iC-WE 3-CHANNEL 75 Ω LINE DRIVER Rev D1, Page 1/10 FEATURES Ë Ë Ë Ë Ë Ë Ë Ë Ë Ë Ë Ë Ë Ë Ë Ë APPLICATIONS 3 current-limited and short-circuit-proof push-pull drivers Built-in adaption to 75 Ω characteristic impedance High driver current of 300 mA at 24 V typ. Low saturation voltage up to 30 mA load current Short switching times and high slew rates by npn circuitry Wide driver supply range VB = 4.5 V to 30 V Internal free-wheeling diodes to VB and GND Schmitt trigger inputs with integrated pull-up current sources Inputs compatible to TTL and CMOS Inverting and non-inverting driver mode Bus capability due to Tri-State switching Compatible to EIA standard RS-422 Thermal shutdown with hysteresis Short-circuit-proof OC error output reports thermal shutdown or undervoltage at VCC or VB Driver disabled in case of fault extended temperature range of up to 130 °C in TSSOP20tp 4.4 mm package Ë Ë 24 V signal transfer Line driver in PLC environment PACKAGES SO20 TSSOP20 thermal pad SO16W BLOCK DIAGRAM 2 VB VCC 10 TNER 8 TRI 9 INV MODE ERROR NER 3 LOW VOLTAGE T.SHUTDOWN SO20 1 12 iC-WE E1 A1 11 A2 13 A3 18 CHAN 1 20 E2 CHAN 2 19 E3 CHAN 3 GND 4-7,14-17 Copyright © 2003, iC-Haus www.ichaus.com iC-WE 3-CHANNEL 75 Ω LINE DRIVER Rev D1, Page 2/10 DESCRIPTION The iC-WE is a high-speed monolithic line driver circuit for three independent channels with built-in characteristic impedance adaption for 75Ω lines. The push-pull outputs are designed for a high driver power of typ. 300mA at 24V. They are current-limited and short-circuit protected by thermal shut-down at overtemperature. Clamp diodes to VB and to GND protect the IC outputs against echoes of mismatched lines and against damage due to ESD according to MIL-STD-883. All inputs are Schmitt triggers and contain current sources from the 5V supply VCC which select a defined High Level without external wiring. Clamp diodes to VCC and to GND furnish ESD protection. Using the INVert input it is possible to switch all channels to inverting or non-inverting operation. This enables a data transmission with balanced line activation using two iC-WE devices. For bus applications the final stages can be forced to a high impedance state using the TRI-State input. The circuit monitors supply voltages VB and VCC as well as the chip temperature and switches all final stages to high impedance in the event of a fault. The NER output which is constructed as an open collector and is also short-circuit proof reports the fault via the connected line. The error input TNER can be linked to message outputs of other ICs and allows iC-WE to report a system fault message. If the supply voltage VCC cancels, NER becomes highly resistive. PACKAGES SO20, SO16W, TSSOP20 to JEDEC Standard PIN CONFIGURATION, top view (scale 2:1) SO20 SO16W TSSOP20tp 4.4 mm (low power applications only) PIN FUNCTIONS Name Function VCC E1 E2 E3 TRI INV TNER +5 V (± 10 %) Input Supply Voltage Channel 1 Input Channel 2 Input Channel 3 Input Tristate Input, high active Invert Mode Input, high active Error Input Name Function VB A1 A2 A3 NER GND +4.5..+30 V Driver Supply Voltage Channel 1 Output Channel 2 Output Channel 3 Output Error Output, low active Ground To enhance heat removal, the TSSOP20 package offers a large area pad to be soldered (a connection is only permitted to GND). iC-WE 3-CHANNEL 75 Ω LINE DRIVER Rev D1, Page 3/10 ABSOLUTE MAXIMUM RATINGS Values beyond which damage may occur; device operation is not guaranteed. Item Symbol Parameter Conditions Fig. Unit Min. Max. G001 VCC Supply Voltage 0 7 V G002 VB Driver Supply Voltage 0 32 V -800 800 mA -4 4 mA G003 I(A) Output Current in A1..3 G004 I(E) Input Current in E1..3, INV, TRI, TNER G005 V(NER) Voltage at NER 32 V G006 I(NER) Current in NER 25 mA E001 Vd() ESD Susceptibility at all pins 2 kV TG1 Tj Operating Junction Temperature -40 165 °C TG2 Ts Storage Temperature Range -40 150 °C MIL-STD-883, Method 3015, HBM 100 pF discharged through 1.5 kΩ THERMAL DATA Operating Conditions: VB = 4.5..30 V, VCC = 5 V ± 10 % Item Symbol Parameter Conditions Fig. Unit Min. T1 Ta Operating Ambient Temperature iC-WE SO16W Range iC-WE SO20, iC-WE TSSOP20 (extended range to -40 °C on request) T2 Rthja Thermal Resistance SO20 Chip to Ambient surface mounted with ca. 2 cm2 heat sink at leads (see Demo Board) T3 Rthja Thermal Resistance SO16W Chip to Ambient T4 Rthja Thermal Resistance TSSOP20 Chip to Ambient Typ. 125 130 °C °C 35 45 K/W surface mounted with ca. 2 cm2 heat sink at leads 55 75 K/W surface mounted, thermal pad soldered to ca. 2 cm2 heat sink 30 40 K/W All voltages are referenced to ground unless otherwise noted. All currents into the device pins are positive; all currents out of the device pins are negative. -25 -25 Max. iC-WE 3-CHANNEL 75 Ω LINE DRIVER Rev D1, Page 4/10 ELECTRICAL CHARACTERISTICS Operating Conditions: VB = 4.5..30 V, VCC = 5 V ± 10 %, Tj = -40..125 °C, unless otherwise noted Item Symbol Parameter Conditions Tj °C Fig. Unit Min. Typ. Max. Total Device 001 VCC Permissible Supply Voltage Range 4.5 5.5 V 002 I(VCC) Supply Current in VCC 24 23 21 19 mA mA mA mA 003 VB Permissible Driver Supply Voltage Range 30 V 004 I(VB)lo Supply Current in VB A1..3 = lo -40 27 80 125 8 6 5 4 16 14 12 11 24 21 18 15 mA mA mA mA 005 I(VB)hi Supply Current in VB A1..3 = hi, I(A1..3) = 0 -40 27 80 125 7 6 4 3 11 9 7 5 14 12 10 8 mA mA mA mA 006 I(VB)Tri Supply Current in VB, Outputs Tri-State TRI = hi, V(A1..3) = -0.3..VB + 0.3 V -40 1.2 1.4 mA mA -40 27 80 125 8 8 8 8 15 14 13 12 4.5 Driver Outputs A1..3 101 Vs()lo Saturation Voltage lo I(A) = 10 mA -40 27 80 125 1.15 1.05 1.05 1.0 V V V V 102 Vs()lo Saturation Voltage lo I(A) = 30 mA -40 27 80 125 1.55 1.5 1.5 1.4 V V V V 103 Vs()hi Saturation Voltage hi Vs()hi = VB - V(A), I(A) = -10 mA -40 27 80 125 1.1 1.0 1.0 0.9 V V V V 104 Vs()hi Saturation Voltage hi Vs()hi = VB - V(A), I(A) = -30 mA -40 27 80 125 1.45 1.4 1.4 1.3 V V V V 105 Isc()hi Short-Circuit Current hi VB = 30 V, V(A) = 0 -800 -500 -300 mA 106 Isc()lo Short-Circuit Current lo VB = 30 V, V(A) = VB 300 500 800 mA 107 Rout() Output Impedance VB = 30 V, V(A) = 15 V 40 75 100 Ω 108 SR()hi Slew-Rate hi VB = 30 V, CL = 100 pF 250 V/µs 109 SR()lo Slew-Rate lo VB = 30 V, CL = 100 pF 1500 V/µs 110 I0() Off-State Current TRI = hi, V(A) = 0..VB -50 50 µA 111 Vc()hi Clamp Voltage hi Vc()hi = V(A) - VB, TRI = hi, I(A) = 100 mA 0.4 1.5 V 112 Vc()lo Clamp Voltage lo TRI = hi, I(A) = -100 mA -1.5 -0.4 V 40 %VCC Inputs E1..3 201 Vt()hi Threshold Voltage hi 202 Vt()lo Threshold Voltage lo 203 Vt()hys Input Hysteresis 30 Vhys = Vt()hi - Vt()lo 35 %VCC 110 mV iC-WE 3-CHANNEL 75 Ω LINE DRIVER Rev D1, Page 5/10 ELECTRICAL CHARACTERISTICS Operating Conditions: VB = 4.5..30 V, VCC = 5 V ± 10 %, Tj = -40..125 °C, unless otherwise noted Item Symbol Parameter Conditions Tj °C Fig. Unit Min. Typ. Max. Inputs E1..3 (continued) 204 Ipu() Pull-Up Current V(E) = 0..VCC - 1 V 40 280 µA 205 Vc()hi Clamp Voltage hi Vc(E)hi = V(E) - VCC, I(E) = 4 mA 0.4 1.25 V 206 Vc()lo Clamp Voltage lo I(E) = -4 mA 207 tp(E-A) Propagation Delay E6 A -1.25 -0.4 V 200 300 330 330 ns ns ns 25 150 ns 80 125 208 ∆tp()INV Delay Skew E6 A for INV = lo vs. INV = hi Error Detection 301 VCCon Turn-on Threshold VCC 4.0 4.49 V 302 VCCoff Undervoltage Threshold at VCC decreasing Supply VCC 3.8 4.30 V 303 VCChys Hysteresis VCChys = VCCon - VCCoff 130 304 VBon Turn-on Threshold VB -40 4.49 4.6 4.35 305 VBoff Undervoltage Threshold at VB decreasing Supply VB 3.8 306 VBhys Hysteresis Vbhys = Vbon - VBoff 130 307 VCC Supply Voltage VCC for NER Operation 308 Vs(NER) Saturation Voltage lo at NER V(NER) = 0..30 V V(NER) = 0..30 V, NER = off or VCC < 0.3 V 311 Toff Thermal Shutdown Threshold 312 Ton Thermal Lock-on Threshold decreasing temperature 313 Thys Thermal Shutdown Hysteresis Thys = Toff - Ton V 5.5 V 0.7 V 30 mA 10 µA 150 175 °C 125 160 °C I(NER) = 5 mA 310 I0(NER) V V mV 2.6 309 Isc(NER) Short-Circuit Current lo in NER Collector Off-State Current in NER mV 4.0 4.0 5 20 °C Mode Select INV, TRI, TNER 401 Vt()hi Threshold Voltage hi 40 402 Vt()lo Threshold Voltage lo 403 Vt()hys Input Hysteresis Vt()hys = Vt()hi - Vt()lo 30 40 90 404 Ipu() Pull-Up Current V() = 0..VCC - 0.8 V 35 100 405 Vc()hi Clamp Voltage hi Vc()hi = V() - VCC, I() = 4 mA 406 Vc()lo Clamp Voltage lo I() = -4 mA 407 tpz (TRI-A) Propagation Delay TRI 6 A (A: lo,hi 6 Tri-State) RL(A) = 1 kΩ, RL(VCC,A) = 1 kΩ %VCC %VCC mV 250 µA 0.4 1.25 V -1.25 -0.4 V 5 µs 408 tp(INV-A) Propagation Delay INV 6 A 5 µs 409 tp(TNER- Propagation Delay TNER 6 NER NER) 5 µs iC-WE 3-CHANNEL 75 Ω LINE DRIVER Rev D1, Page 6/10 APPLICATIONS INFORMATION Line drivers for automation & control equipment connect digital signals with TTL or CMOS levels to 24 V systems via cables. Due to possible short-circuits, the drivers are current-limited and lock out in the event of overtemperature. 32 The maximum permissible signal frequency depends on the capacitive load of the outputs (cable length) or the 28 consequential power dissipation in the iC-WE. VB = 30V 24 Except for saturation voltages, the maximum output voltage corresponds to supply voltage VB when the output is open. Fig. 1 shows the typical DC output characteristic of a driver as a function of the load. The differential output resistance is about 75 Ω in broad ranges. Every open-circuited input is set to high level by an internal pull-up current source; an additional interconnection with VCC enhances the interference immunity. An input can be set to low level in response to a short-circuit or a resistance (<7.5 kΩ) to GND. A=High 20 16 12 8 4 0 0 50 100 150 200 250 300 Load Current [ mA ] 350 400 450 500 Fig. 1: Influence of load on output voltage LINE EFFECTS In PLC systems, data transmission with 24 V signals is generally conducted without a line termination with the characteristic impedance. A mismatched line end produces reflections which travel back and forth if there is no line adapter at the driver end either. The transmission is disrupted in case of high-speed pulse trains. In the iC-WE, signal reflection is prevented by an integrated characteristic impedance adapter, as shown in Fig. 2. During a pulse transmission the amplitude at the output of the iC-WE initially only increases to about one half the level of supply voltage VB since the internal resistance of the driver and the line characteristic impedance form a voltage divider. A wave with this amplitude is injected into the line and experiences a total reflection at the high impedance end of the line following a delay based on the length of the cable. The open or high impedance terminated end of the line exhibits a voltage maximum with double amplitude since outgoing and reflected wave are superimposed. Fig. 2: Reflections due to open line end Fig. 3: Pulse transmission and transit times Following a further delay the reflected wave also increases the driver output to twice the amplitude of the wave initially injected, possibly capped by the integrated diode suppressor circuit. The integrated characteristic impedance adaption in the iC-WE prevents another reflection and the voltage achieved is maintained along and at the end of the line. A mismatch between the iC-WE and the line influences the level of the initially injected wave and produces reflections at the driver end. The output signal may have a number of graduations. Nonetheless, lines with characteristic impedances in the range 40 to 150 Ω permit satisfactory transmissions. Fig. 3 shows the transmission of a short pulse of 1.5 µs. The signal delay to the end of the cable (here 100 m) is markedly longer than the transit time in the iC-WE driver. iC-WE 3-CHANNEL 75 Ω LINE DRIVER Rev D1, Page 7/10 EXAMPLE 1: Balanced data transmission over twisted-pair cables For balanced data transmission two iC-WE devices can be operated in parallel at the inputs with different programming of the individual INVert input. The OC error outputs NER are linked for the system fault message. +5 V +24 V 2 ERROR TRI-STATE VCC 10 8 9 TNER MODE CMOS/TTL INPUTS ERROR 12 VB NER ERROR 3 TRI LOW VOLTAGE T.SHUTDOWN INV SO20 1 +24 V LINE 100 m iC-WE A1 E1 PLC 11 CHAN1 20 A2 E2 13 CHAN2 19 A3 E3 18 CHAN3 GND D1 4-7,14-17 D2 +5 V D3 +24 V 2 VCC 10 8 9 TNER MODE ERROR NER 3 TRI LOW VOLTAGE T.SHUTDOWN INV SO20 1 12 VB iC-WE A1 E1 11 CHAN1 20 A2 E2 13 CHAN2 19 A3 E3 18 CHAN3 GND 4-7,14-17 Fig. 4: Balanced data transmission EXAMPLE 2: Incremental encoder Fig. 5 shows the iC-WE being used in an optical encoder system together with the iC-Haus incremental encoder iC-WT. The iC-WT device is an evaluating IC for photodiode arrays used in incremental lengths and angle measuring systems. It preprocesses the sensor signals for transmission with line driver iC-WE. At the receive end the programmable logic controller (PLC) interface can be via optocoupler. The preprocessed sensor signals are transmitted over cable by the iC-WE with asymmetrical activation. A high interference immunity is achieved as a result of the high output amplitude and the integrated characteristic adaption of the iC-WE. The 24 V power supply is conducted over the cable from the PLC end. A voltage regulator generates the 5 V supply to the encoder system. It is favourable to use the iC-WD switching regulator device instead of aconventional voltage regulator. This switched-mode power supply IC operates from 8 to 30 V input voltage and contains two 5 V post regulators. Analog and digital devices can thus receive separate supply voltages. iC-WE 3-CHANNEL 75 Ω LINE DRIVER Rev D1, Page 8/10 The error input TNER on the iC-WE can be utilized to conduct a fault signal from the incremental encoder to the output NER and then to the receiver. For protection against voltage peaks from the cable, the state input TRI is wired to the RC combination R1, R2 and C5, which can be dimensioned for levels of up to 30 V at the PLC. Fig. 5: Line driver iC-WE in the incremental encoder PRINTED CIRCUIT BOARD LAYOUT The iC-WE's 8 GND terminals (pins 4-7 and 14-17) simultaneously function as thermal conductors and must be soldered to copper tracks with the greatest possible area of the PCB to ensure proper heat dissipation. Blocking capacitors to smooth the local IC supply voltages must be connected to VCC, VB and GND pins at the shortest possible intervals. C1 on the regulator in Fig. 3 is only necessary if the voltage regulator is more than about 3 cm away from the other ICs. C3 should not be less than 1 µF in order to block the 24 V supply. iC-WE 3-CHANNEL 75 Ω LINE DRIVER Rev D1, Page 9/10 DEMO BOARD The device iC-WE with SO20 package is equipped with a Demo Board for test purposes. Figures 6 to 8 show the wiring as well as the top and bottom layout of the test PCB. CVB 1µF VB C02 1µF/40V IC2 MC7805C IN OUT GND CVCC 1µF VCC C01 1µF/16V D01 LED 2 VCC TNER TRI INV 10 8 9 TNER MODE E1 VB NER ERROR 3 D02 1N4148 NER TRI LOW VOLTAGE T.SHUTDOWN INV iC-WE 1 R01 470Ω 12 SO20 A1 E1 11 A1 CHAN1 E2 20 A2 E2 13 A2 CHAN2 E3 19 A3 E3 18 A3 CHAN3 GND GND 4-7,14-17 Fig. 6: Schematic diagram of the Demo Board Fig. 7: Demo Board (components side) Fig. 8: Demo Board (solder dip side) This specification is for a newly developed product. iC-Haus therefore reserves the right to modify data without further notice. Please contact us to ascertain the current data. The data specified is intended solely for the purpose of product description and is not to be deemed guaranteed in a legal sense. Any claims for damage against us - regardless of the legal basis - are excluded unless we are guilty of premeditation or gross negligence. We do not assume any guarantee that the specified circuits or procedures are free of copyrights of third parties. Copying - even as an excerpt - is only permitted with the approval of the publisher and precise reference to source. iC-WE 3-CHANNEL 75 Ω LINE DRIVER Rev D1, Page 10/10 ORDERING INFORMATION Type Package iC-WE SO20 iC-WE SO20 SO16W iC-WE SO16W TSSOP20tp 4.4 mm iC-WE TSSOP20 WE Demo Board Order designation WE DEMO For information about prices, terms of delivery, options for other case types, etc., please contact: iC-Haus GmbH Am Kuemmerling 18 D-55294 Bodenheim GERMANY Tel +49-6135-9292-0 Fax +49-6135-9292-192 http://www.ichaus.com