I2c electrical characteristics, C electrical characteristics, Figure 3. series resistors (r – Rainbow Electronics MAXQ2010 User Manual
Page 10: For protecting against high-voltage spikes
MAXQ2010
16-Bit Mixed-Signal Microcontroller with LCD
10
______________________________________________________________________________________
I
2
C ELECTRICAL CHARACTERISTICS
(V
DVDD
= V
AVDD
= 2.7V to 3.6V, T
A
= -40°C to +85°C.)
Note 19: Devices that use nonstandard supply voltages that do not conform to the intended I
2
C bus system levels must relate their
input levels to the voltage to which the pullup resistors R
P
are connected. See Figure 3.
Note 20: C
B
—Capacitance of one bus line in pF.
Note 21: The maximum fall time of 300ns for the SDA and SCL bus lines shown in the
I
2
C Bus Controller Timing table is longer than
the specified maximum t
OF_I2C
of 250ns for the output stages. This allows series protection resistors (R
S
) to be connected
between the SDA/SCL pins and the SDA/SCL bus lines as shown in the
I
2
C Bus Controller Timing (Acting as I
2
C Slave)
table without exceeding the maximum specified fall time. See Figure 3.
SDA
P6.7
SCL
P6.6
R
S
R
S
I
2
C
DEVICE
R
S
R
S
I
2
C
DEVICE
R
P
R
P
V
DVDD
MAXQ2010
Figure 3. Series Resistors (R
S
) for Protecting Against High-Voltage Spikes
STANDARD MODE
FAST MODE
PARAMETER SYMBOL
TEST
CONDITIONS
MIN MAX MIN MAX
UNITS
Input Low Voltage (Note 19)
V
IL_I2C
-0.5
0.3
x
V
DVDD
-0.5 0.3
x
V
DVDD
V
Input High Voltage (Note 19)
V
IH_I2C
0.7
x
V
DVDD
0.7
x
V
DVDD
V
DVDD
+ 0.5V
V
Input Hysteresis (Schmitt)
V
IHYS_I2C
V
DVDD
> 2V
0.05 x V
DVDD
V
Output Logic-Low (Open
Drain or Open Collector)
V
OL_I2C
V
DVDD
> 2V, 3mA sink
current
0 0.4 0 0.4
V
Output Fall Time from
V
IH_MIN
to V
IL_MAX
with Bus
Capacitance from 10pF to
400pF (Notes 20, 21)
t
OF_I2C
250
20
+
0.1C
B
250
ns
Pulse Width of Spike
Filtering That Must Be
Suppressed by Input Filter
t
SP_I2C
0
50
ns
Input Current on I/O
I
IN_I2C
Input voltage from 0.1 x
V
DVDD
to 0.9 x V
DVDD
-10 +10 -10 +10
μA
I/O Capacitance
C
IO_I2C
10 10
pF