DS1212
Nonvolatile Controller x 16 Chip
www.dalsemi.com
FEATURES
Converts full CMOS RAM into nonvolatile
memory
Unconditionally write protects when V
CC
is
out of tolerance
Automatically switches to battery when
power-fail occurs
4 to 16 decoder provides control for up to 16
CMOS RAMs
Consumes less than 100 nA of battery
current
Tests battery condition on power-up
Provides for redundant batteries
Power fail signal can be used to interrupt
processor on power failure
Optional 5% or 10% power-fail detection
Optional 28-pin PLCC surface mount
package
Optional industrial temperature range of
-40°C to +85°C
PIN ASSIGNMENT
VBAT1
VCCO
TOL
PF
CE15
CE14
CE13
CE12
CE11
D
C
B
A
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VCCI
VBAT2
CE
CE0
CE1
CE2
CE3
CE4
CE5
CE6
CE7
CE8
CE9
CE10
28-Pin DIP (600-mil)
See Mech. Drawings Section
PF
TOL
VCCO
VBAT1
VCCI
VBAT2
CE
4
3
2
1
28
27
26
25
24
23
22
21
20
19
12
13
14
15
16
17
18
PIN DESCRIPTION
A, B, C, D
CE
CE0
-
CE15
GND
V
BAT1
V
BAT2
TOL
V
CCI
V
CCO
PF
- Address Inputs
- Chip Enable
- Chip Enable Outputs
- Ground
- + Battery 1
- + Battery 2
- Power Supply Tolerance
- +5V Supply
- RAM Supply
- Power Fail
CE15
CE14
CE13
CE12
CE11
D
C
5
6
7
8
9
10
11
CE0
CE1
CE2
CE3
CE4
CE5
CE6
28-Pin PLCC
See Mech. Drawings Section
DESCRIPTION
The DS1212 Nonvolatile Controller x16 Chip is a CMOS circuit that solves the application problem of
converting CMOS RAMs into nonvolatile memories. Incoming power is monitored for an out-of-
tolerance condition. When such a condition is detected, the chip enables are inhibited to accomplish write
protection and the battery is switched on to supply the RAMs with uninterrupted power. Special circuitry
uses a low-leakage CMOS process that affords precise voltage detection at extremely low battery
consumption.
1 of 7
111899
B
A
GND
CE10
CE9
CE8
CE7
DALLAS [ DALLAS SEMICONDUCTOR ]
