TI CD74HC4538QM96G4Q1

The CD74HC4538 is a dual retriggerable/resettable precision monostable multivibrator designed for fixed-voltage timing applications. The timing and accuracy of the circuit are controlled by external resistor RX and external capacitor CX. Adjusting RX and CX allows a wide range of output pulse widths at the Q and Q-not terminals. The propagation delay from trigger input to output transition and from reset input to output transition are independent of RX and CX. Both rising-edge trigger (A) and falling-edge trigger (B-not) inputs are provided, enabling triggering from either edge of the input pulse. Unused A inputs should be tied to GND, and unused B-not inputs should be tied to VCC. The device resets upon power-up. Unused reset pins and unused units must be terminated. During normal operation, the circuit retriggeres with each new trigger pulse applied. To operate in non-retriggerable mode, connect Q-not to B-not when using rising-edge trigger (A), or connect Q to A when using falling-edge trigger (B-not). The period τ can be calculated by τ = 0.7 RX CX; the minimum value of RX is 5kΩ and the minimum value of CX is 0pF.

• Automotive-grade compliant
• Retriggerable/resettable capability
• Trigger and reset propagation delays independent of RX, CX
• Rising or falling edge trigger selectable
• Buffered Q and Q̄ outputs
• Independent reset
• Wide output pulse width range
• Schmitt-trigger inputs on A and B
• Retrigger time independent of CX
• Standard outputs drive 10 LSTTL loads
• Bus driver outputs drive 15 LSTTL loads
• Balanced propagation delays and transition times
• Significantly lower power consumption vs. LSTTL logic ICs
• VCC operating voltage range: 2 V to 6 V
• High noise immunity: NIL or NIH up to 30% of VCC at VCC = 5 V