Filter
Top Products
Philips Semiconductors
ISP1521
Hi-Speed USB hub controller
Product data Rev. 03 — 24 November 2004 43 of 53
9397 750 13702
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
[1] f
SCL
=
1
⁄
64
× f
XTAL
.
[2] Rise time is determined by C
b
and pull-up resistor value R
p
(typical 4.7 kΩ).
Table 46: Dynamic characteristics: I
2
C-bus (pins SDA and SCL)
V
CC
and T
amb
within recommended operating range; V
DD
=5V; V
SS
=V
GND
; V
IL
and V
IH
between V
SS
and V
DD
.
Symbol Parameter Conditions Min Typ Max Unit
Clock frequency
f
SCL
SCL clock frequency f
XTAL
=12MHz
[1]
0 93.75 100 kHz
General timing
t
LOW
SCL LOW time 4.7 - - µs
t
HIGH
SCL HIGH time 4.0 - - µs
t
r
SCL and SDA rise time
[2]
- - 1000 ns
t
f
SCL and SDA fall time - - 300 ns
C
b
capacitive load for each bus line - - 400 pF
SDA timing
t
BUF
bus free time 4.7 - - µs
t
SU;STA
set-up time for (repeated) START
condition
4.7 - - µs
t
HD;STA
hold time (repeated) START condition 4.0 - - µs
t
SU;DAT
data set-up time 250 - - ns
t
HD;DAT
data hold time 0 - - µs
t
SU;STO
set-up time for STOP condition 4.0 - - µs
Additional I
2
C-bus timing
t
VD;DAT
SCL LOW to data-out valid time - - 0.4 µs
Fig 16. I
2
C-bus timing.
P
S Sr
P
004aaa485
t
HD;STA
t
BUF
t
SU;STA
t
SU;DAT
t
f
t
HIGH
t
LOW
t
SU;STO
t
r
t
HD;DAT
SDA
SCL