5962-8688601EA

5962-8688601EA Features

• Retriggerable/Resettable Capability • Trigger and Reset Propagation Delays Independent ofRX, CX • Triggering from the Leading or Trailing Edge • Q and Q Buffered Outputs Available • Separate Resets • Wide Range of Output Pulse Widths • Schmitt Trigger Input on A and B Inputs • Retrigger Time is Independent of CX • Fanout (Over Temperature Range)- Standard Outputs. . . . . . . . . . . . . . . 10 LSTTL Loads- Bus Driver Outputs . . . . . . . . . . . . . 15 LSTTL Loads • Wide Operating Temperature Range . . . -55oC to 125oC • Balanced Propagation Delay and Transition Times • Significant Power Reduction Compared to LSTTLLogic ICs • HC Types- 2V to 6V Operation- High Noise Immunity: NIL = 30%, NIH = 30% of VCCat VCC = 5V • HCT Types- 4.5V to 5.5V Operation- Direct LSTTL Input Logic Compatibility,VIL= 0.8V (Max), VIH = 2V (Min)- CMOS Input Compatibility, Il ≤ 1µA at VOL, VOH

5962-8688601EA Description

The’HC4538and’HCT4538aredualretriggerable/resettable monostable precision multivibratorsfor fixed voltage timing applications. An external resistor(RX) and an external capacitor (CX) control the timing andthe accuracy for the circuit. Adjustment of RX and CXprovides a wide range of output pulse widths from the Q andQ terminals. The propagation delay from trigger input-to-output transition and the propagation delay from reset input-to-output transition are independent of RX and CX.Leading-edge triggering (A) and trailing edge triggering (B)inputs are provided for triggering from either edge of theinput pulse. An unused “A” input should be tied to GND andan unused B should be tied to VCC. On power up the IC isreset. Unused resets and sections must be terminated. Innormal operation the circuit retriggers on the application ofeach new trigger pulse. To operate in the non-triggerablemode Q is connected to B when leading edge triggering (A)is used or Q is connected to A when trailing edge triggering(B) is used. The period (τ) can be calculated from τ = (0.7)RX, CX; RMIN is 5kΩ. CMIN is 0pF.141516913121110123457681CX1RXCX1R1A1B1QGND1QVCC2RXCX2R2A2B2Q2Q2CX