DS1726U+ Maxim Integrated Products, DS1726U+ Datasheet - Page 7

• Manufacturer Part Number: DS1726U+
• Description: IC THERMOMETER/STAT DIG HP 8MSOP
• Manufacturer: Maxim Integrated Products

Specifications of DS1726U+

• Function: Thermometer, Thermostat
• Topology: ADC (Sigma Delta), Comparator, Register Bank
• Sensor Type: Internal
• Sensing Temperature: -55°C ~ 125°C
• Output Type: 3-Wire Serial
• Output Alarm: Yes
• Output Fan: No
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -55°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Full Temp Accuracy: +/- 2 C
• Digital Output - Bus Interface: Serial (3-Wire)
• Digital Output - Number Of Bits: 12 bit
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Table 2. 12-BIT RESOLUTION TEMPERATURE/DATA RELATIONSHIP
OPERATION—THERMOSTAT FUNCTION
The DS1626/DS1726 thermostat outputs (T
conversion and remain at the updated values until the next conversion completes. T
the measured temperature is higher than or equal to the value stored in the T
asserted when the temperature is equal to or falls below the value in the T
uses both T
exceeds T
below T
The Write TH and Write TL commands are used to program the 12-bit T
defined two’s complement values. The MSb (bit 11) of each register contains the two’s complement sign
bit (S). For the T
Any unused LSbs in the T
The unused LSbs are determined by the conversion resolution set by R1 and R0 in the configuration
register. Therefore, for 9-bit conversions bits 2 through 0 will be 0, for 10-bit conversions bit 1 and bit 0
will be 0, and for 11-bit conversions bit 0 will be 0. All bits are used for 12-bit conversions, so no bits are
forced to 0. However, regardless of the conversion resolution, when writing to T
must be sent following the Write TH or Write TL commands. The reason is that data written to T
is not saved to EEPROM until the DS1626/DS1726 have received 12 bits, so if the operation is
terminated before 12 bits have been received, the data will be lost. Any additional bits sent after the first
twelve are ignored (e.g., if two 8-bit words are written).
Another DS1626/DS1726 thermostat feature is the temperature-high flag (THF) and temperature-low flag
(TLF) in the configuration register. These bits provide a record of whether the temperature has been
greater than or equal to T
powered up. If the temperature is greater than or equal to the T
configuration register will be set to 1. If the temperature is less than or equal to the T
TLF bit in the configuration register will be set to 1. Once THF and/or TLF has been set, it will remain
set until the user overwrites it with a 0 or until the power is cycled.
TEMPERATURE (°C)
L
. All three thermostat outputs are active-high outputs.
H
+25.0625
-25.0625
, T
+10.125
-10.125
H
+125
+0.5
-0.5
-55
and T
COM
0
COM
is asserted and it remains asserted until the temperature falls to a value equal to or
L
thermostat output to function correctly, the T
to provide programmable hysteresis: when the measured temperature equals or
H
H
and T
or less than or equal to T
L
DIGITAL OUTPUT
registers are forced to 0 regardless of the data written to those bits.
0111 1101 0000
0001 1001 0001
0000 1010 0010
0000 0000 1000
0000 0000 0000
1111 1111 1000
1111 0101 1110
1110 0110 1111
1100 1001 0000
(BINARY)
HIGH
, T
7 of 12
LOW
, and T
L
at any time since the DS1626/DS1726 were
COM
L
) are updated after every temperature
DIGITAL OUTPUT
H
value must be less than the T
register value, the THF bit in the
L
(HEX)
7D0h
0A2h
FF8h
F5Eh
E6Fh
C90h
H
191h
008h
000h
register (see Figure 5). T
and T
H
H
register, and T
L
or T
HIGH
L
registers with user-
register value, the
L
is asserted when
at least 12 bits
DS1626/DS1726
H
H
and T
LOW
value.
COM
is
L