Datasheet

PCA9551_8 © NXP B.V. 2008. All rights reserved.
Product data sheet Rev. 08 — 31 July 2008 17 of 26
NXP Semiconductors
PCA9551
8-bit I
2
C-bus LED driver with programmable blink rates
12. Test information
Rise and fall times refer to V
IL
and V
IH
.
Fig 21. I
2
C-bus timing diagram
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
002aab175
t
SU;STO
protocol
START
condition
(S)
bit 7
MSB
(A7)
bit 6
(A6)
bit 0
(R/W)
acknowledge
(A)
STOP
condition
(P)
1
/f
SCL
t
r
t
VD;DAT
R
L
= load resistor for LEDn. R
L
for SDA and SCL > 1 kΩ (3 mA or less current).
C
L
= load capacitance includes jig and probe capacitance.
R
T
= termination resistance should be equal to the output impedance Z
o
of the pulse generators.
Fig 22. Test circuitry for switching times
PULSE
GENERATOR
V
O
C
L
50 pF
R
L
500 Ω
002aab880
R
T
V
I
V
DD
DUT
V
DD
open
V
SS