Technical Note

4/18

www.rohm.com

2010.12 - Rev.B

© 2010 ROHM Co., Ltd. All rights reserved.

●Pin assignment and description

Terminal

name

Input

/Output

Function

Vcc

-

Power source to be connected

GND

-

All input / output reference voltage, 0V

CSB

Input

Chip select input

SCK

Input

Serial clock input

SI

Input

Start bit, ope code, address, and serial data input

SO

Output

Serial data output

HOLDB

Input

Hold input

Command communications may be suspended temporarily

(HOLD status)

WPB

Input

Write protect input

Write command is prohibited

Write status register command is prohibited

●Sync data input / output timing

●AC timing characteristics conditions

Parameter

Symbol

Limits

Unit

Min.

Typ.

Max.

Load capacity

-

-

30

pF

Input rise time

-

-

-

50

ns

Input fall time

-

-

-

50

ns

Input voltage

-

0.2Vcc/0.8Vcc

V

Input / Output judgment voltage

-

0.3Vcc/0.7Vcc

V

●Characteristic data (The following characteristic data are Typ. Values.)

Vcc

HOLDB

SCK

SI

CSB

SO

WPB

GND

BR25S320-W

BR25S640-W

BR25S128-W

BR25S256-W

Fig.2 Pin assignment diagram

Fig.3

Input timing

CSB

SCK

SI

SO

tCS

tCSS

tSCKS

tSCKWL

tSCKWH

tDIS

tDIH

tRC

tFC

High-Z

SI is taken into IC inside in sync with data rise edge of

SCK. Input address and data from the most significant bit

MSB

Fig.4

Input / Output timing

CSB

SCK

SI

SO

tPD

tOH

tRO,tFO

tOZ

tCSH tSCKH

tCS

High-Z

Fig.5

HOLD timing

CSB

SCK

SI

n+1

"H"

"L"

n

Dn

n-1

Dn

Dn-1

HOLDB

SO

Dn+1

tHFS

tHFH

tHOZ

tHRS tHRH

tDIS

tHPD

High-Z

SO is output in sync with data fall edge of SCK. Data is

output from the most significant bit MSB.

0

0.2

0.4

0.6

0.8

1

0

12

345

6

IOL[mA]

Ta=-40℃

Ta=25℃

Ta=85℃

SPEC

Fig.8　"L" output voltage　VOL1 (Vcc=2.5V)

0

1

2

3

4

5

6

01

2

34

56

Vcc[V]

SPEC

Ta=-40℃

Ta=25℃

Ta=85℃

Fig.6

　"H" input voltage　VIH(CSB,SCK,SI,HOLDB,WPB)

0

1

2

3

4

5

6

01

2

3

456

Vcc[V]

SPEC

Ta=-40℃

Ta=25℃

Ta=85℃

Fig.7 　"L" input voltage　VIL(CSB,SCK,SI,HOLDB,WPB)