M48T08Y 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”.

技术特性
  • 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
功能框图
M48T08Y 订购信息
订购型号 产品状态 美金价格 数量 封装 包装形式 温度范围 材料声明
M48T08Y-10MH1F Active     SO-28 Tube 0 °C-70°C M48T08Y-10MH1F
DATASHEET
描述 版本 大小
M48T08Y : DS0494: 5 V, 64 Kbit (8 Kb x 8) TIMEKEEPER® SRAM 11 493KB
APPLICATION NOTES
描述 版本 大小
AN968: VMEbus TIMEKEEPER® requirements 1 38KB
AN925: Time update in ST's TIMEKEEPER® devices 1 31KB
AN923: TIMEKEEPER® rolling into the year 2000 (21st century, Y2K) 1 20KB
AN1012: Predicting the battery life and data retention period of NVRAMs and serial RTCs 4 440KB
AN934: How to use the digital calibration feature in TIMEKEEPER® and serial real-time clock (RTC) products 4 124KB
AN1011: Battery technology used in NVRAM and real-time clock (RTC) products from ST 4 249KB
AN1009: 'Negative undershoot' NVRAM data corruption 1 34KB