DS1221
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
PIN ASSIGNMENT
VCCO VBAT1
- RST A B
- RD
- WE GND 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VCCI VBAT2 CE CE0 CE1 CE2 CE3
- D/Q
DS1221 16-Pin DIP (300-mil) See Mech. Drawings Section
VCCO VBAT1
- RST A B
- RD
- WE GND 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VCCI VBAT2 CE CE0 CE1 CE2 CE3
- D/Q
PIN DESCRIPTION
A, B
CE CE0
- CE3
VBAT1 VBAT2
- RST VCCI VCCO
- RD
- WE
- D/Q
- Address Inputs
- Chip Enable Input
- Chip Enable Outputs
- + Battery 1
- + Battery 2
- Reset
- +5V Supply
- RAM Supply
- Read Inpu
- Write Input
- Data...
