Product Summary

The DS1251W is an SRAM with Phantom Clock which is a fully static nonvolatile RAM (organized as 512k words by 8 bits) with a built-in real-time clock. The DS1251Y has a self-contained lithium energy source and control circuitry, which constantly monitors VCC for an out-of-tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent garbled data in both the memory and real-time clock. The phantom clock provides timekeeping information including hundredths of seconds, seconds, minutes, hours, days, dates, 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 phantom clock operates in either 24-hour or 12-hour format with an AM/PM indicator.

Parametrics

DS1251W absolute maximum ratings: (1)Voltage Range on Any Pin Relative to Ground： -0.3V to +6.0V; (2)Soldering Temperature Range: +260℃ for 10 seconds (DIP).

Features

DS1251W features: (1)Real-time clock keeps track of hundredths of seconds, minutes, hours, days, date of the; (2)month, months, and years; (3)512k x 8 NV SRAM directly replaces volatile static RAM or EEPROM; (4)Embedded lithium energy cell maintains calendar operation and retains RAM data; (5)Watch function is transparent to RAM operation; (6)Month and year determine the number of days in each month; valid up to 2100; (7)Over 10 years of data retention in the absence of power; (8)Full 10% operating range; (9)Lithium energy source is electrically disconnected to retain freshness until power is applied for the first time.

Diagrams

DS1251W PIN ASSIGNMENT 

Image Part No Mfg Description Data Sheet Download Pricing
(USD)		 Quantity
DS1251W-120IND+
DS1251W-120IND+
Maxim Integrated Products
Real Time Clock 4096K NV SRAM w/Phantom Clock
Data Sheet
0-1: $25.34
1-25: $19.91
25-50: $18.35
50-100: $16.39
DS1251WP-120
DS1251WP-120
Maxim Integrated Products
Real Time Clock 4096K NV SRAM w/Phantom Clock
Data Sheet
Negotiable 
DS1251WP-120+
DS1251WP-120+
Maxim Integrated Products
Real Time Clock 4096K NV SRAM w/Phantom Clock
Data Sheet
0-20: $25.33
20-25: $18.10
25-50: $15.20
DS1251WP-120+C01
DS1251WP-120+C01
Maxim Integrated Products
Real Time Clock 4096K NV SRAM w/Phantom Clock
Data Sheet
0-1: $23.36
1-50: $19.00
50-100: $17.48
100-250: $17.18
DS1251WP-120IND
DS1251WP-120IND

IC NVSRAM 4MBIT 120NS 34PCM
Data Sheet
Negotiable 
DS1251W-120IND
DS1251W-120IND

IC NVSRAM 4MBIT 120NS 32DIP
Data Sheet
Negotiable 
DS1251W-120+
DS1251W-120+
Maxim Integrated Products
Real Time Clock 4096K NV SRAM w/Phantom Clock
Data Sheet
0-1: $22.03
1-25: $17.31
25-50: $15.97
50-100: $14.26
DS1251W-120
DS1251W-120

IC NVSRAM 4MBIT 120NS 32DIP
Data Sheet
Negotiable