DS18S20-PAR+T&R Maxim Integrated Products, DS18S20-PAR+T&R Datasheet - Page 4

• Manufacturer Part Number: DS18S20-PAR+T&R
• Description: Board Mount Temperature Sensors Prgmble Resolution 1-Wire Parasite Pwr
• Manufacturer: Maxim Integrated Products

Specifications of DS18S20-PAR+T&R

• Full Temp Accuracy: +/- 0.5 C
• Package / Case: TO-92
• Digital Output - Bus Interface: Serial (1-Wire)
• Digital Output - Number Of Bits: 9 bit
• Maximum Operating Temperature: + 100 C
• Minimum Operating Temperature: - 55 C
• Output Type: Digital
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

16 (10h). After reading the scratchpad, the TEMP_READ value is obtained by truncating the 0.5°C bit
(bit 0) from the temperature data (see Figure 3). The extended resolution temperature can then be
calculated using the following equation:
TEMPERATURE REGISTER FORMAT Figure 3
TEMPERATURE/DATA RELATIONSHIP Table 2
OPERATION – ALARM SIGNALING
After the DS18S20-PAR performs a temperature conversion, the temperature value is compared to the
user-defined two’s complement alarm trigger values stored in the 1-byte T
4). The sign bit (S) indicates if the value is positive or negative: for positive numbers S = 0 and for
negative numbers S = 1. The T
when the device is powered down. T
explained in the MEMORY section of this datasheet.
T
Only bits 8 through 1 of the temperature register are used in the T
are 8-bit registers. If the result of a temperature measurement is higher than T
alarm condition exists and an alarm flag is set inside the DS18S20-PAR. This flag is updated after every
temperature measurement; therefore, if the alarm condition goes away, the flag will be turned off after the
next temperature conversion.
The master device can check the alarm flag status of all DS DS18S20-PARs on the bus by issuing an
Alarm Search [ECh] command. Any DS18S20-PARs with a set alarm flag will respond to the command,
MS Byte
H
LS Byte
AND T
bit 7
TEMPERATUR
S
L
REGISTER FORMAT Figure 4
bit 15
*The power-on reset value of the temperature register is +85°C
bit 7
TEMPERATURE
2
S
6
bit 6
+85.0°C*
2
+25.0°C
-25.0°C
-55.0°C
+0.5°C
-0.5°C
6
0°C
E
bit 14
bit 6
=
2
S
TEMP
5
bit 5
H
2
5
and T
_
H
READ
and T
bit 13
bit 5
DIGITAL OUTPUT
0000 0000 1010 1010
0000 0000 0011 0010
0000 0000 0000 0001
0000 0000 0000 0000
1111 1111 1111 1111
1111 1111 1100 1110
1111 1111 1001 0010
2
S
L
4
registers are nonvolatile (EEPROM) so they will retain data
bit 4
L
-
2
can be accessed through bytes 2 and 3 of the scratchpad as
5
. 0
(Binary)
25
4 of 20
bit 12
+
bit 4
2
S
COUNT
3
bit 3
2
5
_
bit 11
bit 3
PER
2
COUNT
S
2
DIGITAL OUTPUT
H
bit 2
and T
_
2
2
C
-
_
00AAh
FFCEh
FFFFh
FF92h
0000h
0032h
0001h
COUNT
L
(Hex)
bit 10
H
PER
bit 2
2
comparison since T
S
and T
1
_
bit 1
2
C
H
1
L
_
or lower than T
registers (see Figure
REMAIN
bit 1
bit 9
2
S
0
bit 0
2
0
H
and T
bit 0
bit 8
2
L
S
-1
, an
L