54121/DM54121/DM74121 One-Shot with Clear and Complementary Outputs Y General Description Y The DM54/74121 is a monostable multivibrator featuring both positive and negative edge triggering with complementary outputs. An internal 2kX timing resistor is provided for design convenience minimizing component count and layout problems. This device can be used with a single external capacitor. Inputs (A) are active-low trigger transition inputs and input (B) is an active-high transition Schmitt-trigger input that allows jitter-free triggering from inputs with transition rates as slow as 1 volt/second. A high immunity to VCC noise of typically 1.5V is also provided by internal circuitry at the input stage. To obtain optimum and trouble free operation please read operating rules and NSC one-shot application notes carefully and observe recommendations. Features Y Y Triggered from active-high transition or active-low transition inputs Variable pulse width from 30 ns to 28 seconds Connection Diagram Y Y Y Y Y Jitter free Schmitt-trigger input Excellent noise immunity typically 1.2V Stable pulse width up to 90% duty cycle TTL, DTL compatible Compensated for VCC and temperature variations Input clamp diodes Alternate Military/Aerospace device (54121) is available. Contact a National Semiconductor Sales Office/ Distributor for specifications. Functional Description The basic output pulse width is determined by selection of an internal resistor RINT or an external resistor (RX) and capacitor (CX). Once triggered the output pulse width is independent of further transitions of the inputs and is a function of the timing components. Pulse width can vary from a few nano-seconds to 28 seconds by choosing appropriate RX and CX combinations. There are three trigger inputs from the device, two negative edge-triggering (A) inputs, one positive edge Schmitt-triggering (B) input. Function Table Inputs Dual-In-Line Package TL/F/6538 – 1 Order Number 54121DMQB, 54121FMQB, DM54121J, DM54121W or DM74121N See NS Package Number J14A, N14A or W14B C1995 National Semiconductor Corporation TL/F/6538 Outputs A1 A2 B Q Q L X X H H X L X H v v v v H H L X H H H L X X L u u L L L L É É É É É H H H H ß ß ß ß ß H H e High Logic Level L e Low Logic Level X e Can Be Either Low or High u v e Positive Going Transition e Negative Going Transition É e A Positive Pulse ß e A Negative Pulse RRD-B30M105/Printed in U. S. A. 54121/DM54121/DM74121 One-Shot with Clear and Complementary Outputs June 1989 Absolute Maximum Ratings (Note) Note: The ‘‘Absolute Maximum Ratings’’ are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the ‘‘Electrical Characteristics’’ table are not guaranteed at the absolute maximum ratings. The ‘‘Recommended Operating Conditions’’ table will define the conditions for actual device operation. If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Supply Voltage 7V Input Voltage 5.5V Operating Free Air Temperature Range b 55§ C to a 125§ C DM54 DM74 0§ C to a 70§ C Storage Temperature Range b 65§ C to a 150§ C Recommended Operating Conditions Symbol DM54121 Parameter VCC Supply Voltage VT a Positive-Going Input Threshold Voltage at the A Input (VCC e Min) VTb Negative-Going Input Threshold Voltage at the A Input (VCC e Min) VT a Positive-Going Input Threshold Voltage at the B Input (VCC e Min) VTb Negative-Going Input Threshold Voltage at the B Input (VCC e Min) DM74121 Nom Max Min Nom Max 4.5 5 5.5 4.75 5 5.25 V 1.4 2 1.4 2 V 0.8 1.4 1.5 0.8 0.8 2 1.3 IOH High Level Output Current IOL Low Level Output Current 16 tW Input Pulse Width (Note 1) dV/dt Rate of Rise or Fall of Schmidt Input (B) (Note 1) dV/dt Rate of Rise or Fall of Logic Input (A) (Note 1) REXT External Timing Resistor (Note 1) CEXT External Timing Capacitance (Note 1) DC Duty Cycle (Note 1) 40 1.4 V 1.5 0.8 b 0.4 TA Units Min 2 1.3 V b 0.4 mA 16 mA 40 ns 1 1 1 V/s 1 V/ms 1.4 30 1.4 40 kX 0 1000 0 1000 mF RT e 2 kX 67 67 RT e REXT (Max) 90 90 Free Air Operating Temperature V b 55 125 0 70 % §C Note 1: TA e 25§ C and VCC e 5V. Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol Parameter Conditions Min Typ (Note 1) Max Units b 1.5 V VI Input Clamp Voltage VOH High Level Output Voltage VCC e Min, II e b12 mA VCC e Min, IOH e Max, VIL e Max, VIH e Min VOL Low Level Output Voltage VCC e Min, IOL e Max, VIH e Min, VIL e Max II Input Current Input Voltage VCC e Max, VI e 5.5V IIH High Level Input Current VCC e Max VI e 2.4V A1, A2 40 B 80 Low Level Input Current VCC e Max VI e 0.4V A1, A2 b 1.6 B b 3.2 Short Circuit Output Current VCC e Max (Note 2) Supply Current VCC e Max IIL IOS ICC @ Max 2.4 3.4 0.2 V 0.4 V 1 mA DM54 b 20 b 55 DM74 b 18 b 55 Quiescent 13 25 Triggered 23 40 Note 1: All typicals are at VCC e 5V, TA e 25§ C. Note 2: Not more than one output should be shorted at a time. 2 mA mA mA mA Switching Characteristics at VCC e 5V and TA e 25§ C (See Section 1 for Test Waveforms and Outout Load) Parameter From (Input) To (Output) tPLH Propagation Delay Time Low to High Level Output A1, A2 to Q tPLH Propagation Delay Time Low to High Level Output B to Q tPHL Propagation Delay Time High to Low Level Output tPHL Propagation Delay Time High to Low Level Output tW(OUT) Output Pulse Width Using the Internal Timing Resistor Symbol tW(OUT) tW(OUT) Conditions Min Max Units 70 ns 55 ns A1, A2 to Q 80 ns B to Q 65 ns 150 ns 50 ns 600 800 ns 6 8 ms CEXT e 80 pF RINT to VCC CL e 15 pF RL e 400X A1, A2 or B to Q, Q CEXT e 80 pF RINT to VCC RL e 400X CL e 15 pF Output Pulse Width Using Zero Timing Capacitance A1, A2 to Q, Q CEXT e 0 pF RINT to VCC RL e 400X CL e 15 pF Output Pulse Width Using External Timing Resistor A1, A2 to Q, Q CEXT e 100 pF RINT e 10 kX RL e 400X CL e 15 pF A1, A2 to Q, Q CEXT e 1 mF RINT e 10 kX RL e 400X CL e 15 pF 70 Operating Rules 1. To use the internal 2 kX timing resistor, connect the RINT pin to VCC. 2. An external resistor (RX) or the internal resistor (2 kX) and an external capacitor (CX) are required for proper operation. The value of CX may vary from 0 to any necessary value. For small time constants use high-quality mica, glass, polypropylene, polycarbonate, or polystyrene capacitors. For large time constants use solid tantalum or special aluminum capacitors. If the timing capacitors have leakages approaching 100 nA or if stray capacitance from either terminal to ground is greater than 50 pF the timing equations may not represent the pulse width the device generates. 3. The pulse width is essentially determined by external timing components RX and CX. For CX k 1000 pF see Figure 1 design curves on TW as function of timing components value. For CX l1000 pF the output is defined as: tW e K RX CX where [RX is in Kilo-ohm] [CX is in pico Farad] [TW is in nano second] [K & 0.7] TL/F/6538 – 2 FIGURE 1 4. If CX is an electrolytic capacitor a switching diode is often required for standard TTL one-shots to prevent high inverse leakage current (Figure 2) . TL/F/6538 – 3 FIGURE 2 3 Operating Rules (Continued) 5. Output pulse width versus VCC and operation temperatures: Figure 3 depicts the relationship between pulse width variation versus VCC. Figure 4 depicts pulse width variation versus ambient temperature. 6. The ‘‘K’’ coefficient is not a constant, but varies as a function of the timing capacitor CX. Figure 5 details this characteristic. TL/F/6538 – 6 FIGURE 5 7. Under any operating condition CX and RX must be kept as close to the one-shot device pins as possible to minimize stray capacitance, to reduce noise pick-up, and to reduce I c R and Ldi/dt voltage developed along their connecting paths. If the lead length from CX to pins (10) and (11) is greater than 3 cm, for example, the output pulse width might be quite different from values predicted from the appropriate equations. A non-inductive and low capacitive path is necessary to ensure complete discharge of CX in each cycle of its operation so that the output pulse width will be accurate. 8. VCC and ground wiring should conform to good high-frequency standards and practices so that switching transients on the VCC and ground return leads do not cause interaction between one-shots. A 0.01 mF to 0.10 mF bypass capacitor (disk ceramic or monolithic type) from VCC to ground is necessary on each device. Furthermore, the bypass capacitor should be located as close to the VCCpin as space permits. TL/F/6538 – 4 FIGURE 3 TL/F/6538 – 5 FIGURE 4 For further detailed device characteristics and output performance please refer to the NSC one-shot application note, AN-366. 4 Physical Dimensions inches (millimeters) 14-Lead Ceramic Dual-In-Line Package (J) Order Number 54121DMQB or DM54121J NS Package Number J14A 14-Lead Molded Dual-In-Line Package (N) Order Number DM74121N NS Package Number N14A 5 54121/DM54121/DM74121 One-Shot with Clear and Complementary Outputs Physical Dimensions inches (millimeters) (Continued) 14-Lead Ceramic Flat Package (W) Order Number 54121FMQB or DM54121W NS Package Number W14B 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: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure 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. National Semiconductor Corporation 1111 West Bardin Road Arlington, TX 76017 Tel: 1(800) 272-9959 Fax: 1(800) 737-7018 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. 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