PCA9541A All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet Rev. 5 — 24 April 2014 31 of 45
NXP Semiconductors
PCA9541A
2-to-1 I
2
C-bus master selector with interrupt logic and reset
[4] C
b
= total capacitance of one bus line in pF.
[5] Measurements taken with 1 k pull-up resistor and 50 pF load.
[6] Resetting the device while actively communicating on the bus may cause glitches or errant STOP conditions.
[7] Upon reset, the full delay is the sum of t
rst
and the RC time constant of the SDA bus.
Fig 23. Definition of timing on the I
2
C-bus
t
SP
t
BUF
t
HD;STA
PP S
t
LOW
t
r
t
HD;DAT
t
f
t
HIGH
t
SU;DAT
t
SU;STA
Sr
t
HD;STA
t
SU;STO
SDA
SCL
002aaa986
0.7 × V
DD
0.3 × V
DD
0.7 × V
DD
0.3 × V
DD
Rise and fall times, refer to V
IL
and V
IH
.
Fig 24. I
2
C-bus timing diagram
002aab175
protocol
START
condition
(S)
bit 7
MSB
(A7)
bit 6
(A6)
bit 0
(R/W)
acknowledge
(A)
STOP
condition
(P)
SCL
SDA
t
HD;STA
t
SU;DAT
t
HD;DAT
t
f
t
BUF
t
SU;STA
t
LOW
t
HIGH
t
VD;ACK
t
SU;STO
1
/ f
SCL
t
r
t
VD;DAT
0.3 × V
DD
0.7 × V
DD
0.3 × V
DD
0.7 × V
DD
