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XT
April 1999
4.5.99
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Table 11: Serial Interface Timing Specifications
Unless otherwise stated, all power supplies = 3.3V ± 5%, no load on any output, and ambient temperature range TA = 0°C to 70°C. Parameters denoted with an asterisk ( * ) represent nominal
characterization data and are not currently production tested to any specific limits. MIN and MAX characterization data are
± 3σ from typical.
PARAMETER
SYMBOL
CONDITIONS/DESCRIPTION
MIN.
MAX.
UNITS
Clock frequency
fSCL
SCL
10
400
kHz
Bus free time between STOP and START
tBUF
4.7
µs
Set up time, START (repeated)
tsu:STA
4.7
µs
Hold time, START
thd:STA
4.0
µs
Set up time, data input
tsu:DAT
SDA
250
ns
Hold time, data input
thd:DAT
SDA
300
ns
Output data valid from clock
tAA
Minimum delay to bridge undefined region of the fall-
ing edge of SCL to avoid unintended START or STOP
3.5
µs
Rise time, data and clock
tr
SDA, SCL
1000
ns
Fall time, data and clock
tf
SDA, SCL
300
ns
High time, clock
tH
SCL
4.0
µs
Low time, clock
tL
SCL
4.7
µs
Set up time, STOP
tsu:STO
4.0
µs
Figure 12: Bus Timing Data
SCL
SDA
STOP
t
su:STO
t
hd:STA
START
t
su:STA
ADDRESS OR
DATA VALID
DATA CAN
CHANGE
Figure 13: Data Transfer Sequence
SCL
SDA
IN
t
hd:DAT
t
hd:STA
t
su:STA
t
su:STO
t
L
t
H
SDA
OUT
t
su:DAT
t
BUF
t
r
t
f
t
AA
t
AA