S-93C46C/56C/66C/76C/86C

21

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Write Protect Function during the Low Power Supply Voltage

This IC provides a built-in detection circuit to detect a low power supply voltage. When the power supply voltage is low or

at power-on, the write instructions (WRITE, ERASE, WRAL, and ERAL) are cancelled, and the write disable (EWDS)

status is automatically set. The detection voltage and the release voltage are 1.2 V typ. (refer to Figure 20).

Therefore, when a write operation is performed after the power supply voltage has dropped and then risen again up to

the level at which writing is possible, a write enable instruction (EWEN) must be sent before a write instruction (WRITE,

ERASE, WRAL, or ERAL) is executed.

When the power supply voltage drops during a write operation, the data being written to an address at that time is not

guaranteed.

Write instructions are cancelled

Write disable status (EWDS) is automatically set

Release voltage (

1.2 V typ.

Power supply voltage

Detection voltage (

1.2 V typ.

Figure 20 Operation during the Low Power Supply Voltage