SGS Thomson Microelectronics M48T08Y Datasheet

5V, 64 Kbit (8 Kb x 8) TIMEKEEPER® SRAM

FEATURES SUMMARY

■ INTEGRATED ULTRA LOW POWER SRAM,

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

■ BYTEWIDE™ RAM-LIKE CLOCK ACCESS

■ BCD CODED YEAR, MONTH, DAY, DATE,

HOURS, MINUTES, and SECONDS

■ TYPICAL CLOCK ACCURACY OF ±1 MINUTE

A MONTH, AT 25°C

■ AUTOMATIC POWER-FAIL CHIP DESELECT

and WRITE PROTECTION

■ WRITE PROTECT VOLTAGES

= Power-fail Deselect Voltage):

PFD

– M48T08: V

4.5V ≤ V

– M48T18/T08Y: V

4.2V ≤ V

■ SOFTWARE CONTROLLED CLOCK

CALIBRATION FOR HIGH ACCURACY APPLICATIONS

■ SELF-CONTAINED BATTERY and CRYSTAL

IN THE CAPHAT™ DIP PACKAGE

■ PACKAGING INCLU DES A 28-LEAD SOIC and

SNAPHAT

■ (to be Ordered Separately)

■ SOIC PACKAGE PROVIDES DIR EC T

CONNECTION F OR A SNAPHAT TOP WHI CH CONTAINS THE BATTERY and CRYSTAL

■ PIN and FUNCTION COMPATIBLE WITH

DS1643 and JEDEC STANDARD 8K x 8 SRAMs

= 4.75 to 5. 5V

≤ 4.75V

PFD

≤ 4.5V

PFD

TOP

= 4.5 to 5.5V

M48T08

M48T08Y, M48 T18

Figure 1. 28-pin PCDIP, CAPHAT™ Package

PCDIP28 (PC) Battery/Crystal

CAPHAT

Figure 2. 28-pi n S O I C Package

SNAPHAT (SH)

Battery/Crystal

SOH28 (MH)

Rev. 4.0

1/26March 2003

M48T08, M48T18, M48T08Y

SUMMARY DESCRIPTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Figure 3. Logic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Table 1. Signal Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Figure 4. DIP Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Figure 5. SOIC Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Figure 6. Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

MAXIMUM RATING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Table 2. Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

DC AND AC PARAMETERS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Table 3. Operating and AC Measurement Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 7. AC Testing Load Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Table 4. Capacitance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Table 5. DC Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

OPERATION MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Table 6. Operating Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

READ Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Figure 8. READ Mode AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Table 7. READ Mode AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

WRITE Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Figure 9. WRITE Enable Controlled, WRITE AC Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Figure 10. Chip Enable Controlled, WRITE AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Table 8. WRITE Mode AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Data Retention Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Figure 11. Power Down/Up Mode AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Table 9. Power Down/Up AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Table 10. Power Down/Up Trip Points DC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

CLOCK OPERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Reading the Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Setting the Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Table 11. Register Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Stopping and Starting the Oscillator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Calibrating the Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Figure 12. Crystal Accuracy Across Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Figure 13. Clock Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Noise And Negative Going Transients. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Figure 14. Supply Voltage Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

PACKAGE MECHANICAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

PART NUMBERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Table 17. SNAPHAT Battery Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

REVISION HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

2/26

M48T08, M48T18, M48T08Y

SUMMARY DESCRIPTION

The M48T08/18/08Y TIMEKEEPER

RAM is an 8K x 8 non-volatile static RAM and real time clock which is pin and functional compatible with the DS1643. The monolithic chip is available in two special packages to provide a highly integrated battery backed-up memory and real time clock solution.

The M48T08/18/08Y is a non-volatile pin and function equivalent to any JEDEC standard 8K 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 CAPHAT™ houses the M48T08/18/08Y 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 connection to a separate SNAPHAT 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. Insertion of the SNAPHAT housing after reflow prevents potential battery and c rystal dam age due to the high temperatures required for device surfacemounting. The SNAPHAT housing is keyed to prevent reverse insertion.

The SOIC and battery/crystal packages are shipped separately in plastic anti-static tubes or in Tape & Reel form. For t he 2 8 le ad S OIC , t he ba ttery/crystal package (e.g., SNAPHAT) part number is “M4T28-BR12SH” or “M4T32-BR12SH” (see Table 17, page 24).

Figure 3. Logic Diagram Table 1. Signal Names

A0-A12 Address Inputs DQ0-DQ7 Data Inputs / Outputs INT E1

Power Fail Interrupt (Open Drain) Chip Enable 1

A0-A12

DQ0-DQ7

housing con-

E1 INT

M48T08

M48T08Y

M48T18

AI01020

E2 Chip Enable 2 G W V V

Output Enable WRITE Enable Supply Voltage Ground

3/26

M48T08, M48T18, M48T08Y

Figure 4. DIP C on ne ctions Figure 5. SOI C Co nn e ct io ns

INT V

A12

2 3

A3 A2 A1 A0

DQ0

8 9 10 11

M48T08 M48T18

12 13

DQ2

Figure 6. Block Diagram

32,768 Hz CRYSTAL

A11

A10

DQ7

DQ6

DQ5DQ1

DQ4

DQ3V

AI01182

OSCILLATOR AND

CLOCK CHAIN

INT V

A12

A7 A6 A5 A4 A3 A2 A1 A0

DQ0

1 2 3 4 5 6 7 8 9 10 11

M48T08Y

DQ2

8 x 8 BiPORT

SRAM ARRAY

13 14

28 27 26 25 24 23 22 21 20 19 18 17 16 15

AI01021B

A0-A12

W E2 A8 A9 A11 G A10 E1 DQ7 DQ6 DQ5DQ1 DQ4 DQ3V

LITHIUM

CELL

VOLTAGE SENSE

AND

SWITCHING

CIRCUITRY

INTV

POWER

PFD

8184 x 8

SRAM ARRAY

DQ0-DQ7

E1 E2 W G

AI01333

4/26

M48T08, M48T18, M48T08Y

MAXIMUM RATI N G

Stressing the device ab ove the rating listed in t he “Absolute Maximum Ratings” table may cause permanent damage to the device. These are stress ratings only and operation of the dev ice at these or any other conditions above those indicated in the Operating sections of this specification is

Table 2. Absolute Maximum Ratings

Symbol Parameter Value Unit

STG

(1,2)

SLD

Note: 1. For DIP package: Soldering temperature not to exceed 260°C for 10 seconds (total thermal budget not to exceed 150°C for longer

than 30 seco nd s) .

2. For SO pa ck age: Re flow at pea k temp era ture of 2 15°C t o 225° C fo r < 60 se conds (tot al t herm al bu dge t not to excee d 180 °C for between 90 t o 120 seco nds).

CAUTION: Negative undershoots below –0.3V are not allowed on any pin while in the Battery Back-up mode. CAUTION: Do NOT wave solder SOIC t o avoid damaging SNAP HAT sockets.

Ambient Operating Temperature 0 to 70 °C Storage Temperature (VCC Off, Oscillator Off)

Lead Solder Temperature for 10 seconds 260 °C Input or Output Voltages –0.3 to 7 V Supply Voltage –0.3 to 7 V

Output Current 20 mA Power Dissipation 1 W

not implied. Exposure to Absol ute Maxim um Ra ting conditions for extended periods may affect device reliability. Refer also to the STMicroelectronics SURE Program and other relevant quality documents.

–40 to 85 °C

5/26

M48T08, M48T18, M48T08Y

DC AND AC PARAMETERS

This section summarizes the operat ing and measurement conditions, as well as the DC and AC characteristics of the device. The parameters in the following DC and AC Characteristic tables are derived from tests performed under the M easure-

Table 3. Operating and AC Measurement Conditions

Parameter M48 T08 M48T18/T08Y Unit

ment Conditions listed in the rel evant tables. Designers should check that the operating conditions in their projects match the measurement conditions when using the quoted parameters.

Supply Voltage (V Ambient Operating Temperature (T Load Capacitance (C

)

4.75 to 5.5 4.5 to 5.5 V 0 to 70 0 to 70 °C

100 100 pF Input Rise and Fall Times ≤ 5 ≤ 5ns Input Pulse Voltages 0 to 3 0 to 3 V Input and Output Timing Ref. Voltages 1.5 1.5 V

Note: Output Hi-Z is defined as the point wh ere data is no l onger driv en.

Figure 7. AC Testing Load Circuit

1.8kΩ

DEVICE

UNDER

TEST

1kΩ

OUT

CL = 100pF

CL includes JIG capacitance

AI01019

Table 4. Capacitance

Symbol

Note: 1. Effecti ve capacit ance meas ured with po wer supp l y at 5V ; sampled only, not 100% tested.

2. At 25°C, f = 1MHz.

3. Outputs desele ct ed.

Input Capacitance 10 pF

(3)

Input / Output Capacitance 10 pF

Parameter

6/26

(1,2)

Min Max Unit

Table 5. DC Characteristics

Symbol Parameter

Test Condition

(1)

M48T08, M48T18, M48T08Y

M48T08/M48T18/T08Y

Unit

Min Max

(2)

(3)

CC1

(3)

CC2

(4)

Input Leakage Current Output Leakage Current

Supply Current Outputs open 80 mA Supply Current (Standby) TTL

Supply Current (Standby) CMOS

Input Low Voltage –0.3 0.8 V Input High Voltage 2.2

0V ≤ V

E2 = V

Output Low Voltage

Output Low Voltage (INT

Note: 1. Valid for Ambien t Operating T em perature: TA = 0 to 70°C; VCC = 4.75 to 5.5V or 4.5 to 5.5V ( except whe re noted).

2. Outputs desele ct ed.

3. Measured with Control Bits set as follows: R = '1'; W, ST, FT = '0.'

4. Negative s p i k e s of –1V allo wed for up t o 10 ns once pe r Cycle.

5. The INT

Output High Voltage

pin is Open Drain.

(5)

)

≤ V

OUT

= V

E2 = V

IH,

= VCC – 0.2V,

+ 0.2V

= 2.1mA

IOL = 0.5mA I

= –1mA

±1 µA ±1 µA

3mA

+ 0.3

0.4 V

2.4 V

7/26

M48T08, M48T18, M48T08Y

OPERATION MODES

As Figure 6, page 4 s hows, the static memory array and the quartz-controlled clock oscillator of the M48T08/18/08Y are integrated on one silicon chip. The two circuits are interconnected at the upper eight memory locations to provide user accessible BYTEWIDE™ clock information in the by tes with addresses 1FF8h-1FFFh.

The clock locations contain the year, month, date, day, hour, minute, and second in 24 hour BCD format. Corrections for 28, 29 (leap yea r - valid until

2100), 30, and 31 day months are made automatically. Byte 1FF8h is the clock control register. This byte controls user access to the clock information and also stores the clock calibration setting.

The eight clock bytes are not the actual clock counters themselves; they are memory locat ions consisting of BiPORT™ READ/WRITE memory

Table 6. Operating Modes

4.75 to 5.5V

4.5 to 5.5V

VSO to V

≤ V

PFD

(min)

(1)

E1 E2 G W DQ0-DQ7 Power

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

X X X High Z Standby

Mode

Deselect Deselect X WRITE READ READ Deselect

Deselect

Note: X = VIH or VIL; VSO = Batte ry Back -up Swit c h over Vol tage.

1. See Table 10, page 15 for detail s.

cells. The M48T08/18/08Y 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.

The M48T08/18/08Y also has its own Power-fail Detect circuit. The control circuitry constantly monitors the single 5V supply for an out of tolerance condition. When V

is out of tolerance, the circuit

write protects the S RAM, p roviding a high degree of data security in the midst of unpredictable s ystem operation brought on by low V

. As VCC falls

below the Battery Back-up Switchover Voltage

), the control circuitry connects the battery

which maintains data and clock operation until valid power returns.

X X High Z Standby X

OUT

High Z Active

Active Active

8/26

+ 18 hidden pages

SGS Thomson Microelectronics M48T08Y Datasheet

FEATURES SUMMARY

Figure 1. 28-pin PCDIP, CAPHAT™ Package

Figure 2. 28-pi n S O I C Package

TABLE OF CONTENTS

SUMMARY DESCRIPTION

Figure 3. Logic Diagram Table 1. Signal Names

Figure 4. DIP C on ne ctions Figure 5. SOI C Co nn e ct io ns

Figure 6. Block Diagram

MAXIMUM RATI N G

Table 2. Absolute Maximum Ratings

DC AND AC PARAMETERS

Table 3. Operating and AC Measurement Conditions

Figure 7. AC Testing Load Circuit

Table 4. Capacitance

Table 5. DC Characteristics

OPERATION MODES

Table 6. Operating Modes