HD26LS31 Quadruple Differential Line Drivers With 3 State Outputs ADE-205-576 (Z) 1st. Edition Dec. 2000 Description The HD26LS31 features quadruple differential line drivers which satisfy the requirements of EIA standard RS-422A. This device is designed to provide differential signals with high current capability on bus lines. The circuit provides enable input to control all four drivers. The output circuit has active pull up and pull down and is capable of sinking or sourcing 40 mA. Logic Diagram 1A 1Y 1Z 2A 2Y 2Z 3A 3Y 3Z 4A 4Y 4Z Enable G Enable G HD26LS31 Pin Arrangement 1A 1 16 VCC 1Y 2 15 4A 1Z 3 14 4Y Enable G 4 13 4Z 2Z 5 12 Enable G 2Y 6 11 3Z 2A 7 10 3Y GND 8 9 3A (Top view) Function Table Input Enables A G G Y Z H H X H L L H X L H H X L H L L X L L H L H Z Z X H L X Z 2 : : : : High level Low level Irrelevant High impedance (Off) Outputs HD26LS31 Absolute Maximum Ratings Item Symbol Ratings Unit Supply Voltage VCC 7.0 V Input Voltage VIN 7.0 V Output Voltage VOUT 5.5 V Power Dissipation PT 1 W Storage Temperature Range Topr 0 to +70 °C Lead Temperature Range Tstg –65 to +150 °C Note: 1. 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 Application Terminal Supply Voltage VCC 4.75 5.0 5.25 V VCC Output Current I OH — — –40 mA All Output Output Current I OL — — 40 mA All Output Operating Temperature Topr 0 25 70 — — 3 HD26LS31 Electrical Characteristics (Ta = 0 to +70°C) Item Symbol Min Typ*1 Max Unit Application Terminal Input Voltage VIH 2.0 — — V All Inputs VIL — — 0.8 Input Clamp Voltage VIK — — –1.5 Output Voltage VOH 2.5 — — VOH — — 2.4 I OH = –40 mA VOL — — 0.5 I OL = 40 mA I OZL — — –20 I OZH — — 20 II — — 0.1 mA I IH — — 20 µA VI = 2.7 V — — –0.36 mA VI = 0.4 V –30 — –150 All Outputs VCC = 5.25 V — 32 80 VCC VCC = 5.25 V Output Current Input Current I IL Short Circuit Output I OS* Current Supply Current 2 I CC Conditions VCC = 4.75 V, II = –18 mA All Outputs VCC = 4.75 V I OH = –20 mA mA VCC = 5.25 V VO = 0.5 V VCC = 5.25 V VO = 2.5 V All Inputs VCC = 5.25 V VI = 7 V Notes: 1. All typical values are at V CC = 5 V, Ta = 25°C 2. Not more than one output should be shorted at a time and duration of the short circuit should not exceed one second. Switching Characteristics (VCC = 5 V, Ta = 25°C) Item Symbol Application Test Min Typ Max Unit terminal circuit Conditions Propagation Delay Time t PLH — 14 20 ns 1 CL = 30 pF t PHL — 14 20 ns t ZH — 25 40 ns 2 CL = 30 pF, RL = 75 Ω t ZL — 37 45 ns 3 CL = 30 pF, RL = 180 Ω t HZ — 21 30 ns 2 CL = 10 pF t LZ — 23 35 ns 3 CL = 10 pF — 1 6 ns 1 CL = 30 pF Output Enable Time Output Disable Time Complementary Output To Skew Output 4 All Outputs HD26LS31 Test Circuit 1 4.5 V G Input Output G Pulse Generator PRR = 1MHz Duty Cycle 50% Zout = 50Ω A Z CL = 30 pF Y CL = 30 pF Output Note: 1. CL includes probe and jig capacitance. Waveforms tr tf 2.7 V 1.3 V Input 3V 2.7 V 1.3 V 0.3 V 0.3 V t PLH 0V t PHL VOH Output Y 1.5 V 1.5 V Skew t PHL Skew VOL t PLH VOH Output Z 1.5 V 1.5 V VOL 5 HD26LS31 Test Circuit 2 VCC 4.5 V Output 180 Ω A Y Input Pulse Generator PRR = 1 MHz Duty Cycle 50% Zout = 50Ω CL Z Output 1. 180 Ω G G CL Note: S1 75 Ω S1 75 Ω CL includes probe and jig capacitance. Waveforms tf tr Enable G Enable G 2.7 V 1.5 V 0.3 V 0.3 V S1 : Open t ZH Output 1.5 V S1 Open 6 3V 2.7 V 1.5 V 0V S1 : Closed t HZ 0.5 V VOH 1.5 V 0V HD26LS31 Test Circuit 3 4.5 V VCC Output 180 Ω A Y Input CL 75 Ω S2 Z Pulse Generator PRR = 1 MHz Duty Cycle 50% Zout = 50Ω Output G 180 Ω G CL 75 Ω S2 Note: 1. CL includes probe and jig capacitance. Waveforms tf tr Enable G Enable G 2.7 V 1.5 V 0.3 V 0.3 V S2 : Open t ZL Output 3V 2.7 V 1.5 V 0V S2 : Closed t LZ 4.5 V 1.5 V 1.5 V 0.5 V VOL 7 HD26LS31 HD26LS31 Line Driver Applications The HD26LS31 is a line driver that meets the EIA RS-422A conditions, and has been designed to supply a high current for differential signals to a bus line. Its features are listed below. • • • • • Operates on a single 5 V power supply. High output impedance when power is off Three-state output On-chip current limiter circuit Sink current and source current both 40 mA A block diagram is shown in figure 1. The enable function is common to all four drivers, and either activehigh or active-low can be selected. The output section consists of two output stages (the Y side and Z side), each of which has the same sink current and source current capacity. Input is TTL compatible, and an output current limiter circuit is built into the output stage as shown in figure 2. 1A 1Y 1Z 2A 2Y 2Z 3A 3Y 3Z 4A 4Y 4Z Enable G Enable G Figure 1 HD26LS31 Block Diagram The output current limiter circuit consists of transistor Q1 and resistance R1, and operates when the voltage drop on both sides of R 1 reaches approximately 0.7 V. At this time the current, i, is as follows: i = 0.7 (V) / 9 (Ω) ≈ 78 (mA) When a current greater than this flows, Q1 is turned on, the Q2 base current flows to the output side, and the flow of an excessively large output current is prevented. However, since this type of current limiter circuit has the characteristics shown in figure 3, the output stage power dissipation is large. Therefore, when the output is shorted, this should be limited to a maximum of one second for one pin only. The IOL vs. V OL characteristic for low-level output is shown in figure 4. 8 HD26LS31 An example of termination resistance connection when the HD26LS31 is used as a balanced differential type driver is shown. VCC Q2 Q3 Q1 R1 9Ω Output Q4 Figure 2 Output Stage Circuit Configuration When termination resistance RT is connected between the two transmission lines, as shown in figure 7 the current path situation is that current IOH on the side outputting a high level (in this case, the Y output) flows to the side outputting a low level (in this case, the Z output) via RT, with the result that the low level rise is large. If termination resistance RT is dropped to GND on both transmit lines, as shown in figure 5 the current path situation is that the current that flows into the side outputting a low level (in this case, the Z output) is only the input bias current from the receiver. As this input bias current is small compared with the signal current, it has almost no effect on the differential input signal at the receiver end. Figure 6 shows the output voltage characteristics when termination resistance RT is varied. Also, when used in a party line system, etc., the low level rises further due to the receiver input bias current, so that it is probably advisable to drop the termination resistance to GND. However, the fact that it is possible to make the value of RT equal to the characteristic impedance of the transmission line offers the advantage of being able to hold the power dissipation on the side outputting a high level to a lower level than in the above case. Consequently, the appropriate use must be decided according to the actual operating conditions (transmission line characteristics, transmission distance, whether a party line is used, etc.). Figure 8 shows the output voltage characteristics when termination resistance RT is varied. 9 HD26LS31 5.0 VCC = 5.0 V Output Voltage VOH (V) 4.0 Ta = 25°C VC = C 5.25 V 3.0 VC = C 4.75 V 2.0 1.0 0 –20 –40 –60 –80 –100 Output Current IOH (mA) Figure 3 IOH vs. VOH Characteristics Output Voltage VOL (V) 0.5 Ta = 25°C 0.4 VCC = 4.75 V 0.3 VCC = 5.0 V VCC = 5.25 V 0.2 0.1 0 10 20 30 40 Output Current IOL (mA) Figure 4 IOL vs. V OL Characteristics 10 50 HD26LS31 Y "H" IOH RT RT "L" Z IIN (Receiver) Z RT = O 2 ZO is the transmission line characteristic impedance Output Voltage VOH (Y), VOL (Z) (V) Figure 5 Example of Driver Use-1 5 VOH (Y) 2 1.0 VCC = 5 V Ta = 25°C Y RT 0.5 "H" VOL (Z) Z 0.1 0.05 10 VOH RT 0.2 GND 20 VOL 50 100 200 500 1 k 2 k 5 k 10 k 20 k 50 k Termination Resistance RT (Ω) Figure 6 Termination Resistance vs. Output Voltage Characteristics Y "H" IOH RT "L" Z IOL IIN (Receiver) RT = ZO ZO is the transmission line characteristic impedance Figure 7 Example of Driver Use-2 11 HD26LS31 A feature of termination implemented as shown in figure 9 is that power dissipation is low when the duty of the transmitted signal is high. However, care is required, since if R T is sufficiently small, when the output on the pulled-up side goes low, since the inverter transistor (Q 4 in figure 2) has no protection circuit, and so a large current will flow and the output low level will rise. Figure 10 shows the output voltage characteristics when termination resistance RT is varied. Output Voltage VOH (Y), VOL (Z) (V) With the method of using the driver described above, if termination resistance RT becomes sufficiently small, the region within which the output current limiter circuit operates will be entered, as can be seen from the I OH vs. V OH characteristics shown in figure 3. In this region, the output stage power dissipation is large and the output voltage changes abruptly. A measure such as insertion of a capacitor in series with the termination resistance is therefore necessary. Consequently, when selecting the transmission line, the circuit termination resistance to be used requires careful consideration. 5 VOH (Y) 2 1.0 0.5 VCC = 5 V Ta = 25°C Y 0.2 VOL (Z) RT "H" VOH 0.1 Z 0.05 10 20 50 100 200 500 1 k 2 k 5 k 10 k 20 k Termination Resistance RT (Ω) 50 k GND Figure 8 Termination Resistance vs. Output Voltage Characteristics VCC Y RT Data input Z RT Figure 9 Example of Driver Use-3 12 VOL Output Voltage VOH (Y), VOL (Z) (V) HD26LS31 5 VOH (Z) 2 1.0 Y RT VCC VCC = 5 V Ta = 25°C 0.5 "L" VOL VOL (Y) 0.2 Z 0.1 0.05 10 20 50 100 200 500 1 k 2 k 5 k 10 k 20 k Termination Resistance RT (Ω) RT GND VOH 50 k Figure 10 Termination Resistance vs. Output Voltage Characteristic 13 HD26LS31 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 HD26LS31 Cautions 1. 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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. Semiconductor & Integrated Circuits. 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