Nxp Semiconductors PCA8565 用户手册
NXP Semiconductors
UM10301
User Manual PCF85x3, PCA8565 and PCF2123, PCA2125
UM10301_1
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 01 — 23 December 2008
41 of 52
b
r
P
C
t
R
⋅
=
8473
.
0
(max)
002aac883
C
b
(pF)
0
600
400
200
8
12
4
16
20
R
p(max)
(k
Ω
)
0
(1)
(2)
(3)
(1) Standard-mode
(2) Fast-mode
(3) Fast-mode
(2) Fast-mode
(3) Fast-mode
Plus
Fig 17. R
p(max)
as a function of bus capacitance
Below R
p(max)
is calculated for both Standard-mode and Fast-mode I
2
C bus. The result
has been rounded down to E6 standard values.
400 kHz I
2
C bus:
Ω
=
⋅
⋅
⋅
=
⋅
=
−
−
−
k
C
t
R
b
r
kHz
P
22
10
9
.
14
8473
.
0
10
300
8473
.
0
12
9
400
100 kHz I
2
C bus:
Ω
=
⋅
⋅
⋅
=
⋅
=
−
−
−
k
C
t
R
b
r
kHz
P
68
10
9
.
14
8473
.
0
10
1
8473
.
0
12
6
100
Two examples of an application diagram are shown in Fig 18 and Fig 19. In these
examples the INT output is left unused. If used, a pull-up to V
examples the INT output is left unused. If used, a pull-up to V
DD
is required.
The first example is using PCF8563 (Fig 18), the second example is using PCA2125
(Fig 19). In both examples the optional backup supply is realized using a 1 F capacitor.
(Fig 19). In both examples the optional backup supply is realized using a 1 F capacitor.