1. General description

The 74HC123; 74HCT123 is a dual retriggerable monostable multivibrator with reset. The basic

output pulse width is programmed by selection of external components (REXT and CEXT). Once

triggered this basic pulse width may be extended by retriggering either of the edge triggered

inputs (nA or nB). By repeating this process, the output pulse period (nQ = HIGH, nQ = LOW)

can be made as long as desired. Alternatively, an output delay can be terminated at any time by

a LOW-going edge on input nRD. Inputs include clamp diodes. This enables the use of current

limiting resistors to interface inputs to voltages in excess of VCC.

Schmitt-trigger action in the nA and nB inputs, makes the circuit highly tolerant to slower input rise

and fall times.

2. Features and benefits

? Wide supply voltage range from 2.0 V to 6.0 V

? CMOS low power dissipation

? High noise immunity

? Latch-up performance exceeds 100 mA per JESD 78 Class II Level B

? Complies with JEDEC standards:

? JESD8C (2.7 V to 3.6 V)

? JESD7A (2.0 V to 6.0 V)

? Input levels:

? For 74HC123: CMOS level

? For 74HCT123: TTL level

? DC triggered from active HIGH or active LOW inputs

? Retriggerable for very long pulses up to 100 duty factor

? Direct reset terminates output pulse

? Schmitt-trigger action on all inputs except for the reset input

? ESD protection:

? HBM JESD22-A114F exceeds 2000 V

? MM JESD22-A115-A exceeds 200 V

? Multiple package options

? Specified from -40 °C to +85 °C and from -40 °C to +125 °C

74HC123屬于集成電路（IC） > 多諧振蕩器。安世半導(dǎo)體(中國)有限公司制造生產(chǎn)的74HC123多諧振蕩器多諧振蕩器是簡單的雙態(tài)器件，盡管它們的典型使用方式在很大程度上具有模擬特性，但通常被認(rèn)為是數(shù)字邏輯元器件。單穩(wěn)型也稱為“單發(fā)”，具有一種穩(wěn)定狀態(tài)；但施加觸發(fā)信號可使它們離開此狀態(tài)一段時(shí)間，該時(shí)間通常由所連接電容器的值來確定。這些器件對于去彈跳開關(guān)觸頭等應(yīng)用非常有用。非穩(wěn)型沒有穩(wěn)定狀態(tài)，在兩個(gè)狀態(tài)之間按一定頻率持續(xù)轉(zhuǎn)換，該頻率通常也是由所連接電容器的值來確定。