PCA9551_8 © NXP B.V. 2008. All rights reserved.
Product data sheet Rev. 08 — 31 July 2008 15 of 26
NXP Semiconductors
PCA9551
8-bit I
2
C-bus LED driver with programmable blink rates
11. Dynamic characteristics
[1] t
VD;ACK
= time for Acknowledgement signal from SCL LOW to SDA (out) LOW.
[2] t
VD;DAT
= minimum time for SDA data output to be valid following SCL LOW.
[3] C
b
= total capacitance of one bus line in pF.
[4] Resetting the device while actively communicating on the bus may cause glitches or errant STOP conditions.
[5] Upon reset, the full delay will be the sum of t
rst
and the RC time constant of the SDA bus.
Table 13. Dynamic characteristics
Symbol Parameter Conditions Standard-mode
I
2
C-bus
Fast-mode I
2
C-bus Unit
Min Max Min Max
f
SCL
SCL clock frequency 0 100 0 400 kHz
t
BUF
bus free time between a STOP and
START condition
4.7 - 1.3 - µs
t
HD;STA
hold time (repeated) START condition 4.0 - 0.6 - µs
t
SU;STA
set-up time for a repeated START
condition
4.7 - 0.6 - µs
t
SU;STO
set-up time for STOP condition 4.0 - 0.6 - µs
t
HD;DAT
data hold time 0 - 0 - ns
t
VD;ACK
data valid acknowledge time
[1]
- 600 - 600 ns
t
VD;DAT
data valid time LOW-level
[2]
- 600 - 600 ns
HIGH-level
[2]
- 1500 - 600 ns
t
SU;DAT
data set-up time 250 - 100 - ns
t
LOW
LOW period of the SCL clock 4.7 - 1.3 - µs
t
HIGH
HIGH period of the SCL clock 4.0 - 0.6 - µs
t
r
rise time of both SDA and SCL signals - 1000 20 + 0.1C
b
[3]
300 ns
t
f
fall time of both SDA and SCL signals - 300 20 + 0.1C
b
[3]
300 ns
t
SP
pulse width of spikes that must be
suppressed by the input filter
- 50 - 50 ns
Port timing
t
v(Q)
data output valid time - 200 - 200 ns
t
su(D)
data input set-up time 100 - 100 - ns
t
h(D)
data input hold time 1 - 1 - µs
Reset timing
t
w(rst)
reset pulse width 8 - 8 - ns
t
rec(rst)
reset recovery time 0 - 0 - ns
t
rst
reset time
[4][5]
400 - 400 - ns
