74HC5555D View Datasheet(PDF) - NXP Semiconductors.

Part Name

Description

Manufacturer

74HC5555D

Programmable delay timer with oscillator

NXP Semiconductors. 

Philips Semiconductors

Programmable delay timer with oscillator

APPLICATION INFORMATION

Product specification

74HC/HCT5555

handbook, halfpage

R bias = 560 kΩ

VCC

0.47 µF input

vi

(f = 1 kHz)

output 100 µF

A io

GND

MGA645

Fig.11 Test set-up for measuring forward

transconductance gfs = dio/dvi at vo is

constant (see Fig.12) and MR = LOW.

handbookg,

14

hfsalfpage

(mA/V)

12

10

MBA333

max.

typ.

8

min.

6

4

2

0

1

2

3

4

5

6

VCC (V)

Fig.12 Typical forward transconductance gfs as a

function of the supply voltage at VCC at

Tamb = 25 °C.

handbook1, 0ha5lfpage

f osc

(Hz)

10 4

103

Rt

Ct

MGA647

102

10

103

10 – 4

104

10 – 3

105 R t (Ω) 106

10 – 2 C t ( µF) 10 – 1

Ct curve at Rt = 100 kΩ; R2 = 200 kΩ.

Rt curve at Ct = 1 nF; R2 = 2 x Rt.

RC oscillator frequency as a function of Rt and Ct

at VCC = 2 to 6 V; Tamb = 25 °C.

Fig.13 Application information.

handbook, halfpage

MR (from logic)

1 RS

C2

R2

R TC

2

C TC

3

Rt

Ct

MGA646

Typical formula for oscillator frequency:

fosc = 2----.--5----×-----1R-----t--×-----C----t

Fig.14 Example of an RC oscillator.

September 1993

20

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