DESCRIPTION

The DS1746 is a full function, year 2000 compliant (Y2KC), real-time clock/calendar (RTC) and 128k x 8 non-volatile static RAM. User access to all registers within the DS1746 is accomplished with a bytewide interface as shown in Figure 1. The Real Time Clock (RTC) information and control bits reside in the eight uppermost RAM locations. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour BCD format. Corrections for the date of each month and leap year are made automatically.

FEATURES

■ Integrated NV SRAM, real time clock, crystal, power-fail control circuit and lithium energy source

■ Clock registers are accessed identical to the static RAM. These registers are resident in the eight top RAM locations.

■ Century byte register; ie., Y2K compliant

■ Totally nonvolatile with over 10 years of operation in the absence of power

■ BCD coded century, year, month, date, day, hours, minutes, and seconds with automatic leap year compensation valid up to the year 2100

■ Battery voltage level indicator flag

■ Power-fail write protection allows for ±10 VCC power supply tolerance

■ Lithium energy source is electrically disconnected to retain freshness until power is applied for the first time

■ DIP Module only

- Standard JEDEC bytewide 128k x 8 static RAM pinout

■ PowerCap® Module Board only

- Surface mountable package for direct connection to PowerCap containing battery and crystal

- Replaceable battery (PowerCap)

- Power-On Reset Output

- Pin for pin compatible with other densities of DS174XP Timekeeping RAM