Revised July 2001 DM74121 One-Shot with Clear and Complementary Outputs General Description Features The DM74121 is a monostable multivibrator featuring both positive and negative edge triggering with complementary outputs. An internal 2kΩ 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 and active-HIGH transition Schmitttrigger 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. ■ Triggered from active-HIGH transition or active-LOW transition inputs ■ Variable pulse width from 30 ns to 28 seconds ■ 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 To obtain optimum and trouble free operation please read operating rules and one-shot application notes carefully and observe recommendations. Ordering Code: Order Number DM74121N Package Number N14A Package Description 14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide Connection Diagram Function Table Inputs A2 B Q Q L X H L H X L H L H X X L L H H H X H ↓ H ↓ H H ↓ ↓ H L X ↑ X L H = HIGH Logic Level L = LOW Logic Level X = Can Be Either LOW or HIGH = A Positive Pulse = A Negative Pulse Outputs A1 ↑ L H ↑ = Positive Going Transition ↓ = Negative Going Transition 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 function of the timing components. Pulse width can vary from a © 2001 Fairchild Semiconductor Corporation DS006538 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. www.fairchildsemi.com DM74121 One-Shot with Clear and Complementary Outputs June 1989 DM74121 Operating Rules 1. To use the internal 2 kΩ timing resistor, connect the RINT pin to VCC. 2. An external resistor (RX) or the internal resistor (2 kΩ) 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. FIGURE 1. 3. The pulse width is essentially determined by external timing components RX and CX. For CX < 1000 pF see Figure 1 design curves on tW as function of timing components value. For CX > 1000 pF the output is defined as: t W = K RX CX FIGURE 2. where [RX is in Kilo-ohm] [CX is in pico Farad] [tW is in nano second] [K ≈ 0.7] 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. 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. FIGURE 3. 6. The “K” coefficient is not a constant, but varies as a function of the timing capacitor CX. Figure 5 details this characteristic. 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 X 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 noninductive 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. FIGURE 4. 8. VCC and ground wiring should conform to good highfrequency standards and practices so that switching transients on the VCC and ground return leads do not cause interaction between one-shots. A 0.01 µF to 0.10 µF 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 VCC-pin as space permits. For further detailed device characteristics and output performance please refer to the one-shot application note, AN366. FIGURE 5. www.fairchildsemi.com 2 Supply Voltage 7V Input Voltage Note 1: 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 tables are not guaranteed at the absolute maximum ratings. The Recommended Operating Conditions table will define the conditions for actual device operation. 5.5V 0°C to +70°C Operating Free Air Temperature Range −65°C to +150°C Storage Temperature Range Recommended Operating Conditions Symbol Parameter VCC Supply Voltage VT+ Positive-Going Input Threshold Voltage Min Nom Max Units 4.75 5 5.25 V 1.4 2 V at the A Input (VCC = Min) VT− Negative-Going Input Threshold Voltage 0.8 at the A Input (VCC = Min) VT+ Positive-Going Input Threshold Voltage 1.5 at the B Input (VCC = Min) VT− 1.4 Negative-Going Input Threshold Voltage 0.8 at the B Input (VCC = Min) V 2 1.3 V V IOH HIGH Level Output Current −0.4 mA IOL LOW Level Output Current 16 mA tW Input Pulse Width (Note 2) dV/dt Rate of Rise or Fall of 40 ns 1 V/s 1 V/µs 1.4 40 kΩ 0 1000 µF Schmidt Input (B) (Note 2) dV/dt Rate of Rise or Fall of Schmidt Input (A) (Note 2) REXT External Timing Resistor (Note 2) CEXT External Timing Capacitance (Note 2) DC Duty Cycle (Note 2) TA RT = 2 kΩ 67 RT = REXT (Max) 90 Free Air Operating Temperature 0 % 70 °C Max Units −1.5 V Note 2: TA = 25°C and VCC = 5V Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol Parameter Conditions VI Input Clamp Voltage VCC = Min, II = −12 mA VOH HIGH Level Output VCC = Min, IOH = Max, Voltage VIL = Max, VIH = Min VOL LOW Level Output VCC = Min, IOL = Max, II Voltage VIH = Max, VIL = Min Input Current @ VCC = Max, VI = 5.5V Min 2.4 Typ (Note 3) 3.4 0.2 V 0.4 1 Max Input Voltage IIH IIL HIGH Level VCC = Max, A1, A2 Input Current VI = 2.4V B LOW Level VCC = Max, A1, A2 B Input Current VI = 0.4V IOS Short Circuit Output Current VCC = Max (Note 4) ICC Supply Current VCC = Max 40 80 −1.6 −3.2 −18 V mA µA mA −55 mA mA Quiescent 13 25 Triggered 23 40 Note 3: All typicals are at VCC = 5V, TA = 25°C. Note 4: Not more than one output should be shorted at a time. 3 www.fairchildsemi.com DM74121 Absolute Maximum Ratings(Note 1) DM74121 Switching Characteristics At VCC = 5V and TA = 25°C (See Test Waveforms and Output Load Section) From (Input) Symbol Parameter To (Output) tPLH tPLH tPHL tPHL tW(OUT) Conditions Propagation Delay Time A1, A2 CEXT = 80 pF LOW-to-HIGH Level Output to Q RINT to VCC Propagation Delay Time B to CL = 15 pF LOW-to-HIGH Level Output Q RL = 400Ω Propagation Delay Time A1, A2 HIGH-to-LOW Level Output to Q Propagation Delay Time B HIGH-to-LOW Level Output to Q Output Pulse A1, A2 or B Width Using the to Q, Q Min Max Units 70 ns 55 ns 80 ns 65 ns 150 ns 50 ns 600 800 ns 6 8 ms CEXT = 80 pF RINT to VCC RL = 400Ω Internal Timing Resistor 70 CL = 15 pF tW(OUT) Output Pulse A1, A2 CEXT = 0 pF Width Using Zero to Q, Q RINT to VCC RL = 400Ω Timing Capacitance CL = 15 pF tW(OUT) Output Pulse A1, A2 CEXT = 100pF Width Using External to Q, Q RINT = 10 kΩ RL = 400Ω Timing Resistor CL = 15pF A1, A2 CEXT = 1 µF to Q, Q RINT = 10 kΩ RL = 400Ω CL = 15 pF www.fairchildsemi.com 4 DM74121 One-Shot with Clear and Complementary Outputs Physical Dimensions inches (millimeters) unless otherwise noted 14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide Package Number N14A Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right at any time without notice to change said circuitry and specifications. LIFE SUPPORT POLICY FAIRCHILD’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 FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 2. A critical component in 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. 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 (c) 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. www.fairchildsemi.com 5 www.fairchildsemi.com