M541 datasheet(4/6 Pages) NSC

4 / 6 page

Operating Rules (Continued)

6 The retriggerable pulse width is calculated as shown be-

low

T e TW a tPLH e Kc RX c CX a tPLH

The retriggered pulse width is equal to the pulse width

plus a delay time period

(Figure 4)

TLF6539 – 6

FIGURE 4

7 Under any operating condition CX and RX must be kept

as close to the one-shot device pins as possible to mini-

mize stray capacitance to reduce noise pick-up and to

reduce I c R and Ldidt voltage developed along their

connecting paths If the lead length from CX to pins (6)

and (7) or pins (14) and (15) is greater than 3 cm for

example the output pulse width might be quite different

from values predicted from the appropriate equations A

non-inductive and low capacitive path is necessary to en-

sure complete discharge of CX in each cycle of its opera-

tion so that the output pulse width will be accurate

8 VCC and ground wiring should conform to good high-fre-

quency standards and practices so that switching tran-

sients on the VCC and ground return leads do not cause

interaction between one-shots A 001 mF to 010 mF by-

pass capacitor (disk ceramic or monolithic type) from VCC

to ground is necessary on each device Furthermore the

bypass capacitor should be located as close to the VCC

pin as space permits

For further detailed device characteristics and output performance

please refer to the NSC one-shot application note AN-366

M541 数据表(PDF) 4 Page - National Semiconductor (TI)