M48T08 ST Microelectronics, M48T08 Datasheet
M48T08
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M48T08 Summary of contents
Page 1
... BCD CODED YEAR, MONTH, DAY, DATE, HOURS, MINUTES and SECONDS TYPICAL CLOCK ACCURACY of a MONTH AUTOMATIC POWER-FAIL CHIP DESELECT and WRITE PROTECTION WRITE PROTECT VOLTAGES (V = Power-fail Deselect Voltage): PFD – M48T08: 4.5V V 4.75V PFD – M48T18: 4.2V V 4.5V PFD SOFTWARE CONTROLLED CLOCK CALIBRATION for HIGH ACCURACY ...
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... M48T08, M48T18 Figure 2A. DIP Pin Connections INT 1 A12 M48T08 A2 8 M48T18 DQ0 11 DQ1 12 DQ2 AI01182 Table 2. Absolute Maximum Ratings Symbol T Ambient Operating Temperature A T Storage Temperature (V STG (2) T Lead Solder Temperature for 10 seconds ...
Page 3
... The 28 pin 600mil DIP CAPHAT M48T08/18 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 housing containing the battery and crystal ...
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... OH Parameter As Figure 3 shows, the static memory array and the quartz controlled clock oscillator of the M48T08/18 are integrated on one silicon chip. The two circuits are interconnected at the upper eight memory lo- cations to provide user accessible BYTEWIDE clock information in the bytes with addresses 1FF8h-1FFFh ...
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... F may cause corruption of RAM data. FB exceeds V (min) and is guaranteed to go high t CC PFD tDR tFB tPFX rises above V (min) but before normal system operations begin. Even CC PFD M48T08, M48T18 Min Max 0 300 120 after V exceeds V PFH ...
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... Address Transition to Output Transition AXQX Figure 6. Read Mode AC Waveforms A0-A12 DQ0-DQ7 Note: Write Enable (W) = High. 6/19 Parameter tAVAV VALID tAVQV tE1LQV tE1LQX tE2HQV tE2HQX tGLQV tGLQX M48T08 / M48T18 -100 -150 Min Max Min Max 100 150 100 150 100 150 100 150 ...
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... The eight clock bytes are not the actual clock counters themselves; they are memory locations consisting of BiPORT The M48T08/18 includes a clock control circuit which updates the clock bytes with current informa- Byte tion once per second. The information can be accessed by the user in the same manner as any other location in the static memory array ...
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... M48T08, M48T18 Figure 7. Write Enable Controlled, Write AC Waveforms A0-A12 DQ0-DQ7 Figure 8. Chip Enable Controlled, Write AC Waveforms A0-A12 tAVE1L E1 tAVE2H E2 W DQ0-DQ7 8/19 tAVAV VALID tAVWH tAVE1L tAVE2H tWLWH tAVWL tWLQZ tDVWH tAVAV VALID tAVE1H tE1LE1H tAVE2L tE2HE2L tAVWL DATA INPUT tDVE1H ...
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... As V falls below CC WRITE MODE The M48T08/ the Write Mode whenever W, E1, and E2 are active. The start of a write is referenced from the latter occurring falling edge E1, or the rising edge of E2. A write is terminated by the earlier rising edge E1, or the falling edge of E2 ...
Page 10
... SYSTEM BATTERY LIFE The useful life of the battery in the M48T08/18 is expected to ultimately come to an end for one of two reasons: either because it has been dis- charged while providing current to the RAM and clock in the battery back-up mode, or because the ...
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... In the above example, this would be 25 years. Reference for System Life Each M48T08/18 is marked with a nine digit manu- facturing date code in the form of H99XXYYZZ. For line repre- example, H995B9431 is: 1% ...
Page 12
... The STOP bit is the MSB of the seconds register. Setting ’1’ stops the oscillator. The M48T08/18 is shipped from STMicroelectronics with the STOP bit set to a ’1’. When reset to a ’0’, the M48T08/18 oscillator starts within 1 second ...
Page 13
... The FT bit must be set using the same method used to set the clock, using the Write bit. The LSB of the Seconds Register is monitored by holding the M48T08/ extended read of the Seconds Register, without having the Read bit set. The FT bit MUST be reset to ’0’ for normal clock operations to resume ...
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... M48T08, M48T18 POWER SUPPLY DECOUPLING and UNDER- SHOOT PROTECTION I transients, including those produced by output CC switching, can produce voltage fluctuations, result- ing in spikes on the V bus. These transients can CC be reduced if capacitors are used to store energy, which stabilizes the V bus. The energy stored in ...
Page 15
... V = 4.2V to 4.5V PFD Notes: 1. The M48T08 part is offered with the PCDIP28 (i.e. CAPHAT) package only. 2. The SOIC package (SOH28) requires the battery/crystal package (SNAPHAT) which is ordered separately under the part number "M4T28-BR12SH1" in plastic tube or "M4T28-BR12SH1TR" in Tape & Reel form. Caution: Do not place the SNAPHAT battery/crystal package "M4T18-BR12SH1" in conductive foam since this will drain the lithium button-cell battery ...
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... M48T08, M48T18 PCDIP28 - 28 pin Plastic DIP, battery CAPHAT Symb Typ Drawing is not to scale. 16/19 mm Min Max 8.89 9.65 0.38 0.76 8.38 8.89 0.38 0.53 1.14 1.78 0.20 0.31 39.37 39.88 17.83 18.34 2.29 2.79 29.72 36.32 15.24 16.00 3.05 3. inches Typ Min Max 0.350 0.380 0.015 0.030 0.330 0.350 0.015 0.021 0.045 ...
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... Drawing is not to scale. mm Min Max 3.05 0.05 0.36 2.34 2.69 0.36 0.51 0.15 0.32 17.71 18.49 8.23 8.89 – – 0.050 3.20 3.61 11.51 12.70 0. M48T08, M48T18 inches Typ Min Max 0.120 0.002 0.014 0.092 0.106 0.014 0.020 0.006 0.012 0.697 0.728 0.324 0.350 – 0.126 0.142 0.453 0.500 0.016 0.050 0 28 0.004 – 8 17/19 ...
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... M48T08, M48T18 SH - SNAPHAT Housing for 28 lead Plastic Small Outline Symb Typ Drawing is not to scale. 18/19 mm Min Max 9.78 6.73 7.24 6.48 6.99 0.38 0.46 0.56 21.21 21.84 14.22 14.99 15.55 15.95 3.20 3.61 2.03 2. inches Typ Min Max 0.385 0.265 0.285 0.255 0.275 0.015 0.018 0.022 0.835 0.860 0.560 0.590 0.612 0.628 ...
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... CAPHAT, BYTEWIDE and BiPORT are trademarks of STMicroelectronics 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. © 1999 STMicroelectronics - All Rights Reserved STMicroelectronics GROUP OF COMPANIES M48T08, M48T18 19/19 ...