MM74HC4538 Dual Retriggerable Monostable Multivibrator February 1984 Revised August 2000 MM74HC4538 Dual Retriggerable Monostable Multivibrator Pulse width stability over a wide range of temperature and General Description supply is achieved using linear CMOS techniques. The out- The MM74HC4538 high speed monostable multivibrator put pulse equation is simply: PW = 0.7(R)(C) where PW is (one shots) is implemented in advanced silicon-gate in seconds, R is in ohms, and C is in farads. This device is CMOS technology. They feature speeds comparable to low pin compatible with the CD4528, and the CD4538 one power Schottky TTL circuitry while retaining the low power shots. All inputs are protected from damage due to static and high noise immunity characteristic of CMOS circuits. discharge by diodes to V and ground. CC Each multivibrator features both a negative, A, and a posi- tive, B, transition triggered input, either of which can be Features used as an inhibit input. Also included is a clear input that Schmitt trigger on A and B inputs when taken low resets the one shot. The MM74HC4538 is retriggerable. That is, it may be triggered repeatedly while Wide power supply range: 26V their outputs are generating a pulse and the pulse will be Typical trigger propagation delay: 32 ns extended. Fanout of 10 LS-TTL loads Low input current: 1 A max Ordering Code: Order Number Package Number Package Description MM74HC4538M M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow MM74HC4538SJ M16D 16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide MM74HC4538N N16E 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Devices also available in Tape and Reel. Specify by appending the suffix letter X to the ordering code. Connection Diagram Truth Table Inputs Outputs Clear A B Q Q LX X L H XH X L H XX L L H HL H H H = HIGH Level L = LOW Level = Transition from LOW-to-HIGH = Transition from HIGH-to-LOW = One HIGH Level Pulse = One LOW Level Pulse X = Irrelevant 2000 Fairchild Semiconductor Corporation DS005217 www.fairchildsemi.comBlock Diagrams Note: Pin 1 and Pin 15 must be hard-wired to GND. Logic Diagram www.fairchildsemi.com 2 MM74HC4538