NM232DDC Series NM NOT RECOMMENDED OT

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NM232DDC Series
NM
OT RECOMMENDED
NOT
Isolated Dual EIA-232-D
Isolate
23
Transmitter and Receiver
NS
FOR NEW DESIG
ELECTRICAL CHARACTERISTICS
Parameter
Test conditions
High threshold input logic, VIH
Low threshold input logic, VIL
Input Hysteresis, ΔVT
Leakage Current, IL
Input capacitance, CIN
Low level output voltage, VOL
High level output voltage, VOH
Input pull up current
±VREF Current
TXIN, SHUTDOWN, ENABLE
TXIN, SHUTDOWN, ENABLE
TXIN
TXIN , SHUTDOWN or ENABLE = VCC
TXIN
IOUT = 3.2mA
IOUT = -1.0mA
VIN = OV
TXOUT = 3kΩ, RXOUT = 2.2kΩ
FEATURES
ELECTRICAL CHARACTERISTICS - EIA-232-D
„
RoHS compliant
Parameter
Test conditions
„
Single 5V supply
Positive going threshold, VT+
Negative going threshold, VTInput Hysteresis, ΔVT
Input resistance
Output voltage, VPP
Output leakage current, IL
Output slew rate, SR
Propagation delay, TL
Propagation delay, TR
Transmission rate
Supply voltage, VCC
RXIN
RXIN
RXIN
RXIN
TXOUT, RL=3kΩ to ISO GND
SHUTDOWN=VCC, TXOUT=±15V
RL=3kΩ, CL=2500pF
Logic to RS232
RS232 to logic
RL=3kΩ, CL=2500pF
„
50μW low power shutdown
„
TTL/CMOS Logic compatible
„
EIA-232-D/E and CCITT V.28 compatible
„
Dual transmitters and receivers
„
1.5kVrms Isolation
DESCRIPTION
The NM232DDC is an electrically isolated dual
transmitter and receiver designed to interface data terminal equipment (DTE) with data
communications equipment (DCE). The device
provides two data receive channels and two data
transmit channels. Each channel is EIA-232-D,
EIA-232-E and CCITT V.28 compatible at the
interface boundary and TTL/CMOS compatible at
the logic connections. No external components
are needed and a single 5V input supply powers
all functions either side of the isolation boundary.
A low-power shutdown mode and high impedance
state for receiver outputs is effected via two pins,
SHUTDOWN and ENABLE. The device is supplied
in a low profile 24 pin DIL package.
Supply current, ICC
Shutdown current ICC
ENABLE input current, IEN
Shutdown input current, ISHUTDOWN
MTTF1
Min..
Typ.
Max.
Units
2.4
0.8
1.8
1.3
0.5
4.0
20
3.0
V
V
V
μA
pF
V
V
μA
mA
Min..
Typ.
Max.
Units
3.0
0.6
1.8
1.2
0.6
3.0
±5.0
-10
±7.0
V
V
V
kΩ
V
μA
V/μs
μs
μs
kbps
V
10
5.0
0.4
2.4
7.0
3.0
20
10
9.6
5.5
4.5
TXIN=0.8V, TXOUT=3kΩ,
RXIN=3.0V, RXOUT=2.2kΩ
10
30
53
SHUTDOWN=1
ENABLE=OV to VCC
SHUTDOWN=OV to VCC
mA
1.0
10
1.0
1.0
μA
μA
μA
kHrs
Typ.
Max.
Units
70
125
ºC
ºC
187
TEMPERATURE CHARACTERISTICS
Parameter
Min..
Operating free-air temperature range
Storage temperature range
0
-55
ABSOLUTE MAXIMUM RATINGS
Supply voltage VCC with respect to pin 10
Input voltage to logic pins 3, 7, 8, & 11 with respect to
pin 10
-0.3V to +6V
-0.3V to
VCC+0.3V
EIA-232-D input voltage, pins 17 & 18
EIA-232-D input voltage, pins 19 & 20
Positive input voltage, pins 16 & 21
Negative input voltage, pin 23
Voltages with respect to ISO GND pin 22
Short circuit on pins 19 & 20
Power dissipation
NM232DDC maximum data rate
Lead case temperature 1.5mm from case for 10 seconds
-30V to +30V
-15V to +15V
+14V
-14V
Indefinite
700mW
9.6kbps
300ºC
ISOLATION CHARACTERISTICS
For full details go to
www.murata-ps.com/rohs
Parameter
Conditions
Min..
Isolation test voltage
Flash tested for 1 second
1500
Typ.
Max.
Units
Vrms
1. Calulated using MIL-HDBK-217F.
All data taken at TA=25°C, VCC=5V.
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KII_NM232DD.A04 Page 1 of 5
NM232DDC Series
Isolated Dual EIA-232-D Transmitter and Receiver
APPLICATION NOTES
The NM232DDC is an isolated interface device providing EIA-232-D compatibility.
A single supply from the logic side provides all necessary power for the device.
The isolation feature allows the protective or frame ground of DTEs or DCEs to
be isolated from each other, eliminating ground loop currents and inherently long
noise paths. The voltage level between different ground points can be up to ±5V
or ±6V and this level flucuates as the power taken varies. This voltage appears, in
non-isolated equipment, as normal mode noise on the signals. With such high noise
levels present it is clearly very difficult with single ended signals to have reliable
communication. Isolating the input from output so that one side floats relative to
the other allows reliable communication in environments with considerable degrees
of noise between equipments.
Figure 1
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Figure 1 shows a typical pcb track layout with a clear separation between the logic
pin connections (pins 1-12) and the EIA-232-D connections (pins 13-24). Between
the two sides of the layout is a track which can be connected to frame or equipment ground, this can be seen as the boundary between the logic and EIA-232-D
side of the device. No other rules or speed conditions need to be applied other than
to keep the two halves’ separation to a maximum.
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An example of a DTE application circuit is shown in figure 2. The schematic is
illustrative of the way the NM232DDC may be connected to implement an isolated
EIA-232-D interface with a typical UART and processor bus. Precise circuitry will
depend on the application and in particular the use of the control lines shown will
need to be altered to suit the situation.
The ENABLE control line (pin 11), puts the receiver output pins 1 and 12 into a high
impedance state when set to a high level. The shutdown control line (pin 3) sets the
device into a shutdown power mode when it is at high logic level. The maximum
power drawn in shutdown mode is 50μW, a low enough level for consideration in
battery powered equipment.
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Figure 2
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Figure 3
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Where to use the NM232DDC
The function of the NM232DDC is to provide an isolated signal path between a
UART or similar device and the EIA-232-D interface ‘D’ connector, providing two
receivers and two transmitters which can be used in a number of handshake
modes. One receiver and transmitter will normally be used for the signal lines and
the remaining pair will act as handshake lines. Figure 3 shows simply where the
device will be connected.
Figure 4
More complicated schemes for controlled signal interchange will require two or
more such devices. As the devices are self contained no external DC/DC converter
is required. The enable line provides a means for creating a communications bus
where each NM232DDC can have a different logical address via a decoder. This
would allow one UART to talk with many EIA-232-D connected interfaces (see
figure 4).
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RoHS COMPLIANCE INFORMATION
This series is compatible with RoHS soldering systems with a peak wave solder temperature of 300ºC for 10 seconds. The pin termination
finish on this product series is Matte Tin over Nickel Preplate. The series is backward compatible with Sn/Pb soldering systems.
For further information, please visit www.murata-ps.com/rohs
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KII_NM232DD.A04 Page 2 of 5
NM232DDC Series
Isolated Dual EIA-232-D Transmitter and Receiver
TYPICAL OPERATING CHARACTERISTICS
POWER UP TO TRANSMITTER OUTPUT DELAY
7
SHUTDOWN TO POWER UP DELAY
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TRANSMITTER SLEW RATE VS TEMPERATURE
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5SBOTNJUUFS4MFX3BUF7˜T
TRANSMITTER SLEW RATE VS LOAD CAPACITANCE
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ENABLE & DISABLE TIMES VS TEMPERATURE
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PROPAGATION DELAY VS TEMPERATURE
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KII_NM232DD.A04 Page 3 of 5
NM232DDC Series
Isolated Dual EIA-232-D Transmitter and Receiver
PACKAGE SPECIFICATIONS
MECHANICAL DIMENSIONS
1.28 (32.60) MAX
NM232DDC
XYYWW
0.16
(4.10)
0.3 (7.60)
MAX
0.02 (0.002)
0.50 (0.005)
0.1 (2.54)
Weight: 5.5g Typ.
All pins on a 0.1 (2.54) pitch.
All dimensions are in inches (mm) ±0.01 (0.25).
1.1 (27.94)
PIN CONNECTIONS
0.6673
(16.95) MAX
RECOMMENDED FOOTPRINT
Description
Receiver output number 1, TTL/CMOS logic
No internal connection
SHUTDOWN input, High=SHUTDOWN, Low=normal operation
No internal connection
+5V supply
No internal connection
Transmitter input number 2, TTL/CMOS logic
Transmitter input number 1, TTL/CMOS logic
No internal connection
Ground
Output ENABLE, High-Hi Z on R1/R2OUT, low-normal operation
Receiver output number 2, TTL/CMOS logic
No internal connection
No internal connection
No internal connection
Isolated+V supply out internally connected to pin 21
Receiver input number 2, RS232 levels
Receiver input number 1, RS232 levels
Transmitter output number 2, RS232 levels
Transmitter output number 1, RS232 levels
Isolated +V supply out internally connected to pin 16
Isolated ground
Isolated +V supply outNo internal connection

All dimensions are in inches (mm) ±0.01 (0.25)
TUBE OUTLINE DIMENSIONS
œœ
œœ
œœ
Function
R1OUT
NC
SHUTDOWN
NC
VCC
NC
T2IN
T1IN
NC
GND
ENABLE
R2OUT
NC
NC
NC
+VREF
R2IN
R1IN
T2OUT
T1OUT
+VREF
ISO GND
-VREF
NC
œœ
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
0.012 (0.30)
0.008 (0.20)
œœ
0.58
(14.72)
œœ
œ
œ
All dimensions are in inches (mm) ±0.01 (0.25)
Tube Quantity : 15
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KII_NM232DD.A04 Page 4 of 5
NM232DDC Series
Isolated Dual EIA-232-D Transmitter and Receiver
TECHNICAL NOTES
ISOLATION VOLTAGE
‘Hi Pot Test’, ‘Flash Tested’, ‘Withstand Voltage’, ‘Proof Voltage’, ‘Dielectric Withstand Voltage’ & ‘Isolation Test Voltage’ are all terms that relate to the same thing, a test voltage, applied for a specified time, across a component designed to provide electrical isolation, to verify the integrity of that isolation.
Murata Power Solutions NM232DDC series of DC/DC converters are all 100% production tested at their stated isolation voltage. This is 1.5kVrms for 1 second.
A question commonly asked is, “What is the continuous voltage that can be applied across the part in normal operation?”
For a part holding no specific agency approvals, such as the NM232DDC series, both input and output should normally be maintained within SELV limits i.e. less than 42.4V peak,
or 60VDC. The isolation test voltage represents a measure of immunity to transient voltages and the part should never be used as an element of a safety isolation system. The part
could be expected to function correctly with several hundred volts offset applied continuously across the isolation barrier; but then the circuitry on both sides of the barrier must be
regarded as operating at an unsafe voltage and further isolation/insulation systems must form a barrier between these circuits and any user-accessible circuitry according to safety
standard requirements.
REPEATED HIGH-VOLTAGE ISOLATION TESTING
It is well known that repeated high-voltage isolation testing of a barrier component can actually degrade isolation capability, to a lesser or greater degree depending on materials,
construction and environment. The NM232DDC series has toroidal isolation transformers, with no additional insulation between primary and secondary windings of enameled wire.
While parts can be expected to withstand several times the stated test voltage, the isolation capability does depend on the wire insulation. Any material, including this enamel (typically polyurethane) is susceptible to eventual chemical degradation when subject to very high applied voltages thus implying that the number of tests should be strictly limited. We
therefore strongly advise against repeated high voltage isolation testing, but if it is absolutely required, that the voltage be reduced by 20% from specified test voltage.
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
This product is subject to the following operating requirements
and the Life and Safety Critical Application Sales Policy:
Refer to: http://www.murata-ps.com/requirements/
Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other
technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply
the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without
notice.
© 2012 Murata Power Solutions, Inc.
www.murata-ps.com/support
KII_NM232DD.A04 Page 5 of 5