BR24L02FJ-WE2 Rohm Semiconductor, BR24L02FJ-WE2 Datasheet - Page 13

• Manufacturer Part Number: BR24L02FJ-WE2
• Description: IC EEPROM 2KBIT 400KHZ 8SOP
• Manufacturer: Rohm Semiconductor

Specifications of BR24L02FJ-WE2

• Format - Memory: EEPROMs - Serial
• Memory Type: EEPROM
• Memory Size: 2K (256 x 8)
• Speed: 400kHz
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 1.8 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-SOPJ
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: BR24L02FJ-WE2; BR24L02FJ-WE2TR

Cautions on microcontroller connection
Rs
In I
SDA port, insert a series resistance Rs between the pull up resistance Rpu and the SDA terminal of EEPROM. This controls over
current that occurs when PMOS of the microcontroller and NMOS of EEPROM are turned ON simultaneously. Rs also plays the role of
protection of SDA terminal against surge. Therefore, even when SDA port is open drain input / output, Rs can be used.
Maximum value of Rs
The maximum value of Rs is determined by the following relations.
Minimum value of Rs
The minimum value of Rs is determined by over current at bus collision. When over current flows, noises in power source line, and
instantaneous power failure of power source may occur. When allowable over current is defined as I, the following relation must be
satisfied. Determine the allowable current in consideration of impedance of power source line in set and so forth. Set the over current
to EEPROM 10mA or below.
(1) SDA rise time to be determined by the capacity (CBUS) of bus line of Rpu and SDA should be tR or below.
(2) The bus electric potential
2
C BUS, it is recommended that SDA port is of open drain input /output. However, when to use CMOS input / output of tri state to
And AC timing should be satisfied even when SDA rise time is late.
sufficiently secure the input "L" level (V
V
IL
Microcontroller
Fig.53 I/O circuit diagram
"H" output
Microcontroller
Microcontroller
R
Fig.55 I/O circuit diagram
PU
Fig.56 I/O circuit diagram
A
V
CC
R
to be determined by Rpu and Rs at the moment when EEPROM outputs "L" to SDA bus should
S
R
Bus line
capacity CBUS
Over current I
PU
R
EEPROM
PU
I
R
OL
S
A
R
S
IL
) of microcontroller including recommended noise margin 0.1Vcc.
EEPROM
EEPROM
"L" output
V
OL
13/16
Example) When Vcc = 3V, V
SCL
SDA
Example) When Vcc = 3V, I = 10mA,
R
V
"H" output of microcontroller
R
S
CC
S
≥
(V
from (2),
≤ I
CC
R
R
V
R
S
S
CC
I
-V
PU
≤ 1.67 [k ]
≤
≤
OL
R
+R
V
S
0.3×3-0.4-0.1×3
) × R
IL
Fig.54 Input / output collision timing
≥
≥ 300 [ ]
S
1.1×3-0.3×3
-V
1.1V
Over current flows to SDA line by "H" output of
microcontroller and "L" output of EEPROM.
10×10
OL
S
-0.1V
CC
3
+ V
-V
IL
-3
OL
IL
CC
= 0.3Vcc, V
+0.1V
"L" output of EEPROM
× R
ACK
× 20×10
CC
PU
≤ V
OL
IL
3
= 0.4V, R
PU
= 20k ,