M48T129Y datasheet(19/28 Pages) STMICROELECTRONICS

номер детали	M48T129Y

подробное описание детали	5.0 or 3.3 V, 1 Mbit (128 Kbit x 8) TIMEKEEPER짰 SRAM

PDF	28 Pages

Scroll/Zoom	100%

производитель	STMICROELECTRONICS [STMicroelectronics]

домашняя страница	http://www.st.com

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19 / 28 page

M48T129V, M48T129Y

Clock operations

Doc ID 5710 Rev 4

19/28

3.11

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 (see

Figure 12) 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, 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 12.

Supply voltage protection

AI02169

VCC

0.1µF

DEVICE

VCC

VSS

M48T129Y датащи(PDF) 19 Page - STMicroelectronics