Datasheet4U Logo Datasheet4U.com

54121 Datasheet Monostable Multivibrator

Manufacturer: National Semiconductor (now Texas Instruments)

Overview: 54121 DM54121 DM74121 One-Shot with Clear and Complementary Outputs June 1989 54121 DM54121 DM74121 One-Shot with Clear and Complementary.

General Description

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 Y Y 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

Key Features

  • Y Y Triggered from active-high transition or active-low transition inputs Variable pulse width from 30 ns to 28 seconds Connection Diagram Dual-In-Line Package Function Table Inputs A1 L X X H H A2 X L X H B H H L X H H H Q L L L L Outputs Q H H H H v H v v L X H L X TL F 6538.
  • 1 v X L u u e High Logic Level e Low Logic Level e Can Be Either Low or High e Positive Going Transition e Negative Going Transition e A Positive Pulse e A Negative Pulse u v Order Number 54121DMQB 5412.

More Datasheets from National Semiconductor (now Texas Instruments)

Part Number Description
54122 Retriggerable Resettable Multivibrator
54125 Quad TRI-STATE Buffers
5410 Triple 3-Input NAND Gates
54132 Quad 2-Input NAND Gates
54148 8-3 Line Priority Encoder
54150 Data Selectors/Multiplexers
54151 Data Selectors/Multiplexers
54151A Data Selectors/Multiplexers
54153 Dual 4-Line to 1-Line Data Selectors/Multiplexers
54154 4-Line to 16-Line Decoders/Demultiplexers

54121 Distributor