DS8921/DS8921A/DS8921AT Differential Line Driver and Receiver Pair General Description The DS8921, DS8921A are Differential Line Driver and Receiver pairs designed specifically for applications meeting the ST506, ST412 and ESDI Disk Drive Standards. In addition, these devices meet the requirements of the EIA Standard RS-422. The DS8921, DS8921A receivers offer an input sensitivity of 200 mV over a ± 7V common mode operating range. Hysteresis is incorporated (typically 70 mV) to improve noise margin for slowly changing input waveforms. The DS8921, DS8921A drivers are designed to provide unipolar differential drive to twisted pair or parallel wire transmission lines. Complementary outputs are logically ANDed and provide an output skew of 0.5 ns (typ.) with propagation delays of 12 ns. The DS8921, DS8921A are designed to be compatible with TTL and CMOS. Features 12 ns typical propagation delay Output skew - 0.5 ns typical Meet the requirements of EIA Standard RS-422 Complementary Driver Outputs High differential or common-mode input voltage ranges of ± 7V n ± 0.2V receiver sensitivity over the input voltage range n Receiver input hysteresis-70 mV typical n DS8921AT industrial temperature operation: (−40˚C to +85˚C) n n n n n Connection Diagram DS008512-1 Order Number DS8921M, DS8921N, DS8921AM, DS8921AN, DS8921ATM, or DS8921ATN See NS Package Number M08A or N08E Truth Table Receiver Input Driver VOUT Input VOUT VID ≥ VTH (MAX) 1 1 1 0 VID ≤ VTH (MIN) 0 0 0 1 Open 1 © 1998 National Semiconductor Corporation DS008512 VOUT www.national.com DS8921/DS8921A/DS8921AT Differential Line Driver and Receiver Pair May 1998 Absolute Maximum Ratings (Note 1) Storage Temperature Range Lead Temperature (Soldering, 4 sec.) Maximum Junction Temperature If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage 7V Driver Input Voltage −0.5V to +7V Output Voltage 5.5V Receiver Output Sink Current 50 mA ± 10V Receiver Input Voltage ± 12V Differential Input Voltage Maximum Package Power Dissipation @ +25˚C M Package 730 mW N Package 1160 mW Derate M Package 9.3 mW/˚C above +25˚C Derate N Package 5.8 mW/˚C above +25˚C −65˚C to +165˚C +260˚C +260˚C +150˚C Recommended Operating Conditions Supply Voltage Temperature (TA) DS8921/DS8921A DS8921AT Min 4.5 Max 5.5 Units V 0 −40 70 +85 ˚C ˚C DS8921/DS8921A Electrical Characteristics (Notes 2, 3, 4) Symbol Conditions Min Typ Max Units −200 ± 35 +200 15 70 mV 4.0 6.0 kΩ RECEIVER VTH −7V ≤ VCM ≤ +7V VHYST −7V ≤ VCM ≤ +7V VIN = −7V, +7V (Other Input = GND) RIN IIN VIN = 10V VIN = −10V IOH = −400 µA IOL = 8 mA 2.5 VOL ISC VCC = MAX, VOUT = 0V −15 VOH mV 3.25 mA −3.25 mA V 0.5 V −100 mA 0.8 V −200 µA 20 µA 100 µA DRIVER VIH 2.0 V VIL IIL IIH II VCL VOH VOL IOFF VCC = MAX, VIN = 0.4V VCC = MAX, VIN = 2.7V VCC = MAX, VIN = 7.0V VCC = MIN, IIN = −18 mA −40 −1.5 VCC = MIN, IOH = −20 mA VCC = MIN, IOL = +20 mA VCC = 0V, V OUT = 5.5V 2.5 |VT| – |VT | VT ISC 0.5 V 100 µA 0.4 V 0.4 V −150 mA 35 mA 2.0 |VOS – VOS | VCC = MAX, VOUT = 0V −30 V V V DRIVER and RECEIVER ICC www.national.com VCC = MAX, VOUT = Logic 0 2 Receiver Switching Characteristics Figure 1(Figure 2) Symbol Conditions Min Typ Max Units 8921 8921A 8921AT TpLH CL = 30 pF 14 22.5 20 20 ns TpHL (Figures 1, 2 ) CL = 30 pF 14 22.5 20 20 ns |TpLH–T pHL| (Figures 1, 2) CL = 30 pF 0.5 5 3.5 5 ns (Figures 1, 2 ) Driver Switching Characteristics SINGLE ENDED CHARACTERISTICS (Figures 3, 4) Symbol Conditions Min Typ Max Units 8921 8921A 8921AT TpLH CL = 30 pF 10 15 15 15 ns TpHL (Figures 3, 4) CL = 30 pF 10 15 15 15 ns TTLH (Figures 3, 4) CL = 30 pF 5 8 8 9.5 ns TTHL (Figures 7, 8) CL = 30 pF 5 8 8 9.5 ns Skew (Figures 7, 8) CL = 30 pF 1 5 3.5 3.5 ns (Figures 3, 4) Driver Switching Characteristics(Note 6) DIFFERENTIAL CHARACTERISTICS (Figures 3, 5) Symbol Conditions Min Typ Max Units 8921 8921A 8921AT TpLH CL = 30 pF 10 15 15 15 ns TpHL (Figures 3, 5, 6) CL = 30 pF 10 15 15 15 ns |TpLH–T pHL| (Figures 3, 5, 6) CL = 30 pF 0.5 6 2.75 2.75 ns (Figures 3, 5, 6) Note 1: “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the device should be operated at these limits. The Table of “Electrical Characteristics” provides conditions for actual device operation. Note 2: All currents into device pins are shown as positive values; all currents out of the device are shown as negative; all voltages are referenced to ground unless otherwise specified. All values shown as max or min are classified on absolute value basis. Note 3: All typical values are VCC = 5V, TA = 25˚C. Note 4: Only one output at a time should be shorted. Note 5: Difference between complementary outputs at the 50% point. Note 6: Differential Delays are defined as calculated results from single ended rise and fall time measurements. This approach in establishing AC performance specifications has been taken due to limitations of available Automatic Test Equipment (ATE). The calculated ATE results assume a linear transition between measurement points and are a result of the following equations: Where: Tcr = Crossing Point Tra, Trb, Tfa and T fb are time measurements with respect to the input. See Figure 6 . 3 www.national.com AC Test Circuits and Switching Diagrams DS008512-2 FIGURE 6. DS008512-3 FIGURE 1. DS008512-10 FIGURE 7. DS008512-4 FIGURE 2. DS008512-11 FIGURE 8. DS008512-5 FIGURE 3. DS008512-6 FIGURE 4. DS008512-7 FIGURE 5. www.national.com 4 Typical Applications ST506 and ST412 Application DS008512-8 ESDI Application DS008512-9 5 www.national.com 6 Physical Dimensions inches (millimeters) unless otherwise noted SO Package (M) Order Number DS8921M, DS8921AM or DS8921ATM NS Package Number M08A Molded Dual-In-Line Package (N) Order Number DS8921N, DS8921AN or DS8921ATN NS Package Number N08E 7 www.national.com DS8921/DS8921A/DS8921AT Differential Line Driver and Receiver Pair LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 2. A critical component in any component of a life support 1. Life support devices or systems are devices or sysdevice or system whose failure to perform can be reatems which, (a) are intended for surgical implant into sonably expected to cause the failure of the life support the body, or (b) support or sustain life, and whose faildevice or system, or to affect its safety or effectiveness. ure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 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