M34D64WMN6P datasheet(9/27 Pages) STMICROELECTRONICS

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M34D64-W

Signal description

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2.5

VSS ground

VSS is the reference for the VCC supply voltage.

2.6

Supply voltage (VCC)

2.6.1

Operating supply voltage VCC

Prior to selecting the memory and issuing instructions to it, a valid and stable VCC voltage

within the specified [VCC(min), VCC(max)] range must be applied (see Table 7). In order to

secure a stable DC supply voltage, it is recommended to decouple the VCC line with a

suitable capacitor (usually of the order of 10 nF to 100 nF) close to the VCC/VSS package

pins.

This voltage must remain stable and valid until the end of the transmission of the instruction

and, for a Write instruction, until the completion of the internal write cycle (tW).

2.6.2

Power-up conditions

When the power supply is turned on, VCC rises from VSS to VCC, the VCC rise time must not

vary faster than 1 V/µs.

2.6.3

Device reset

In order to prevent inadvertent write operations during power-up, a power-on-reset (POR)

circuit is included. At power-up (continuous rise of VCC), the device does not respond to any

instruction until VCC has reached the power-on-reset threshold voltage (this threshold is

lower than the minimum VCC operating voltage defined in Table 7). When VCC passes over

the POR threshold, the device is reset and enters the Standby Power mode. It must not be

accessed until VCC reaches a valid and stable VCC voltage within the specified [VCC(min),

VCC(max)] range.

In a similar way, during power-down (continuous decrease in VCC), as soon as VCC drops

below the power-on-reset threshold voltage, the device stops responding to any instruction

sent to it.

2.6.4

Power-down conditions

During power-down (continuous decrease in VCC), the device must be in Standby Power

mode (mode reached after decoding a Stop condition, assuming that there is no internal

Write cycle in progress).

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