Dallas Semiconductor DS1211N, DS1211, DS1211SN, DS1211S Datasheet

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VCCI
VBAT2

VBAT1

VCCO

TOL

PF

CE7
CE6

C

B

A

GND

CE
CE0

CE1
CE2

CE3
NC
CE4
CE5

1

2
3

4

5
6
7
8

9
10

20

19
18
17
16
15
14
13

12
11

VBAT1

VCCO

TOL

PF
CE7
CE6

C
B

A

GND

VCCI
VBAT2
CE
CE0
CE1
CE2
CE3
NC
CE4
CE5

1
2

3

4
5
6

7

8
9
10

20
19
18
17
16
15
14
13
12
11

20-Pin DIP (300-mil)
See Mech. Drawings

Section

20-Pin SOIC (300-mil)

See Mech. Drawings

Section

FEATURES

 Converts full CMOS RAMs into nonvolatile

memories

 Unconditionally write protects when VCC is

out of tolerance

 Automatically switches to battery when

power-fail occurs

 3 to 8 decoder provides control for up to eight

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 20-pin SOIC surface mount package
 Optional industrial temperature range of

-40°C to +85°C

PIN ASSIGNMENT

PIN DESCRIPTION

A, B, C - Address Inputs

CE - Chip Enable Input
CE0 - CE7 - Chip Enable Outputs

GND - Ground
V

BAT1

- + Battery 1

V

BAT2

- + Battery 2
TOL - Power Supply Tolerance
V

CCI

- +5V Supply
V

CC0

- RAM Supply

PF - Power-fail

NC - No Connection

DESCRIPTION

The DS1211 Nonvolatile Controller x 8 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 enables are inhibited to accomplish write
protection and the battery is switched on to supply RAMs with uninterrupted power. Special circuitr y
uses a low-leakage CMOS process which affords precise voltage detection at extremely low battery
consumption.

By combining the DS1211 nonvolatile controller/decoder chip and lithium batteries, nonvolatile RAM
operation can be achieved for up to eight CMOS memories.

See the data sheet for the DS1212 Nonvolatile Controller x 16 Chip for electrical specifications and
operation.

DS1211

Nonvolatile Controller x 8 Chip

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