NM232DDC Isolated Dual EIA-232-D Transmitter and Receiver ELECTRICAL CHARACTERISTICS FEATURES n RoHS compliant n Single 5V supply n 50µW low power shutdown n TTL/CMOS Logic compatible n EIA-232-D/E and CCITT V.28 compatible n Dual transmitters and receivers n 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. 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 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 ELECTRICAL CHARACTERISTICS - EIA-232-D Parameter Test conditions 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 Supply current, ICC Shutdown current ICC ENABLE input current, IEN Shutdown input current, ISHUTDOWN MTTF1 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 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. www.cd4power.com KII_NM232DDC.1 Page of 5 NM232DDC 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 3065 7$$ 5*/ 5*/ (/% 3065 Figure 2 5PGSBNFHSPVOE Figure 1 shows a typical pcb track layout with a clear separation between the logic pin connections (pins 1-12) and the EIA-232-D connections (pins 13-24). Between the two sides of the layout is a track which can be connected to frame or equipment ground, this can be seen as the boundary between the logic and EIA-232-D side of the device. No other rules or speed conditions need to be applied other than to keep the two halves’ separation to a maximum. An example of a DTE application circuit is shown in figure 2. The schematic is illustrative of the way the NM232DDC may be connected to implement an isolated EIA‑232‑D interface with a typical UART and processor bus. Precise circuitry will depend on the application and in particular the use of the control lines shown will need to be altered to suit the situation. The ENABLE control line (pin 11), puts the receiver output pins 1 and 12 into a high impedance state when set to a high level. The shutdown control line (pin 3) sets the device into a shutdown power mode when it is at high logic level. The maximum power drawn in shutdown mode is 50µW, a low enough level for consideration in battery powered equipment. %# 7$$ $54 39% 59% 354 1SPDFTTPS#VT 5065 *40(/% 5*/ 3065 3065 5*/ 4)65%08/ 3*/ 3*/ &/"#-& 5065 " (/% % *TPMBUJPO#PVOEBSZ Figure 3 6"35 /.%% Where to use the NM232DDC The function of the NM232DDC is to provide an isolated signal path between a UART or similar device and the EIA-232-D interface ‘D’ connector, providing two receivers and two transmitters which can be used in a number of handshake modes. One receiver and transmitter will normally be used for the signal lines and the remaining pair will act as handshake lines. Figure 3 shows simply where the device will be connected. More complicated schemes for controlled signal interchange will require two or more such devices. As the devices are self contained no external DC/DC converter is required. The enable line provides a means for creating a communications bus where each NM232DDC can have a different logical address via a decoder. This would allow one UART to talk with many EIA-232-D connected interfaces (see figure 4). Figure 4 "EESFTT%FDPEFS 6"35 www.cd4power.com &/"#-& 59*/ 59065 &/"#-& 59*/ 59065 /.%%$ /.%%$ 39065 39*/ 39065 39*/ KII_NM232DDC.1 Page of 5 NM232DDC 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. C&D Technologies 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. 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.cd4power.com/rohs www.cd4power.com KII_NM232DDC.1 Page of 5 NM232DDC Isolated Dual EIA-232-D Transmitter and Receiver TYPICAL OPERATING CHARACTERISTICS POWER UP TO TRANSMITTER OUTPUT DELAY 7 SHUTDOWN TO POWER UP DELAY 7 7$$ 5065-0"%Lû 7 7$$7 74IVUEPXO 7 3-Lû $*Q' &BDI0VUQVU 7 NTEJW NTEJW 5' O'&*"4QFD-JNJU 53 3-Lû7$$7 $%5SBOTGPSNFS TRANSMITTER SLEW RATE VS TEMPERATURE 5SBOTNJUUFS4MFX3BUF7T 5SBOTNJUUFS4MFX3BUF7T TRANSMITTER SLEW RATE VS LOAD CAPACITANCE -PBE$BQBDJUBODFO' ENABLE & DISABLE TIMES VS TEMPERATURE 1SPQBHBUJPO%FMBZT 5JNFOT &OBCMF %JTBCMF 5FNQFSBUVSF¡$ www.cd4power.com WFFEHF WFFEHF 5FNQFSBUVSF¡$ PROPAGATION DELAY VS TEMPERATURE 55-WFFEHF 55-WFFEHF 55-WFFEHF 55-WFFEHF 5FNQFSBUVSF¡$ KII_NM232DDC.1 Page of 5 NM232DDC Isolated Dual EIA-232-D Transmitter and Receiver PACKAGE SPECIFICATIONS MECHANICAL DIMENSIONS ."9 /.%%$ 9::88 ."9 Weight: 5.5g TYP. All pins on a 0.1 (2.54) pitch. All dimensions are in inches (mm) ±0.01 (0.25). PIN CONNECTIONS ."9 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 All dimensions are in inches (mm) ±0.01 (0.25) C&D Technologies (NCL) Limited reserve the right to alter or improve the specification, internal design or manufacturing process at any time, without notice. Please check with your supplier or visit our website to ensure that you have the current and complete specification for your product before use. © C&D Technologies (NCL) Limited 2005 KII_NM232DDC.1 No part of this publication may be copied, transmitted or stored in a retrieval system or reproduced in any way including, but not limited to, photography, photocopy, magnetic or other recording means, without prior written permission from C&D Technologies (NCL) Limited. Instructions for use are available from www.cd4power.com www.cd4power.com 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 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 Tube Quantity : 15 C&D Technologies (NCL) Ltd Tanners Drive, Blakelands North Milton Keynes MK14 5BU, UK C&D Technologies, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151, USA Tel: +44 (0)1908 615232 Fax: +44 (0)1908 617545 email: [email protected] Tel: +1 (508) 339-3000 Fax: +1 (800) 233-2765 email: [email protected] KII_NM232DDC.1 Page of 5