DS1821 View Datasheet(PDF) - Maxim Integrated

Part Name

Description

Manufacturer

DS1821

Programmable Digital Thermostat and Thermometer

Maxim Integrated 

DS1821

ORDERING INFORMATION

PART

DS1821C+

DS1821S+

PACKAGE MARKING

DS1821

DS1821S

DS1821S+T&R

DS1821S

+Denotes a lead(Pb)-free/RoHS-compliant package.

T&R = Tape and reel.

PIN-PACKAGE

3 TO92

8 SO (208 mils)

8 SO (208 mils), 2000 Piece

Tape-and-Reel

DETAILED PIN DESCRIPTIONS Table 1

TO92 8-PIN SYMBOL

SO*

DESCRIPTION

1

2

GND Ground pin.

2

1

DQ Open drain data input/output pin – 1-Wire operation; Open drain

thermostat output pin –thermostat operation.

3

8

VDD Power supply pin.

*All pins not specified in this table are “No Connect” pins.

OVERVIEW

Figure 1 shows a block diagram of the DS1821 and pin descriptions are given in Table 1. The DS1821

can operate as a standalone thermostat with user-programmable trip-points or as 8-bit temperature sensor

with a 1-Wire digital interface. The open-drain DQ pin functions as the thermostat output for thermostat

operation and as the data I/O pin for 1-Wire communications. The 1-Wire interface provides user access

to the nonvolatile (EEPROM) thermostat trip-point registers (TH and TL), the status/configuration register,

and the temperature register.

When configured as standalone thermostat, temperature conversions start immediately at power-up. In

this mode, the DQ pin becomes active when the temperature of the DS1821 exceeds the limit

programmed into the TH register, and remains active until the temperature drops below the limit

programmed into the TL register.

The DS1821 uses Maxim’s exclusive 1-Wire bus protocol that implements bus communication with one

control signal. This system is explained in detail in the 1-Wire BUS SYSTEM section of this datasheet.

2 of 19

Share Link: