Product Summary

The DS1647-120 is a 512k × 8 nonvolatile static RAM with a full-function real-time clock, which are both accessible in a byte-wide format. The nonvolatile timekeeping RAM is functionally equivalent to any JEDEC standard 512k × 8 SRAM. The DS1647-120 can also be easily substituted for ROM, EPROM and EEPROM, providing read/write nonvolatility and the addition of the real-time clock function. The real-time clock information resides in the eight uppermost RAM locations. The RTC registers contain year, month, date, day, hours, minutes, and seconds data in 24-hour BCD format. Corrections for the day of the month and leap year are made automatically. The DS1647-120 also contains its own power-fail circuitry, which deselects the device when the VCC supply is in an out-of-tolerance condition. This feature prevents loss of data from unpredictable system operation brought on by low VCC as errant access and update cycles are avoided.

Parametrics

DS1647-120 absolute maximum ratings: (1)Voltage on Any Pin Relative to Ground: -0.3V to +7.0V; (2)Storage Temperature: -40 to +85℃; (3)Soldering Temperature: 260℃ for 10 seconds (DIP Package).

Features

DS1647-120 features: (1)Integrates NV SRAM, real-time clock, crystal, power-fail control circuit and lithium energy source; (2)Clock registers are accessed identically to the static RAM. These registers are resident in the eight top RAM locations; (3)Totally nonvolatile with over 10 years of operation in the absence of power; (4)BCD coded year, month, date, day, hours, minutes, and seconds with leap year compensation valid up to 2100; (5)Power-fail write protection allows for ±10% VCC power supply tolerance; (6)DS1647 only (DIP Module); (7)Standard JEDEC byte-wide 128k × 8 RAM pin out.

Diagrams

DS1647-120 block diagram

Image Part No Mfg Description Data Sheet Download Pricing
(USD)		 Quantity
DS1647-120
DS1647-120
Maxim Integrated Products
Real Time Clock
Data Sheet
Negotiable 
DS1647-120+
DS1647-120+
Maxim Integrated Products
Real Time Clock NV Timekeeping RAM
Data Sheet
0-1: $34.82
1-25: $24.37
25-50: $17.66
50-100: $16.25