DS1670 Datasheet, PDF (7/17 Pages) Dallas Semiconductor – Portable System Controller

DS1670
The DS1670 nonvolatilizes the external SRAM(s) by write protecting the SRAM(s) and by providing a
back-up power supply in the absence of V_CC. When V_CC falls below 2.88 volts (typical), access to the
external SRAM(s) are prohibited by forcing CEOL and CEOH high regardless of the level of CEI , BLE ,
and BHE . Also at this point, the SRAM power supply (V_CCO) is switched from V_CC to V_BAT. Upon
power up, access is prohibited until the end of t_RPU.
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