ADM2209EARUZ Datasheet ADM2209EARUZ, ADM2209EARUZ-REEL7, ADM2209EARUZ-REEL | P10-P12

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ADM2209E

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(Electrical Fast Transient) discharges. A simplified schematic of

the protection structure is shown in Figures 22a and 22b. Each

input and output contains two back-to-back high speed clamping

diodes. During normal operation with maximum RS-232 signal

levels, the diodes have no effect as one or the other is reverse-

biased, depending on the polarity of the signal. If, however, the

voltage exceeds about ±50 V, reverse breakdown occurs and the

voltage is clamped at this level. The diodes are large p-n junctions

designed to handle the instantaneous current surge which can

exceed several amperes.

The transmitter outputs and receiver inputs have a similar pro-

tection structure. The receiver inputs can also dissipate some of

the energy through the internal 5 kΩ resistor to GND as well as

through the protection diodes.

The protection structure achieves ESD protection up to ±15 kV

and EFT protection up to ±2 kV on all RS-232 I-O lines. The

methods used to test the protection scheme are discussed later.

RECEIVER

INPUT

Figure 22a. Receiver Input Protection Scheme

TRANSMITTER

OUTPUT

Figure 22b. Transmitter Output Protection Scheme

ESD TESTING (IEC1000-4-2)

IEC1000-4-2 (previously 801-2) specifies compliance testing

using two coupling methods, contact discharge and air-gap

discharge. Contact discharge calls for a direct connection to the

unit being tested. Air-gap discharge uses a higher test voltage

but does not make direct contact with the unit under test. With

air discharge, the discharge gun is moved towards the unit un-

der test developing an arc across the air gap, hence the term air-

discharge. This method is influenced by humidity, temperature,

barometric pressure, distance and rate of closure of the discharge

gun. The contact-discharge method, while less realistic, is more

repeatable and is gaining acceptance in preference to the air-gap

method.

Although very little energy is contained within an ESD pulse,

the extremely fast rise time coupled with high voltages can cause

failures in unprotected semiconductors. Catastrophic destruc-

tion can occur immediately as a result of arcing or heating. Even

if catastrophic failure does not occur immediately, the device

may suffer from parametric degradation, which may result in

degraded performance. The cumulative effects of continuous

exposure can eventually lead to complete failure.

I-O lines are particularly vulnerable to ESD damage. Simply

touching or plugging in an I-O cable can result in a static dis-

charge that can damage or completely destroy the interface

product connected to the I-O port. Traditional ESD test meth-

ods such as the MIL-STD-883B method 3015.7 do not fully

test a product’s susceptibility to this type of discharge. This test

was intended to test a product’s susceptibility to ESD damage

during handling. Each pin is tested with respect to all other

pins. There are some important differences between the tradi-

tional test and the IEC test:

(a) The IEC test is much more stringent in terms of discharge

energy. The peak current injected is over four times greater.

(b) The current rise time is significantly faster in the IEC test.

It is possible that the ESD discharge could induce latch-up in the

device under test. This test is therefore more representative of a

real-world I-O discharge where the equipment is operating nor-

mally with power applied. For maximum peace of mind, however,

both tests should be performed, to ensure maximum protection

both during handling and later, during field service.

R1 R2

DEVICE

UNDER TEST

HIGH

VOLTAGE

GENERATOR

ESD TEST METHOD R2 C1

H. BODY MIL-STD-883B 1.5kV 100pF

IEC1000-4-2 330V 150pF

Figure 23. ESD Test Standards

100

PEAK

– %

36.8

TIME t

Figure 24. Human Body Model ESD Current Waveform

100

PEAK

– %

TIME t

30ns

60ns

0.1 TO 1ns

Figure 25. IEC1000-4-2 ESD Current Waveform

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ADM2209E

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The ADM2209E is tested using both of the above-mentioned

test methods. All pins are tested with respect to all other pins as

per the MIL-STD-883B specification. In addition, all I-O pins

are tested as per the IEC test specification. The products were

tested under the following conditions:

(a) Power-On—Normal Operation

(b) Power-Off

There are four levels of compliance defined by IEC1000-4-2.

The ADM2209E meets the most stringent compliance level for

both contact and air-gap discharge. This means that the products

are able to withstand contact discharges in excess of 8 kV and air-

gap discharges in excess of 15 kV.

Table IV. IEC1000-4-2 Compliance Levels

Contact Discharge Air Discharge

Level kV kV

12 2

24 4

36 8

48 15

Table V. ADM2209E ESD Test Results

ESD Test Method I-O Pins Other Pins

MIL-STD-883B ±15 kV ±2.5 kV

IEC1000-4-2

Contact ±8 kV

Air ±15 kV

FAST TRANSIENT BURST TESTING (IEC1000-4-4)

IEC1000-4-4 (previously 801-4) covers electrical fast-transient/

burst (EFT) immunity. Electrical fast transients occur as a

result of arcing contacts in switches and relays. The tests simu-

late the interference generated when, for example, a power relay

disconnects an inductive load. A spark is generated due to the

well-known back EMF effect. In fact the spark consists of a burst

of sparks as the relay contacts separate. The voltage appearing

on the line, therefore, consists of a burst of extremely fast tran-

sient impulses. A similar effect occurs when switching on fluo-

rescent lights.

The fast transient burst test defined in IEC1000-4-4 simulates

this arcing and its waveform is illustrated in Figure 26. It con-

sists of a burst of 2.5 kHz to 5 kHz transients repeating at

300 ms intervals. It is specified for both power and data lines.

300ms 15ms

5ns

0.2/0.4ms

50ns

Figure 26. IEC1000-4-4 Fast Transient Waveform

Table VI.

V Peak (kV) V Peak (kV)

Level PSU I-O

1 0.5 0.25

2 1 0.5

321

442

A simplified circuit diagram of the actual EFT generator is

illustrated in Figure 27.

HIGH

VOLTAGE

SOURCE

50V

OUTPUT

Figure 27. IEC1000-4-4 Fast Transient Generator

The transients are coupled onto the signal lines using an EFT

coupling clamp. The clamp is 1 meter long and it completely

surrounds the cable, providing maximum coupling capacitance

(50 pF to 200 pF typ) between the clamp and the cable. High

energy transients are capacitively coupled onto the signal lines.

Fast rise times (5 ns) as specified by the standard result in very

effective coupling. This test is very severe since high voltages

are coupled onto the signal lines. The repetitive transients can

often cause problems where single pulses do not. Destructive

latch-up may be induced due to the high energy content of the

transients. Note that this stress is applied while the interface

products are powered up and transmitting data. The EFT test

applies hundreds of pulses with higher energy than ESD. Worst

case transient current on an I-O line can be as high as 40 A.

Test results are classified according to the following:

1. Normal performance within specification limits.

2. Temporary degradation or loss of performance which is self-

recoverable.

3. Temporary degradation or loss of function or performance

which requires operator intervention or system reset.

4. Degradation or loss of function which is not recoverable due

to damage.

The ADM2209E has been tested under worst case conditions

using unshielded cables and meets Classification 2. Data trans-

mission during the transient condition is corrupted, but it may

be resumed immediately following the EFT event without user

intervention.

IEC1000-4-3 RADIATED IMMUNITY

IEC1000-4-3 (previously IEC801-3) describes the measure-

ment method and defines the levels of immunity to radiated

electromagnetic fields. It was originally intended to simulate the

electromagnetic fields generated by portable radio transceivers

or any other device that generates continuous wave radiated

electromagnetic energy. Its scope has since been broadened to

include spurious EM energy which can be radiated from fluores-

cent lights, thyristor drives, inductive loads, etc.

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ADM2209E

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Testing for immunity involves irradiating the device with an EM

field. There are various methods of achieving this, including use

of an echoic chamber, stripline cell, TEM cell, GTEM cell. A

stripline cell consists of two parallel plates with an electric field

developed between them. The device under test is placed within

the cell and exposed to the electric field. There are three severity

levels having field strengths ranging from 1 V to 10 V/m. Results

are classified in a fashion similar to those for IEC1000-4-4.

1. Normal operation.

2. Temporary degradation or loss of function that is self-

recoverable when the interfering signal is removed.

3. Temporary degradation or loss of function that requires

operator intervention or system reset when the interfering

signal is removed.

4. Degradation or loss of function that is not recoverable due to

damage.

The ADM2209E easily meets Classification 1 at the most strin-

gent (Level 3) requirement. In fact, field strengths up to 30 V/m

showed no performance degradation and error-free data trans-

mission continued even during irradiation.

Table VII. Test Severity Levels (IEC1000-4-3)

Field Strength

Level V/m

310

EMISSIONS/INTERFERENCE

EN55 022, CISPR22 defines the permitted limits of radiated

and conducted interference from Information Technology (IT)

equipment. The objective of the standard is to minimize the

level of emissions, both conducted and radiated.

APPLICATIONS INFORMATION

In a typical Data Terminal Equipment (DTE) to Data Circuit

Terminating Equipment (DCE) 9-lead de facto interface imple-

mentation, two data lines (TxD and RxD) and six control lines

(RTS, DTR, DSR, CTS and RI) are required. With its six

drivers and ten receivers, the ADM2209E offers a single-chip

solution for the two RS-232 ports normally supplied as standard

in a desktop or notebook personal computer, as shown in Figure

28. The flow-through pinout of the device allows for a very

simple PCB layout, and allows a ground plane to be placed

beneath the IC, and ground lines to be inserted between the

signal lines to minimize crosstalk, without the complication of

multilayer PCBs.

Note that the two receivers kept active by the standby supply

(R5

A and R5

B) should be connected to the Ring In (RI)

line, so that the system can be awakened when a peripheral

device begins to communicate.

FAIL-SAFE RECEIVER OUTPUTS

The ADM2209E has fail-safe receiver outputs that assume a

high output level if the receiver input is zero or open-circuit.

LAPLINK COMPATIBILITY

The ADM2209E can operate up to 460 kbps data rate under

maximum driver load conditions of C

= 1000 pF and

= 3 kΩ at minimum power supply voltages.

SUPER I/O

CHIP

DCD

DSR

RxD

RTS

TxD

CTS

DTR

DCD

DSR

RxD

RTS

TxD

CTS

DTR

DCD

DSR

RxD

RTS

TxD

CTS

DTR

DCD

DSR

RxD

RTS

TxD

CTS

DTR

0.1mF

+12V

+3V or +5V

9-WAY D

CONNECTOR

COM2

9-WAY D

CONNECTOR

COM1

ADM2209E

0.1mF

Figure 28. Typical Application for a Dual Serial Port

P1-P3 P4-P6 P7-P9 P10-P12 P13-P13

ADM2209EARUZ

Mfr. #:

Buy ADM2209EARUZ

Manufacturer:

Analog Devices Inc.

Description:

RS-232 Interface IC Dual-Port 6 Tx/10 Rx

Lifecycle:

New from this manufacturer.

Delivery:

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ADM2209EARUZ

ADM2209EARUZ

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