Rainbow Electronics BR24L02FVM-W - Manual (Page 21)

BR24L02-W / BR24L02F-W / BR24L02FJ-W /
Memory ICs BR24L02FV-W / BR24L02FVM-W
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•
The maximum value of R S
The maximum value of R S is determined by following factors.
c SDA rise time determined by R PU and the capacitance of bus line (CBUS) of SDA must be less than t R . And the
other timing must also keep the conditions of the AC timing.
d When the device outputs LOW on SDA line, the voltage of the bus A determined by R PU and R S must be
lower than the inputs LOW level of the controller, including recommended noise margin (0.1V CC ).
V OL
V IL
R PU
V CC
R S
I OL
CONTROLLER EEPROM
A
CAPACITANCE OF
BUS LINE (CBUS)
R S
≤ × R PU
V IL
− V OL
− 0.1V CC
1.1V CC
− V IL
R S
≤ Ч
20
Ч
10 3
0.3
Ч
3
−
0.4
−
0.1
Ч
3
1.1
Ч
3
−
0.3
Ч
3
+
V OL
+
0.1V CC
≤
V IL
(V CC
−
V OL )
×
R S
R PU
+
R S
≤ 1.67 [k Ω ]
Examples : when V CC
=
3V, V IL
=
0.3V CC , V OL
=
0.4V, R PU
=
20k
Ω
According to 2
•
The minimum value of R S
The minimum value of R S is determined by the current overload due to the conflict on the bus.
The current overload may cause noise on the power line and instantaneous power down.
The following conditions must be met, where
Ι
is the maximum permissible current.
The maximum permissible current depends on V CC line impedance and so on. It need to be less than 10mA for
EEPROM.
R S
≥
V CC
Ι
R S
≥
3
10
×
10
− 3
≤ Ι V CC
R S
≥
300 [
Ω
]
Examples : When V CC
=
3V,
Ι=
10mA
R PU
R S
CONTROLLER EEPROM
"L" OUTPUT
"H" OUTPUT
MAXIMUM
CURRENT
Ι