DS1321_04 Datasheet, PDF (1/12 Pages) Dallas Semiconductor – Flexible Nonvolatile Controller with Lithium Battery Monitor

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FEATURES
§ Converts CMOS SRAM into nonvolatile
memory
§ Unconditionally write-protects SRAM when
V_CC is out of tolerance
§ Automatically switches to battery backup
supply when V_CC power failure occurs
§ Flexible memory organization
- Mode 0: 4 banks with 1 SRAM each
- Mode 1: 2 banks with 2 SRAMs each
- Mode 2: 1 bank with 4 SRAMs each
§ Monitors voltage of a lithium cell and
provides advanced warning of impending
battery failure
§ Signals low-battery condition on active low
Battery Warning output signal
§ Resets processor when power failure occurs
and holds processor in reset during system
power-up
§ Optional 5% or 10% power-fail detection
§ 16-pin DIP, 16-pin SOIC and 20-pin TSSOP
packages
§ Industrial temperature range of -40°C to
+85°C
PIN DESCRIPTION
V_CCI
V_CCO
V_BAT
A, B
- +5V Power Supply Input
- SRAM Power Supply Output
- Backup Battery Input
- Address Inputs
CEI1 - CEI4 - Chip Enable Inputs
CEO1 - CEO4 - Chip Enable Outputs
TOL
- V_CC Tolerance Select
BW
- Battery Warning Output (Open
Drain)
RST
- Reset Output (Open Drain)
MODE
- Mode Input
GND
- Ground
NC
- No Connection
DS1321
Flexible Nonvolatile Controller with
Lithium Battery Monitor
PIN ASSIGNMENT
VCCO
1
VBAT
2
TOL
3
CEI1 4
CEI2
5
A/CEI3 6
B/CEI4
7
GND 8
16
VCCI
15 RST
14 BW
13 CEO1
12 CEO2
11 CEO3
10 CEO4
9 MODE
DS1321 16-Pin DIP
(300-mil)
VCCO
1
VBAT
2
TOL
3
CEI1 4
CEI2
5
A/CEI3 6
B/CEI4
7
GND 8
16
VCCI
15 RST
14 BW
13 CEO1
12 CEO2
11 CEO3
10 CEO4
9 MODE
DS1321S 16-Pin SOIC
(150-mil)
VCCO
1
VBAT
2
TOL 3
CEI1 4
CEI2 5
NC 6
A/CEI3 7
B/CEI4 8
NC 9
GND 10
20
VCCI
19 RST
18 BW
17 CEO1
16 CEO2
15 NC
14 CEO3
13 CEO4
12 NC
11 MODE
DS1321E 20-Pin TSSOP
1 of 12
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