器件名称: 74LV123D
功能描述: Dual retriggerable monostable multivibrator with reset
文件大小: 134.29KB 共23页
简 介:74LV123
Dual retriggerable monostable multivibrator with reset
Rev. 05 — 8 November 2007 Product data sheet
1. General description
The 74LV123 is a low-voltage Si-gate CMOS device and is pin and function compatible with the 74HC123; 74HCT123. It is a dual retriggerable monostable multivibrator which uses three methods to control the output pulse width: 1. The basic pulse time is programmed by the selection of an external resistor (REXT) and capacitor (CEXT). These are normally connected as shown in Figure 9. 2. Once triggered, the basic output pulse width may be extended by retriggering the gated active LOW-going edge input (nA) or the active HIGH-going edge input (nB). By repeating this process, the output pulse period (nQ = HIGH, nQ = LOW) can be made as long as desired (see Figure 12). 3. Alternatively, an output delay can be terminated at any time by a LOW-going edge on input nRD, which also inhibits the triggering (see Figure 13). Schmitt-trigger action in the nA and nB inputs makes the circuit highly tolerant of slower input rise and fall times.
2. Features
s s s s s s s s Optimized for low-voltage applications: 1.0 V to 5.5 V Accepts TTL input levels between VCC = 2.7 V and VCC = 3.6 V Typical output ground bounce: < 0.8 V at VCC = 3.3 V and Tamb = 25 °C Typical HIGH-level output voltage (VOH) undershoot: > 2 V at VCC = 3.3 V and Tamb = 25 °C DC triggered from active HIGH or active LOW inputs Retriggerable for very long pulses up to 100 % duty factor Direct reset ter……
