m48t37v STMicroelectronics, m48t37v Datasheet - Page 11

• Manufacturer Part Number: m48t37v
• Description: 5.0 Or 3.3v, 256 Kbit 32 Kbit X 8 Timekeeper Sram
• Manufacturer: STMicroelectronics

Table 4.
1. Valid for ambient operating temperature: T
2. C
3. If E goes low simultaneously with W going low, the outputs remain in the high impedance state.
2.3
Note:
t
t
WHQX
WLQZ
Symbol
noted).
t
t
t
t
t
t
t
t
t
t
t
t
t
WLWH
WHAX
DVWH
WHDX
AVWH
AVWL
EHAX
DVEH
EHDX
AVEH
L
ELEH
AVAV
AVEL
= 5pF.
(2)(3)
(2)(3)
Write mode AC characteristics
Data retention mode
With valid V
RAM. Should the Supply Voltage decay, the RAM will automatically power-fail deselect,
write protecting itself when V
become high impedance, and all inputs are treated as “Don't care.”
A power failure during a WRITE cycle may corrupt data at the currently addressed location,
but does not jeopardize the rest of the RAM's content. At voltages below V
user can be assured the memory will be in a write protected state, provided the V
is not less than t
The M48T37Y/V may respond to transient noise spikes on V
window during the time the device is sampling V
supply lines is recommended. When V
power to the internal battery which preserves data and powers the clock. The internal button
cell will maintain data in the M48T37Y/V for an accumulated period of at least 7 years at
room temperature when V
above V
Normal RAM operation can resume t
For more information on Battery Storage Life refer to the Application Note AN1012.
WRITE Cycle Time
Address Valid to WRITE Enable Low
Address Valid to Chip Enable Low
WRITE Enable Pulse Width
Chip Enable Low to Chip Enable High
WRITE Enable High to Address Transition
Chip Enable High to Address Transition
Input Valid to WRITE Enable High
Input Valid to Chip Enable High
WRITE Enable High to Input Transition
Chip Enable High to Input Transition
WRITE Enable Low to Output Hi-Z
Address Valid to WRITE Enable High
Address Valid to Chip Enable High
WRITE Enable High to Output Transition
SO
, the battery is disconnected and the power supply is switched to external V
CC
applied, the M48T37Y/V operates as a conventional BYTEWIDE™ static
F
Parameter
.
A
= 0 to 70°C or –40 to 85°C; V
CC
(1)
CC
is less than V
falls within the V
REC
CC
after V
drops below V
SO
. As system power returns and V
CC
CC
PFD
Min
70
50
55
30
30
60
60
CC
0
0
0
0
5
5
5
M48T37Y
. Therefore, decoupling of the power
reaches V
= 4.5 to 5.5V or 3.0 to 3.6V (except where
(max), V
–70
SO
Max
25
, the control circuit switches
CC
PFD
PFD
that reach into the deselect
(min) window. All outputs
(max).
Min
100
80
80
10
10
50
50
80
80
10
0
0
5
5
M48T37V
–100
PFD
Max
50
CC
(min), the
CC
rises
fall time
Unit
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
CC
11/29
.