M40Z111 データシートの表示（PDF） - STMicroelectronics
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M40Z111 Datasheet PDF : 20 Pages
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Operation
M40Z111, M40Z111W
Table 2. Power down/up AC characteristics
Symbol
Parameter(1)
Min
Max
Unit
tF(2)
tFB(3)
VPFD (max) to VPFD (min) VCC fall time
VPFD (min) to VSS VCC fall time
300
µs
10
µs
tR
VPFD (min) to VPFD (max) VCC rise time
10
µs
tRB
VSS to VPFD (min) VCC rise time
1
µs
tEDL Chip enable propagation delay
M40Z111
M40Z111W
15
ns
20
ns
M40Z111
10
ns
Obsolete Product(s) - Obsolete Product(s) 2.2
tEDH
tER(4)
tWPT
Chip enable propagation delay
Chip enable recovery
Write protect time
M40Z111W
40
M40Z111
40
M40Z111W 40
20
ns
200
ms
150
µs
250
µs
1. Valid for ambient operating temperature: TA = –40 to 85 °C; VCC = 4.5 to 5.5 V or 2.7 to 3.6 V (except
where noted).
2. VPFD (max) to VPFD (min) fall time of less than tF may result in deselection/write protection not occurring
until 200 µs after VCC passes VPFD (min).
3. VPFD (min) to VSS fall time of less than tFB may cause corruption of RAM data.
4. tER (min) = 20 ms for industrial temperature range - grade 6 device.
VCC noise and negative going transients
ICC transients, including those produced by output switching, can produce voltage
fluctuations, resulting in spikes on the VCC bus. These transients can be reduced if
capacitors are used to store energy which stabilizes the VCC bus. The energy stored in the
bypass capacitors will be released as low going spikes are generated or energy will be
absorbed when overshoots occur. A ceramic bypass capacitor value of 0.1 µF (as shown in
Figure 6) is recommended in order to provide the needed filtering.
In addition to transients that are caused by normal SRAM operation, power cycling can
generate negative voltage spikes on VCC that drive it to values below VSS by as much as
one volt. These negative spikes can cause data corruption in the SRAM while in battery
backup mode. To protect from these voltage spikes, STMicroelectronics recommends
connecting a Schottky diode from VCC to VSS (cathode connected to VCC, anode to VSS).
Schottky diode 1N5817 is recommended for through hole and MBRS120T3 is
recommended for surface mount.
Figure 6. Supply voltage protection
VCC
VCC
0.1µF
DEVICE
VSS
AI00622
10/20
Doc ID 5676 Rev 5
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