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

The M48T08/18/08Y TIMEKEEPER®RAM is an 8 K x 8 non-volatile static RAM and real-time clock which is pin and function compatible with the DS1643. The monolithic chip is available in two special packages to provide a highly integrated battery-backed memory and real-time clock solution.

The M48T08/18/08Y is a non-volatile pin and function equivalent to any JEDEC standard 8 K 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, 600 mil 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, 330 mil SOIC provides sockets with gold-plated contacts at both ends for direct connection to a separate SNAPHAT® housing containing 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 crystal damage due to the high temperatures required for device surface-mounting. 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 the 28-lead SOIC, the battery/crystal package (e.g., SNAPHAT®) part number is “M4T28-BR12SH” or “M4T32-BR12SH”.

Key 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 VPFD = power-fail deselect voltage):
    • M48T08: VCC = 4.75 to 5.5 V; 4.5 V ≤ VPFD ≤ 4.75 V
    • M48T18/T08Y: VCC = 4.5 to 5.5 V; 4.2 V ≤ VPFD ≤ 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

Circuit Diagram

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circuit_diagram_2411_thumbnail.png

Design

Quality & Reliability

Product Certifications
Description Version Size
Products Underwriter Laboratories (UL) Information 2.1 543 KB
Products Underwriter Laboratories (UL) Information 2.1 162 KB

Technical Documentation

Product Specifications
Description Version Size
DS0494 DS0494: 5 V, 64 Kbit (8 Kb x 8) TIMEKEEPER® SRAM 11.1 492 KB
Support & Community

Sample & Buy

Part Number Package Packing Type Marketing Status Quantity ECCN (EU) ECCN (US) Country of Origin More info Order from ST Order from Distributors
M48T08-100PC1 PDIP 28 .7 Tube Active 1000 NEC EAR99 MALAYSIA MORE INFO DISTRIBUTOR AVAILABILITY
M48T08-150PC1 PDIP 28 .7 Tube Active 1000 NEC EAR99 MALAYSIA MORE INFO DISTRIBUTOR AVAILABILITY
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(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office  or our Distributors

Quality & Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
M48T08-100PC1 ActivePDIP 28 .7IndustrialEcopack1
M48T08-150PC1 ActivePDIP 28 .7IndustrialEcopack1
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(**) The Material Declaration forms available on st.com may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.

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