M48T512Y-70PM1 STMicroelectronics, M48T512Y-70PM1 Datasheet - Page 10

• Manufacturer Part Number: M48T512Y-70PM1
• Description: IC TIMEKPR NVRAM 4MBIT 5V 32-DIP
• Manufacturer: STMicroelectronics
• Series: Timekeeper®r
• Type: Clock/Calendar/NVSRAMr

Specifications of M48T512Y-70PM1

• Memory Size: 4M (512K x 8)
• Time Format: HH:MM:SS (24 hr)
• Date Format: YY-MM-DD-dd
• Interface: Parallel
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 32-DIP (600 mil) Module
• Clock Format: BCD
• Clock Ic Type: Timekeeper
• Memory Configuration: 512K X 8
• Supply Voltage Range: 4.5V To 5.5V
• Digital Ic Case Style: DIP
• No. Of Pins: 32
• Operating Temperature Range: 0°C To +70°C
• Rohs Compliant: Yes
• Nvram Features: RTC, Internal Battery, XTAL
• Access Time: 70ns
• Memory Case Style: DIP
• Bus Type: Parallel
• User Ram: 512KB
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 4.5V
• Operating Temperature Classification: Commercial
• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Pin Count: 32
• Mounting: Through Hole
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 497-2856-5

M48T512Y, M48T512V
Figure 9. Chip Enable Controlled, Write AC Waveforms
Assuming that the oscillator is running at exactly
32,768Hz, each of the 31 increments in the Cali-
bration byte would represent +10.7 or –5.35 sec-
onds per month which corresponds to a total range
of +5.5 or –2.75 minutes per month. Figure 10 il-
lustrates a TIMEKEEPER calibration waveform.
One method for ascertaining how much calibration
a given M48T512Y/V may require involves setting
the clock, letting it run for a month and comparing
it to a known accurate reference and recording de-
viation over a fixed period of time.
Calibration values, including the number of sec-
onds lost or gained in a given period, can be found
in STMicroelectronics Application Note: TIME-
KEEPER CALIBRATION. This allows the designer
to give the end user the ability to calibrate the
clock as the environment requires, even if the final
product is packaged in a non-user serviceable en-
closure. The designer could provide a simple utility
that accesses the Calibration bits. For more infor-
mation on calibration, see Application Note (TIME-
KEEPER CALIBRATION) on the ST Web Site.
10/14
A0-A18
E
W
DQ0-DQ7
tAVEL
tAVWL
tAVEH
tAVAV
VALID
tELEH
POWER SUPPLY DECOUPLING
and UNDERSHOOT PROTECTION
Note: I
output switching, can produce voltage fluctua-
tions, resulting in spikes on the V
transients can be reduced if capacitors are used to
store energy, which stabilizes the V
energy stored in the bypass capacitors will be re-
leased as low going spikes are generated or ener-
gy will be absorbed when overshoots occur. A
ceramic bypass capacitor value of 0.1µF is recom-
mended 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 V
below V
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 V
nected to V
1N5817 is recommended for through hole and
MBRS120T3 is recommended for surface mount).
tDVWH
CC
SS
DATA INPUT
transients, including those produced by
by as much as one volt. These negative
CC
, anode to V
tWHDX
CC
CC
tEHAX
to V
that drive it to values
SS
). (Schottky diode
SS
CC
AI02387
(cathode con-
CC
bus. These
bus. The