M48T02 STMICROELECTRONICS | Alldatasheet
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Technical content
16 Kbit (2Kb x8) TIMEKEEPER SRAM
INTEGRATED ULTRA LOW POWER SRAM, REAL TIME CLOCK and POWER-FAIL CONTROL CIRCUIT BYTEWIDE RAM-LIKECLOCK ACCESS BCD CODED YEAR, MONTH, DAY, DATE, HOURS, MINUTES and SECONDS TYPICAL CLOCK ACCURACY of ± 1 MINUTE a MONTH, AT 25°C SOFTWARE CONTROLLED CLOCK CALIBRATION for HIGH ACCURACY
APPLICATIONS
AUTOMATIC POWER-FAILCHIP DESELECTand WRITE PROTECTION WRITE PROTECT VOLTAGES PFD = Power-fail Deselect Voltage): – M48T02: 4.5V≤ VPFD ≤ 4.75V – M48T12: 4.2V≤ VPFD ≤ 4.5V SELF-CONTAINED BATTERY and CRYSTAL in the CAPHAT DIP PACKAGE PIN and FUNCTION COMPATIBLE with JEDEC STANDARD 2Kb x8 SRAMs
DESCRIPTION
The M48T02/12 TIMEKEEPER RAM is a 2Kb x8 non-volatile static RAM and real time clock which is pin and functional compatible with the DS1642. A special 24 pin 600mil DIP CAPHAT package houses the M48T02/12silicon with a quartz crystal and a long life lithium button cell to form a highly integratedbatterybacked-upmemoryand realtime clock solution. AI01027 A0-A10 W DQ0-DQ7 VCC M48T02 M48T12 G VSS E Figure 1. Logic Diagram Table 1. Signal Names
- 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 –0.3 volts are not allowed on any pin while in the Battery Back-up mode. Table 2. Absolute Maximum Ratings(1) Notes:X=V IH or VIL;VSO = Battery Back-up Switchover Voltage. Table 3. Operating Modes Figure 2. DIP Pin Connections equivalent to any JEDEC standard 2Kb x8 SRAM. 31 day months are made automatically.
Notes:1. Outputs Deselected.
- Measured with Control Bits set as follows: R = ’1’; W, ST, KS, FT = ’0’.
Table 6. DC Characteristics Notes:1. Effective capacitance measured with power supply at 5V. Table 5. Capacitance(1) Notes:1. All voltages referenced to VSS . Table 7. Power Down/Up Trip Points DC Characteristics(1)
- VPFD (min) to VSO fall time of less than tFB may cause corruption of RAM data.
Table 8. Power Down/Up Mode AC Characteristics Figure 5. Power Down/Up Mode AC Waveforms reset is being applied to the processor, a reset condition may not occur until after the system clock is running.
Table 9. Read Mode AC Characteristics Figure 6. Read Mode AC Waveforms Note: Write Enable (W) = High.
Table 10. Write Mode AC Characteristics (Write Enable) is high and E (Chip Enable) is low. one of the 2,048 bytes of data is to be accessed. ELQV ) or Output Enable Access time (tGLQV ).
state, provided the VCC fall time is not less than tF. refer to the Application Note AN1012. as a ’1’ remains in that position, updating is halted. at the moment the halt command was issued. normal TIMEKEEPER and RAM operation. Figure 9. Checking the BOK Flag Status
clock up, subtracting counts slows the clock down. first 12 will be affected, and so on. much calibration a given M48T02/12 may require. utility that accesses the Calibration byte. Table 11. Register Map
cation Note AN924 ”TIMEKEEPER Calibration”. Figure 12. Supply Voltage Protection in order to provide the needed filtering. MBRS120T3 is recommended for surface mount.
ORDERING INFORMATION SCHEME Supply Voltage and Write Protect Voltage 02 V CC = 4.75V to 5.5V VPFD = 4.5V to 4.75V 12 V CC = 4.5V to 5.5V VPFD = 4.2V to 4.5V Speed -70 70ns -150 150ns -200 200ns Package PC PCDIP24 Temp. Range 1 0 to 70 °C Example: M48T02 -70 PC 1 For a list of availableoptions(Speed, Package,etc...) or for further information on any aspect ofthis device, please contact the STMicroelectronics Sales Office nearest to you. M48T02, M48T12
A L B1 B e1 D E N C eA Symb mm inches Typ Min Max Typ Min Max A 8.89 9.65 0.350 0.380 A1 0.38 0.76 0.015 0.030 A2 8.38 8.89 0.330 0.350 B 0.38 0.53 0.015 0.021 B1 1.14 1.78 0.045 0.070 C 0.20 0.31 0.008 0.012 D 34.29 34.80 1.350 1.370 E 17.83 18.34 0.702 0.722 e1 2.29 2.79 0.090 0.110 e3 25.15 30.73 0.990 1.210 eA 15.24 16.00 0.600 0.630 L 3.05 3.81 0.120 0.150 N2 4 2 4 Drawing is not to scale. PCDIP24 - 24 pin Plastic DIP, battery CAPHAT M48T02, M48T12
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics 1998 STMicroelectronics - All Rights Reserved TIMEKEEPER is a registered trademark of STMicroelectronics CAPHAT,BYTEWIDE and BiPORT are trademarks of STMicroelectronics STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - France - Germany - Italy - Japan - Korea - Malaysia - Malta - Mexico - Morocco - The Netherlands - Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A. http://www.st.com M48T02, M48T12