M48T18-100PC1 Datasheet M48T18-100PC1, M48T08-150PC1, M48T08-100PC1 | P1-P3

June 2011 Doc ID 2411 Rev 11 1/31

M48T08

M48T08Y, M48T18

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

SRAM

Features

■ 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

PFD

= power-fail deselect voltage):

–M48T08: V

= 4.75 to 5.5 V;

4.5 V ≤ V

PFD

≤ 4.75 V

– M48T18/T08Y: V

= 4.5 to 5.5 V;

4.2 V ≤ V

PFD

≤ 4.5 V

■ Software controlled clock calibration for high

accuracy applications

■ Self-contained battery and crystal in the

CAPHAT

™

DIP package

■ Packaging includes a 28-lead SOIC and

SNAPHAT

top (to be ordered separately)

■ SOIC package provides direct connection for a

snaphat top which contains the battery and

crystal

■ Pin and function compatible with DS1643 and

JEDEC standard 8 K x 8 SRAMs

■ RoHS compliant

– Lead-free second level interconnect

PCDIP28

battery/crystal

CAPHAT™

SNAPHAT

battery/crystal

SOH28

www.st.com

Contents M48T08, M48T08Y, M48T18

2/31 Doc ID 2411 Rev 11

Contents

1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2 Operation modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.1 READ mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.2 WRITE mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.3 Data retention mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2.4 Power-fail interrupt pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3 Clock operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.1 Reading the clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.2 Setting the clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.3 Stopping and starting the oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.4 Calibrating the clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.5 V

noise and negative going transients . . . . . . . . . . . . . . . . . . . . . . . . . 18

4 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

5 DC and AC parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

7 Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

8 Environmental information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

M48T08, M48T08Y, M48T18 List of tables

Doc ID 2411 Rev 11 3/31

List of tables

Table 1. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Table 2. Operating modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Table 3. READ mode AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Table 4. WRITE mode AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Table 5. Register map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Table 6. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Table 7. Operating and AC measurement conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Table 8. Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Table 9. DC characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table 10. Power down/up AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Table 11. Power down/up trip points DC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Table 12. PCDIP28 – 28-pin plastic DIP, battery CAPHAT™, package mech. data . . . . . . . . . . . . . 23

Table 13. SOH28 – 28-lead plastic SO, 4-socket battery SNAPHAT

, package mech. data. . . . . . . 24

Table 14. SH – 4-pin SNAPHAT

housing for 48 mAh battery & crystal, package mech. data . . . . . 25

Table 15. SH – 4-pin SNAPHAT

housing for 120 mAh battery & crystal, package mech. data . . . . 26

Table 16. Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Table 17. SNAPHAT® battery table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Table 18. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

P1-P3 P4-P6 P7-P9 P10-P12 P13-P15 P16-P18 P19-P21 P22-P24 P25-P27 P28-P30 P31-P31

M48T18-100PC1

Mfr. #:

Buy M48T18-100PC1

Manufacturer:

STMicroelectronics

Description:

Real Time Clock 64K (8Kx8) 100ns

Lifecycle:

New from this manufacturer.

Delivery:

DHL FedEx Ups TNT EMS

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M48T18-100PC1

M48T18-100PC1

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