ADM1487. Preliminary Technical Data. PRELIMINARY TECHNICAL DATA Ultra-Low Power RS-485/RS-422 Transceiver with Low EMI and +/-10kV ESD Protection

Transcription

1 a PELIMINY TECHNICL DT Ultra-Low Power S-/S-22 Transceiver with Low EMI and +/-0kV ESD Protection Preliminary Technical Data DM7 FETUES Low Power - 20µ Max ICC with Driver Disabled High Input Impedance Up to 26 Transceivers on us Low-Current (µ) Shutdown Mode Slew ate Control for Error-Free Data Transmission and Low EMI ±0kV ESD Protection (Human ody Model) on S- I/O pins Thermal Protection of Driver Glitch-Free Driver Power-Up llows Hot Connection Driver Maintains High Output Impedance with Power Off Wide Common-Mode ange llows ±7V Ground Differences etween Devices Pin-Compatible with Industry Standard 776 GENEL SCIPTION The DM7 is an ultra-low power S-/S-22 transceiver consisting of one driver and one receiver per package. Quiescent operating current is typically 0µ and µ in shutdown mode. The driver and receiver both have three-state outputs. This allows multiple drivers to be connected to an S-/S-22 bus, or several receiver outputs to be connected to a serial data bus. The driver will maintain a high-impedance output state even with power off, while the receiver features fail-safe operation that guarantees a logic high output if the inputs are left open-circuit. The device has slew-rate limited drivers to minimize electromagnetic interference (EMI) and reduce reflections caused by incorrectly terminated cables. PPLICTIONS attery-powered S-/S-22 Systems Level Translation FUNCTIONL LOCK DIGM O DI D GND DM7 EV. PrC 0/02 Information furnished by nalog Devices is believed to be accurate and reliable. However, no responsibility is assumed by nalog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of nalog Devices. One Technology Way, P.O. ox 906, Norwood, M , U.S.. Tel: 7/ Fax: 7/ nalog Devices, Inc., 2002

2 DM7 DM7 SPECIFICTIONS PELIMINY TECHNICL DT DC ELECTICL CHCTEISTICS ( = +V ±%, T = 0 C TO +70 C, UNLESS OTHEWISE NOTED) Parameter Min Typ Max Units Test Conditions/Comments Differential Driver Output Voltage,V OD V Unloaded, I O = 0 Differential Driver Output Voltage, V OD2 2.0 V Figure, = 0 (S-22). V Figure, = 27 (S-) Change in Magnitude of Driver 0.2 V Figure, = 27 or = 0 Differential Output Voltage for Complementary Output States, VOD Driver Common-Mode Output 3 V Figure, = 27 or = 0 Voltage, V OC Change in Magnitude of Driver 0.2 V = 27 or = 0 Common-Mode Output Voltage for Complementary Output States, V OC Input High Voltage (, DI, E), V IH 2 V Input Low Voltage (, DI, E), V IL 0. V Input Current (, DI, E), I IN ±2 µ Input Current (, ), I IN m = 0, = 0V or.2v, V IN = 2V -0. m = 0, = 0V or.2v, V IN = 7V Differential Input Threshold Voltage V 7V V CM 2V for eceiver, V TH eceiver Input Hysteresis, V TH mv V CM = 0V eceiver Output High Voltage, V OH 3. V I O =-m, V ID = 200mV eceiver Output Low Voltage, V OL 0. V I O = m, V ID = 200mV Three-State (High Impedance) Output ± µ = Max, 0.V Vo 2.V Current at eceive, I OZ eceiver Input esistance, IN k 7V V CM 2V Supply Current, I CC µ No Load, Output Enabled 0 20 µ No Load, Output Disabled Supply Current in Shutdown Mode, I SHDN 0 µ = 0V, E = Driver Short-Circuit Ourrent, I OSD 3 20 m V OUT = HIGH, 7V V O 2V Driver Short-Circuit Ourrent, I OSD m V OUT = LOW, 7V Vo 2V eceiver Short-Circuit Current, I OS 7 m 0V V O V OC 2 ev. PrC

3 DM7 SPECIFICTIONS (continued) ELECTICL CHCTEISTICS (VCC = +V ±%, T = -0 C TO + C, UNLESS OTHEWISE NOTED) Parameter Min Typ Max Units Test Conditions/Comments Differential Driver Output Voltage, V OD V Unloaded, I O = 0 Differential Driver Output Voltage, V OD2 2.0 V Figure, = 0 (S-22). V Figure, = 27 (S-) DM7 Driver Common-Mode 3 V Figure, = 27 or = 0 Output Voltage, V OC Differential Input Threshold V 7V V CM 2V Voltage for eceiver, V TH eceiver Input Hysteresis, V TH mv V CM = 0V Supply Current, I CC µ No Load, Output Enabled 0 20 µ No Load, Output Disabled Supply Current in Shutdown Mode, I SHDN 0 µ = 0V, E = Driver Input to Output High, t DPLH ns Figures 2, 3, DIFF =, Driver Input to Output Low, t DPHL ns Figures 2, 3, DIFF =, Driver Output to Output, t SKEW ns Figures 2, 3, DIFF =, Driver ise or Fall Time, t D, t DF ns Figures 2, 3, DIFF =, eceiver Input to Output High, t PLH ns Figures 2,, DIFF =, eceiver Input to Output Low, t HL ns Figures 2,, DIFF =, Differential eceiver Skew, t SKD 3 ns Figures 2,, DIFF =, t PLH -t PHL Maximum Data ate, f MX 20 kbps SWITCHING CHCTEISTICS ( = +V ±%, T = -0 C TO + C, UNLESS OTHEWISE NOTED) Parameter Min Typ Max Units Test Conditions/Comments Driver Input to Output High, t DPLH ns Figures 2, 3, DIFF =, Driver Input to Output, t DPHL ns Figures 2, 3, DIFF =, Driver Output to Output, t SKEW ns Figures 2, 3, DIFF =, Driver ise or Fall Time, t D, t DF ns Figures 2, 3, DIFF =, Driver Enable to Output High, t DZH ns Figures, 6, C L = 00pF, S2 Closed Driver Enable to Output Low, t DZL ns Figures, 6, C L = 00pF, S Closed Driver Disable Time from Low, t DLZ 0 00 ns Figures, 6, C L = lpf, S Closed ev. PrC 3

4 DM7 PELIMINY TECHNICL DT DM7 SPECIFICTIONS (continued) SWITCHING CHCTEISTICS ( = +V ±%, T = -0 C TO + C, UNLESS OTHEWISE NOTED) Parameter Min Typ Max Units Test Conditions/Comments Driver Disable Time from High, t DHZ 0 00 ns Figures, 6, C L = lpf, S2 Closed eceiver Input to Output, t PLH ns Figures.2,, DIFF =, eceiver Input to Output Low, t PHL ns Figures.2,, DIFF =, DifferentialeceiverSkew, t SKD 3 ns Figures.2,, DIFF =, t PLH -t PHL eceiver Enable to Output Low, t ZL 20 0 ns Figures 7,, C L = lpf, S Closed eceiver Enable to Output High, t ZH 20 0 ns Figures 7,, C L = lpf, S2 Closed eceiver Disable from Low, t LZ 20 0 ns Figures 7,, C L = lpf, S Closed eceiver Disable from High, t HZ 20 0 ns Figures 7,, C L = lpf, S2 Closed Maximum Data ate, f MX 20 kbps Time to Shutdown, t SHDN ns = 0, E = low to high transition Driver Enable from Shutdown to 2000 ns Figures, 6, C L = 00pF, S2 Closed Output High, t DZH(SHDN) Driver Enable from Shutdown to 2000 ns Figures, 6, C L = 00pF, S Closed Output Low, t DZL(SHDN) eceiver Enable from Shutdown to 2000 ns Figures 7,, C L = lpf, S2 Closed Output High, t ZH(SHDN) eceiver Enable from Shutdown to 2000 ns Figures 7,, C L = lpf, S Closed Output Low, t ZL(SHDN) NOTES bsolute maximum ratings are those beyond which the safety of the device cannot be guaranfeed. 2 ll currents into device pins are positive; all currents out ot device pins are negative. ll voltages are referenced to device ground unless otherwise specified. 3 ll typicals are given for Vcc = V and Tp = 2 C. The DM7 is not tested and is not quality-assurance sampled at -0 C and at C. These specifications are guaranteed by design, correlation, andlor inference from 0 C, 2 C and/or 70 C tests. SOLUTE MXIMUM TINGS Supply Voltage (Vcc) V Control Input Voltage V to Vcc + 0.V Driver Input Voltage V to Vcc + 0.V Driver Output Voltage ±V eceiver InputVoltage ±V eceiver Output Voltage V to Vcc + 0.V Operating Temperature ange C T 70 C Lead Temperature (Soldering, 0 sec) C *Stresses above those listed under bsolute Maximum atings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. THEML CHCTEISTICS -Pin Plastic DIP Package θ J = tbd K/Watt, θ JC = tbd K/Watt -Pin Plastic SO Package θ J = tbd K/Watt, θ JC = tbd K/Watt PIN CONFIGUTION O DM7 7 TOP VIEW (Not to Scale) 6 OING INFOMTION DI 2 3 Model Temperature ange Package Option DM7JN 0 C to +70 C Pin Plastic DIP DM7J 0 C to +70 C Pin SO DM7N 0 C to + C Pin Plastic DIP DM7 0 C to + C Pin SO GND ev. PrC

5 DM7 TEST CICUITS ND TIMING DM7 V OD V OC OUTPUT UN TEST C L pf TEST POINT 00V S S2 Figure. Driver DC Load Test Circuit 3V Figure. Test Load for Driver Enable/Disable Time Test DI D V OD2 DIFF C L C L2 pf O 3V 0V V, V OL # # t DZL(SHDN), t DZL 2.3V OUTPUT NOMLLY LOW t DLZ.V V OL + 0.V Figure 2. Driver/eceiver Timing Test Circuit # # 3V DI.V 0V V OH, OUTPUT NOMLLY HIGH 2.3 V OL V t DZH(SHDN), t DZH t DHZ Figure 6. Driver Enable and Disable Times V OH - 0.V t DPLH t DPHL V 0 V DIFF 0V -V 0 V 0 V 0 /2 0% 90% V DIFF = V - V 90% 0% TEST POINT kv S t D t SKEW = t DPLH -t DPHL t DF O Figure 3. Driver Propagation Delays C L pf S2 # # kv Figure 7. Test Load for eceiver Enable/Disable Time Test Figure. eceiver Propagation Delays # #. V V. OUTPUT NOMLLY LOW V 0.V V OUTPUT NOMLLY HIGH. V 0.V Figure. eceiver Enable and Disable Delay Times ev. PrC

6 DM7 PELIMINY TECHNICL DT DM7 TYPICL PEFOMNCE CHCTEISTICS W ITING D T W ITING D T W ITING D T TPC. No-load Supply Current vs. Temperature TPC2. Output Current vs. eceiver Output High Voltage TPC3. Output Current vs. eceiver Output Low Voltage W ITING D T W ITING D T W ITING D T TPC. eceiver Output High Voltage vs. Temperature TPC. eceiver Output Low Voltage vs. Temperature TPC6. Shutdown Current vs. Temperature PIN FUNCTION SCIPTION Pin Mnemonic Description O eceiver Output. When E is low and - (more positive than) 200mV, O will be high. When E is low and - (more negative than) 200mV, O will be low. 2 E eceiver Output Enable. Take E low to enable O; O is high impedance when E is high. Take E high and low to enter low-power shutdown mode. 3 D E Driver Output Enable. Take high to enable driver outputs. These outputs are high impedance when is low. Take E high and low to enter low-power shutdown mode. D I Driver Input. With high, a low on DI forces non-inverting output low and inverting output high. Similarly, a high on DI forces non-inverting output high and inverting output low. GND Ground 6 Non-Inverting eceiver Input and Non-Inverting Driver Output 7 Inverting eceiver Input and Inverting Driver Output Positive Supply.7V = =.2V 6 ev. PrC

7 DM7 VICE TUTH TLES TNSMITTING INPUTS OUTPUTS E DI Z Y X 0 X X High-Z High-Z 0 X Shutdown* X = Don t care CICUIT SCIPTION The DM7 is a differential input, differential output transceiver designed S-/S-22 serial data communications over twisted-pair cables. It is a half-duplex device intended for alternate transmission and reception of data over a single twisted-pair cable, and the driver outputs and receiver inputs are internally linked and brought out to a single pair of pins. Its principal features include ultra-low power operation, a controlled slew-rate driver that minimizes electromagnetic interference (EMI) and signals reflections due to incorrectly terminated lines, and high input impedance that allows up to 26 receivers to be connected to a bus. THEE-STTE US CONNECTION The DM7 has a Driver Enable pin () that enables the driver outputs when taken high or puts the driver outputs into a high-impedance state when taken low. This allows several driver outputs to be connected to an S-22/ S- bus. Similarly, the device has a (active-low) eceiver Enable pin (E). Taking this low enables the receiver, while taking it high puts the receiver outputs into a high-impedance state. This allows several receiver outputs to be connected to a serial data bus. The input impedance of the device is 96k, which is times higher than the standard S- load of 2k. standard driver can driver 32 standard loads, so up to 26 DM7 receivers, or a combination of DM7 and other devices up to 32 unit loads, may be connected to an S-22/S bus driven by a single driver. LOW POWE OPETION The DM7 draws very little supply current (typically 0µ) when the driver outputs are disabled or unloaded. This will increase by up to 72µ if the driver outputs are enabled (but unloaded) and applying the maximum output swing of V across the receiver input resistors. However, in practical applications with the device driving and S-/S22 cable or bus, the current drain is dominated by the current sourced into the line termination resistors and any other devices on the bus. With a half-termination (20 load) between the driver outputs, the load current can be in excess of 3m as the drivers force a minimum of.v across the line, and can be greater than 2m with a fully terminated 60 line attached. ECEIVING INPUTS OUTPUT E - O 0 X 0.2V 0 X -0.2V 0 0 X Open/shorted 0 X Shutdown* *In shutdown mode, driver and receiver outputs high impedance SHUTDOWN MO If E is taken high while is taken low, the device will enter a low-power shutdown mode, in which the supply current is typically µ. If the driver outputs are active immediately before shutdown ( high), the supply current will not drop to µ until the driver outputs have settled to their three-state mode, which can take up to 2.6µs worst-case. If is already low and shutdown is entered by taking E high, the supply current will drop to µ very quickly. When E is taken low and/or is takem high, the device will wake up within 3.µs. If shutdown mode is not used, the fact that is activehigh and E is active-low offers a convenient way of switching the device between transmit and receive, by tying and E together. This is useful, for example, in applications using half duplex operation and where several receiver outputs are connected to a serial bus. The device is guaranteed not to enter shutdown mode if and E are driven in this way. If is low and E is high for less than 0ns the device will not enter shutdown. If is low and E is high for greater than 600ns, the device is guaranteed to enter shutdown. ECEIVE INPUTS The DM7 receiver has an input common-mode range covering the entire S- range of 7V to 2V. Internal 96k input resistors from each line terminal to ground provide a / unit load to the S bus. Differential signals greater than ±200mV within the specified input common-mode range are converted to a TTLcompatible logic signal at the receiver output. small amount of input hysteresis is included to minimize the effects of noise on the line signals. If the line is terminated or the receiver inputs are shorted together, the receiver output will retain the last valid line signal due to the mv of hysteresis incorporated in the receiver circuit. If the receiver inputs are left floating (unterminated), an internal pull-up of 0µ at the input will force the receiver output to a guranteed high output state. DIVE OUTPUT STGE The S- specification requires that a transceiver withstand common-mode voltages of up to 2V above or 7V below system ground at the S- line connections. In addition, the transceiver must be protected against both ESD and latch-up. This precludes the use of conventional ev. PrC 7

8 DM7 PELIMINY TECHNICL DT CMOS outout stages, which include parasitic diodes from their driver outputs to each supply rail and can latch up when these diodes conduct. SCHOTTKY EVESE-ISED WHEN OUTPUT > +V D PSITIC DIO D P PSITIC DIO D P SCHOTTKY EVESE-ISED WHEN OUTPUT < GND - V D Figure 9. DM7 Driver Output Stage The DM7 output includes Schottky diodes in series with the positive supply to the drain of the P-channel output device and in series with the drain of the N-channel output device. These diodes prevent the P-channel's parasitic diode from conducting when the output voltage exceeds and prevent the N-channel's parasitic diode from conducting when the output voltage falls below ground. SLEW TE CONTOL The driver output stage of the DM7 has a controlled slew rate to minmize signal reflections on incorrectly terminated lines and to reduce electromagnetic interference (EMI). CUENT LIMIT ND THEML SHUTDOWN The DM7 incorporates two protection mechanisms to guard the drivers against short-circuits, bus contention or other fault conditions. The first is a current-limited output stage that protects the driver against short-circuits over the entire common-mode voltage range by limiting the output current to about 70m. Under extreme fault condtions where the current limit is not effective, a thermal shutdown circuit puts the driver outputs into a high-impedance state if the die temperature exceeds 0 C, and does not turn them back on until the temperature has fallen to 30 C. ENHNCED ESD POTECTION ll nalog Devices parts incorporate protection against electrostatic discharge (ESD) to protect the devices during handling, assembly and normal operation. In addition, the DM7 has enhanced ESD protection up to ±0kV on the and I/O pins to protect against severe operational conditions such as line transients, connection and disconnection. PPLICTION INFOMTION Figure 0 shows a typical application of the DM7. This is a half-duplex S-/S-22 network. Up to 2 additional DM7s can be connected along the cable (termination resistors are only required at each end). ECEIVE OUTPUT (O) ECEIVE ENLE DIVE ( ENLE DT () IN (DI) 2 3 D DM7 7 6 T +V (V 00n CC ) CLE TEMINTED T ENDS 6 T 7 +V ( ) 00n DDITIONL DM7s D DM7 3 2 DI O Figure 0. Typical Half-Duplex S-/S-22 Network -Pin Plastic Dual-In-Line Package (N-) OUTLINE DIMENSIONS Dimensions shown in inches and (mm). -Pin SO Package (-) 0.30 (0.92) 0.3 (.) 0.96 (.00) 0.90 (.0) 0.20 (.33) MX PIN 0.20 (7.) 0.20 (6.0) (.2) 0.0 (0.3) 0.60 (.06) 0. (2.93) (0.) (.77) 0.0 (0.36) (2.) 0.0 (.) SC 0.30 (3.30) MIN SETING PLNE 0.32 (.2) (7.62) 0.0 (0.3) 0.00 (0.20) 0.9 (.9) 0. (2.93) 0.20 (6.20) 0.22 (.0) (0.2) (0.0) SETING PLNE PIN (.27) SC 0.7 (.00) 0.97 (3.0) 0.02 (2.9) 0.09 (2.39) (0.9) (0.2) 0.03 (0.3) (0.9) (0.0) (0.2) x (.27) (0.) ev. PrC