Datasheet

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AVAILABLE

Functional Diagrams

Pin Configurations appear at end of data sheet.

Functional Diagrams continued at end of data sheet.

UCSP is a trademark of Maxim Integrated Products, Inc.

For pricing, delivery, and

ordering information, please contact Maxim Direct

at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.

FEATURES

§ Requires no external components

§ Supply voltage range covers from 2.7V to

5.5V

§ Measures temperatures from -55°C to +125°C

in 0.5°C increments; Fahrenheit equivalent is

-67°F to +257°F in 0.9°F increments

§ Temperature is read as a 9-bit value

§ Converts temperature to digital word in 750

ms (max)

§ Thermostatic settings are user-definable and

nonvolatile

§ Data is read from/written via a 3-wire serial

interface (CLK, DQ, RST )

§ Applications include thermostatic controls,

industrial systems, consumer products,

thermometers, or any thermally sensitive

system

§ 8-pin DIP or SOIC (208-mil) packages

PIN ASSIGNMENT

PIN DESCRIPTION

DQ - 3-Wire Input/Output

CLK/ CONV - 3-Wire Clock Input and

Stand-alone Convert Input

RST - 3-Wire Reset Input

GND - Ground

HIGH

- High Temperature Trigger

LOW

- Low Temperature Trigger

COM

- High/Low Combination Trigger

- Power Supply Voltage (3V - 5V)

DESCRIPTION

The DS1620 Digital Thermometer and Thermostat provides 9–bit temperature readings which indicate

the temperature of the device. With three thermal alarm outputs, the DS1620 can also act as a thermostat.

HIGH

is driven high if the DS1620’s temperature is greater than or equal to a user–defined temperature

TH. T

LOW

is driven high if the DS1620’s temperature is less than or equal to a user–defined temperature

TL. T

COM

is driven high when the temperature exceeds TH and stays high until the temperature falls

below that of TL.

DS1620

Digital Thermometer and

Thermostat

www.maxim-ic.com

CLK/CONV

RST

GND

HIGH

LOW

COM

DS1620S 8-Pin SOIC (208-mil)

CLK/CONV

RST

GND

HIGH

LOW

COM

DS1620 8-Pin DIP (300-mil)

053105

Summary of content (12 pages)

PAGE 1
LE AVAILAB DS1620 Digital Thermometer and Thermostat www.maxim-ic.com FEATURES § § § § § § § § § PIN ASSIGNMENT Requires no external components Supply voltage range covers from 2.7V to 5.5V Measures temperatures from -55°C to +125°C in 0.5°C increments; Fahrenheit equivalent is -67°F to +257°F in 0.
PAGE 2
DS1620 User–defined temperature settings are stored in nonvolatile memory, so parts can be programmed prior to insertion in a system, as well as used in standalone applications without a CPU. Temperature settings and temperature readings are all communicated to/from the DS1620 over a simple 3–wire interface.
PAGE 3
DS1620 DS1620 FUNCTIONAL BLOCK DIAGRAM Figure 1 The DS1620 measures temperature using a bandgap-based temperature sensor. The temperature reading is provided in a 9–bit, two’s complement reading by issuing a READ TEMPERATURE command. The data is transmitted serially through the 3–wire serial interface, LSB first. The DS1620 can measure temperature over the range of -55°C to +125°C in 0.5°C increments. For Fahrenheit usage, a lookup table or conversion factor must be used.
PAGE 4
DS1620 Table 3 describes the exact relationship of output data to measured temperature. . TEMPERATURE/DATA RELATIONSHIPS Table 3 TEMP +125˚C +25˚C +½˚C +0˚C -½˚C -25˚C -55˚C DIGITAL OUTPUT (Binary) 0 11111010 0 00110010 0 00000001 0 00000000 1 11111111 1 11001110 1 10010010 DIGITAL OUTPUT (Hex) 00FA 0032h 0001h 0000h 01FFh 01CEh 0192h Higher resolutions may be obtained by reading the temperature, and truncating the 0.5°C bit (the LSB) from the read value. This value is TEMP_READ.
PAGE 5
DS1620 THERMOSTAT OUTPUT OPERATION Figure 3 THIGH TLOW TCOM TH TL T(°C) OPERATION AND CONTROL The DS1620 must have temperature settings resident in the TH and TL registers for thermostatic operation. A configuration/status register also determines the method of operation that the DS1620 will use in a particular application and indicates the status of the temperature conversion operation.
PAGE 6
DS1620 1SHOT = One–Shot Mode. If 1SHOT is 1, the DS1620 will perform one temperature conversion upon reception of the Start Convert T protocol. If 1SHOT is 0, the DS1620 will continuously perform temperature conversion. This bit is stored in nonvolatile E2 memory, capable of at least 50,000 writes. The DS1620 is shipped with 1SHOT=0. For typical thermostat operation, the DS1620 will operate in continuous mode.
PAGE 7
DS1620 Write TL [02h] This command writes to the TL (LOW TEMPERATURE) register. After issuing this command the next nine clock cycles clock in the 9–bit temperature limit which will set the threshold for operation of the TLOW output. Read TH [A1h] This command reads the value of the TH (HIGH TEMPERATURE) register. After issuing this command the next nine clock cycles clock out the 9–bit temperature limit which sets the threshold for operation of the THIGH output.
PAGE 8
DS1620 DS1620 COMMAND SET Table 4 INSTRUCTION Read Temperature Read Counter Read Slope Start Convert T Stop Convert T Write TH Write TL Read TH Read TL Write Config Read Config 3-WIRE BUS DATA AFTER ISSUING DESCRIPTION PROTOCOL PROTOCOL TEMPERATURE CONVERSION COMMANDS Reads last converted temperature AAh value from temperature register. Reads value of count remaining A0h from counter. Reads value of the slope A9h accumulator. Initiates temperature conversion.
PAGE 9
DS1620 FUNCTION EXAMPLE Example: CPU sets up DS1620 for continuous conversion and thermostatic function.
PAGE 10
DS1620 WRITE DATA TRANSFER Figure 5 NOTE: tCL, tCH, tR, and tF apply to both read and write data transfer. ABSOLUTE MAXIMUM RATINGS* Voltage on Any Pin Relative to Ground Operating Temperature Storage Temperature Soldering Temperature –0.5V to +6.0V –55°C to +125°C –55°C to +125°C 260°C for 10 seconds * This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied.
PAGE 11
DS1620 DC ELECTRICAL CHARACTERISTICS PARAMETER Thermometer Error Thermometer Resolution Logic 0 Output Logic 1 Output Input Resistance Active Supply Current Standby Supply Current Input Current on Each Pin Thermal Drift SYMBOL TERR VOL VOH RI ICC ISTBY (-55°C to +125°C; VDD=2.7V to 5.5V) CONDITION 0°C to +70°C 3.0V ≤ VDD ≤ 5.5V 0°C to +70°C 2.7V ≤ VDD < 3.0V -55°C to +125°C MIN MAX ±0.5 DQ, CLK to VDD 0°C to +70°C 0°C to +70°C 0.4 < VI/O < 0.9 x VDD NOTES 2 ±1.25 ±2.0 12 0.
PAGE 12
DS1620 AC ELECTRICAL CHARACTERISTICS PARAMETER Input Capacitance I/O Capacitance EEPROM SYMBOL CI CI/O (-55°C to +125°C; VDD=2.7V to 5.5V) MIN TYP 5 10 MAX UNITS pF pF NOTES AC ELECTRICAL CHARACTERISTICS (-55°C to +125°C; VDD=2.7V to 5.5V) PARAMETER EEPROM Write Cycle Time EEPROM Writes EEPROM Data Retention CONDITIONS MIN -55°C to +55°C -55°C to +55°C 50k 10 TYP 4 MAX 10 UNITS Ms Writes Years NOTES: 1. All voltages are referenced to ground. 2. Valid for design revisions D1 and above.