Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsDS1726U+

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DESCRIPTION

The DS1626 and DS1726 digital

thermometers/thermostats provide temperature

measurements and stand-alone thermostat

capability over a -55°C to +125°C range. The

DS1626 offers ±0.5°C accuracy from 0°C to

+70°C and the DS1726 has ±1°C accuracy from

-10°C to +85°C. The resolution of the measured

temperature is user selectable from 9 to 12 bits.

Communication with the DS1626 and DS1726 is

achieved through a 3-wire serial bus.

The DS1626 and DS1726 offer thermostatic

functionality with three dedicated thermostat

outputs (T

HIGH

, T

LOW

, and T

COM

), and

overtemperature (T

) and undertemperature (T

)

user-programmable thresholds stored in on-chip

EEPROM. For stand-alone thermostat operation,

and T

can be programmed prior to

installation, and the DS1626/DS1726 can be

configured to automatically begin taking

temperature measurements at power-up. Table 1

summarizes the user-accessible registers. Figure

1 shows a functional diagram.

APPLICATIONS

Thermostatic Controls

Industrial Controls

Consumer Products

Any Space-Constrained Thermally Sensitive

Application

FEATURES

 Temperature Measurements Require No

External Components

 Measure Temperatures from -55°C to

+125°C (-67°F to +257°F)

 DS1626: ±0.5°C Accuracy from 0°C to

+70°C

 DS1726: ±1°C Accuracy from -10°C to

+85°C

 Output Resolution is User Selectable to 9,

10, 11, or 12 Bits

 Wide Power-Supply Range (2.7V to 5.5V)

 Convert Temperature to Digital Word in

750ms (max)

 Stand-Alone Thermostat Capability

 Thermostatic Settings are User Definable and

Nonvolatile (NV)

 Data is Read/Written Through a 3-Wire

Serial Interface

 Available in 8-Pin μSOP Package

PIN CONFIGURATION

ORDERING INFORMATION

PART TEMP RANGE PIN-PACKAGE TOP MARK

DS1626U -55°C to +125°C

8 μSOP

1626

DS1626U+ -55°C to +125°C

8 μSOP

1626

DS1626U/T&R -55°C to +125°C

8 μSOP, 3000-Piece

1626

DS1626U+T&R -55°C to +125°C

8 μSOP, 3000-Piece

1626

DS1726U -55°C to +125°C

8 μSOP

1726

DS1726U+ -55°C to +125°C

8 μSOP

1726

DS1726U/T&R -55°C to +125°C

8 μSOP, 3000-Piece

1726

DS1726U+T&R -55°C to +125°C

8 μSOP, 3000-Piece

1726

+Denotes a lead-free package. A “+” symbol will also be marked on the package near the Pin 1 indicator.

T&R = Tape and reel.

DS1626/DS1726

High-Precision 3-Wire Digital

Thermometer and Thermostat

www.maxim-ic.com

CLK/

SOP

HIGH

LOW

COM

GND

DS1626

DS1726

TOP VIEW

Summary of content (12 pages)

PAGE 1
DS1626/DS1726 High-Precision 3-Wire Digital Thermometer and Thermostat www.maxim-ic.com DESCRIPTION FEATURES The DS1626 and DS1726 digital thermometers/thermostats provide temperature measurements and stand-alone thermostat capability over a -55°C to +125°C range. The DS1626 offers ±0.5°C accuracy from 0°C to +70°C and the DS1726 has ±1°C accuracy from -10°C to +85°C. The resolution of the measured temperature is user selectable from 9 to 12 bits.
PAGE 2
DS1626/DS1726 PIN DESCRIPTION PIN 1 NAME DQ 2 CLK/CNV 3 4 5 6 7 8 RST GND TCOM TLOW THIGH VDD FUNCTION Data Input/Output Pin (Tri-State) for 3-Wire Serial Communication Clock Input Pin for 3-Wire Serial Communication. Controls temperature measurements when the DS1626/DS1726 is configured as a stand-alone thermostat.
PAGE 3
DS1626/DS1726 ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Pin Relative to Ground...................................................................-0.5V to +6.0V Operating Temperature Range.............................................................................................-55°C to +125°C Storage Temperature Range ................................................................................................-55°C to +125°C Solder Dip Temperature (10s) ............................................
PAGE 4
DS1626/DS1726 EEPROM AC ELECTRICAL CHARACTERISTICS (VDD = 2.7V to 5.5V, TA = -55°C to +125°C.) PARAMETER EEPROM Write Cycle Time EEPROM Writes EEPROM Data Retention SYMBOL CONDITIONS twr NEEWR -55°C to +55°C tEEDR -55°C to +55°C MIN TYP 4 MAX 10 UNITS ms Writes Years TYP MAX 93.75 187.5 375 750 UNITS 50k 10 AC ELECTRICAL CHARACTERISTICS (VDD = 2.7V to 5.5V, TA = -55°C to +125°C.
PAGE 5
DS1626/DS1726 Figure 2. TYPICAL OPERATING CURVES DS1726 ERROR (°C) ERROR °C DS1626 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 +3σ MEAN -3σ 0 10 20 30 40 50 60 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 +3σ MEAN -3σ -10 70 0 10 20 30 40 50 60 70 80 REFERENCE TEMPERATURE (°C) REFERENCE TEMPERATURE (°C) Figure 3.
PAGE 6
DS1626/DS1726 OPERATION—MEASURING TEMPERATURE The DS1626/DS1726 measure temperature using a bandgap-based temperature sensor. A delta-sigma analog-to-digital converter (ADC) converts the measured temperature to a digital value that is calibrated in degrees Celsius; for Fahrenheit applications a lookup table or conversion routine must be used. Communication with the DS1626/DS1726 is achieved through a 3-wire serial interface, and all data is transmitted LSb first.
PAGE 7
DS1626/DS1726 Table 2. 12-BIT RESOLUTION TEMPERATURE/DATA RELATIONSHIP TEMPERATURE (°C) +125 +25.0625 +10.125 +0.5 0 -0.5 -10.125 -25.
PAGE 8
DS1626/DS1726 CPU BIT AND STAND-ALONE THERMOSTAT OPERATION In stand-alone thermostat mode, DS1626/DS1726 thermostat functionality can be used without requiring a microcontroller to start/stop temperature conversions. The CPU bit in the configuration register determines if stand-alone mode is enabled. When CPU = 1 stand-alone mode is disabled, and the only way to start/stop temperature conversions is by using a microcontroller to transmit Start Convert T and Stop Convert T commands, respectively.
PAGE 9
DS1626/DS1726 CONFIGURATION REGISTER The configuration register allows the user to customize the DS1626/DS1726 conversion and thermostat options. It also provides information to the user about conversion status, EEPROM activity, and thermostat activity. The configuration register is arranged as shown in Figure 6 and detailed descriptions of each bit are provided in Table 3. This register can be accessed using the Read Config and Write Config commands.
PAGE 10
DS1626/DS1726 Table 4. RESOLUTION CONFIGURATION R1 R0 RESOLUTION (BITS) 0 0 1 1 0 1 0 1 9 10 11 12 CONVERSION TIME (MAX) (ms) 93.75 187.5 375 750 3-WIRE SERIAL DATA BUS The 3-wire bus consists of three signals: RST (active-low reset), CLK (clock), and DQ (data). 3-wire communication is controlled by the RST signal, which functions as “chip select” signal. All data is transferred LSb first over the 3-wire bus. All communication with the DS1626/DS1726 is initiated by driving RST high.
PAGE 11
DS1626/DS1726 Figure 7. 3-WIRE COMMUNICATION a) Start Temperature Conversion RST CLK DQ 1 0 0 0 0 1 1 0 Start Convert T [51h] Command b) Write to the TH/TL Registers ⋅⋅⋅ RST CLK ⋅⋅⋅ DQ C0 C1 0 0 0 0 0 0 D0 D1 D3 D2 Write TH [01h] or TL [02h] Command D5 D4 D6 D7 D8 D9 D10 D11 TH or TL Data from Master c) Write to the Configuration Register RST CLK DQ 0 0 1 1 0 0 0 D0 0 Write Config [0Ch] Command D1 D2 D3 D4 D5 D6 D7 Configuration Reg.
PAGE 12
DS1626/DS1726 DS1626/DS1726 COMMAND SET The DS1626/DS1726 command set is detailed below: Start Convert T 51h 0101 0001 Initiates temperature conversions. If the DS1626/DS1726 are in one-shot mode (1SHOT = 1), only one conversion will be performed. If the devices are in continuous mode (1SHOT = 0), continuous conversions will be performed until a Stop Convert T command is issued. Stop Convert T 22h 0010 0010 Stops temperature conversions when the devices are in continuous conversion mode (1SHOT = 0).