Maxim > Products > Supervisors, Voltage Monitors, Sequencers > DS1231

DS1231

Power Monitor

Overview

Technical Documents

Ordering Info

Status

Active: In Production.

Description

With precise, temperature-compensated comparators, the DS1231 Power Monitor Chip monitors input power and a 5V system power supply. If unsafe voltages are detected, a nonmaskable interrupt sends a warning signal to the processor in advance of power failure. Processing is unconditionally halted when power falls below a user-selectable 5% or 10% threshold level, with time to shutdown proportional to the available hold-up time of the power supply. Upon return of power, the DS1231 maintains reset until power conditions stabilize.

The DS1231 enhances system reliability by closely monitoring both processor and upstream power levels, warning of impending failure, and automatically suspending and restarting processor operation. An input sense also supports a connection to switched inputs such as an opto-isolator for LED function. All external reset components (i.e., pull-up resistor and delay timing capacitor) are contained in one package, saving space and cost.

Data Sheet

Download	Rev 1	(PDF, 67kB)
E-Mail

Key Features

Monitors input and power supply and warns of impending failure
Provides orderly shutdown
Initiates and holds processor reset until levels are unsafe
Tolerance threshold levels can be set for 5% or 10%
Automatically restarts processor on power-up
Pauses restart until system stabilizes
Operating range: 0°C to +70°C (DS1231 and DS1231S)
-40°C to +85°C (DS1231-N and DS1231S-N)
Optional active-low NMI Hysteresis (200mV = "-20", 350mV = "-35", 500mV = "-50")

Key Specifications:

Supervisors (1 Monitored Voltage)

Part Number

Reset Thresh.
(V)

Reset Out

t_RESET

Watchdog Feature

Supervisor Features

Reset Thresh. Accur.
(%)

I_CC
(µA)

Budgetary Price

min

@ +25°C

max

See Notes

DS1231

3.3 to 5.5

Active Low

Open Drain

85ms to 300ms

No Watchdog

Power Fail Comparator/Low Battery Detect

2.5

2000

$3.65 @1k

See All Supervisors (1 Monitored Voltage) (274)

Pricing 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.

Diagram

Block Diagram

Application Notes

Application Note 245

Adding Hysteresis to CPU Supervisor Voltage Sense Inputs Monitoring Upstream Voltage Supplies for Power-Fail Warnings

Reliability Reports

Reliability Report:

DS1231.pdf

Software/Models

none

Ordering Information

Filters:

Part Number:

Package:

Temperature:

Tape and Reel

Sample

Part Number	Notes	Free Sample	Buy	Status	Recommended Replacement	Package: TYPE PINS FOOTPRINT DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS1231-20	200mV Hysteresis			Active	DS1231-20+	PDIP(N);8 pin;79.7 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P8-2*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS1231-20+	200mV Hysteresis			Active		PDIP(N);8 pin;79.7 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P8+2*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1231-20N	200mV Hysteresis			Active	DS1231-20N+	PDIP(N);8 pin;79.7 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P8-2*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
DS1231-20N+				Active		PDIP(N);8 pin;79.7 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P8+2*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1231-35	350mV Hysteresis			Active	DS1231-35+	PDIP(N);8 pin;79.7 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P8-2*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS1231-35+				Active		PDIP(N);8 pin;79.7 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P8+2*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1231-35N	350mV Hysteresis			Active	DS1231-35N+	PDIP(N);8 pin;79.7 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P8-2*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
DS1231-35N+				Active		PDIP(N);8 pin;79.7 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P8+2*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1231-50	500mV Hysteresis			Active	DS1231-50+	PDIP(N);8 pin;79.7 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P8-2*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS1231-50+				Active		PDIP(N);8 pin;79.7 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P8+2*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
Part Number	Notes	Free Sample	Buy	Status	Recommended Replacement	Package: TYPE PINS FOOTPRINT DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS1231-50/G				Active		PDIP(N);8 pin;79.7 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P8-2*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS1231-50N	500mV Hysteresis			Active	DS1231-50N+	PDIP(N);8 pin;79.7 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P8-2*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
DS1231-50N+				Active		PDIP(N);8 pin;79.7 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P8+2*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1231S-20	200mV Hysteresis			Active	DS1231S-20+	SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS1231S-20+				Active		SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16+1*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1231S-20+T&R				Active		SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16+1*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1231S-20/T&R	200mV Hysteresis			Active	DS1231S-20+T&R	SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS1231S-20N	200mV Hysteresis			Active	DS1231S-20N+	SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
DS1231S-20N+				Active		SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1231S-35	350mV Hysteresis			Active	DS1231S-35+	SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
Part Number	Notes	Free Sample	Buy	Status	Recommended Replacement	Package: TYPE PINS FOOTPRINT DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS1231S-35+				Active		SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16+1*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1231S-35/T&R	350mV Hysteresis			Active	DS1231S-35+T&R	SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS1231S-35N/T&R				Active		SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
DS1231S-50	500mV Hysteresis			Active	DS1231S-20+	SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS1231S-50+				Active		SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16+1*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1231S-500+T&R				Active		SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16+1*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1231S-500/T&R				Active	DS1231S-20+T&R	SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS1231S-50N	500mV Hysteresis			Active	DS1231S-50N+	SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
DS1231S-50N+				Active		SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1231S-50N/T&R				Active		SOIC(W);16 pin;111.8 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0107 (PDF) Use pkgcode/variation: W16-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis

Notes:

Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt; -D = drypack; -U/+U on DS parts = cut tape. More: See Full Data Sheet or Maxim Product 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.

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Information Index

Overview		Technical Documents		Ordering Info		Related Products
Description Key Features Applications/Uses Key Specifications Diagram Notes and Comments		Data Sheet Application Notes Evaluation Kits Product Guides Reliability Reports Software/Models		Price and Availability Samples Buy Online Package Information Lead-Free Information		Similar Products by Function Similar Products by Application Evaluation Kits Products with Similar Part Numbers Products Used With This

Rev 1; 1998-02-26
This page last modified: 2009-10-26