BR24G04-3A(2013) 데이터 시트보기 (PDF) - ROHM Semiconductor

부품명

상세내역

제조사

BR24G04-3A
(Rev.:2013)

Serial EEPROM series Standard EEPROM I2C BUS EEPROM (2-Wire)

ROHM Semiconductor 

BR24G04-3A

Datasheet

●I/O Peripheral Circuit

○Pull up resistance of SDA terminal

SDA is NMOS open drain, so requires pull up resistance. As for this resistance value (RPU), select an appropriate value to

this resistance value from microcontroller VIL, IL, and VOL-IOL characteristics of this IC. If RPU is large, action frequency is

limited. The smaller the RPU, the larger the supply current.

○Maximum value of RPU

The maximum value of RPU is determined by the following factors.

①SDA rise time to be determined by the capacitance (CBUS) of bus line of RPU and SDA should be tR or below.

And AC timing should be satisfied even when SDA rise time is late.

②The bus electric potential A to be determined by input leak total (IL) of device connected to bus at output of 'H' to

SDA bus and RPU should sufficiently secure the input 'H' level (VIH) of microcontroller and EEPROM including

recommended noise margin 0.2Vcc.

VCC－ILRPU－0.2 VCC ≧ VIH

∴

RPU

≦

0.8VCC－VIH

IL

Ex.) VCC =3V IL=10μA VIH=0.7 VCC

from②

Microcontroller

RPU

A

EEPROM

SDA terminal

RPU

≦

0.8×3－0.7×3

10×10-6

IL

IL

≦ 30 ［kΩ］

Bus line

capacity

CBUS

Figure 45. I/O circuit diagram

○ Minimum value of RPU

The minimum value of RPU is determined by the following factors.

When IC outputs LOW, it should be satisfied that VOLMAX=0.4V and IOLMAX=3mA.

VCC－VOL

RPU

≦

IOL

∴

RPU

≧

VCC－VOL

IOL

②VOLMAX=0.4V should secure the input 'L' level (VIL) of microcontroller and EEPROM including recommended

noise margin 0.1Vcc.

VOLMAX ≦ VIL－0.1 VCC

Ex.) VCC =3V, VOL=0.4V, IOL=3mA, microcontroller, EEPROM VIL=0.3Vcc

from①

RPU

≧

3－0.4

3×10 -3

≧ 867 ［Ω］

And

VOL=0.4［V］

VIL=0.3×3

=0.9［V］

Therefore, the condition ② is satisfied.

○Pull up resistance of SCL terminal

When SCL control is made at CMOS output port, there is no need, but in the case there is timing where SCL becomes

'Hi-Z', add a pull up resistance. As for the pull up resistance, one of several kΩ to several ten kΩ is recommended in

consideration of drive performance of output port of microcontroller.

www.rohm.co

© 2014 ROHM Co., Ltd. All rights reserved.

TSZ22111・15・001

20/33

TSZ02201-0R2R0G100560-1-2

27.Aug.2014 REV.003

Share Link: