 | |
|
Industry's Most Accurate RTC Offers NV SRAM Functionality in a 300-mil SO Package
Note to Editor:
- The DS32X35 is an accurate I2C real-time-clock (RTC) with integrated TCXO, crystal, and FRAM.
- This product provides an 80% savings in footprint size and a 70% savings in height compared to encapsulated DIP modules.
By replacing the parallel-address SRAM with an I2C FRAM (ferroelectric random access memory), the pin count is reduced and the battery is eliminated from the package.
- The DS32X35 RTC is ideal for GPS, utility power metering, and server applications.
|
DALLAS, TX—May 7, 2007—Dallas Semiconductor, a wholly owned subsidiary of Maxim Integrated Products (NASDAQ: MXIM), adds nonvolatile FRAM memory to its real-time clock (RTC) product line with the DS32B35 (2k x 8 bits) and DS32C35 (8k x 8 bits), the industry's most accurate RTCs. The tuning-fork crystal typically used as the time base for RTCs produces an error of one hour per year when exposed to temperature extremes. However, the DS32B35/DS32C35 are capable of keeping time to within one minute per year over the temperature range of 0°C to +70°C because they measure temperature and adjust the crystal frequency by varying the load capacitance on the crystal.
The FRAM memory used in the DS32B35/DS32C35 offers true nonvolatility with no energy source required for data retention and none of the write-cycle or block-erase limitations of EEPROM or flash memory. A separate battery or capacitor can be sized for the backup requirements of the real-time clock, giving designers flexibility in the layout and sourcing of components.
Both the RTC and FRAM are accessed through an I2C interface, rather than the byte-wide interface used in battery-backed SRAM modules. For applications that have traditionally stored critical data using battery-backed SRAM modules, which require unlimited read/write cycles, the DS32B35/DS32C35 offer the ability to migrate this functionality to the I2C data bus. This migration greatly reduces the number of interconnects between the memory and CPU, thereby making PCB layout easier.
The reduction in pin count and elimination of the internal backup battery allows the DS32B35/DS32C35 to be offered in an ROHS-compliant, 20-pin, 300-mil SO package, rather than the larger through-hole modules conventionally used. These RTCs are available in either the commercial (0°C to +70°C) or industrial (-40°C to +85°C) temperature range. Prices start at $4.00 for the DS32B35 and $4.80 for the DS32C35 (1000-up, FOB USA).
|
|
|
|
|
|
