74hct5555 NXP Semiconductors, 74hct5555 Datasheet - Page 20

• Manufacturer Part Number: 74hct5555
• Description: Programmable Delay Timer With Oscillator
• Manufacturer: NXP Semiconductors

Philips Semiconductors
APPLICATION INFORMATION
September 1993
handbook, halfpage
handbook, halfpage
Programmable delay timer with oscillator
Fig.11 Test set-up for measuring forward
C
R
RC oscillator frequency as a function of R
at V
t
t
f osc
(Hz)
curve at R
curve at C
CC
10
10
10
10
10
(f = 1 kHz)
3
2
5
4
10
10
= 2 to 6 V; T
v i
3
transconductance g
constant (see Fig.12) and MR = LOW.
– 4
0.47 F
t
t
Fig.13 Application information.
= 100 k ; R2 = 200 k .
= 1 nF; R2 = 2 x R
amb
input
= 25 C.
10
10
R
bias
4
C t
– 3
= 560 k
t
.
V CC
fs
R t
output 100 F
= di
10
10
t
and C
5
o
– 2
/dv
t
R ( )
MGA645
C ( F)
i
at v
t
t
A
MGA647
o
i o
GND
is
10
10
6
– 1
20
handbook, halfpage
handbook, halfpage
Fig.12 Typical forward transconductance g
Typical formula for oscillator frequency:
f
osc
(mA/V)
C2
g
=
fs
------------------------------- -
2.5 R
Fig.14 Example of an RC oscillator.
function of the supply voltage at V
T
14
12
10
8
6
4
2
amb
1
0
t
R2
1
= 25 C.
C
t
RS
1
MR (from logic)
2
3
74HC/HCT5555
R TC
2
R t
4
Product specification
max.
V
MGA646
CC
5
MBA333
(V)
min.
typ.
CC
C TC
3
fs
C t
at
6
as a