M48T08Y: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
Product Specifications
DescriptionVersionSize
DS0494: 5 V, 64 Kbit (8 Kb x 8) TIMEKEEPER® SRAM11.1492 KB
Application Notes
DescriptionVersionSize
AN1011: Battery technology used in NVRAM and real-time clock (RTC) products from ST4.0248 KB
AN934: How to use the digital calibration feature in TIMEKEEPER® and serial real-time clock (RTC) products4.1123 KB
AN923: Managing century information using serial real-time clocks and TIMEKEEPER® NVRAMs4.0142 KB
AN1009: Negative undershoot NVRAM data corruption2.082 KB
AN1012: Predicting the battery life and data retention period of NVRAMs and serial RTCs4.1439 KB
AN925: Time update in ST's TIMEKEEPER® devices2.0119 KB
Product Certifications
DescriptionVersionSize
Products Underwriter Laboratories (UL) Information2.1162 KB
Sample & Buy
Part NumberPackagePacking TypeQuantityECCN (EU)ECCN (US)Country of Origin
M48T08Y-10MH1FSO-28Tape And Reel1000NECEAR99MALAYSIA
Quality & Reliability
Part NumberPackageGradeRoHS Compliance GradeMaterial Declaration**
M48T08Y-10MH1FSO-28IndustrialEcopack1
5 V, 64 Kbit (8 Kb x 8) TIMEKEEPER® SRAM M48T18
circuit_diagram_2411_thumbnail.png M48T18
ST NVRAM 和实时时钟(RTC)产品中使用的电池技术 M4Z28-BR00SH
How to use the digital calibration feature in TIMEKEEPER® and serial real-time clock (RTC) products M41T60
Managing century information using serial real-time clocks and TIMEKEEPER® NVRAMs M41T60
Negative undershoot NVRAM data corruption M48Z58Y
预测NVRAM 和串行RTC 的电池寿命和数据保存期限 M4Z28-BR00SH
Time update in ST's TIMEKEEPER® devices M48T37Y
Predicting the battery life and data retention period of NVRAMs and serial RTCs M48Z58Y