JS28F256P33BFE datasheet(44/90 Pages) MICRON

44 / 90 page

P33-65nm

Datasheet

Aug 2009

Order Number: 320003-08

12.3

Power Supply Decoupling

Flash memory devices require careful power supply de-coupling. Three basic power

supply current considerations are: 1) standby current levels; 2) active current levels;

and 3) transient peaks produced when CE# and OE# are asserted and deasserted.

When the device is accessed, many internal conditions change. Circuits within the

device enable charge-pumps, and internal logic states change at high speed. All of

these internal activities produce transient signals. Transient current magnitudes depend

on the device outputs’ capacitive and inductive loading. Two-line control and correct

de-coupling capacitor selection suppress transient voltage peaks.

Because Numonyx MLC flash memory devices draw their power from VCC, VPP, and

VCCQ, each power connection should have a 0.1 µF ceramic capacitor to ground. High-

frequency, inherently low-inductance capacitors should be placed as close as possible

to package leads.

Additionally, for every eight devices used in the system, a 4.7 µF electrolytic capacitor

should be placed between power and ground close to the devices. The bulk capacitor is

meant to overcome voltage droop caused by PCB trace inductance.

Figure 13: Reset Operation Waveforms

(A) Reset during

read mode

(B) Reset during

program or block erase

≤ P2

program or block erase

≥ P2

RST# [P]

Abort

Complete

Abort

Complete

(D) VCC Power-up to

RST# high

JS28F256P33BFE 데이터시트(PDF) 44 Page - Micron Technology