DatasheetQ Logo
Electronic component search and free download site.
Transistors,MosFET ,Diode,Integrated circuits

M48Z129V View Datasheet(PDF) - STMicroelectronics

Part Name
Description
Manufacturer
M48Z129V Datasheet PDF : 16 Pages
1 2 3 4 5 6 7 8 9 10 Next Last
M48Z129Y*, M48Z129V
Data Retention Mode
With valid VCC applied, the M48Z129Y/V operates
as a conventional BYTEWIDE™ static RAM.
Should the supply voltage decay, the RAM will au-
tomatically deselect, write protecting itself when
VCC falls between VPFD (max), VPFD (min) win-
dow. All outputs become high impedance and all
inputs are treated as “Don’t care”.
Note: A power failure during a WRITE cycle may
corrupt data at the current addressed location, but
does not jeopardize the rest of the RAM’s content.
At voltages below VPFD(min), the memory will be
in a write protected state, provided the VCC fall
time is not less than tF. The M48Z129Y/V may re-
spond to transient noise spikes on VCC that cross
into the deselect window during the time the de-
vice is sampling VCC. Therefore, decoupling of the
power supply lines is recommended.
When VCC drops below VSO, the control circuit
switches power to the internal battery, preserving
data. The internal energy source will maintain data
in the M48Z129Y/V for an accumulated period of
at least 10 years at room temperature. As system
power rises above VSO, the battery is disconnect-
ed, and the power supply is switched to external
VCC. Deselect continues for tREC after VCC reach-
es VPFD(max).
For more information on Battery Storage Life refer
to the Application Note AN1012.
VCC Noise And Negative Going Transients
ICC transients, including those produced by output
switching, can produce voltage fluctuations, re-
sulting in spikes on the VCC bus. These transients
can be reduced if capacitors are used to store en-
ergy 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 by-
pass capacitor value of 0.1µF (as shown in Figure
9.) is recommended in order to provide the needed
filtering.
In addition to transients that are caused by normal
SRAM operation, power cycling can generate neg-
ative 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, it is recommended to con-
nect 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
VCC
0.1µF
VCC
DEVICE
VSS
AI02169
9/16
 

Share Link: 

datasheetq.com  [ Privacy Policy ]Request Datasheet ] [ Contact Us ]