DS1321 Flexible Nonvolatile Controller with Lithium Battery

Description

The DS1321 Flexible Nonvolatile Controller with Lithium Battery Monitor is a CMOS circuit which solves the application problem of converting CMOS SRAMs into nonvolatile memory. Incoming power is monitored for an out-of-tolerance condition. When such a condition is detected, chip enable outputs are inhibited to accomplish write protection and the battery is switched on to supply the SRAMs with uninterrupted power. Special circuitry uses a low-leakage CMOS process which affords precise voltage detection at extremely low battery consumption. One DS1321 can support as many as four SRAMs arranged in any of three memory configurations.

In addition to battery-backup support, the DS1321 performs the important function of monitoring the remaining capacity of the lithium battery and providing a warning before the battery reaches end-of-life. Because the open-circuit voltage of a lithium backup battery remains relatively constant over the majority of its life, accurate battery monitoring requires loaded-battery voltage measurement. The DS1321 performs such measurement by periodically comparing the voltage of the battery as it supports an internal resistive load with a carefully selected reference voltage. If the battery voltage falls below the reference voltage under such conditions, the battery will soon reach end-of-life. As a result, the Battery Warning pin is activated to signal the need for battery replacement.

Key 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
UL Certified
Underwriters Laboratories (UL®) Recognized

Key Specifications: Non-Volatile RAM Controllers

Part Number

CE Control

Smart-Socket with Internal Battery

Li Battery Monitor

Power Fail Output

Number of RAMs Controlled

RESET Output

Supply Voltage (V)

RoHS Available

Package

Price^**

DS1321

Yes

PDIP/16
SOIC/16
TSSOP/20

$4.05 @ 1k

See All Non-Volatile RAM Controllers (16)

Notes:
^**This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Ordering Information

Notes:

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Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions.
* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.

Devices: 1-10 of 10

DS1321

Free
Sample

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Package:	TYPE PINS FOOTPRINT
	DRAWING CODE/VAR *

Temp

RoHS/Lead-Free?
Materials Analysis

DS1321

PDIP;16 pin;
Dwg: 21-0043 (PDF)
Use pkgcode/variation: P16-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

DS1321+

PDIP;16 pin;
Dwg: 21-0043 (PDF)
Use pkgcode/variation: P16+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

DS1321S+T&R

SOIC;16 pin;
Dwg: 21-0041 (PDF)
Use pkgcode/variation: S16+2*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

DS1321S+

SOIC;16 pin;
Dwg: 21-0349 (PDF)
Use pkgcode/variation: S16+10*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

DS1321S

SOIC;16 pin;
Dwg: 21-0349 (PDF)
Use pkgcode/variation: S16-10*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

DS1321S/T&R

SOIC;16 pin;
Dwg: 21-0349 (PDF)
Use pkgcode/variation: S16-10*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

DS1321E+T&R

TSSOP;20 pin;
Dwg: 21-0066 (PDF)
Use pkgcode/variation: U20+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

DS1321E+

TSSOP;20 pin;
Dwg: 21-0066 (PDF)
Use pkgcode/variation: U20+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

DS1321E

TSSOP;20 pin;
Dwg: 21-0066 (PDF)
Use pkgcode/variation: U20-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

DS1321E/T&R

TSSOP;20 pin;
Dwg: 21-0066 (PDF)
Use pkgcode/variation: U20-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis