FEATURES
Keeps track of hundredths of seconds, seconds, minutes, hours, days, date of the month, months, and years
Converts standard 2k x 8 up to 512k x 8 CMOS static RAMs into nonvolatile memory
Embedded lithium energy cell maintains watch information and retains RAM data
Watch function is transparent to RAM operation
Month and year determine the number of days in each month; leap-year compensation valid up to 2100
Lithium energy source is electrically disconnected to retain freshness until power is applied for the first time
Proven gas-tight socket contacts
Full 10% operating range
Operating temperature range: 0C to +70C
Accuracy is better than 1 minute/month @ +25C
ORDERING INFORMATION
DS1216B, DS1216C, DS1216D, DS1216E, DS1216F, DS1216H (See Figure 2 for letter suffix marking identification.)
PIN DESCRIPTION
RST - RESET
DQ0 - Data Input/Output 0 [RAM]
A2 - Address Bit 2 (Read/Write [ROM])
A0 - Address Bit 0 (Data Input [ROM])
GND - Ground CE - Conditioned Chip Enable
OE - Output Enable
WE - Write Enable
Vcc - Switched VCC for 28-/32-Pin RAM
VCCB - Switched VCC for 24-Pin RAM
VCCD - Switched VCC for 28-Ppin RAM
DESCRIPTION
The DS1216 SmartWatch RAM and SmartWatch ROM Sockets are 600mil-wide DIP sockets with a built-in CMOS watch function, an NV RAM controller circuit, and an embedded lithium energy source. The sockets provide an NV RAM solution for memory sized from 2k x 8 to 512k x 8 with package sizes from 26 pins to 32 pins. When a socket is mated with a CMOS SRAM, it provides a complete solution to problems associated with memory volatility and uses a common energy source to maintain time and date. The SmartWatch ROM sockets use the embedded lithium source to maintain the time and date only. A key feature of the SmartWatch is that the watch function remains transparent to the RAM. The SmartWatch monitors VCC for an out-of-tolerance condition. When such a condition occurs, an internal lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent loss of watch and RAM data.
Using the SmartWatch saves PC board space since the combination of SmartWatch and the mated RAM take up no more area than the memory alone. The SmartWatch uses the VCC, data I/O 0, CE , OE , and WE for RAM and watch control. All other pins are passed straight through to the socket receptacle.
The SmartWatch provides timekeeping information including hundredths of seconds, seconds, minutes, hours, days, date, months, and years. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. The SmartWatch operates in either 24-hour or 12-hour format with an AM/PM indicator.
(Picture: Pinout)
