SGS Thomson Microelectronics M48T129Y-70PM1, M48T129Y, M48T129V Datasheet

3.3V-5V 1 Mbit (128Kb x8) TIMEKEEPERSRAM

■ INTEGRATED ULTRA LOW POWER SRAM,

REAL TIME CLOCK, POWER-FAIL CONTROL
CIRCUIT, BATTERY ANDCRYSTAL

■ YEAR 2000 COMPLIANT

■ BCD CODED CENTURY, YEAR, MONTH,

DAY, DATE, HOURS, MINUTES, and
SECONDS

■ BATTERY LOW WARNING FLAG

■ AUTOMATIC POWER-FAIL CHIP DESELECT

and WRITE PROTECTION

■ TWO WRITE PROTECT VOLTAGES:

(V

= Power-fail Deselect Voltage)

PFD

– M48T129Y: 4.2V ≤ V
– M48T129V: 2.7V ≤ V

■ CONVENTIONAL SRAM OPERATION;

UNLIMITED WRITE CYCLES

■ SOFTWARE CONTROLLED CLOCK

CALIBRATION for HIGH ACCURACY
APPLICATIONS

■ 10 YEARS of DATA RETENTION and CLOCK

OPERATION in the ABSENCE of POWER

■ SELF CONTAINED BATTERY and CRYSTAL

in DIP PACKAGE

■ MICROPROCESSOR POWER-ON RESET

(Valid even during battery back-up mode)

■ PROGRAMMABLE ALARM OUTPUT ACTIVE

in BATTERY BACK-UP MODE

■ SURFACE MOUNT CHIP SET PACKAGING

INCLUDES a 44-PIN SOIC and a 32-LEAD
TSOP (SNAPHAT TOP TO BE ORDERED
SEPARATELY)

■ SOIC PACKAGE PROVIDES DIRECT

CONNECTION for a SNAPHAT TOP WHICH
CONTAINS the BATTERY and CRYSTAL

■ SNAPHAT



HOUSING (BATTERY/CRYSTAL)

IS REPLACEABLE

PFD
PFD

≤ 4.5V
≤ 3.0V

M48T129Y
M48T129V

32

1

PMDIP32(PM)

Module

SNAPHAT (SH)

Battery

TSOP32

(8 x 20mm)

Surface Mount Chip Set Solution (CS)

Figure 1. Logic Diagram

V

CC

17

A0-A16 DQ0-DQ7

W RST

E

G

M48T129Y
M48T129V

SOH44

8

IRQ/FT

V

SS

AI02260

1/22April 2000

M48T129Y, M48T129V

Figure 2. DIP Connections

RST V

1

A16

2
A14
A12

4

A7

5

A6

6

A5

7

A4

8

M48T129Y
A3
A2
A1
A0

DQ0

M48T129V

9
10
11
12
13
14

DQ2

15
16

SS

Table 2. Absolute Maximum Ratings

Symbol Parameter Value Unit

T

A

T

STG

V

IO

V

CC

I

O

P

Note: 1. Stresses greater than those listed under ”Absolute Maximum Ratings” may cause permanent damage to the device. Thisis a stress

2. Soldering temperature not to exceed 260°C for 10 seconds (total thermal budget not to exceed 150°C for longer than 30 seconds).

CAUTION: Negative undershoots below –0.3V are not allowed on any pin while in the Battery Back-up mode.

Ambient Operating Temperature 0 to 70 °C
Storage Temperature (VCCOff, Oscillator Off)
Input or Output Voltages

Supply Voltage

Output Current 20 mA
Power Dissipation 1 W

D

rating only and functional operation of the device at these or any other conditions above those indicated in the operational section
of this specification is not implied. Exposure to the absolute maximum rating conditions for extended periods of time may affect
reliability.

32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17

AI02261

CC

A15
IRQ/FT3
W
A13
A8
A9
A11
G
A10
E
DQ7
DQ6
DQ5DQ1
DQ4
DQ3V

(1)

Table 1. Signal Names

A0-A16 Address Inputs

DQ0-DQ7 Data Inputs / Outputs
E Chip Enable Input

G Output Enable Input

W Write Enable Input

RST Reset Output (open drain)

IRQ/FT

V

CC

V

SS

M48T129Y –0.3 to 7.0 V
M48T129V –0.3 to 4.6 V

Interrupt / Frequency Test Output
(open drain)

Supply Voltage

Ground

–40 to 85 °C

–0.3 to V

CC

+0.3

V

DESCRIPTION

The M48T129Y/V TIMEKEEPER RAM is a 128Kb
x 8 non-volatile static RAM and real time clock,
with programmable alarms and a watchdog timer.
The special DIP package provides a fully integrat­ed battery back-up memoryandrealtime clock so­lution. The M48T129Y/V directly replaces industry
standard 128Kb x 8 SRAM. It also provides the
non-volatility of Flash without any requirement for
special write timing or limitations on the number of
writes that can be performed.

2/22

For surface mount environments ST provides a
Chip Set solution consisting of a 44 pin 330mil
SOIC TIMEKEEPER Supervisor (M48T201V/Y)
and a 32 pin TSOP (8 x 20mm) LPSRAM
(M68Z128/W) packages.

The 44 pin 330mil SOIC provides sockets with
gold plated contacts at both ends for direct con­nection to a separate SNAPHAT housing contain­ing the battery.

The unique design allows the SNAPHAT battery
package to be mounted on top of the SOIC pack­age after the completion of the surface mount pro-

Figure 3. Block Diagram

M48T129Y, M48T129V

AND

V

CC

AND

POWER

SENSE

32,768

Hz

CRYSTAL

LITHIUM

CELL

OSCILLATOR

CLOCK CHAIN

VOLTAGE

SWITCHING

CIRCUITRY

cess. Insertion of the SNAPHAT housing after
reflow prevents potential battery damage due to
the hightemperatures required for device surface­mounting. The SNAPHAT housing is keyed to pre­vent reverse insertion.

The SNAPHAT battery package is shipped sepa­rately in plastic anti-static tubes or in Tape & Reel
form. The part number is ”M4Txx-BR12SH1”.

The 32 pin 600 mil DIP Hybrid houses a controller
chip, SRAM, quartz crystal, and a long life lithium
button cell in a single package.

Figure 3 illustratesthestaticmemoryarray andthe
quartz controlled clock oscillator. The clock loca­tions contain the century, year, month, date, day,
hour, minute, and second in 24 hour BCD format.
Corrections for 28, 29 (leap year), 30, and 31 day
months are made automatically. The nine clock
bytes (1FFFFh-1FFF9h and 1FFF1h) are not the
actual clock counters, they are memory locations
consisting of BiPORT read/write memory cells
within the static RAM array.

The M48T129Y/V includes a clock control circuit
which updates the clock bytes with current infor­mation once per second. The information can be
accessed by the user in the same manner as any
other location in the static memory array. Byte

16 x 8

TIMEKEEPER

REGISTERS

RST
IRQ/FT

A0-A16

DQ0-DQ7

E
W
G

AI02583

V

PFD

131,056 x 8

SRAM ARRAY

V

SS

1FFF8his the clock control register.Thisbyte con­trols user access to the clock information and also
stores the clock calibration setting.

Byte 1FFF7h contains the watchdog timer setting.
The watchdog timer can generate either a reset or
an interrupt, depending on the state of the Watch­dogSteering bit(WDS).Bytes 1FFF6h-1FFF2h in­clude bits that, when programmed, provide for
clock alarm functionality. Alarms are activated
when the register content matches the month,
date, hours, minutes, and seconds of the clock
registers. Byte 1FFF1h contains century informa­tion.Byte 1FFF0h contains additionalflaginforma­tion pertaining to the watchdog timer, the alarm
condition and the battery status. The M48T129Y/V
also has its own Power-Fail Detect circuit. This
control circuitry constantly monitors the supply
voltage for an out of tolerance condition. When
VCCis out of tolerance, the circuit write protects
the TIMEKEEPER register data and external
SRAM, providing data security in the midst of un­predictable system operation. As VCCfalls, the
control circuitry automatically switches to the bat­tery, maintaining data and clock operation until
valid power is restored.

3/22

M48T129Y, M48T129V

Figure 4. Hardware Hookup for SMT Chip Set

Hz

LITHIUM

CELL

(3)

A0-A16

M48T201Y/V

V

CC

E
W
G
WDI
RSTIN1
RSTIN2
V

SS

DQ0-DQ7

SNAPHAT
BATTERY/CRYSTAL

32,768
CRYSTAL

5V

0.1µF

(1)

V

OUT

(2)

ECON

GCON

RST

IRQ/FT

SQW

0.1µF

V

CC

M68Z128/W

E
W
G

V

SS

A0-A16

(2)

DQ0-DQ7

Note: 1. For pin connections, see individual data sheets for M48T201Y/V and M68Z128/W atwww.st.com.

2. For 5V, M48T129Y (M48T201Y + M68Z128). For 3.3V, M48T129V (M48T201V + M68Z128W).

3. SNAPHAT Top ordered separately.

READ MODE

The M48T129Y/V is in the Read Mode whenever
W (Write Enable) is high and E (Chip Enable) is
low. The unique address specified by the 17 Ad­dress Inputs defines which one of the 131,072
bytes of data is to be accessed. Valid data will be
available at the Data I/O pins within t

AVQV

(Ad­dress Access Time) after the last address input
signal is stable, providing the E and G access
times are also satisfied. If the E and G access
times are not met, valid data will be available after
the latterof the Chip Enable Access Times (t
or Output Enable Access Time (t

GLQV

ELQV

).

The state of the eight three-state Data I/O signals
is controlled by E and G. If the outputs are activat­ed before t
indeterminate state until t

, the data lines will be driven to an

AVQV

. If the Address In-

AVQV

puts are changed while E and G remain active,
output data will remain valid for t

AXQX

(Output

Data Hold Time) but will go indeterminate until the
next Address Access.

WRITE MODE

The M48T129Y/V is in the Write Mode whenever
W (Write Enable) and E (Chip Enable) are low
state after the address inputs are stable.

The start of a write is referencedfrom the latter oc­curring falling edgeof W orE. A write is terminated
by the earlierrisingedge of W or E. The addresses
must be held valid throughout the cycle. E or W

)

must return high for a minimum of t
Enable or t

from Write Enable prior to the ini-

WHAX

tiation of another read or write cycle. Data-in must
be valid t
valid for t

prior to the end of write and remain

DVWH

afterward. G should be kept high

WHDX

during write cycles to avoid bus contention; al­though, if the output bus has been activated by a
low on E and G a low on Wwill disable the outputs
t

after W falls.

WLQZ

AI03632

EHAX

fromChip

4/22

M48T129Y, M48T129V

≤ V

V

or

PFD

SO

CC

(1)

(min)

(2)

(2)

E G W DQ0-DQ7 Power

V

IH

V

IL

V

IL

V

IL

X X X High Z CMOS Standby
X X X High Z Battery Back-up Mode

Table 3. Operating Modes

Mode

Deselect
Write
Read
Read

Deselect
Deselect

Note: 1. X = VIHor VIL;VSO= Battery Back-up Switchover Voltage.

2. See Table 7 for details.

4.5V to 5.5V

3.0V to 3.6V

to V

V

SO

DATA RETENTION MODE

With valid VCCapplied, the M48T129Y/V operates
as a conventional BYTEWIDE static RAM.
Should the supply voltage decay, the RAM will au­tomatically deselect, write protecting itself when
VCCfalls between V

PFD

(max), V

PFD

(min) win­dow. All outputs become high impedance and all
inputs are treated as ”don’t care”.

Note: Apower failureduring 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 V

(min), the memory will be

PFD

in a write protected state, provided the VCCfall
time is not less than tF. The M48T129Y/V may re­spond to transient noise spikes on VCCthat cross
into the deselect window during the time the de­vice issampling VCC. Therefore, decouplingof the
power supply lines is recommended.

When VCCdrops below VSO, the control circuit
switches power to the internal battery, preserving
data and powering the clock. The internal energy
source will maintain data in the M48T129Y/V for
an accumulated period of at least 10 years atroom
temperature. As system power rises above VSO,
the battery is disconnected, and the power supply
is switched to external VCC. Deselect continues for
t

after VCCreaches V

REC

(max). For a further

PFD

more detailed review of lifetime calculations,
please see Application Note AN1012.

TIMEKEEPER REGISTERS

The M48T129Y/V offers 16 internal registers
which contain TIMEKEEPER, Alarm, Watchdog,
Interrupt, Flag, and Control data. These registers
are memory locations which contain external (user
accessible) andinternal copies ofthe data (usually
referred to as BiPORT TIMEKEEPER cells). The

X X High Z Standby
X

V

IL

V

IH

V

IL

V

IH

V

IH

D

IN

D

OUT

High Z Active

Active
Active

Table 4. AC Measurement Conditions

Input Rise and Fall Times ≤ 5ns
Input Pulse Voltages 0 to 3V
Input and Output Timing Ref. Voltages 1.5V

Note thatOutput Hi-Z is defined as the point wheredata is no longer
driven.

Figure 5. AC Testing Load Circuit

DEVICE
UNDER

TEST

CLincludes JIG capacitance

Note: Excluding open drain output pins

650Ω

CL= 100pF

1.75V

AI01803C

external copies are independent of internal func­tions except that they are updated periodically by
the simultaneoustransferof theincrementedinter­nal copy. TIMEKEEPER and Alarm Registers
store data in BCD.

5/22

M48T129Y, M48T129V

CLOCK OPERATIONS
Reading the Clock

Updates to the TIMEKEEPER registers should be
halted beforeclock data is read to prevent reading
data in transition. Because the BiPORT TIME­KEEPER cellsin the RAM array are only data reg­isters, and not the actual clock counters, updating
the registers can be halted without disturbing the
clock itself.

Updating is halted when a ’1’ is written to the
READ bit, D6 in the Control Register (1FFF8h). As
long as a ’1’ remains in that position, updating is
halted. After a halt is issued, the registers reflect
the count;thatis,the day,date, and time that were
current at the moment the halt command was is­sued. All ofthe TIMEKEEPER registers are updat­ed simultaneously. A halt will not interrupt an
update in progress. Updating occurs 1 second af­ter the READ bit is reset to a’0’.

Setting the Clock

Bit D7 of the Control Register (1FFF8h) is the
WRITE bit. Setting the WRITE bit to a ’1’, like the
READ bit, halts updates to the TIMEKEEPER reg­isters. The user can then load them with the cor­rect day, date, and time data in 24 hour BCD
format (see Table 11).

Resetting the WRITE bit to a ’0’then transfers the
values of all time registers (1FFFFh-1FFF9h,
1FFF1h) to theactual TIMEKEEPER counters and
allows normal operation to resume. After the
WRITE bit isreset, thenextclockupdate willoccur
approximately one second later.

Note: Upon power-up following a power failure,
both the WRITE bit and the READ bit will be reset
to ’0’.

Stopping and Starting the Oscillator

The oscillator may be stopped at any time. If the
device is going to spend a significant amount of
time on the shelf, the oscillator can be turned off to
minimize current drain on the battery. The STOP
bit is located at Bit D7 within 1FFF9h. Setting it to

a ’1’ stops the oscillator. When reset to a ’0’, the
M48T129Y/V oscillator starts within one second.

Note: It is not necessary to set the WRITE bit
when setting or resetting the FREQUENCY TEST
bit (FT) or the STOP bit (ST).

SETTING ALARM CLOCK

Registers 1FFF6h-1FFF2h contain the alarm set­tings. The alarm can be configured to go off at a
prescribed time on a specific month, date, hour,
minute, or second or repeat every month, day,
hour, minute, or second. It can also be pro­grammed to go off while the M48T129Y/V is in the
battery back-upto serveasa systemwake-upcall.
Bits RPT5-RPT1 putthe alarm in the repeat mode
of operation. Table 12 shows the possible config­urations.Codes not listedin the tabledefaultto the
once per second mode toquickly alert the user of
an incorrect alarm setting.

Note: User must transition address (or toggleChip
Enable) to see Flag Bit change.

When the clock information matches the alarm
clock settings based on the match criteria defined
by RPT5-RPT1, the AF (Alarm Flag)is set. If AFE
(Alarm Flag Enable) is also set, the alarm condi­tion activates the IRQ/FT pin. To disable alarm,
write ’0’ to the Alarm Date register and RPT1-4.
The IRQ/FT output is cleared by a read to the
Flags register as shown in Figure 12. A subse­quent read of the Flags register will reset the
Alarm Flag (D6; Register 1FFF0h).

The IRQ/FT pin can also be activated in the bat­tery back-up mode. The IRQ/FT will go low if an
alarm occurs and both ABE (Alarm in Battery
Back-up Mode Enable)and AFE areset. The ABE
and AFE bits are reset during power-up, therefore
an alarm generated during power-up will only set
AF. Theuser can read the Flag Register at system
boot-up to determine if an alarm was generated
while the M48T129Y/V was in the deselect mode
during power-up. Figure 13 illustratesthe back-up
mode alarm timing.

6/22

M48T129Y, M48T129V

Table 5. Capacitance

(1)

(TA=25°C, f = MHz)

Symbol Parameter Test Condition Min Max Unit

C

IN

C

IO

Note: 1. Effective capacitance measured with power supply at 5V (M48T129Y) or 3.3V (M48T129V). Sampled only, not 100% tested.

2. Outputs deselected.

Input Capacitance

(2)

Input / Output Capacitance

V

V

OUT

IN

=0V

=0V

20 pF
20 pF

Table 6A. DC Characteristics

(TA= 0 to 70 °C; VCC= 4.5V to 5.5V)

Symbol Parameter Test Condition Min Max Unit

(1)

I

LI

I

LO

I
I
I

V

V

V

Note: 1. Outputs deselected.

Input Leakage Current 0V ≤ VIN≤ V

(1)

Output Leakage Current
Supply Current Outputs open 95 mA

CC

Supply Current (Standby) TTL

CC1

Supply Current (Standby) CMOS

CC2

Input Low Voltage –0.3 0.8 V

V

IL

Input High Voltage 2.2

IH

Output Low Voltage

OL

Output High Voltage

OH

0V ≤ V

E=V

I

OL

I

OH

OUT

E=V

CC

= 2.1mA

= –1mA

CC

≤ V

IH

–0.2V

CC

2.4 V

±2 µA
±2 µA

8mA
4mA

V

CC

+ 0.3

V

0.4 V

Table 6B. DC Characteristics

(TA= 0 to 70 °C; VCC= 3.0V to 3.6V)

Symbol Parameter Test Condition Min Max Unit

(1)

I

LI

I

LO

I
I
I

V

V

V

Note: 1. Outputs deselected.

Input Leakage Current

(1)

Output Leakage Current
Supply Current Outputs open 50 mA

CC

Supply Current (Standby) TTL E = V

CC1

Supply Current (Standby) CMOS

CC2

Input Low Voltage –0.3 0.4 V

V

IL

Input High Voltage 2.2

IH

Output Low Voltage IOL= 2.1mA 0.4 V

OL

Output High Voltage

OH

0V ≤ V

0V ≤ V

E=V

I

OH

≤ V

IN

≤ V

OUT

IH

–0.2V

CC

= –1mA

CC

CC

±2 µA
±2 µA

4mA
3mA

V

+ 0.3

CC

2.2 V

V

7/22