DS1821+ Maxim Integrated Products, DS1821+ Datasheet - Page 14

• Manufacturer Part Number: DS1821+
• Description: IC THERMOMETER/STAT PROG 3-PR35
• Manufacturer: Maxim Integrated Products

Specifications of DS1821+

• Function: Thermometer, Thermostat
• Topology: Comparator, Register Bank
• Sensor Type: Internal
• Sensing Temperature: -55°C ~ 125°C
• Output Type: Digital
• Output Alarm: No
• Output Fan: No
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -55°C ~ 125°C
• Mounting Type: Through Hole
• Package / Case: TO-92-3 (Long Body), TO-226
• Temperature Threshold: Programmable
• Full Temp Accuracy: +/- 1 C
• Digital Output - Bus Interface: 1-Wire
• Digital Output - Number Of Bits: 8 bit
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.7 V
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• Supply Current: 1000 uA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DS1821 OPERATION EXAMPLE
In this example, the master device programs the DS1821 with T
that the data has been saved correctly. The master then programs the status/configuration register so that
the device will power-up in thermostat mode (T/R ¯ = 1) and the thermostat output will have active high
polarity (POL = 1).
MASTER
MODE
RX
RX
RX
RX
RX
RX
RX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
⎯
DATA (LSB
Presence
Presence
Presence
Presence
Presence
FIRST)
Reset
Reset
Reset
Reset
Reset
0Ah
A1h
A2h
0Ah
0Ch
01h
28h
02h
28h
06h
⎯
Master issues reset pulse.
DS1821 responds with presence pulse.
Master issues Write TH command.
Master sends data for T
Master issues reset pulse.
DS1821 responds with presence pulse.
Master issues Write TL command.
Master sends data for T
Master issues reset pulse.
DS1821 responds with presence pulse.
Master issues Read TH command.
Master reads stored T
Master issues reset pulse.
DS1821 responds with presence pulse.
Master issues Read TL command.
Master reads stored T
Master issues reset pulse.
DS1821 responds with presence pulse.
Master issues Write Status command.
Master sends status/configuration data to the DS1821 with T/R ¯ =
1 (thermostat mode at power-up) and POL = 1 (active high
thermostat output).
Power is cycled; DS1821 powers-up in thermostat mode.
14 of 18
H
L
value to verify data.
value to verify data.
H
L
= +10°C.
= +40°C.
COMMENTS
L
= +10°C and T
H
= +40°C and verifies