SA3291 Datasheet, PDF (6/20 Pages) ON Semiconductor – Preconfigured Wireless DSP System for Hearing Aids

AYRE SA3291
Table 3. I²C TIMING
Standard Mode
Fast Mode
Parameter
Symbol
Min
Clock Frequency
f_{PC_CLK}
0
Hold time (repeated) START condition. After this
t_HD;STA
4.0
period, the first clock pulse is generated.
Max
100
−
Min
Max
Units
0
400
kHz
0.6
−
msec
LOW Period of the PC_CLK Clock
HIGH Period of the PC_CLK Clock
Set−up time for a repeated START condition
Data Hold Time:
for CBUS Compatible Masters
for I²C−bus Devices
t_LOW
t_HIGH
t_SU;STA
t_HD;DAT
4.7
−
4.0
−
4.7
−
5.0
−
0 (Note 1) 3.45 (Note 2)
−
−
−
−
0 (Note 1)
−
−
−
−
0.9 (Note 2)
msec
msec
msec
msec
Data set−up time
t_SU;DAT
250
Rise time of both PC_SDA and PC_CLK signals
t_r
−
−
1000
100
−
20 + 0.1 C_b
300
(Note 4)
nsec
nsec
Fall time of both PC_SDA and PC_CLK signals
t_f
−
300
20 + 0.1 C_b
300
nsec
(Note 4)
Set−up time for STOP condition
Bus free time between a STOP and
START condition
t_SU;STO
4.0
−
t_BUF
4.7
−
0.6
−
nsec
1.3
−
msec
Output fall time from V_IHmin to V_ILmax with a bus
t_of
−
capacitance from 10 pF to 400 pF
250
20 + 0.1 C_b
250
nsec
(Note 4)
Pulse width of spikes which must be suppressed
t_SP
n/a
n/a
by the input filter
0
50
nsec
Capacitive load for each bus line
C_b
−
400
−
400
pF
1. A device must internally provide a hold time of at least 300 ns for the PC_SDA signal to bridge the undefined region of the falling edge of PC_CLK.
2. The maximum t_HD;DAT has only to be met if the device does not stretch the LOW period (t_LOW) of the PC_CLK signal.
3. A Fast−mode I²C−bus device can be used in a Standard−mode I²C−bus system, but the requirement t_SU;DAT P250ns must then be met.
This will automatically be the case if the device does not stretch the LOW period of the PC_CLK signal. If such a device does stretch the
LOW period of the PC_CLK signal, it must output the next data bit to the PC_SDA line t_r max + t_SU;DAT = 1000 + 250 = 1250 ns (according
to the Standard−mode I²C−bus specification) before the PC_CLK line is released.
4. C_b = total capacitance of one bus line in pF.
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