74LS121

54121 NSC | Alldatasheet

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Technical content

Features

Y Triggered from active-high transition or active-low tran- sition inputs Y Variable pulse width from 30 ns to 28 seconds Y Jitter free Schmitt-trigger input Y Excellent noise immunity typically 1.2V Y Stable pulse width up to 90% duty cycle Y TTL, DTL compatible Y Compensated for V CC and temperature variations Y Input clamp diodes Y Alternate Military/Aerospace device (54121) is avail- able. Contact a National Semiconductor Sales Office/ Distributor for specifications. Functional Description The basic output pulse width is determined by selection of an internal resistor R INT or an external resistor (R X) and capacitor (C X). Once triggered the output pulse width is in- dependent of further transitions of the inputs and is a func- tion of the timing components. Pulse width can vary from a few nano-seconds to 28 seconds by choosing appropriate R X and C X combinations. There are three trigger inputs from the device, two negative edge-triggering (A) inputs, one pos- itive edge Schmitt-triggering (B) input. Connection Diagram Dual-In-Line Package TL/F/6538–1 Order Number 54121DMQB, 54121FMQB, DM54121J, DM54121W or DM74121N See NS Package Number J14A, N14A or W14B Function Table Inputs Outputs A1 A2 B Q Q LX H L H XL H L H XXL L H HHX L H H v H Éß v HH Éß vv H Éß LX u Éß XL u Éß H e High Logic Level L e Low Logic Level X e Can Be Either Low or High u e Positive Going Transition v e Negative Going Transition É e A Positive Pulse ß e A Negative Pulse C1995 National Semiconductor Corporation RRD-B30M105/Printed in U. S. A.

Absolute Maximum Ratings (Note) 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 DM54 b55§Ct o a125§C DM74 0 §Ct o a70§C Storage Temperature Range b65§Ct o a150§C Note: The ‘‘Absolute Maximum Ratings’’ are those values beyond which the safety of the device cannot be guaran- teed. 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. Recommended Operating Conditions Symbol Parameter DM54121 DM74121 Units Min Nom Max Min Nom Max VCC Supply Voltage 4.5 5 5.5 4.75 5 5.25 V VTa Positive-Going Input Threshold 1.4 2 1.4 2 VVoltage at the A Input (V CC e Min) VTb Negative-Going Input Threshold 0.8 1.4 0.8 1.4 VVoltage at the A Input (V CC e Min) VTa Positive-Going Input Threshold 1.5 2 1.5 2 VVoltage at the B Input (V CC e Min) VTb Negative-Going Input Threshold 0.8 1.3 0.8 1.3 VVoltage at the B Input (V CC e Min) IOH High Level Output Current b0.4 b0.4 mA IOL Low Level Output Current 16 16 mA tW Input Pulse Width (Note 1) 40 40 ns dV/dt Rate of Rise or Fall of 1 1 V/sSchmidt Input (B) (Note 1) dV/dt Rate of Rise or Fall of 11 V / msLogic Input (A) (Note 1) REXT External Timing Resistor (Note 1) 1.4 30 1.4 40 k X CEXT External Timing Capacitance (Note 1) 0 1000 0 1000 mF DC Duty Cycle (Note 1) R T e 2k X 67 67 % RT e REXT (Max) 90 90 TA Free Air Operating Temperature b55 125 0 70 §C Note 1: TA e 25§C and V CC e 5V. Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol Parameter Conditions Min Typ Max Units(Note 1) VI Input Clamp Voltage V CC e Min, I I eb 12 mA b1.5 V VOH High Level Output V CC e Min, I OH e Max, 2.4 3.4 VVoltage V IL e Max, V IH e Min VOL Low Level Output V CC e Min, I OL e Max, 0.2 0.4 VVoltage V IH e Min, V IL e Max II Input Current @ Max V CC e Max, V I e 5.5V 1m AInput Voltage IIH High Level Input V CC e Max A1, A2 40 mACurrent V I e 2.4V B8 0 IIL Low Level Input V CC e Max A1, A2 b1.6 mACurrent V I e 0.4V B b3.2 IOS Short Circuit V CC e Max DM54 b20 b55 mAOutput Current (Note 2) DM74 b18 b55 ICC Supply Current V CC e Max Quiescent 13 25 mA Triggered 23 40 Note 1: All typicals are at V CC e 5V, T A e 25§C. Note 2: Not more than one output should be shorted at a time.

Physical Dimensions inches (millimeters) 14-Lead Ceramic Dual-In-Line Package (J) Order Number 54121DMQB or DM54121J 14-Lead Molded Dual-In-Line Package (N) Order Number DM74121N

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 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 2. A critical component is any component of a life systems which, (a) are intended for surgical implant support device or system whose failure to perform can into the body, or (b) support or sustain life, and whose be reasonably expected to cause the failure of the life failure to perform, when properly used in accordance support device or system, or to affect its safety or with instructions for use provided in the labeling, can effectiveness. be reasonably expected to result in a significant injury to the user. National Semiconductor National Semiconductor National Semiconductor National Semiconductor Corporation Europe Hong Kong Ltd. Japan Ltd.

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a49) 0-180-530 85 86 13th Floor, Straight Block, Tel: 81-043-299-2309 Arlington, TX 76017 Email: cnjwge @ tevm2.nsc.com Ocean Centre, 5 Canton Rd. Fax: 81-043-299-2408 Tel: 1(800) 272-9959 Deutsch Tel: ( a49) 0-180-530 85 85 Tsimshatsui, Kowloon Fax: 1(800) 737-7018 English Tel: ( a49) 0-180-532 78 32 Hong Kong Fran3ais Tel: ( a49) 0-180-532 93 58 Tel: (852) 2737-1600 Italiano Tel: ( a49) 0-180-534 16 80 Fax: (852) 2736-9960 National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.