1/27
May 2002
M48T58
M48T58Y
5.0V, 64 Kbit (8 Kb x 8) TIMEKEEPER
SRAM
FEATURES SUMMARY
s
INTEGRATED, ULTRA LOW POWER SRAM,
REAL TIME CLOCK, POWER-FAIL CONTROL
CIRCUIT and BATTERY
s
BYTEWIDETM RAM-LIKE CLOCK ACCESS
s
BCD CODED YEAR, MONTH, DAY, DATE,
HOURS, MINUTES, and SECONDS
s
FREQUENCY TEST OUTPUT FOR REAL
TIME CLOCK
s
AUTOMATIC POWER-FAIL CHIP DESELECT
and WRITE PROTECTION
s
WRITE PROTECT VOLTAGES
(V
PFD
= Power-fail Deselect Voltage):
M48T58: V
CC
= 4.75 to 5.5V
4.5V
V
PFD
4.75V
M48T58Y: V
CC
= 4.5 to 5.5V
4.2V
V
PFD
4.5V
s
SELF-CONTAINED BATTERY and CRYSTAL
IN THE CAPHATTM DIP PACKAGE
s
PACKAGING INCLUDES a 28-LEAD SOIC and
SNAPHAT
TOP (to be Ordered Separately)
s
SOIC PACKAGE PROVIDES DIRECT
CONNECTION FOR A SNAPHAT HOUSING
CONTAINING THE BATTERY and CRYSTAL
s
PIN and FUNCTION COMPATIBLE WITH
JEDEC STANDARD 8 Kb x 8 SRAMs
Figure 1. 28-pin PCDIP, CAPHATTM Package
Figure 2. 28-pin SOIC Package
28
1
PCDIP28 (PC)
Battery/Crystal
CAPHAT
28
1
SNAPHAT (SH)
Battery/Crystal
SOH28 (MH)
M48T58, M48T58Y
2/27
TABLE OF CONTENTS
SUMMARY DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Logic Diagram (Figure 3.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Signal Names (Table 1.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
DIP Connections (Figure 4.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
SOIC Connections (Figure 5.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Block Diagram (Figure 6.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
MAXIMUM RATING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Absolute Maximum Ratings (Table 2.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
DC AND AC PARAMETERS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Operating and AC Measurement Conditions (Table 3.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
AC Measurement Load Circuit (Figure 7.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Capacitance (Table 4.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
DC Characteristics (Table 5.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
OPERATION MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Operating Modes (Table 6.). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
READ Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
READ Mode AC Waveforms (Figure 8.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
READ Mode AC Characteristics (Table 7.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
WRITE Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
WRITE Enable Controlled, WRITE AC Waveform (Figure 9.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Chip Enable Controlled, WRITE AC Waveforms (Figure 10.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
WRITE Mode AC Characteristics (Table 8.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Data Retention Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Power Down/Up Mode AC Waveforms (Figure 11.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Power Down/Up AC Characteristics (Table 9.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Power Down/Up Trip Points DC Characteristics (Table 10.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3/27
M48T58, M48T58Y
CLOCK OPERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Reading the Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Register Map (Table 11.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Setting the Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Stopping and Starting the Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Calibrating the Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Battery Low Flag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Century Bit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Crystal Accuracy Across Temperature (Figure 12.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Clock Calibration (Figure 13.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
V
CC
Noise And Negative Going Transients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Supply Voltage Protection (Figure 14.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
PART NUMBERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
SNAPHAT Battery Table (Table 13.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
PACKAGE MECHANICAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
REVISION HISTORY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
M48T58, M48T58Y
4/27
SUMMARY DESCRIPTION
The M48T58/Y TIMEKEEPER
RAM is a 8Kb x 8
non-volatile static RAM and real time clock. The
monolithic chip is available in two special packag-
es to provide a highly integrated battery backed-up
memory and real time clock solution.
The M48T58/Y is a non-volatile pin and function
equivalent to any JEDEC standard 8Kb x 8 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 CAPHATTM houses the
M48T58/Y 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 con-
taining 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. The SOIC and battery/crys-
tal packages are shipped separately in plastic anti-
static tubes or in Tape & Reel form.
For the 28-lead SOIC, the battery/crystal package
(e.g.,
SNAPHAT)
part
number
is
"M4T28-
BR12SH" (see Table 13, page 21).
Figure 3. Logic Diagram
Table 1. Signal Names
AI01374B
13
A0-A12
W
DQ0-DQ7
VCC
M48T58
M48T58Y
G
E2
VSS
8
E1
FT
A0-A12
Address Inputs
DQ0-DQ7
Data Inputs / Outputs
FT
Frequency Test Output (Open
Drain)
E1
Chip Enable 1
E2
Chip Enable 2
G
Output Enable
W
WRITE Enable
V
CC
Supply Voltage
V
SS
Ground
5/27
M48T58, M48T58Y
Figure 4. DIP Connections
Figure 5. SOIC Connections
Figure 6. Block Diagram
A1
A0
DQ0
A7
A4
A3
A2
A6
A5
E2
A10
A8
A9
DQ7
W
A11
G
E1
DQ5
DQ1
DQ2
DQ3
VSS
DQ4
DQ6
A12
FT
VCC
AI01375B
M48T58
M48T58Y
8
1
2
3
4
5
6
7
9
10
11
12
13
14
16
15
28
27
26
25
24
23
22
21
20
19
18
17
AI01376B
8
2
3
4
5
6
7
9
10
11
12
13
14
22
21
20
19
18
17
16
15
28
27
26
25
24
23
1
A1
A0
DQ0
A7
A4
A3
A2
A6
A5
E2
A10
A8
A9
DQ7
W
A11
G
E1
DQ5
DQ1
DQ2
DQ3
VSS
DQ4
DQ6
A12
FT
VCC
M48T58Y
AI01377C
LITHIUM
CELL
OSCILLATOR AND
CLOCK CHAIN
VPFD
FT
VCC
VSS
32,768 Hz
CRYSTAL
VOLTAGE SENSE
AND
SWITCHING
CIRCUITRY
8 x 8 BiPORT
SRAM ARRAY
8184 x 8
SRAM ARRAY
A0-A12
DQ0-DQ7
E1
E2
W
G
POWER
PDF 
ZIP