使用四只0.1µF外部电容

_______________________________________________________________________________________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.)

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

3.0V至5.5V、低功耗、1Mbps、真RS-232收发器，使用四只0.1µF外部电容4_______________________________________________________________________________________

典型工作特性

Ω, T A = +25°C, unless otherwise noted.)

LOAD CAPACITANCE (pF)0

246810121416182022150

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

51015

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

3.0V至5.5V、低功耗、1Mbps、真RS-232收发器，

使用四只0.1µF外部电容

_______________________________________________________________________________________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

____________________________________________________________________典型工作特性(续)

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

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

3.0V至5.5V、低功耗、1Mbps、真RS-232收发器，使用四只0.1µF外部电容6_______________________________________________________________________________________

__________________________________________________________________________引脚说明

MAX3222/MAX3232/MAX3237/MAX3241

使用四只0.1µF外部电容

_______________________________详细说明

双电荷泵电压转换器

MAX3222/MAX3232/MAX3237/MAX3241的内部电源由两路稳压型电荷泵组成，只要输入电压(V CC )在3.0V至5.5V范围以内，即可提供+5.5V (倍压电荷泵)和-5.5V (反相电荷泵)输出电压。电荷泵工作在非连续模式，一旦输出电压低于5.5V，将开启电荷泵；输出电压超过5.5V时，即刻关闭电荷泵。每个电荷泵需要一个飞电容(C1、C2)和一个储能电容(C3、C4)，产生V+和V-电压。

RS-232发送器

发送器为反相电平转换器，将CMOS逻辑电平转换成5.0V EIA/TIA-232电平。

MAX3222/MAX3232/MAX3241在最差工作条件(3k Ω电阻与1000pF电容的并联负载)下能够保证120kbps的数据速率，提供PC至PC通信软件(例如LapLink TM )兼容性。通常情况下，这三款器件能够工作于235kbps数据速率。发送器可并联驱动多个接收器或鼠标。

器件处于关断模式时，MAX3222/MAX3237/MAX3241输出级关断(置为高阻)。关闭电源时，MAX3222/MAX3232/MAX3237/MAX3241允许输出端驱动至最高±12V。发送器输入没有上拉电阻，将未使用的输入连接至GND或V CC 。

MAX3237 MegaBaud工作模式

常规工作模式(MBAUD =GND)下，MAX3237发送器能够在最差工作条件(3k Ω电阻与1000pF电容的并联负载)下保证250kbps的数据速率，提供PC至PC通信软件(例如LapLink)的兼容性。

为了获得更高的串行通信速率，MAX3237提供MegaBaud工作模式。在MegaBaud工作模式(MBAUD =V CC )下，MAX3237发送器能够在最差工作条件(3k Ω电阻与250pF电容的并联负载，3.0V 图1. 摆率测试电路

LapLink是Traveling Software, Inc.的商标。

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

使用四只0.1µF外部电容

MAX3222/MAX3232/MAX3237/MAX3241使用四只0.1µF外部电容电源去耦大多数情况下，使用一个0.1µF旁路电容即可满足要求。在对电源噪声敏感的应用中，采用与电荷泵电容C1相同的电容将V CC旁路到地，进行去耦。旁路电容应尽量靠近IC放置。工作在最低2.7V当电源电压低至2.7V时，发送器输出仍可满足EIA/TIA-562要求的±3.7V电平。退出关断模式时发送器的输出图3所示为退出关断模式时的两路发送器输出。当两路发送器输出有效时，发送器输出与RS-232电平反相的信号(一路发送器输入为高电平，另一路为低电平)。每个发送器负载为3kΩ电阻并联2500pF电容。退出关断模式时，发送器输出显示没有振铃，也不存在所不希望的瞬变电压。注意，只有在V-幅值超过3V左右时，才会使能发送器。鼠标驱动能力MAX3241设计用于串口鼠标驱动，能够工作在较低的电源电压。该器件经过一些重要的鼠标生产厂家的测试，例如Microsoft和Logitech。MAX3241能够成功驱动所有测试的串口鼠标，满足相应的电流、电压要求。图4a所示为3.0V供电时，发送器输出电压随负载电流的变化情况；图4b所示为使用MAX3241时典型的鼠标连接。

50µs/div

CC = 3.3V

C1–C4 = 0.1µF

图3. 退出关断模式或上电时发送器的输出

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

使用四只0.1µF外部电容

MAX3222/MAX3232/MAX3237/MAX3241

使用四只0.1µF外部电容

高数据速率

即使工作在高数据速率下，MAX3222/MAX3232/MAX3241仍然能够保持RS-232标准要求的±5.0V最小发送器输出电压。图5所示为发送器环回测试电路，图6所示为120kbps 数据速率下的环回测试结果，图7所示为235kbps数据速率下的相同测试。图6中，所有发送器同时以120kbps的数据速率驱动并联了1000pF电容的RS-232负载。图7中，单个发送器工作在235kbps数据速率，所有发送器的负载都是并联了1000pF电容的RS-232接收器。

MAX3237在高达1Mbps的数据速率下能够保持RS-232标准要求的±5.0V最小发送器输出电压。图8所示为1Mbps下，MBAUD = V CC 时电路的环回测试结果。对于图8，所有发送器负载为并联了250pF电容的RS-232接收器。

CC = 3.3V

5µs/div

MAX3241在120kbps数据速率下的环回测试结果

CC = 3.3V

2µs/div

MAX3241在235kbps数据速率下的环回测试结果

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

T_IN

T_OUT = R_IN 5k R_OUT 150pF

200ns/div

CC = 3.3V

MAX3237在1000kbps (MBAUD = V CC )数据速率下的环回测试

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

使用四只0.1µF外部电容______________________________________________________________________典型工作电路

与3V和5V逻辑电平互联

MAX3222/MAX3232/MAX3237/MAX3241可直接与各种5V 逻辑电平接口，包括ACT和HCT CMOS。表3列出了各种可能的互联组合的详细信息。

MAX3222/MAX3232/MAX3237/MAX32413.0V至5.5V、低功耗、1Mbps、真RS-232收发器，使用四只0.1µF外部电容______________________________________________________________________________________13

___________________________________________________________________典型工作电路(续)

M A X 3222/M A X 3232/M A X 3237/M A X 32413.0V至5.5V、低功耗、1Mbps、真RS-232收发器，使用四只0.1µF外部电容

14______________________________________________________________________________________

_______________________________________________________________________引脚配置(续)

MAX3222/MAX3232/MAX3237/MAX32413.0V至5.5V、低功耗、1Mbps、真RS-232收发器，使用四只0.1µF外部电容______________________________________________________________________________________15

__________________________________Maxim提供的3V供电EIA/TIA-232和EIA/TIA-562收发器

定购信息(续)*裸片在T A = +25°C下经过测试，仅限直流参数。

+表示无铅封装。

M A X 3222/M A X 3232/M A X 3237/M A X 32413.0V至5.5V、低功耗、1Mbps、真RS-232收发器，使用四只0.1µF外部电容

16______________________________________________________________________________________

_______________________________芯片拓扑_______________________________芯片信息T1IN T2IN 0.087"(2.209mm)R2OUT R2IN T2OUT

TRANSISTOR COUNT: 339SUBSTRATE CONNECTED TO GND

3.0V至5.5V、低功耗、1Mbps、真RS-232收发器，使用四只0.1µF外部电容MAX3222/MAX3232/MAX3237/MAX3241

_______________________________修订历史

Rev 7中的修改页：1、15、16、17

Maxim不对Maxim产品以外的任何电路使用负责，也不提供其专利许可。Maxim保留在任何时间、没有任何通报的前提下修改产品资料和规格的权利。Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ______________________17©2007 Maxim Integrated Products Maxim 是Maxim Integrated Products, Inc.的注册商标。

_____________________________________________________________________________封装信息如需最近的封装外形信息和焊盘布局，请查询china.maxim-ic.com/packages 。

下载本文