s-25a080a Seiko Instruments Inc., s-25a080a Datasheet - Page 24

• Manufacturer Part Number: s-25a080a
• Description: 25?c Operation Spi Serial E2prom For Automotive Electric Component
• Manufacturer: Seiko Instruments Inc.

24
125°C OPERATION SPI SERIAL E
S-25A080A/160A/320A
1. Connection of input pin
2. Equivalent circuit of I/O pin
Write Protect Function during the Low Power Supply Voltage
I/O Pin
In the Write operation, data in the address written during the low power supply voltage is not assured.
The S-25A080A/160A/320A has a built-in detection circuit which operates with the low power supply voltage. The S-
25A080A/160A/320A cancels the Write operation (WRITE, WRSR) when the power supply voltage drops and power-
on, at the same time, goes in the Write protect status (WRDI) automatically to reset bit WEL. The detection voltage is
1.20 V typ., the release voltage is 1.35 V typ., and its hysteresis is approx. 0.15 V (Refer to Figure 18).
To operate Write, after the power supply voltage dropped once but rose to the voltage level which allows Write again,
be sure to set the Write Enable Latch bit (WEL) before operating Write (WRITE, WRSR).
All input pins in S-25A080A/160A/320A have the CMOS structure. Do not set these pins in high impedance during
operation when you design. Especially, set the CS input in the non-select status “H” during power-on/off and standby.
The error Write does not occur as long as the CS pin is in the non-select status “H”. Set the CS pin to V
resistor (the pull-up resistor of 10 kΩ to 100 kΩ). To prevent the error for sure, it is recommended to set other input
pins than the CS pin via a pull-up resistor.
elements are not included in each input pin, pay attention not to set it in the floating state when you design.
Figure 21 shows the equivalent circuit of the output pin. This pin has the tri-state output of “H” level/“L” level/high
impedance.
Figure 19 and 20 show the equivalent circuits of input pins in S-25A080A/160A/320A. A pull-up and pull-down
Power supply voltage
Detection voltage (−V
1.20 V Typ.
Figure 18 Operation during Low Power Supply Voltage
DET
2
PROM FOR AUTOMOTIVE ELECTRIC COMPONENT
)
Seiko Instruments Inc.
Cancel the Write instruction
Set in Write protect (WRDI) automatically
Hysteresis
approx. 0.15 V
Release voltage (+V
1.35 V Typ.
DET
)
Rev.1.0
CC
via a
_00