ADM2209E
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.
signal lines to minimize crosstalk, without the complication of
multilayer PCBs.
Note that the two receivers kept active by the standby supply
(R5INA and R5INB) 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
1. Normal operation.
The ADM2209E has fail-safe receiver outputs that assume a
high output level if the receiver input is zero or open-circuit.
2. Temporary degradation or loss of function that is self-
recoverable when the interfering signal is removed.
LAPLINK COMPATIBILITY
3. Temporary degradation or loss of function that requires
operator intervention or system reset when the interfering
signal is removed.
The ADM2209E can operate up to 460 kbps data rate under
maximum driver load conditions of CL = 1000 pF and
RL = 3 kΩ at minimum power supply voltages.
4. Degradation or loss of function that is not recoverable due to
damage.
DCD
DSR
RxD
RTS
TxD
DCD
DSR
RxD
RTS
TxD
CTS
DTR
RI
R1
R2
R3
T1
T2
R4
1
2
3
4
5
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.
6
7
8
9
9-WAY D
CONNECTOR
COM1
CTS
DTR
RI
Table VII. Test Severity Levels (IEC1000-4-3)
Field Strength
T3
R5
SUPER I/O
CHIP
Level
V/m
ADM2209E
1
2
3
1
3
10
R1
R2
R3
T1
T2
R4
T3
R5
DCD
DSR
RxD
DCD
DSR
RxD
RTS
TxD
1
2
3
6
7
8
9
EMISSIONS/INTERFERENCE
RTS
TxD
CTS
DTR
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.
9-WAY D
CONNECTOR
COM2
CTS
DTR
RI
4
5
RI
APPLICATIONS INFORMATION
+3V or +5V
+12V
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
0.1F
0.1F
0.1F
0.1F
Figure 28. Typical Application for a Dual Serial Port
REV. 0
–11–
ROCHESTER [ Rochester Electronics ]
