DS18S20Z Maxim Integrated Products, DS18S20Z Datasheet - Page 18

• Manufacturer Part Number: DS18S20Z
• Description: IC THERM MICROLAN HI-PREC 8-SOIC
• Manufacturer: Maxim Integrated Products

Specifications of DS18S20Z

• Sensing Temperature: -55°C ~ 125°C
• Output Type: Digital
• Voltage - Supply: 3 V ~ 5.5 V
• Accuracy: ±0.5°C
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Full Temp Accuracy: +/- 2 C
• Digital Output - Bus Interface: Serial (1-Wire)
• Digital Output - Number Of Bits: 9 bit
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

DS18S20 OPERATION EXAMPLE 1
In this example there are multiple DS18S20s on the bus and they are using parasite power. The bus
master initiates a temperature conversion in a specific DS18S20 and then reads its scratchpad and
recalculates the CRC to verify the data.
DS18S20 OPERATION EXAMPLE 2
In this example there is only one DS18S20 on the bus and it is using parasite power. The master writes to
the T
CRC to verify the data. The master then copies the scratchpad contents to EEPROM.
MASTER MODE
MASTER MODE
H
and T
Tx
Rx
Tx
Tx
Tx
Tx
Tx
Rx
Tx
Tx
Tx
Rx
Tx
Rx
Tx
Tx
Tx
Tx
Rx
Tx
Tx
Rx
Tx
Rx
Tx
Tx
Tx
L
registers in the DS18S20 scratchpad and then reads the scratchpad and recalculates the
DATA (LSB FIRST)
DATA (LSB FIRST)
DQ line held high by
DQ line held high by
64-bit ROM code
64-bit ROM code
strong pullup
strong pullup
9 data bytes
2 data bytes
9 data bytes
Presence
Presence
Presence
Presence
Presence
Reset
Reset
Reset
Reset
Reset
BEh
CCh
CCh
CCh
55h
44h
55h
BEh
4Eh
48h
Master issues reset pulse.
DS18S20s respond with presence pulse.
Master issues Match ROM command.
Master sends DS18S20 ROM code.
Master issues Convert T command.
Master applies strong pullup to DQ for the duration of the
conversion (t
Master issues reset pulse.
DS18S20s respond with presence pulse.
Master issues Match ROM command.
Master sends DS18S20 ROM code.
Master issues Read Scratchpad command.
Master reads entire scratchpad including CRC. The master
then recalculates the CRC of the first eight data bytes from the
scratchpad and compares the calculated CRC with the read
CRC (byte 9). If they match, the master continues; if not, the
read operation is repeated.
Master issues reset pulse.
DS18S20 responds with presence pulse.
Master issues Skip ROM command.
Master issues Write Scratchpad command.
Master sends two data bytes to scratchpad (T
Master issues reset pulse.
DS18S20 responds with presence pulse.
Master issues Skip ROM command.
Master issues Read Scratchpad command.
Master reads entire scratchpad including CRC. The master
then recalculates the CRC of the first eight data bytes from
the scratchpad and compares the calculated CRC with the
read CRC (byte 9). If they match, the master continues; if not,
the read operation is repeated.
Master issues reset pulse.
DS18S20 responds with presence pulse.
Master issues Skip ROM command.
Master issues Copy Scratchpad command.
Master applies strong pullup to DQ for at least 10ms while
copy operation is in progress.
18 of 23
CONV
).
COMMENTS
COMMENTS
H
and T
L
)
DS18S20