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MAX3233EEWP+G36中文资料

________________General Description

The MAX3233E/MAX3235E are EIA/TIA-232 and V.28/V.24communications interfaces with automatic shutdown/wake-up features, high data-rate capabilities, and enhanced electrostatic discharge (ESD) protection. All transmitter outputs and receiver inputs are protected to ±15kV using IEC 1000-4-2 Air-Gap Discharge, to ±8kV using IEC 1000-4-2 Contact Discharge, and to ±15kV using the Human Body Model. The MAX3233E operates from a +3.3V supply; the MAX3235E operates from +5.0V.All devices achieve a 1μA supply current using Maxim’s revolutionary AutoShutdown Plus? feature. These devices automatically enter a low-power shutdown mode when the following two conditions occur: either the RS-232 cable is disconnected or the transmitters of the connected peripherals are inactive, and the UART driving the transmitter inputs is inactive for more than 30 seconds. They turn on again when they sense a valid transition at any transmitter or receiver input.AutoShutdown Plus saves power without changes to the existing BIOS or operating system.

The MAX3233E/MAX3235E have internal dual charge pumps requiring no external capacitors. Both trans-ceivers have a proprietary low-dropout transmitter out-put stage that enables true RS-232 performance from a +3.0V to +3.6V supply for the MAX3233E or a +4.5V to +5.5V supply for the MAX3235E. These devices are guaranteed to operate up to 250kbps. Both are avail-able in space-saving 20-pin wide SO or plastic DIP packages.

________________________Applications

Subnotebook and Palmtop Computers Cellular Phones

Battery-Powered Equipment Handheld Equipment Peripherals

Embedded Systems

____________________________Features

?ESD Protection for RS-232 I/O Pins

±15kV—Human Body Model

±8kV—IEC 1000-4-2, Contact Discharge ±15kV—IEC 1000-4-2, Air-Gap Discharge ?Latchup Free

?1μA Supply Current

?AutoShutdown Plus—1997 EDN Magazine Innovation of the Year ?Single-Supply Operation

+3.0V to +3.6V (MAX3233E)+4.5V to +5.5V (MAX3235E)?250kbps Guaranteed Data Rate ?6V/μs Guaranteed Slew Rate

?Meets EIA/TIA-232 Specifications Down to 3.0V (MAX3233E)

?Internal Charge-Pump Capacitors

MAX3233E ?/MAX3235E

?

±15kV ESD-Protected, 1μA, 250kbps, 3.3V/5V , Dual RS-232 Transceivers with Internal Capacitors

________________________________________________________________Maxim Integrated Products

1

19-1473; Rev 2; 8/04

AutoShutdown Plus is a trademark of Maxim Integrated Products, Inc.

Ordering Information continued at end of data sheet.

Pin Configuration/ Functional Diagram

Typical Operating Circuit appears at end of data sheet.

?Covered by U.S. Patent numbers 4,636,930; 4,679,134; 4,777,577;

4,797,899; 4,809,152; 4,897,774; 4,999,761; 5,649,210; and other patents pending.

For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at https://www.wendangku.net/doc/552167009.html,.

M A X 3233E /M A X 3235E

2_______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(V CC = +3.0V to +3.6V for MAX3233E, V CC = +4.5V to +5.5V for MAX3235E; T A = T MIN to T MAX , unless otherwise noted. Typical val-ues 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.

V CC to GND (MAX3233E).........................................-0.3V to +4V V CC to GND (MAX3235E).........................................-0.3V to +6V V+ to GND (Note 1)..................................................-0.3V to +7V V- to GND (Note 1)...................................................+0.3V to -7V V+ + |V-|(Note 1).................................................................+13V Input Voltages

T_IN, FORCEON, FORCEOFF to GND....................-0.3V to +6V R_IN to GND...................................................................±25V Output Voltages

T_OUT to GND.............................................................±13.2V R_OUT, INVALID to GND......................-0.3V to (V CC + 0.3V)

Short-Circuit Duration

T_OUT to GND......................................................Continuous Continuous Power Dissipation (T A = +70°C)

Wide SO (derate 10mW/°C above +70°C)..................800mW Plastic DIP (derate 11.11mW/°C above +70°C).........889mW Operating Temperature Ranges

MAX323_EC_P...................................................0°C to +70°C MAX323_EE_P................................................-40°C to +85°C Storage Temperature Range.............................-65°C to +150°C Lead Temperature (soldering, 10s) (Note 2)...................+300°C

Note 1:V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.Note 2:Maximum reflow temperature is +220°C.

RS-232 Transceivers with Internal Capacitors

MAX3233E/MAX3235E

_______________________________________________________________________________________3

ELECTRICAL CHARACTERISTICS (continued)

(V CC = +3.0V to +3.6V for MAX3233E, V CC = +4.5V to +5.5V for MAX3235E; T A = T MIN to T MAX , unless otherwise noted. Typical val-ues are at T A = +25°C.)

RS-232 Transceivers with Internal Capacitors

Note 3:A transmitter/receiver edge is defined as a transition through the transmitter/receiver input logic thresholds.

M A X 3233E /M A X 3235E

4_______________________________________________________________________________________

TIMING CHARACTERISTICS

(V CC = +3.0V to +3.6V for MAX3233E, V CC = +4.5V to +5.5V for MAX3235E; T A = T MIN to T MAX , unless otherwise noted. Typical val-ues are at T A = +25°C.)

-10.0

-7.5

V OUT -V OUT +

-5.0-2.502.55.07.510.00

1000

2000

3000

4000

5000

TRANSMITTER OUTPUT VOLTAGE vs.

LOAD CAPACITANCE

M A X 3233E /35E t o c 01

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 )

10525201540353045020001000300040005000

OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE

LOAD CAPACITANCE (pF)

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

02

46810121416

1000

2000

3000

4000

5000

SLEW RATE vs.LOAD CAPACITANCE

LOAD CAPACITANCE (pF)

S L E W R A T E (V /μs )

Note 4:Transmitter skew is measured at the transmitter zero crosspoints.

__________________________________________Typical Operating Characteristics

(V CC = +3.3V for MAX3233E, V CC = +5.0V for MAX3235E; 250kbps data rate; all transmitters loaded with 3k ?and C L ; T A = +25°C,

unless otherwise noted.)

RS-232 Transceivers with Internal Capacitors

MAX3233E/MAX3235E

_______________________________________________________________________________________5

______________________________________________________________Pin Description

RS-232 Transceivers with Internal Capacitors

_______________Detailed Description

Dual Charge-Pump Voltage Converter

The MAX3233E/MAX3235E’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), with no external capaci-tors. The charge pump operates in discontinuous mode: if the output voltages are less than 5.5V, the charge pump is enabled; if the output voltages exceed 5.5V, the charge pump is disabled.

RS-232 Transmitters

The transmitters are inverting level translators that convert CMOS-logic levels to 5.0V EIA/TIA-232 levels.The devices guarantee a 250kbps data rate with worst-case loads of 3k ?in parallel with 1000pF, providing compatibility with PC-to-PC communication software (such as LapLink?). Transmitters can be paralleled to drive multiple receivers. Figure 1 shows a complete system connection.

When FORCEOFF is driven to ground or when the Auto-Shutdown Plus circuitry senses that all receiver and transmitter inputs are inactive for more than 30sec, the transmitters are disabled and the outputs go into a high-impedance state. When powered off or shut down, the outputs can be driven to ±12V. The transmitter inputs do not have pull-up resistors. Connect unused inputs to GND or V CC .

RS-232 Receivers

The receivers convert RS-232 signals to CMOS-logic output levels. They feature inverting outputs that always remain active (Table 1).

The MAX3233E/MAX3235E feature an INVALID output that is enabled low when no valid RS-232 voltage levels have been detected on all receiver inputs. Because INVALID indicates the receiver input’s condition, it is independent of FORCEON and FORCEOFF states (Figures 2 and 3).

AutoShutdown Plus Mode

The devices achieve a 1μA supply current with Maxim’s AutoShutdown Plus feature, which operates when FORCEOFF is high and a FORCEON is low. When these devices do not sense a valid signal transition on any receiver or transmitter input for 30sec, the on-board charge pumps are shut down, reducing supply current to 1μA. This occurs if the RS-232 cable is disconnected,or if the connected peripheral transmitters are turned off and the UART driving the transmitter inputs is inactive.The system turns on again when a valid transition is

M A X 3233E /M A X 3235E

RS-232 Transceivers with Internal Capacitors 6

_______________________________________________________________________________________

Figure 1. Interface Under Control of PMU

LapLink is a trademark of Traveling Software.

Figure 2b. INVALID Functional Diagram, INVALID High

MAX3233E/MAX3235E

RS-232 Transceivers with Internal Capacitors

_______________________________________________________________________________________

7

applied to any RS-232 receiver or transmitter input. As a result, the system saves power without changes to the existing BIOS or operating system.

Figures 2a and 2b depict invalid and valid RS-232receiver voltage levels. INVALID indicates the receiver input’s condition, and is independent of FORCEON and FORCEOFF states. Figure 2 and Tables 1 and 2 sum-marize the operating modes. FORCEON and FORCE-OFF override AutoShutdown Plus circuitry. When nei-ther control is asserted, the IC selects between these states automatically based on the last receiver or trans-mitter input edge received.

When shut down, the device’s charge pumps turn off,V+ is pulled to V CC , V- is pulled to ground, and the transmitter outputs are high impedance. The time required to exit shutdown is typically 100μs (Figure 7).

Table 1. Output Control Truth Table

X = Don’t care

*INVALID connected to FORCEON

**INVALID connected to FORCEON and FORCEOFF

Figure 2c. AutoShutdown Plus Logic Figure 2d. Power-Down Logic

By connecting FORCEON to INVALID , the device shuts down when no valid receiver level and no receiver or transmitter edge is detected for 30sec. It wakes up when a valid receiver level or receiver or transmitter edge is detected.

By connecting FORCEON and FORCEOFF to INVALID ,the device shuts down when no valid receiver level is detected and wakes up when a valid receiver level is detected.

A system with AutoShutdown Plus may need time to wake up. Figure 4 shows a circuit that forces the transmitters on for 100ms, allowing enough time for another system to realize that the MAX3233E/

MAX3235E is awake. If another system outputs valid RS-232 signal transitions within that time, the RS-232ports on both systems remain enabled.

Software-Controlled Shutdown

If direct software control is desired, use INVALID to indicate DTR or Ring Indicator signal. Tie FORCEOFF and FORCEON together to bypass the AutoShutdown Plus so the line acts like a SHDN input.

±15kV ESD Protection

As with all Maxim devices, ESD-protection structures are incorporated on all pins to protect against electrostatic discharges encountered during handling and assembly.The driver outputs and receiver inputs have extra pro-tection 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

M A X 3233E /M A X 3235E

RS-232 Transceivers with Internal Capacitors

8

_______________________________________________________________________________________

Table 2. INVALID Truth Table

Figure 3a. Receiver Positive/Negative Thresholds for INVALID

Figure 3b. AutoShutdown Plus, INVALID,and READY Timing Diagram

MAX3233E/MAX3235E

RS-232 Transceivers with Internal Capacitors

_______________________________________________________________________________________

9

event, Maxim’s E versions keep working without latchup, whereas competing RS-232 products can latch and must be powered down to remove latchup.

ESD protection can be tested in various ways; the transmitter outputs and receiver inputs of this product family are characterized for protection to the following limits:

1)±15kV using the Human Body Model

2)±8kV using the Contact Discharge method specified in IEC 1000-4-2

3)±15kV using IEC 1000-4-2’s Air-Gap Discharge method 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 5a shows the Human Body Model and Figure 5b shows the current waveform it generates when dis-charged into a low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of inter-est, which is then discharged into the test device through a 1.5k ?resistor.

IEC 1000-4-2

The IEC 1000-4-2 standard covers ESD testing and per-formance of finished equipment; it does not specifically refer to integrated circuits. The MAX3233E/MAX3235E help you design equipment that meets Level 4 (the high-est 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 cur-rent 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

Figure 4. AutoShutdown Plus Initial Turn-On to Wake Up Another System

Figure 5b. Human Body Current Waveform

Figure 5a. Human Body ESD Test Model

that measured using the Human Body Model. Figure 6a shows the IEC 1000-4-2 model, and Figure 6b shows the current waveform for the ±8kV, IEC 1000-4-2, Level 4,ESD contact-discharge test.

The air-gap 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 resis-tance. Its objective is to emulate the stress caused by contact that occurs with handling and assembly during

manufacturing. Of course, all pins require this protec-tion during manufacturing, not just RS-232 inputs and outputs. Therefore, after PC board assembly, the Machine Model is less relevant to I/O ports.

__________Applications Information

Charge Pumps

The MAX3233E/MAX3235E do not require external capacitors to operate their internal charge pumps.

The MAX3235E can be operated down to 3.0V by par-alleling the internal C1 capacitor with an external 0.1μF.When using an external capacitor across the C1 termi-nals, check to confirm that the total supply voltage measured from V+ to V- does not exceed the absolute maximum voltage of 13V. With the external 0.1μF capacitor added, the MAX3235E should not be used with a supply greater than +3.9V.

Power-Supply Decoupling

In most applications, a 0.1μF V CC bypass capacitor is adequate. Connect bypass capacitors as close to the IC as possible.

Transmitter Outputs when Exiting Shutdown

Figure 7 shows two transmitter outputs when exiting shutdown mode. As they become active, the two trans-mitter outputs are shown going to opposite RS-232 levels (one transmitter input is high, the other is low).

M A X 3233E /M A X 3235E

RS-232 Transceivers with Internal Capacitors 10

______________________________________________________________________________________

10μs/div

V CC = 3.3V

FORCEON = FORCEOFF

Figure 7. Transmitter Outputs when Exiting Shutdown or Powering Up

Figure 8. Loopback Test Circuit

MAX3233E/MAX3235E

RS-232 Transceivers with Internal Capacitors

______________________________________________________________________________________11

Each transmitter is loaded with 3k ?in parallel with 1000pF. The transmitter outputs display no ringing or undesirable transients as they come out of shutdown.Note that the transmitters are enabled only when the magnitude of V- exceeds approximately -3V.

High Data Rates

The MAX3233E/MAX3235E maintain the RS-232 ±5.0V minimum transmitter output voltage even at high data rates. Figure 8 shows a transmitter loopback test cir-cuit. Figure 9 shows a loopback test result at 120kbps,and Figure 10 shows the same test at 250kbps. For

Figure 9, all transmitters were driven simultaneously at 120kbps into RS-232 loads in parallel with 1000pF. For Figure 10, a single transmitter was driven at 250kbps,and all transmitters were loaded with an RS-232 receiv-er in parallel with 250pF.

Interconnection with 3V and 5V Logic

The MAX3233E/MAX3235E can directly interface with various 5V logic families, including ACT and HCT CMOS. See Table 3 for more information on possible combinations of interconnections.

Figure 9. Loopback Test Result at 120kbps T1IN T1OUT

R1OUT

5V/div 5V/div

5V/div

V CC = 3.3V (MAX3233E), V CC = 5.0V (MAX3235E)

Figure 10. Loopback Test Result at 250kbps

T1IN T1OUT

R1OUT

5V/div

5V/div

5V/div

V CC = 3.3V (MAX3233E), V CC = 5.0V (MAX3235E)

Table 3. Logic Family Compatibility with Various Supply Voltages

M A X 3233E /M A X 3235E

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.

12____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600?2004 Maxim Integrated Products

Printed USA

is a registered trademark of Maxim Integrated Products.

___________________Chip Information

TRANSISTOR COUNT: 1129

Typical Operating Circuit

Ordering Information (continued)

±15kV ESD-Protected, 1μA, 250kbps, 3.3V/5V , Dual RS-232 Transceivers with Internal Capacitors Package Information

For the latest package outline information, go to https://www.wendangku.net/doc/552167009.html,/packages .

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