BR93L66RF-WE2 Rohm Semiconductor, BR93L66RF-WE2 Datasheet - Page 11

• Manufacturer Part Number: BR93L66RF-WE2
• Description: IC EEPROM 4KBIT 2MHZ 8SOP
• Manufacturer: Rohm Semiconductor

Specifications of BR93L66RF-WE2

• Memory Size: 4K (256 x 16)
• Format - Memory: EEPROMs - Serial
• Memory Type: EEPROM
• Speed: 2MHz
• Interface: Microwire, 3-Wire Serial
• Voltage - Supply: 1.8 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-SOP
• Clock Frequency: 2MHz
• Supply Voltage Range: 1.8V To 5.5V
• Memory Case Style: SOP
• No. Of Pins: 8
• Operating Temperature Range: -40°C To +85°C
• Svhc: No SVHC (18-Jun-2010)
• Package /: RoHS Compliant
• Memory Configuration: 256 X 16
• Interface Type: Serial, Microwire
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3) Equivalent circuit
4) I/O peripheral circuit
4-1) Pull down CS.
4-2) DO is available in both pull up and pull down.
DO output become "High-Z" in other READY / BUSY output timing than after data output at read command and write
command.
When malfunction occurs at "High-Z" input of the microcontroller port connected to DO, it is necessary to pull down and
pull up DO.
When there is no influence upon the microcontroller actions, DO may be OPEN.
If DO is OPEN, and at timing to output status READY, at timing of CS = "H", SK = "H", DI = "H", EEPROM recognizes this
as a start bit, resets READY output, and DO = "High-Z", therefore, READY signal cannot be detected. To avoid such
output, pull up DO pin for improvement.
By making CS = "L" at power ON/OFF, mistake in operation and mistake write are prevented.
Output circuit
Input circuit
Pull down resistance Rpd of CS pin
To prevent mistake in operation and mistake write at power ON/OFF, CS pull down resistance is necessary. Select an
appropriate value to this resistance value from microcontroller VOH, IOH, and VIL characteristics of this IC.
DI
Microcontroller
"H" output
VOHM
Fig. 50 CS pull down resistance
Fig. 51 READY output timing at DO = OPEN
Fig. 46
DO
CS
SK
DI
Fig. 48
High-Z
OEint.
IOHM
D0
Output circuit
Input circuit
CSint.
Rpd
(DI)
(DO)
VIHE
"L" input
BUSY
EEPROM
READY
DO
11/16
Enlarged
Input circuit
Input circuit
With the value of Rpd to satisfy the above equation, VOHM becomes
2.4V or higher, and with VIHE (= 2.0V), the equation
Example) When Vcc = 5V, VIHE = 2V, VOHM = 2.4V, IOHM = 2mA,
SK
CS
CS
SK
DO
DO
DI
VIHE : EEPROM VIH specifications
VOHM : Microcontroller VOH specifications
IOHM : Microcontroller IOH specifications
"H"
BUSY
BUSY
VOHM
from the equation
Rpd
Rpd
Rpd
Fig. 47
Fig. 49
Improvement by DO pull up
≥
≥
≥
≥
READY
High-Z
2×10
VOHM
IOHM
VIHE
1.2 (K )
2.4
Input circuit
Input circuit
-3
RESETint.
,
CS = SK = DI = "H"
CS = SK = DI = "H"
When DO = OPEN
When DO = pull up
CSint.
. . .
. . .
(CS)
(SK)
is also satisfied.
CSint.