R2023K datasheet(22/50 Pages) RICOH

部品番号	R2023K

部品情報	2-wire Serial Interface Real Time Clock IC

PDF	50 Pages

Scroll/Zoom	100%

メーカー	RICOH [RICOH electronics devices division]

ホームページ	http://www.ricoh.com

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22 / 50 page

R2023K/T

is because there are two pins of SDA and SCL.

The third member, (charging/discharging times per unit time)

means number of transition from “H” to “L” of the signal line.

Calculation example is shown below:

Pull-up resistor (Rp) = 10k

Ω, Bus capacity = 50pF(both for SCL, SDA), VDD=3V,

In a system with sum of input current and off-state output current of each pin = 0.1

µA,

2C-Bus is used for 10ms every second while the rest of 990ms in the stand-by mode,

In this mode, number of transitions of the SCL pin from “H” to “L” state is 100 while SDA 50, every second.

Bus consumption current

≈

0.1

µA×990msec

990msec + 10msec

× 10msec × 2

10K

Ω × 2 × (990msec + 10msec)

+ 3V

× 50pF × (100 + 50)

≈ 0.099µA + 3.0µA + 0.0225µA ≈ 3.12µA

Generally, the second member of the above formula is larger enough than the first and the third members bus

consumption current may be determined by the second member is many cases.

R2023K データシート(PDF) 22 Page - RICOH electronics devices division