m48t35av STMicroelectronics, m48t35av Datasheet
m48t35av
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m48t35av Summary of contents
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... Automatic power-fail chip deselect and write protection ■ Write protect voltages (V = Power-fail deselect voltage): PFD – M48T35AY 4.5 to 5.5V CC 4.2V V 4.5V PFD – M48T35AV 3.0 to 3.6V CC 2.7V V 3.0V PFD ■ Self-contained battery and crystal in the CAPHAT™ DIP package ■ SOIC package provides direct connection for a ® SNAPHAT ...
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Contents 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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List of tables Table 1. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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List of figures Figure 1. Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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... The monolithic chip is available in two special packages to provide a highly integrated battery backed-up memory and real-time clock solution. The M48T35AV is a non-volatile pin and function equivalent to any JEDEC standard 32Kb 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 ...
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... DQ4 DQ3 AI02798B A14 A12 A13 A11 M48T35AV A10 DQ7 DQ0 11 18 DQ6 DQ1 12 17 DQ5 DQ2 13 16 DQ4 DQ3 AI02799 ...
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Figure 4. Block diagram OSCILLATOR AND CLOCK CHAIN 32,768 Hz CRYSTAL LITHIUM CELL VOLTAGE SENSE POWER V PFD AND SWITCHING CIRCUITRY BiPORT SRAM ARRAY A0-A14 DQ0-DQ7 32,760 x 8 SRAM ARRAY ...
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... SO 2.1 Read mode The M48T35AV is in the READ Mode whenever W (WRITE Enable) is high and E (Chip Enable) is low. The unique address specified by the 15 address inputs defines which one of the 32,768 bytes of data accessed. Valid data will be available at the Data I/O pins within Address Access time (t that the E and G access times are also satisfied ...
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... Address Access. AXQX tAVAV VALID tAVQV tELQV tELQX tGLQV tGLQX (1) Parameter = 0 to 70° 3.0 to 3.6V (except where noted AVQV tAXQX tEHQZ tGHQZ VALID AI00925 M48T35AV –100 Unit Min Max 100 ns 100 ns 100 ...
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... Write mode The M48T35AV is in the WRITE Mode whenever W and E are low. The start of a WRITE is referenced from the latter occurring falling edge WRITE is terminated by the earlier rising edge The addresses must be held valid throughout the cycle must return high for a minimum of t prior to the initiation of another READ or WRITE cycle ...
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... When V drops below V CC preserves data and powers the clock. The internal button cell will maintain data in the M48T35AV for an accumulated period of at least 7 years when V system power returns and V supply is switched to external V plus t (min). E should be kept high as V rec WRITE cycles prior to processor stabilization ...
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Also rises, the battery voltage is checked. If the voltage is less than approximately CC 2.5V, an internal Battery Not OK (BOK) flag will be set. The BOK flag can be checked after power up. If the BOK ...
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... The STOP Bit is the MSB of the seconds register. Setting '1' stops the oscillator. The M48T35AV is shipped from STMicroelectronics with the STOP Bit set to a '1.' When reset to a '0,' the M48T35AV oscillator starts within 1 second. ...
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... Hz. The devices are tested not to exceed 35 ppm (parts per million) oscillator frequency error at 25°C, which equates to about ±1.53 minutes per month. With the calibration bits properly set, the accuracy of each M48T35AV improves to better than +1/–2 ppm at 25°C. The oscillation rate of any crystal changes with temperature (see Most clock chips compensate for crystal frequency and temperature shift error with cumbersome “ ...
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... Two methods are available for ascertaining how much calibration a given M48T35AV may require. The first involves simply setting the clock, letting it run for a month and comparing known accurate reference (like WWV broadcasts) ...
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Figure 9. Crystal accuracy across temperature ppm 20 0 -20 -40 -60 -80 -100 0 5 Figure 10. Clock calibration NORMAL POSITIVE CALIBRATION NEGATIVE CALIBRATION 16/ -0.038 ppm 10 ...
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V noise and negative going transients CC I transients, including those produced by output switching, can produce voltage CC fluctuations, resulting in spikes on the V capacitors are used to store energy which stabilizes the V bypass capacitors will ...
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... These are stress ratings only and operation of the device at these or any other conditions above those indicated in the Operating sections of this specification is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. Refer also to the STMicroelectronics SURE Program and other relevant quality documents. Table 6. ...
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... Effective capacitance measured with power supply at 5V; sampled only, not 100% tested 25° 1MHz. 3. Outputs deselected. Parameter ) ) DEVICE UNDER TEST 50pF (or 5pF includes JIG capacitance (1)(2) Parameter Min M48T35AV Unit 3 ° 1.5 V 1.75V AI02586 Max Unit ...
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... OUT CC Outputs open – 0. 2.1mA –1mA 70° 3.0 to 3.6V (except where noted tFB tDR DON'T CARE HIGH-Z M48T35AV Unit Min Max ±1 µA ±1 µ –0.3 0 0 tRB ...
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Table 10. Power down/up AC characteristics Symbol before power down (max PFD PFD t (3) V (min PFD ...
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Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK packages. These packages have a lead-free second level interconnect. The category of second Level Interconnect is marked on the package and on the inner ...
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Figure 15. SOH28 – 28-lead plastic small outline, 4-socket battery SNAPHAT, package outline SOH-A Note: Drawing is not to scale. Table 13. SOH28 – 28-lead plastic small outline, 4-socket battery SNAPHAT, pack. mech. data Symb Typ ...
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Figure 16. SH – 4-pin SNAPHAT housing for 48mAh battery & crystal, package outline Note: Drawing is not to scale. Table 14. SH – 4-pin SNAPHAT housing for 48mAh battery & crystal, pack. mech. data Symb Typ ...
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Figure 17. SH – 4-pin SNAPHAT housing for 120mAh battery & crystal, pack. outline Note: Drawing is not to scale. Table 15. SH – 4-pin SNAPHAT housing for 120mAh battery & crystal, pack. mech. data Symb Typ ...
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Part numbering Table 16. Ordering information scheme Example: Device type M48T Supply voltage and write protect voltage 35AV = V = 3.0 to 3.6V Speed –10 = 100ns (35AV) Package PC = PCDIP28 ( SOH28 ...
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Revision history Table 18. Document revision history Date Revision Nov-1999 21-Apr-2000 29-May-2000 20-Jul-2001 20-May-2002 31-Mar-2003 01-Apr-2004 21-Nov-2007 1.0 First Issue 2.0 From Preliminary Data to Data Sheet 2.1 t change (Table 10) FB Reformatted; temp./voltage info. added to tables ...
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... Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. ...