HD26LS32 Quadruple Differential Line Receivers With 3 State Outputs ADE-205-577 (Z) 1st. Edition Dec. 2000 Description The HD26LS32 features quadruple line receivers designed to meet the specs of EIA standard RS-422A and RS-423. This device operates from a single 5 V power supply. The enable function is common to all four receivers and offers a choice of active high or active low input. Fail safe design ensures that if the inputs are open, the outputs will always be high. Logic Diagram 1A 1B 2A 2B 3A 3B 4A 4B Enable G Enable G 1Y 2Y 3Y 4Y HD26LS32 Pin Arrangement 1B 1 16 VCC 1A 2 15 4B 1Y 3 14 4A Enable G 4 13 4Y 2Y 5 12 Enable G 2A 6 11 3Y 2B 7 10 3A GND 8 9 3B (Top view) Function Table Differential Input Enable A–B G G Y VID ≥ VTH H X H X L H H X ? X L ? H X L X L L L H Z VTL < VID < VTH VID ≤ VTL X H L X ? Z 2 : : : : : High level Low level Immaterial Irrelevant High impedance Output HD26LS32 Absolute Maximum Ratings Item Symbol Supply Voltage VCC* In Phase Input Voltage VIC 1 2 Ratings Unit 7.0 V ±25 V ±25 V Differential Input Voltage VID* Enable Input Voltage VIN 7 V Output Sink Current Iout 50 mA Continuous Total Dissipation PT 1 W Operating Temperature Range Topr 0 to +70 °C Storage Temperature Range Tstg –65 to 150 °C Notes: 1. All voltage values except for differential input voltage are with respect to network ground terminal. 2. Differential input voltage is measured at the noninverting input with respect to the corresponding inverting onput. 3. The absolute maximum ratings are values which must not individually be exceeded, and furthermore, no two of which may be realized at the same time. Recommended Operating Conditions Item Symbol Min Typ Max Unit Supply Voltage VCC 4.75 5.00 5.25 V In Phase Input Voltage VIC — — ±7.0 V Output Current I OH — — –440 µA I OL — — 8 mA Topr 0 — 70 °C Operating Temperature 3 HD26LS32 Electrical Characteristics (Ta = 0 to +70°C) Item Symbol Min Typ*1 Max Unit Conditions Differential Input High Threshold Voltage VTH — — 0.2 V Differential Input Low VTL — — –0.2 VOL = 0.4 V, IOL = 4 mA Threshold Voltage — — –0.2 VOL = 0.45 V, IOL = 8 mA Input Hysteresis*2 VTH – VTL — 30 — mV Enable Input Voltage VIH 2.0 — — V VIL — — 0.8 Enable Input Clamp Voltage VIK — — 1.5 VCC = 4.75 V, IIN = –18 mA Output Voltage VOH 2.7 — — VCC = 4.75 V VID = 1 V, IOH = –440 µA VOL — — 0.4 VIL (G) = 0.8 V VID = –1 V, IOL = 4 mA — — 0.45 — — 20 — — –20 — — 2.3 — — 2.8 I I (EN) — — 100 I IH — — 20 VI = 2.7 V I IL — — –0.36 mA VI = 0.4 V 6 9.8 — kΩ VIC = –15 to +15 V (Other Inputs AC GND) –15 — –85 mA VCC = 5.25 V — 52 70 Off State (High I OZ Impedance) Output Current Line Input Current Enable Input Current Input Resistance II ri Short Circuit Output Current I OS* Supply Current I CC 3 VIC = –7 to +7 V VOH = 2.7 V, IOH = –440 µA VID = –1 V, IOL = 8 mA µA VCC = 5.25 V VO = 2.4 V VO = 0.4 V mA VI = 15 V, Other Inputs –10 to +15 V VI = –15 V, Other Inputs –15 to +10 V µA VI = 5.5 V VCC = 5.25 V, VI = 0 V (All Outputs Disable) Notes: 1. All typical values are at V CC = 5 V, Ta = 25°C,VIC = 0. 2. Hysteresis is the differential between the positive going input threshold voltage and the negative going input threshold voltage. 3. Not more than one output should be shorted at a time. Switching Characteristics (VCC = 5 V, Ta = 25°C) TItem Symbol Min typ Max Unit Conditions Propagation Delay Time t PLH , t PHL — 17 25 ns CL = 15 pF Output Enable Time t ZH , t ZL — 15 22 Output Disable Time t HZ — 15 22 t LZ — 20 30 4 CL = 5 pF HD26LS32 1. tPLH, tPHL Test circuit VCC Input Output 2 kΩ Pulse Generator CL *1 5 kΩ *3 *2 2V Waveforms 2.5 V Input A 0V 0V –2.5 V 2.5 V Input B 0V 0V –2.5 V t PLH t PHL VOH Output 1.3 V 1.3 V VOL 5 HD26LS32 2. tHZ, tZH Test circuit VCC Output 2 kΩ S1 2.5 V CL 5 kΩ *3 *2 Input Pulse Generator *1 *4 2V Waveforms 3V Enable G 1.3 V 1.3 V 0V 3V 1.3 V 1.3 V Enable G 0V S1 : Open t ZH Output 6 1.3 V S1 : Closed t HZ 0.5 V VOH 1.4 V 0V HD26LS32 3. tLZ, tZL Test circuit VCC Output 2 kΩ –2.5 V CL 5 kΩ Input Pulse Generator S2 2V Waveforms 3V Enable 1.3 V 1.3 V 0V 3V 1.3 V 1.3 V Enable G 0V S2 : Open t ZL S2 : Closed t LZ VOH Output 1.4 V 1.3 V 0.5 V Notes: 1. 2. 3. 4. VOL The pulse generator has the following characteristics : PRR = 1 MHz, 50 % duty cycle, tr ≤ 15 ns, tf ≤ 6 ns, Zout = 50 Ω. CL includes probe and jig capacitance. All diodes are 1S2074 (H) To test G input,ground G input and apply an inverted input waveform. 7 HD26LS32 HD26LS32 Line Receiver Applications The HD26LS32 is a line receiver that meets the EIA RS-422A and RS-423A conditions. It has a high inphase input voltage range, both positive and negative, enabling highly reliable transmission to be performed even in noisy environments. Its main features are listed below. • • • • • • Operates on a single 5 V power supply. Three-state output On-chip fail-safe circuit ±7 V in-phase input voltage range ±200 mV input sensitivity Minimum 6 k input resistance A block diagram is shown in figure 1. The enable function is common to all four drivers, and either activehigh or active-low input can be selected. When exchange is carried out using a party line system, it is better to keep the receiver input bias current constituting the driver load small, as this allows more receivers to be connected. Consequently, whereas an input resistance of 4 k or above is stipulated in RS-422A and RS-423A, the HD26LS32 has been designed to allow a greater margin, with a minimum resistance of 6 k . Figure 2 shows the input current characteristics of the HD26LS32. The shaded areas in the graph indicate the input current allowable range stipulated in RS-422A and RS423A. HD26LS32 output is LS-TTL compatible and has a three-state function, enabling the output to be placed in the high-impedance state, and so making the device suitable for bus line type applications. With an in-phase input voltage range of ±7 V and a ±200 mV input sensitivity, the HD26LS32 can withstand use in noisy environments. Also, since signals sent over a long-distance transmission line require a long transition time, it also takes a long time to cross the receiver’s input threshold level. Therefore, the input is provided with hysteresis of around 30 mV to prevent receiver output misoperation due to noise. An example of input hysteresis is shown in figure 3. The fail-safe function consists of resistances R connecting input A to VCC and input B to GND, as shown in figure 4. 8 HD26LS32 This circuit provides for the receiver input section to be pulled up or down by a high resistance that prevents it from becoming a driver load so that the output goes high in the event of a transmission line breakage or connector detachment. When the input pin is placed in the open state by the pull-up/pull-down resistance, the differential input voltage VID is as follows: VID: (VIA – VIB) ≥ 0.2 V and the output is fixed high. However, if the receiver-side termination resistance remains connected despite a line breakage or connector detachment, the output will be undetermined (figure 5). 1A 1Y 1B 2A 2Y 2B 3A 3Y 3B 4A 4Y 4B Enable G Enable G Figure 1 HD26LS32 Block Diagram 5 Input Current Iin (mA) 4 3 +3.25 mA Ta = 25°C C VC 2 C 1 0 = = 0V 5V 5.2 VC –10 V –3 V +3 V +10 V –1 –2 –3 –4 –3.25 mA –5 –25 –20 –15 –10 –5 0 5 10 15 20 25 Input Voltage Vin (V) Figure 2 Input Voltage vs. Input Current Characteristics 9 HD26LS32 Output Voltage Vout (V) 5 VCC = 5 V, Ta = 25°C Input applied to pin A, with pin B as reference 4 3 VIC = –7 V 2 VIC = 0 V VIC = +7 V 1 0 –100 –80 –60 –40 –20 0 20 40 60 80 100 Differential Input Voltage VID (mV) Figure 3 Differential Input Voltage vs. Output Voltage Characteristics VCC A B R Y R Figure 4 Fail-Safe Function This is because, since the termination resistance is normally matched to the transmission line characteristic impedance, the value falls to several tens of hundreds of ohms, and the differential input pins are shorted by this termination resistance. That is, the differential input voltage VID comes within the range VID: –0.2 V < VIA – VIB < 0.2 V and the output becomes undetermined. To prevent this, resistance R1 is inserted in series with the transmission line as shown in figure 6, minimizing the effect of the termination resistance. Resistance R 2 is added to increase the current flowing between the termination resistance and R 1, enabling the value of R1 to be kept small. Inserting resistances R 1 and R2 in this way provides for the differential input voltage VID to become 200 mV or higher, but the following points must be noted. • Smallest possible R1 value If this value is large, the receiver input sensitivity will fall. • Largest possible R2 value If this value is small, the load on the driver will be large. Figure 7 shows experimental differential input voltages for variations in R1 and R2. 10 HD26LS32 Undetermined RT "H" RT Figure 5 Examples of Transmission Line Disconnection R1 Driver VCC R2 Receiver RT R1 R2 Figure 6 Method of Enhancing Fail-Safe Function kΩ 0k Ω 50 =3 300 kΩ R2 = ∞ VCC 2 0.5 Ω 0k 10 R Differential Input Voltage VID (V) 0.6 VCC = 5 V Ta = 25°C R1 0.4 100 Ω 0.3 R2 VID R1 R2 0.2 0.1 0 5 10 15 R1 (kΩ) Figure 7 R 1, R2 vs. Differential Input Voltage 11 HD26LS32 RS-442A Interface Standard Applications Figure 9 shows sample operation waveforms at various points with 1200 m and 12 m cable lengths. 1. Unidirectional Transmission (1 : 1 Configuration) Driver B Data A input D F Data output RT C Receiver E Figure 8 1 : 1 Unidirectional Transmission Line : 1200 m Frequency : 100 kHz Duty : 50% RT : 100 Ω A D GND GND H : 5 µs/div V : 2 V/div E GND B GND C F GND GND Line : 12 m Frequency : 10 MHz Duty : 50% RT : 100 Ω A D GND GND E B GND GND C F GND GND Figure 9 Sample Transmission Waveforms 12 H : 50 ns/div V : 2 V/div HD26LS32 2. Unidirectional Transmission (1 : n Configuration) Driver Data input RT Data output RT Enable Data output Receiver Data output Data output Figure 10 1 : n Unidirectional Transmission With this connection method, n receivers are connected for one driver. In the RS-422A standard, ten receivers can be connected simultaneously for one driver. Conversely, it is also possible to connect one receiver for n drivers. 3. Bidirectional Transmission Driver Data I/O Receiver RT Data I/O RT Enable Enable Receiver Driver Figure 11 Bidirectional Transmission When bidirectional data exchange is performed using a combination of the HD26LS31 and HD26LS32, since either high or low output control is possible, using complementary enable inputs for the driver and receiver makes it easy to configure the kind of combination illustrated in figure 11 . Extending this combination makes it possible to exchange n-bit data simultaneously, and handle a party line system. 13 HD26LS32 Package Dimensions Unit: mm 19.20 20.00 Max 6.30 9 1 7.40 Max 16 8 1.3 0.48 ± 0.10 7.62 2.54 Min 5.06 Max 2.54 ± 0.25 0.51 Min 1.11 Max + 0.13 0.25 – 0.05 0° – 15° Hitachi Code JEDEC EIAJ Mass (reference value) DP-16 Conforms Conforms 1.07 g Unit: mm 10.06 10.5 Max 9 1 8 1.27 *0.42 ± 0.08 0.40 ± 0.06 0.10 ± 0.10 0.80 Max *0.22 ± 0.05 0.20 ± 0.04 2.20 Max 5.5 16 0.20 7.80 +– 0.30 1.15 0° – 8° 0.70 ± 0.20 0.15 0.12 M *Dimension including the plating thickness Base material dimension 14 Hitachi Code JEDEC EIAJ Mass (reference value) FP-16DA — Conforms 0.24 g HD26LS32 Cautions 1. Hitachi neither warrants nor grants licenses of any rights of Hitachi’s or any third party’s patent, copyright, trademark, or other intellectual property rights for information contained in this document. Hitachi bears no responsibility for problems that may arise with third party’s rights, including intellectual property rights, in connection with use of the information contained in this document. 2. Products and product specifications may be subject to change without notice. Confirm that you have received the latest product standards or specifications before final design, purchase or use. 3. Hitachi makes every attempt to ensure that its products are of high quality and reliability. However, contact Hitachi’s sales office before using the product in an application that demands especially high quality and reliability or where its failure or malfunction may directly threaten human life or cause risk of bodily injury, such as aerospace, aeronautics, nuclear power, combustion control, transportation, traffic, safety equipment or medical equipment for life support. 4. Design your application so that the product is used within the ranges guaranteed by Hitachi particularly for maximum rating, operating supply voltage range, heat radiation characteristics, installation conditions and other characteristics. Hitachi bears no responsibility for failure or damage when used beyond the guaranteed ranges. Even within the guaranteed ranges, consider normally foreseeable failure rates or failure modes in semiconductor devices and employ systemic measures such as failsafes, so that the equipment incorporating Hitachi product does not cause bodily injury, fire or other consequential damage due to operation of the Hitachi product. 5. This product is not designed to be radiation resistant. 6. No one is permitted to reproduce or duplicate, in any form, the whole or part of this document without written approval from Hitachi. 7. Contact Hitachi’s sales office for any questions regarding this document or Hitachi semiconductor products. Hitachi, Ltd. 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