STMicroelectronics, one of the leading suppliers of battery-backed Non-Volatile RAMs (NVRAMs) and Real-Time Clocks, has introduced an industrial temperature version of its popular M48T35 TIMEKEEPER 32Kx8 clock/RAM. The M48T35Y-70MH6 (5.0V +/- 10%) is a fully integrated, surface mounting solution with an expanded operating temperature range of -40 to +85oC (soon to be followed by the M48T35V-85MH6, 3.3V +/- 10%). Both products are ideal for use in applications such as instrumentation, cell phone base stations, payphones, vending machines, satellite receivers/decoders, and industrial control equipment where products may be exposed to more extreme temperature conditions.
The M48T35 integrates an ultra low power SRAM array, a long-life lithium cell, a quartz crystal, power-fail control circuitry and a real time clock circuit within a single package. The device is functionally compatible with JEDEC standard 32K x 8 SRAMs, offering equal read and write cycles with 70ns access times and an unlimited number of write cycles. The upper eight bytes of the SRAM are used to store seconds, minutes, hours, date, day, month, and year information in BCD format. All time data can be accessed by performing a read cycle to the appropriate register address. Other standard features include automatic leap year compensation and on-board clock calibration for precise operation at specific operating temperatures. The M48T35Y-70MH6 and M48T35V-85MH6 are Y2K (Year 2000) compatible, meaning the year register rolls over from 99 to 00 (including automatic Leap Year correction) and are recognized by the Underwriters Laboratory.
Both devices are supplied in ST’s proprietary SNAPHAT package. This is a two-part package comprising a 28-pin, 330 mil Small Outline IC (SOIC) base that houses the chip and a removable SNAPHAT top, which contains the lithium cell and a high-precision quartz crystal. Because the SNAPHAT top is attached after the PCB has been soldered, the battery and crystal are not subjected to the extreme temperatures experienced during solder reflow. The removable SNAPHAT battery/crystal also allows for replacement of expended lithium cells, which can then be disposed or recycled in the proper manner. The SNAPHAT top is ordered separately, under part number M4T32-BR12SH6.
TIMEKEEPER and SNAPHAT are registered trademarks of STMicroelectronics.
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