DS1221

Series: -
Voltage - Supply: 4.5 V ~ 5.5 V
Operating Temperature: 0°C ~ 70°C
Packaging: Tube
Manufacturer: Maxim Integrated Products
Controller Type: Nonvolatile RAM
Package / Case: 16-DIP (0.300", 7.62mm)
Supplier Device Package: 16-PDIP


Features:

Converts CMOS RAMs into nonvolatile memories
 Data is automatically protected during power loss
2-to-4 decoder provides for up to 4 CMOS RAMs
Provides for redundant batteries
Test battery condition on power-up
Full ±10% operating range
Unauthorized access can be prevented with optional security feature
16-pin 0.3-inch DIP saves PC board space
Optional 16-pin SOIC surface mount package
Optional industrial temperature range of -40°C to +85°C available


Pinout




Specifications

Voltage on Any Pin Relative to Ground                 -0.3V to +7.0V
Operating Temperature                                        0°C to 70°C
Storage Temperature                                           -55°C to +125°C
Soldering Temperature                                         260°C for 10 seconds
Short Circuit Output Current                                 20 mA


Description

The DS1221 Nonvolatile Controller x 4 Chip is a CMOS circuit which solves the application problem of converting CMOS RAMs into nonvolatile memories. Incoming power is monitored for an out-oftolerance condition. When such a condition is detected, the chip enable outputs are inhibited to accomplish write protection and the battery is switched on to supply RAMs with uninterrupted power. An optional security code prevents unauthorized users from obtaining access to the memory space. The nonvolatile controller/decoder circuitry uses a low-leakage CMOS process which affords precise voltage detection at extremely low battery consumption. By combining the DS1221 with up to four CMOS memories and lithium batteries, nonvolatile operation can be achieved.