DS1221

DS1221 Datasheet

DS1221 Nonvolatile Controller x 4 Chip

Part	Datasheet
DS1221	DS1221 (pdf)

Related Parts	Information
DS1221S	DS1221S
DS1221SN	DS1221SN

PDF Datasheet Preview
DS1221 Nonvolatile Controller x 4 Chip NOT RECOMMENDED FOR NEW DESIGNS, SEE DS1321 DATASHEET INSTEAD. 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 DESCRIPTION - Address Inputs - Chip Enable Input CE0 - CE3 VBAT1 VBAT2 - Chip Enable Outputs - + Battery 1 - + Battery 2 * RST VCCI VCCO - Reset - +5V Supply - RAM Supply - Read Inpu * WE D/Q - Write Input - Data Input/Output PIN ASSIGNMENT VCCO 1 VBAT1 2 16 VCCI 15 VBAT2 RST 3 A4 14 CE 13 CE0 12 CE1 RD 6 WE 7 GND 8 11 CE2 10 CE3 9 D/Q DS1221 16-Pin DIP 300-mil See Mech. Drawings Section VCCO 1 16 VCCI VBAT1 2 15 VBAT2 RST 3 A4 14 CE 13 CE0 12 CE1 RD 6 11 CE2 WE 7 GND 8 10 CE3 9 D/Q DS1221 16-Pin SOIC 300-mil See Mech. Drawings Section Used with optional security circuit only and must be connected to ground in all other cases. 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. 1 of 8 111899 DS1221 CONTROLLER /DECODER OPERATION

PDF Datasheet Preview

DS1221 Nonvolatile Controller x 4 Chip

NOT RECOMMENDED FOR NEW DESIGNS, SEE DS1321 DATASHEET INSTEAD.

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 DESCRIPTION
- Address Inputs
- Chip Enable Input

CE0 - CE3 VBAT1 VBAT2
- Chip Enable Outputs - + Battery 1 - + Battery 2
* RST VCCI VCCO
- Reset - +5V Supply - RAM Supply
- Read Inpu
* WE *D/Q
- Write Input - Data Input/Output

PIN ASSIGNMENT

VCCO 1 VBAT1 2
16 VCCI 15 VBAT2
*RST 3 A4
14 CE 13 CE0
12 CE1
*RD 6 *WE 7 GND 8
11 CE2 10 CE3
9 *D/Q

DS1221 16-Pin DIP 300-mil See Mech. Drawings Section

VCCO 1
16 VCCI

VBAT1 2
15 VBAT2
*RST 3 A4
14 CE 13 CE0
12 CE1
*RD 6
11 CE2
*WE 7 GND 8
10 CE3 9 *D/Q

DS1221 16-Pin SOIC 300-mil See Mech. Drawings Section
*Used with optional security circuit only and must be connected to ground in all other cases.

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.
1 of 8
111899

DS1221

CONTROLLER /DECODER OPERATION

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Datasheet ID: DS1221 647152