BR34L02FV-W View Datasheet(PDF) - ROHM Semiconductor

Part Name

Description

View to exact match

BR34L02FV-W

256×8 bit Electrically Erasable PROM (based on Serial Presence Detect)

ROHM Semiconductor 

Memory ICs

BR34L02FV-W

6) I/O circuit

• Pull up resister of SDA pin

The pull up resister is needed because SDA is NMOS open drain. Decide the value of this resister (RPU) properly,

by considering VIL, IL characteristics of a controller which control the device and VOH, IOL characteristics of the

device. If large RPU is chosen, clock frequency need to be slow.

In case of small RPU, the operating current increases.

• Maximum of RPU

Maximum of RPU is determined by following factor.

c SDA rise time determined by RPU and the capacitance of bus line (CBUS) must be less than TR.

And the other timing must keep the conditions of AC spec.

d When SDA bus is HIGH, the voltage A of SDA bus determined by a total input leak (IL) of the all devices

connected to the bus and RPU must be enough higher than input HIGH level of a controller and the device,

including noise margin 0.2VCC.

VCC − ILRPU − 0.2VCC ≥ VIH

RPU ≤

0.8VCC − VIH

IL

MICRO

COMPUTER

IL

RPU A

BR24LXX

SDA PIN

IL

Examples : When VCC=3V IL=10µA VIH=0.7VCC

According to 2

RPU ≤

0.8×3−0.7×3

10×10−6

≤ 300 [kΩ]

THE CAPACITANCE OF

BUS LINE (CBUS)

Rev.A 17/24

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