S-93C46C Datasheet, PDF (21/39 Pages) Seiko Instruments Inc – 3-WIRE SERIAL E2PROM

Rev.1.1_00
3-WIRE SERIAL E²PROM
S-93C46C/56C/66C/76C/86C
 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.
Power supply voltage
Detection voltage (−V_DET)
1.2 V typ.
Release voltage (+V_DET)
1.2 V typ.
Write instructions are cancelled
Write disable status (EWDS) is automatically set
Figure 20 Operation during the Low Power Supply Voltage
21