M48T59 ST Microelectronics, M48T59 Datasheet - Page 3

• Manufacturer Part Number: M48T59
• Description: 64 Kbit 8Kb x8 TIMEKEEPER SRAM
• Manufacturer: ST Microelectronics

Figure 3. Block Diagram
DESCRIPTION
The M48T59/59Y/59V TIMEKEEPER
8Kb x8 non-volatile static RAM and real time clock.
The monolithic chip is available in two special
packages to provide a highly integrated battery
backed-up memory and real time clock solution.
The M48T59/59Y/59V is a non-volatile pin and
function equivalent to any JEDEC standard 8Kb x8
SRAM. It also easily fits into many ROM, EPROM,
and EEPROM sockets, providing the non-volatility
of PROMs without any requirement for special
write timing or limitations on the number of writes
that can be performed.
The 28 pin 600mil DIP CAPHAT™ houses the
M48T59/59Y/59V silicon with a quartz crystal and
a long life lithium button cell in a single package.
The 28 pin 330mil SOIC provides sockets with
gold plated contacts at both ends for direct con-
nection to a separate SNAPHAT housing contain-
ing the battery and crystal. The unique design
allows the SNAPHAT battery package to be
mounted on top of the SOIC package after the
completion of the surface mount process. Inser-
tion of the SNAPHAT housing after reflow pre-
vents potential battery and crystal damage due to
the high temperatures required for device surface-
mounting. The SNAPHAT housing is keyed to pre-
vent reverse insertion.
CRYSTAL
32,768 Hz
LITHIUM
CELL
V CC
OSCILLATOR AND
VOLTAGE SENSE
CLOCK CHAIN
SWITCHING
CIRCUITRY
IRQ/FT
AND
®
RAM is an
RST
POWER
V PFD
Table 4. AC Measurement Conditions
Note that Output Hi-Z is defined as the point where data is no longer
driven.
Figure 4. AC Testing Load Circuit
Note: Excluding open-drain output pins.
Input Rise and Fall Times
Input Pulse Voltages
Input and Output Timing Ref. Voltages
C L includes JIG capacitance
DEVICE
UNDER
TEST
SRAM ARRAY
16 x 8 BiPORT
SRAM ARRAY
8176 x 8
V SS
M48T59, M48T59Y, M48T59V
C L = 100pF
645
A0-A12
DQ0-DQ7
E
W
G
AI01383D
0 to 3V
AI02325
1.5V
5ns
1.75V
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