DS1626 Dallas, DS1626 Datasheet - Page 7

no-image

DS1626

Manufacturer Part Number
DS1626
Description
High-Precision 3-Wire Digital Thermometer and Thermostat
Manufacturer
Dallas
Datasheet

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
DS1626S
Manufacturer:
DALLAS
Quantity:
20 000
Part Number:
DS1626S+T&R
Manufacturer:
TI
Quantity:
12 000
Part Number:
DS1626U+
Manufacturer:
MAXIM/美信
Quantity:
20 000
Table 4. 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
when the measured temperature is higher than or equal to the value stored in the T
is asserted when the temperature is equal to or falls below the value in the T
T
or 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
value. Any unused LSbs in the T
those bits. 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
reason is that data written to T
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
the 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.
COM
uses both T
L
. All three thermostat outputs are active-high outputs.
H
H
, T
or T
TEMPERATURE
COM
H
L
and T
+25.0625
-25.0625
at least 12 bits must be sent following the Write TH or Write TL commands. The
+10.125
-10.125
is asserted and it remains asserted until the temperature falls to a value equal to or
COM
+125
(°C)
+0.5
-0.5
-55
0
L
thermostat output to function correctly, the T
to provide programmable hysteresis: when the measured temperature equals
H
H
or less than or equal to T
H
and T
and T
DIGITAL OUTPUT
L
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
L
is not saved to EEPROM until the DS1626/DS1726 have
HIGH
(BINARY)
registers are forced to 0 regardless of the data written to
, T
7 of 13
LOW
, and T
L
at any time since the DS1626/DS1726 were
COM
) are updated after every temperature
H
DIGITAL OUTPUT
register value, the THF bit in the
L
value must be less than the T
(HEX)
H
7D0h
0A2h
F5Eh
E6Fh
C90h
FF8h
191h
008h
000h
and T
L
register (see Figure 5).
L
H
registers with user-
register, and T
L
HIGH
register value,
is asserted
LOW
H

Related parts for DS1626