M48T512V datasheet(14/23 Pages) STMICROELECTRONICS

部品番号	M48T512V

部品情報	5.0 or 3.3 V, 4 Mbit (512 Kbit x 8) TIMEKEEPER짰 SRAM

PDF	23 Pages

Scroll/Zoom	100%

メーカー	STMICROELECTRONICS [STMicroelectronics]

ホームページ	http://www.st.com

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14 / 23 page

Clock operations

M48T512Y, M48T512V

14/23

Doc ID 5747 Rev 6

3.5

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. A ceramic bypass capacitor value of 0.1 µF

is recommended to filter these spikes.

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, ST 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 9.

Supply voltage protection

Caution:

Negative undershoots below –0.3 V are not allowed on any pin while in the battery backup

mode.

AI02169

VCC

0.1µF

DEVICE

VCC

VSS

M48T512V データシート(PDF) 14 Page - STMicroelectronics