
Electrical Specifications
131
November 2002 Revised January 2005
SPRS205D
5.16 I
2
C Timings
Table 539 and Table 540 assume testing over recommended operating conditions (see Figure 537 and
Figure 538).
Table 539. I
2
C Signals (SDA and SCL) Timing Requirements
CV
DD
= 1.2 V
CV
DD
= 1.35 V
CV
DD
= 1.6 V
NO.
STANDARD
MODE
FAST
MODE
STANDARD
MODE
FAST
MODE
UNIT
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
IC1
t
c(SCL)
Cycle time, SCL
10
2.5
10
2.5
μ
s
IC2
t
su(SCLH-SDAL)
Setup time, SCL high
before SDA low for a
repeated START condition
4.7
0.6
4.7
0.6
μ
s
IC3
t
h(SCLL-SDAL)
Hold time, SCL low after
SDA low for a START and
a repeated START
condition
4
0.6
4
0.6
μ
s
IC4
t
w(SCLL)
t
w(SCLH)
Pulse duration, SCL low
4.7
1.3
4.7
1.3
μ
s
μ
s
IC5
Pulse duration, SCL high
4
0.6
4
0.6
IC6
t
su(SDA-SCLH)
Setup time, SDA valid
before SCL high
250
100
250
100
ns
IC7
t
h(SDA-SCLL)
Hold time, SDA valid after
SCL low
0
0
0.9
§
0
0
0.9
§
μ
s
IC8
t
w(SDAH)
Pulse duration, SDA high
between
STOP
START conditions
and
4.7
1.3
4.7
1.3
μ
s
IC9
t
r(SDA)
t
r(SCL)
t
f(SDA)
t
f(SCL)
Rise time, SDA
1000
20 + 0.1C
b
20 + 0.1C
b
20 + 0.1C
b
20 + 0.1C
b
300
1000
20 + 0.1C
b
20 + 0.1C
b
20 + 0.1C
b
20 + 0.1C
b
300
ns
IC10
Rise time, SCL
1000
300
1000
300
ns
IC11
Fall time, SDA
300
300
300
300
ns
IC12
Fall time, SCL
300
300
300
300
ns
IC13
t
su(SCLH-SDAH)
Setup time, SCL high be-
fore SDA high (for STOP
condition)
4.0
0.6
4.0
0.6
μ
s
IC14
t
w(SP)
Pulse
(must be suppressed)
duration,
spike
0
50
0
50
ns
IC15
C
b
Capacitive load for each
bus line
400
400
400
400
pF
A Fast-mode I
2
C-bus device can be used in a Standard-mode I
2
C-bus system, but the requirement t
su(SDA-SCLH)
≥
250 ns must then be met.
This will automatically be the case if the device does not stretch the LOW period of the SCL signal. If such a device does stretch the LOW period
of the SCL signal, it must output the next data bit to the SDA line t
r
max + t
su(SDA-SCLH)
= 1000 + 250 = 1250 ns (according to the Standard-mode
I
2
C-Bus Specification) before the SCL line is released.
A device must internally provide a hold time of at least 300 ns for the SDA signal (referred to the V
IHmin
of the SCL signal) to bridge the undefined
region of the falling edge of SCL.
§
The maximum t
h(SDA-SCLL)
has only to be met if the device does not stretch the LOW period [t
w(SCLL)
] of the SCL signal.
C
b
= total capacitance of one bus line in pF. If mixed with HS-mode devices, faster fall-times are allowed.
I
2
C Bus is a trademark of Koninklijke Philips Electronics N.V.