DS1821

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DS1821

SENSOR DIGITAL -55C-125C TO92-3

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Specifications

Supplier Analog Devices Inc./Maxim Integrated
Package Tray
ProductStatus Obsolete
SensorType Digital, Local
SensingTemperature-Local -55°C ~ 125°C
OutputType 1-Wire®
Voltage-Supply 2.7V ~ 5.5V
Resolution 8 b
Features One-Shot, Output Switch, Programmable Limit, Standby Mode
Accuracy-Highest(Lowest) ±1°C
TestCondition 0°C ~ 85°C
OperatingTemperature -55°C ~ 125°C
MountingType Through Hole
Package/Case TO-226-3, TO-92-3 Long Body

Overview

Description

DS1821 is a Dallas/Maxim digital temperature sensor that uses the 1-Wire protocol. It provides a direct digital temperature reading from an on‑chip sensor and can include basic thermostat/alarm logic in the same device.
Key points:
- Interface: 1-Wire bus with a unique ROM code; can be powered from VDD or via parasite power.
- Reading: temperature is read as a digital value (no external ADC required).
- Resolution: configurable 9–12 bit (affects precision and conversion time).
- Thermostat/Alarm: optional output/flag for high/low temperature conditions.
- Use: simple wiring (data line + VDD + GND), suitable for microcontroller-based monitoring, data loggers, HVAC, and safety/limit applications.
- How it works: issue a Convert T command to start a measurement, then read the scratchpad to obtain the temperature data (with optional CRC check).
Overall, DS1821 offers low-pin-count, easy integration for ambient or device-temperature monitoring with built‑in digital output.

Features

DS1821 features (concise):
- 1-Wire digital thermometer with on-chip temperature sensor
- Temperature range: -55°C to +125°C
- Programmable resolution: 9–12 bits
- Temperature data provided in two bytes (MSB/LSB) in two’s complement
- Simple 1-Wire interface (single data line + ground)
- Alarm capability: configurable high/low temperature alarms
- Low power operation with selectable conversion time
- Supply voltage: 2.7V–5.5V
- Available in common package options (e.g., DIP, SOIC) for various applications
- Suitable for embedded systems, data loggers, HVAC, consumer electronics, and similar uses

Package

DS1821 comes in standard 8-pin packages: DIP-8 and SOIC-8 (surface-mount). No TO-92 version.

Pinout

Pin count: 8 pins (available in 8‑pin DIP/SOIC packages).
Function: the DS1821 is a programmable digital thermostat/temperature monitor. It senses temperature, stores programmable trip-point(s) in nonvolatile memory, and asserts an alarm/thermostat output when temperature crosses the set thresholds. It’s used for temperature monitoring/control and system protection.

Manufacturer

- Manufacturer: Dallas Semiconductor (DS1821).
- Company type: A U.S.-based semiconductor company that designs and manufactures integrated circuits (including temperature sensors and 1-Wire devices); Dallas later became part of Maxim Integrated, and Maxim is now part of Analog Devices.

Application

DS1821 is a 1-Wire programmable-resolution thermometer. Applications:
- Embedded system temperature sensing for control loops
- Industrial process monitoring and safety interlocks
- HVAC, building automation and energy management
- Automotive battery/thermal management
- Medical devices requiring temperature data
- Data loggers, environmental monitoring, weather stations
- Cold-chain and asset tracking
- Consumer electronics, home automation, DIY projects

Equivalent

Do you mean the Maxim/Dallas DS1821 digital thermometer/thermostat? Which features matter (interface: 1‑Wire vs. parallel, accuracy, supply voltage, package, thermostat outputs)? Tell me which specifics you need and I’ll list compatible drop‑in equivalents.

Shipping

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Shipping Fee Reference (DHL/FedEx):

DHL: Shipping cost ranges from $25-$45 (0.5kg), with an estimated delivery time of 2-5 business days.

FedEx: Shipping cost ranges from $25-$40 (0.5kg), with an estimated delivery time of 3-7 business days.

UPS: Shipping cost ranges from $25-$45 (0.5kg), with an estimated delivery time of 3-7 business days.

TNT: Shipping cost ranges from $25-$65 (0.5kg), with an estimated delivery time of 3-7 business days.

EMS: Shipping cost ranges from $30-$50 (0.5kg), with an estimated delivery time of 7-15 business days.

Registered Air Mail: Shipping cost is $2-$4 (0.1kg), with an estimated delivery time of 5-20 business days.

Payments

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