M48T18 TIMEKEEPER SRAM_BDTIC 代理M48T18

M48T18 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

M48T18 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
M48T18-150PC1	Active			PDIP 28 .7	Tube	0 °C-70°C	M48T18-150PC1
M48T18-100PC1	Active			PDIP 28 .7	Tube	0 °C-70°C	M48T18-100PC1

DATASHEET

描述	版本	大小
M48T18 : 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