S-93C46B-H Datasheet, PDF (19/34 Pages) Seiko Instruments Inc – FOR AUTOMOTIVE OPERATION 3-WIRE SERIAL E2PROM

Rev.2.1_02
FOR AUTOMOTIVE 105°C OPERATION 3-WIRE SERIAL E²PROM
S-93C46B/56B/66B H Series
 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 18). 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 18 Operation during Low Power Supply Voltage
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