CD74HC4538NSR屬于集成電路（IC）的多諧振蕩器。由美國(guó)德州儀器公司制造生產(chǎn)的CD74HC4538NSR多諧振蕩器多諧振蕩器是簡(jiǎn)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(chēng)為“單發(fā)”，具有一種穩(wěn)定狀態(tài)；但施加觸發(fā)信號(hào)可使它們離開(kāi)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(lái)確定。這些器件對(duì)于去彈跳開(kāi)關(guān)觸頭等應(yīng)用非常有用。非穩(wěn)型沒(méi)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(lái)確定。

特性 Features

? Retriggerable/Resettable Capability

? Trigger and Reset Propagation Delays Independent of

RX, 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 LSTTL

Logic ICs

? HC Types

- 2V to 6V Operation

- High Noise Immunity: NIL = 30%, NIH = 30% of VCC

at 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

描述 Description

The ’HC4538 and ’HCT4538 are dual

retriggerable/resettable monostable precision multivibrators

for fixed voltage timing applications. An external resistor

(RX) and an external capacitor (CX) control the timing and

the accuracy for the circuit. Adjustment of RX and CX

provides a wide range of output pulse widths from the Q and

Q terminals. The propagation delay from trigger input-tooutput

transition and the propagation delay from reset inputto-

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 the

input pulse. An unused “A” input should be tied to GND and

an unused B should be tied to VCC. On power up the IC is

reset. Unused resets and sections must be terminated. In

normal operation the circuit retriggers on the application of

each new trigger pulse. To operate in the non-triggerable

mode 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.