BR24G16-3_16 Datasheet, PDF (21/40 Pages) Rohm – I2C BUS EEPROM (2-Wire)

BR24G16-3
Datasheet
Power-Up/Down Conditions
At power on, the IC’s internal circuits may go through unstable low voltage area as the Vcc rises, making the IC’s internal
logic circuit not completely reset, hence, malfunction may occur. To prevent this, the IC is equipped with POR circuit and
LVCC circuit. To assure the operation, observe the following conditions at power ON.
1. Set SDA = 'H' and SCL ='L' or 'H’
2. Start power source so as to satisfy the recommended conditions of t_R, t_OFF, and V_bot for operating POR circuit.
tR
VCC
tOFF
Vbot
0
Figure 51. Rise Waveform Diagram
Recommended conditions of t_R, t_OFF,V_bot
t_R
t_OFF
V_bot
10ms or below 10ms or larger 0.3V or below
100ms or below 10ms or larger 0.2V or below
3. Set SDA and SCL so as not to become 'Hi-Z'.
When the above conditions 1 and 2 cannot be observed, take the following countermeasures.
(1) In the case when the above condition 1 cannot be observed such that SDA becomes 'L' at power ON .
→Control SCL and SDA as shown below, to make SCL and SDA, 'H' and 'H'.
VCC
t_LOW
Vcc
SCL
SCL
SDA
After Vcc becomes stable
t_DH
t_SU:DAT
Figure 52. When SCL= 'H' and SDA= 'L'
SDA
After Vcc becomes stable
t_SU:DAT
Figure 53. When SCL='L' and SDA='L'
(2) In the case when the above condition 2 cannot be observed.
→After power source becomes stable, execute software reset(Page 16).
(3) In the case when the above conditions 1 and 2 cannot be observed.
→Carry out (1), and then carry out (2).
Low Voltage Malfunction Prevention Function
LVCC circuit prevents data rewrite operation at low power, and prevents write error. At LVCC voltage (Typ=1.2V) or below,
data rewrite is prevented.
Noise Countermeasures
1. Bypass Capacitor
When noise or surge gets in the power source line, malfunction may occur, therefore, it is recommended to connect a
bypass capacitor (0.1µF) between the IC’s V_CC and GND pins. Connect the capacitor as close to the IC as possible. In
addition, it is also recommended to connect a bypass capacitor between board’s V_CC and GND.
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