DS1212 Datasheet, PDF (1/7 Pages) Dallas Semiconductor – Nonvolatile Controller x 16 Chip

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DS1212
Nonvolatile Controller x 16 Chip
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 DESCRIPTION
A, B, C, D
- Address Inputs
CE
- Chip Enable
CE0 - CE15
GND
V_BAT1
V_BAT2
TOL
V_CCI
V_CCO
PF
- Chip Enable Outputs
- Ground
- + Battery 1
- + Battery 2
- Power Supply Tolerance
- +5V Supply
- RAM Supply
- Power Fail
PIN ASSIGNMENT
VBAT1 1
VCCO 2
TOL 3
PF 4
CE15 5
CE14 6
CE13 7
CE12 8
CE11 9
D 10
C 11
B 12
28 VCCI
27 VBAT2
26 CE
25 CE0
24 CE1
23 CE2
22 CE3
21 CE4
20 CE5
19 CE6
18 CE7
17 CE8
A 13
GND 14
16 CE9
15 CE10
28-Pin DIP (600-mil)
See Mech. Drawings Section
CE15
CE14
CE13
CE12
CE11
D
C
43
5
6
7
8
9
10
11
12 13
2 1 28 27 26
25
24
23
22
21
20
19
14 15 16 17 18
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.
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