S-93C46B_1 Datasheet, PDF (19/50 Pages) Seiko Instruments Inc – 3-WIRE SERIAL E2PROM

Rev.7.0_00
3-WIRE SERIAL E²PROM
S-93C46B/56B/66B
„ Write Protect Function during the Low Power Supply Voltage
The S-93C46B/56B/66B provides a built-in detector. When the power supply voltage is low or at power application,
the write instructions (WRITE, ERASE, WRAL, and ERAL) are cancelled, and the write disable state (EWDS) is
automatically set. The detection voltage is 1.75 V typ., the release voltage is 2.05 V typ., and there is a hysteresis of
about 0.3 V (refer to Figure 21). 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)
1.75 V Typ.
Hysteresis
About 0.3 V
Release voltage (+V_DET)
2.05 V Typ.
Write instruction cancelled
Write disable state (EWDS) automatically set
Figure 21 Operation during Low Power Supply Voltage
Seiko Instruments Inc.
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