BU9829GUL-W_10 Datasheet, PDF (12/17 Pages) Rohm – WL-CSP EEPROM family SPI BUS

BU9829GUL-W
Technical Note
1.3.2 Pull down resistance Rpd of input terminals
Microcontroller
V_OHM
I_OHM
“H” output
EEPROM
V_IHE
Rpd ^{“H” input}
Rpd ≧
V_OHM ≦
V_OHM
I_OHM
V_IHE
…①
…②
Example) When Vcc=5V, VIHE=3.5V, VOHM=2.4V, IOHM=2mA,
from the equation①,
Fig.51 Input terminals Pull down resistance
・VIHE : EEPROM VIH specifications
・VOHM : Microcontroller VOH specifications
・IOHM : Microcontroller IOH specifications
Rpd ≧
∴Rpd ≧
2.4
2×10^-3
1.2 [kΩ]
With the value of Rpd to satisfy the above equation, VOHM
becomes 2.4V or higher, and with VIHE(=3.5V), the equation②is
also satisfied.
1.3.3 Pull up resistance Rpu of SO pin
Microcontroller _Rpu
V_ILM
I_OLE
EEPROM
V_OLE
Rpu ≧
V_OLE ≦
V_CC-V_OLE
I_OLE
V_ILM
…①
…②
“L” input
“L” output
Fig.52 SO Pull up resistance
・VOLE : EEPROM VOL specifications
・IOLE : Microcontroller IOL specifications
・VILM : Microcontroller VIL specifications
Example) When Vcc=5V, VOLE=0.4V, VILM=1.5V, IOLE=2.1mA,
from the equation①,
Rpu ≧
∴Rpu ≧
5-0.4
2.1×10^-3
2.2 [kΩ]
With the value of Rpd to satisfy the above equation, VOLE
becomes 0.4V or higher, and with VILM(=1.5V), the equation②is
also satisfied.
1.3.4 Pull up resistance Rpu of SO pin
Microcontroller
V_IHM
EEPROM
V_OHE
“H” input _Rpd
I_OHE
“H” output
Fig.53 SO Pull down resistance
Rpd ≧
V_OHE ≧
V_OHE
I_OHE
V_IHM
…①
…②
Example) When Vcc=5V, VOHE=Vcc-0.5V, VIHM=Vccx0.7V, IOHE=0.4mA,
from the equation①,
Rpd ≧
∴Rpd ≧
5-0.5
0.4×10^-3
11.3 [kΩ]
・VOHE : EEPROM VOH specifications
・IOHE : EEPROM IOH specifications
・VIHM : Microcontroller VIH specifications
With the value of Rpu to satisfy the above equation, VOHE
becomes 4.5V or higher, and with VIHM(=3.5V), the equation ② is
also satisfied.
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12/16
2010.09 - Rev.A