DS620

DS620 DALLAS | Alldatasheet

Document overview

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Technical content

Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata. GENERAL DESCRIPTION The DS620 digital thermometer and thermostat provides low-voltage (1.7V /g163 VDD /g163 3.5V) temperature measurements with /g1770.5°C accuracy from 0°C to +70°C and an operating temperature range of -55°C to +125°C. The DS620 communicates over a 2-wire digital interface. For distributed-sensing applications, it is multidroppable with three address pins that allow up to eight DS620s to operate on a single bus. The DS620 has thermostat functionality with user- defined thresholds stored in EEPROM registers, and it can be configured for standalone thermostat operation. The programmable output (PO) pin serves as the thermostat output, and this pin can also be configured to function as an active-low control for peripheral devices.

APPLICATIONS

Low-Voltage Temperature-Sensitive Applications Computers/Servers Test Equipment Medical Instruments Industrial Applications TYPICAL OPERATING CIRCUIT

FEATURES

/g167/g32Low-Voltage Operation: 1.7V to 3.5V /g167/g32/g1770.5°C Accuracy from 0°C to +70°C /g167/g32Operating Temperature Range: -55°C to +125°C (-67°F to +257°F) /g167/g32Temperature Measurements Require No External Components /g167/g32Resolution is User-Selectable to 10-, 11-, 12-, or LSb Weight, Respectively) /g167/g32Multidroppable /g167/g32Fast (200ms max) Temperature-to-Digital Conversion Time /g167/g32Thermostatic Settings are User-Definable and Nonvolatile /g167/g32Standalone Thermostat Capability /g167/g32Data is Read/Written Through a 2-Wire Serial Interface /g167/g32Package: 8-Pin /g109SOP

ORDERING INFORMATION

PART TEMP RANGE PIN-PACKAGE DS620U -55°C to +125°C 8 µSOP, Exposed Pad DS620U/T&R -55°C to +125°C 8 µSOP Exposed Pad Tape-and-Reel PIN CONFIGURATION 8SDA SCL PO GND A2 VDD 8-Pin /g109SOP Package DS620 DS620 Low-Voltage, /g1770.5°C Accuracy Digital Thermometer and Thermostat www.maxim-ic.com Exposed Pad VDD PO SDA SCL GND 1.7V to 3.5V HOST SDA SCL 1.7V to 3.5V Thermostat DS620

1 SDA Data Input/Output Pin for serial communication. Open drain. (No diode connection to VDD). 2 SCL Clock Input Pin for 2-wire serial communication. 3 PO Programmable Output Pin. Open drain. (No diode connection to VDD). 6 A1 Address Input Pin. Also serves as an input to trigger one-shot conversions during standalone use. 8 V DD Supply Voltage Pin. +1.7V to +3.5V power supply pin. Figure 1. Block Diagram

DS620 Digital Thermometer and Thermostat 3 of 15 ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Pin, Relative to Ground -0.5V to +4.5V Operating Temperature Range -55°C to +125°C Storage Temperature Range -55°C to +125°C Soldering Temperature See IPC/JEDEC J-STD-020A Specification ESD rating on all pins 4KV HBM Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to the absolute maximum rating conditions for extended periods may affect device. RECOMMENDED DC OPERATING CONDITIONS (3.5V ≥ VDD ≥ 1.7V, TA = -55°C to +125°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Voltage Range on Any Pin, Relative to Ground VDD (Note 1) 1.7 3.5 V Supply Voltage for EEPROM Writes VDD (Note 1) 2.0 3.5 V DC ELECTRICAL CHARACTERISTICS (3.5V ≥ VDD ≥ 1.7V, TA = -55°C to +125°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 0°C to +70°C ±0.5 Thermometer Error T ERR -55°C to +125°C ±2 Input Logic High V IH (Note 1) 0.7 x VDD VDD + 0.5 V Input Logic Low V IL (Note 1) - 0.5 0.3 x VDD V VOL1 3mA sink current (Note 1) 0 0.4 SDA Output Logic Low Voltage VOL2 6mA sink current (Note 1) 0 0.6 V PO Saturation Voltage V OL 4mA sink current (Note 1) 0 0.4 V Input Current for each I/O pin 0.4 < V I/O < 0.9 x VDD -10 +10 µA I/O Capacitance C I/O 10 pF Standby Current I STBY 0°C to +70°C (Note 2) 2 µA Temperature conversion, - 55°C to +85°C (Note 3) 800 Temperature conversion, +85°C to +125°C (Note 3) 900 µA Active Supply Current I DD E2 write (Note 3) 500 µA 10 bit 25 11 bit 50 12 bit 100 Temperature Conversion Time T TC 13 bit 200 ms Note 1: All voltages are referenced to GND. Note 2: Specified with SDA = VDD; A0, A1, A2 = 0V or VDD. Note 3: Specified with A0, A1, A2 = 0V or VDD.

DS620 Digital Thermometer and Thermostat 4 of 15 AC ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS EEPROM Write Cycle Time T WR -40°C to +85°C 10 ms -40°C ≤ TA ≤ +85°C (Note 1) 10k 20k EEPROM Writes N EEWR TA = +25°C (Note 1) 40k 80k writes EEPROM Data Retention t EEDR -40°C to +125°C (Note 2) 10 years 2-Wire AC Electrical Characteristics PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS SCL Frequency f SCL 0 400 KHz Bus Free Time Between a STOP and START Condition tBUF 1.3 µs START and Repeat START Hold Time from Falling SCL tHD:STA (Note 3, 4) 0.6 µs Low Period of SCL t LOW (Note 3) 1.3 µs High Period of SCL t HIGH (Note 3) 0.6 µs Repeated START Condition Setup Time to Rising SCL tSU:STA (Note 3) 0.6 µs Data-Out Hold Time from Falling SCL tHD:DAT (Note 3) 0 0.9 µs Data-In Setup Time to Rising SCL tSU:DAT (Note 3) 100 ns Rise Time of SDA and SCL t R (Note 3, 5) 20 + 0.1xCB 1000 ns Fall Time of SDA and SCL t F (Note 3, 5) 20 + 0.1xCB 300 ns STOP Setup Time to Rising SCL TSU:STO 0.6 µs Capacitive Load for Each BUS Line CB 400 pF Input Capacitance C I 10 pF Spike Pulse Width that can be Suppressed by Input Filter 0 50 ns Note 1: VDD must be 2.0V to 3.5V. Note 2: Write done at 25°C. Note 3: All values referenced to 0.9 VDD and 0.1 VDD. Note 4: After this period the first clock pulse is generated. Note 5: For example, if CB = 300pF, then tR(MIN) = tF(MIN) = 50ns.

Figure 2. Timing Diagram Table 1. Register Summary (i.e., they are not saved) and always read out as 0s. detailed information and power-up/factory state. the term “conversion” is used to refer to the entire temperature measurement and ADC sequence. the Configuration Register section of this data sheet.

initiated by a Start Convert command. resolution at power-up is 13-bits. Note that the conversion time doubles for each additional bit of resolution. resolution, the 12 MSbs (bits 15 through 4) of the temperature register will contain data, and bit 3 will be 0. data and the corresponding temperatures. Figure 3. Temperature, TH, And TL Register Format Table 2. 13-Bit Resolution Temperature/Data Relationship

0 prior to comparison to the measured temperature. (Bits 0 to 2 are automatically set to 0). Another thermostat feature is the temperature high and low flags (THF and TLF) in the configuration register. set, it remains set until the power is cycled or it is overwritten with a 0 by the user. Figure 4. Thermostat Operation conversions at power up (1SHOT = 0) or a single conversion (one-shot) at power up or upon request (1SHOT = 1). until A1 is toggled high. The A1 pin must be toggled low and back high again to start another conversion.

defines the various configuration options for this pin. Table 3. PO Configuration Memory Map is shown in Table 4. the DS620 EEPROM registers and memory map. Table 4. Memory Map power up in the state shown in Table 5.

Figure 5. Configuration Register Table 5. Configuration Register Bit Descriptions DONE = 0—Temperature conversion is in progress. DONE = 1—Temperature conversion is complete. NVB = 0—Nonvolatile memory is not busy. R1* Read/Write Used to set conversion resolution (see Table 6). R0* Read/Write Used to set conversion resolution (see Table 6). Determines whether the DS620 powers up idle or converting. AUTOC = 1—DS620 powers-up converting temperature. AUTOC = 0—DS620 powers-up idle. device returns to a low-power standby state. Convert command or by toggling A1 high.

conversions can be performed. information on writing the 1SHOT bit. When PO2 = 0, PO1 is a “don’t care”. A2 Read Only Shows address bit A 2, as determined by pin A2. A1 Read Only Shows address bit A 1, as determined by pin A1. A0 Read Only Shows address bit A 0, as determined by pin A0. M* Read/Write User memory for general-purpose data storage. Table 6. Resolution Configuration SDA I/O pin. All communication is MSb first. generates the SCL signal and START and STOP conditions. Slave: All devices on the bus other than the master. The DS620 always functions as a slave. (if the SCL output is open-drain). Transmitter: A device (master or slave) that is sending data on the bus. Receiver: A device (master or slave) that is receiving data from the bus. will perform another operation. STOP is issued, the master releases the bus to its idle state.

DS620 Digital Thermometer and Thermostat 12 of 15 the DS620 commands. See Writing to the DS620 or Reading from the DS620 for more information on reading from and writing to the DS620. WRITING TO THE DS620 The master can write data to the DS620 by issuing an address byte following the control byte. The R/ W bit in the control byte must be a 0 (write). After receiving an ACK from the DS620 in response to the control byte, the master sends the address of the first register byte to be written, loading the address counter with the desired location. The DS620 responds with another ACK, after which the master sends the data to be written. After receiving each byte of data, the DS620 responds with an ACK. The master continues to write data to successive address locations until it indicates there is no more data to be written by sending a STOP or repeated START condition. The DS620 ignores any data written once the address increments past ADh, the last defined register in the DS620 memory, and indicates this by sending a NACK after each byte. It also ignores data written to undefined addresses A8h and A9h. All writes to the DS620 are made to the shadow RAM. Once data is written to the shadow RAM, it is only stored to EEPROM by issuance of a Copy Data command from the master. At that time all registers are copied to EEPROM, except the Temperature registers, which are SRAM only, and the undefined registers. The DS620 must be set to the continuous conversion mode and be actively converting temperature to enable the Copy Data command to function properly. See Copying to EEPROM Command Sequence for more information. READING FROM THE DS620 The master can read data from the DS620 by issuing an address byte following the control byte. The R/ W bit in the control byte must be a 0 (write). After receiving an ACK from the DS620 in response to the control byte, the master writes the address of the first register byte to be read, loading the address counter with the desired location. The DS620 will respond with another ACK. The master then must issue a repeated START (or a STOP and a START) followed by a control byte with the same slave address as the first control byte. However, this time the R/ W bit must be a 1 which tells the DS620 that a “read” is being performed. After the DS620 sends an ACK in response to this control byte, it begins transmitting the requested data on the next clock cycle. The master responds with an ACK between each byte of data read from the DS620 until no further bytes of data are to be read, at which time the master responds with a NACK followed by a STOP. The DS620 sends all 1’s (FFh) once the address increments past ADh, the last defined register in the DS620 memory. There is no guaranteed state of data read from the undefined registers, A8h and A9h. The Recall Data command should be issued before a read to assure that the contents of the EEPROM will be in the Shadow RAM when read. COMMAND SET The DS620 command set is detailed below: Start Convert [ 51h ] 0101 0001 Initiates temperature conversions. If the part is in one-shot mode (1SHOT = 1), only one conversion is performed. In continuous mode (1SHOT = 0), continuous temperature conversions are performed until a Stop Convert command is issued (even if 1SHOT is changed to a 1). Stop Convert [ 22h ] 0010 0010 Stops temperature conversions when the device is in continuous conversion mode (1SHOT = 0). This command has no function if the device is in one-shot mode (1SHOT = 1) Recall Data [ B8h ] 1011 1000 Refreshes SRAM shadow register with EEPROM data. Copy Data [ 48h ] 0100 1000 Copies data from all SRAM shadow registers to EEPROM. NOTE: The DS620 must be set to the continuous conversion mode and be actively converting temperature to enable the Copy Data command to function properly. See example command sequence in the Copying to EEPROM Command Sequence section for more information. Software POR [ 54h ] 0101 0100 Initiates a software power-on-reset (POR), which stops temperature conversions and resets all registers and logic to their power-up states. The software POR allows the user to simulate cycling the power without actually powering down the device. This command should not be issued while a Copy Data command is in progress.

DS620 Digital Thermometer and Thermostat 13 of 15 COPYING TO EEPROM COMMAND SEQUENCE Data is written to DS620 and then copied from SRAM to EEPROM BUS MASTER MODE DS620 MODE DATA (MSB FIRST) COMMENTS SEQUENCE NUMBER TX RX START Bus master initiates a START condition. 1 TX RX <address, 0> Bus master sends DS620 address, R/W = 0. 2 RX TX ACK DS620 generates acknowledge bit. 3 TX RX A4h Bus master sends the address location of the first byte of data to be written. (In this case the first byte of user EEPROM). RX TX ACK DS620 generates acknowledge. 5 TX RX <data> Bus master sends one byte of data to the SRAM location for EEPROM address A4h. 6 RX TX ACK DS620 generates acknowledge. 7 TX RX <data> Bus master sends one byte of data to the SRAM location for EEPROM for address A5h. 8 RX TX ACK DS620 generates acknowledge. 9 TX RX <data> Bus master sends one byte of data to the SRAM location for EEPROM for address A6h. 10 RX TX ACK DS620 generates acknowledge. 11 TX RX <data> Bus master sends one byte of data to the SRAM location for EEPROM for address A7h. 12 RX TX ACK DS620 generates acknowledge. 13 TX RX START Bus master generates a repeated start condition. 14 TX RX <address, 0> Bus master sends DS620 address, R/W = 0. 15 RX TX ACK DS620 generates acknowledge. 16 TX RX ACh Bus master sends the address location of the MSb of the configuration register (contains the 1SHOT bit). This writes to the SRAM location corresponding the EEPROM location. NOTE: Sequence numbers 17 through 23 need to be done only if DS620 is in 1SHOT mode: 1SHOT = 1. RX TX ACK DS620 generates acknowledge. 18 TX RX xxxxxxx0b Bus master writes to the configuration register putting the DS620 in continuous conversion mode: 1SHOT = RX TX ACK DS620 generates acknowledge. 20 TX RX START Bus master generates a repeated start condition. 21 TX RX <address, 0> Bus master sends DS620 address, R/W = 0. 22 RX TX ACK DS620 generates acknowledge 23 TX RX 51h Master sends START CONVERT command to DS620 to start temperature conversions. 24 RX TX ACK DS620 generates acknowledge bit and begins conversions. 25 TX RX START Bus master generates a repeated start condition. 26 TX RX <address, 0> Bus master sends DS620 address, R/W = 0. 27 RX TX ACK DS620 generates acknowledge. 28 TX RX ACh Bus master sends the address location of the MSb of the configuration register (contains the 1SHOT bit). This writes to the SRAM location corresponding the EEPROM location. NOTE: command sequence numbers 29 through 34 need only be done if a return to 1SHOT mode operation is needed.

DS620 Digital Thermometer and Thermostat 14 of 15 RX TX ACK DS620 generates acknowledge. 30 TX RX xxxxxxx1b Bus master writes to the configuration register putting the DS620 back in 1SHOT mode: 1SHOT = 1. 31 TX RX START Bus master generates a repeated start condition. 32 TX RX <address, 0> Bus master sends DS620 address, R/W = 0. 33 RX TX ACK DS620 generates acknowledge. 34 TX RX 48h Master sends COPY DATA command to DS620 to copy data in from SRAM memory to EEPROM memory. 35 RX TX ACK DS620 generates acknowledge. 36 TX RX START Bus master generates a repeated start condition. 37 TX RX <address, 0> Bus master sends DS620 address, R/W = 0. 38 RX TX ACK DS620 generates acknowledge. 39 TX RX 22h Bus master sends a STOP CONVERT command to stop the DS620 from continuously converting temperature. NOTE: Bus master should ensure that EEPROM copy operation is complete before executing the STOP CONVERT command by either waiting 10ms from the time of the COPY DATA command or checking the NVB bit in configuration register RX TX ACK DS620 generates acknowledge. 41 TX RX STOP Bus master sends STOP condition to end communication with DS620. (The bus master could send a repeated start condition if additional communication with the DS620 is desired.) WRITING THE 1SHOT BIT COMMAND SEQUENCE Configuring from continuous mode to 1SHOT mode. BUS MASTER MODE DS620 MODE DATA (MSB FIRST) COMMENTS SEQUENCE NUMBER TX RX START Bus master initiates a START condition. 1 TX RX <address, 0> Bus master sends DS620 address, R/W = 0. 2 RX TX ACK DS620 generates acknowledge bit. 3 TX RX 51h Master sends START CONVERT command to DS620 to start temperature conversions. 4 RX TX ACK DS620 generates acknowledge bit and begins conversions. 5 TX RX START Bus master generates a repeated start condition. 6 TX RX <address, 0> Bus master sends DS620 address, R/W = 0. 7 RX TX ACK DS620 generates acknowledge. 8 TX RX ACh Bus master sends the address location of the MSb of the configuration register (contains the 1SHOT bit). This writes to the SRAM location corresponding the EEPROM location. RX TX ACK DS620 generates acknowledge. 10 TX RX xxxxxxx1b Bus master writes to the configuration register putting the DS620 in 1SHOT mode: 1SHOT = 1. 11 RX TX ACK DS620 generates acknowledge. 12 TX RX START Bus master generates a repeated start condition. 13 TX RX <address, 0> Bus master sends DS620 address, R/W = 0. 14 RX TX ACK DS620 generates acknowledge. 15 TX RX 48h Master sends COPY DATA command to DS620 to copy data in from SRAM memory to EEPROM memory.

DS620 Digital Thermometer and Thermostat 15 of 15 RX TX ACK DS620 generates acknowledge. 17 TX RX START Bus master generates a repeated start condition. 18 TX RX <address, 0> Bus master sends DS620 address, R/W = 0. 19 RX TX ACK DS620 generates acknowledge. 20 TX RX 22h Bus master sends STOP CONVERT command to stop the DS620 from continuously converting temperature. NOTE: Bus master should ensure that EEPROM copy operation is complete before executing the STOP CONVERT command by either waiting 10ms from the time of the COPY DATA command or checking the NVB bit in configuration register RX TX ACK DS620 generates acknowledge. 22 TX RX STOP Bus master sends STOP condition to end communication with DS620. (The bus master could send a repeated start condition if additional communication with the DS620 is desired.) Configuring from 1SHOT to mode to continuous conversion mode. BUS MASTER MODE DS620 MODE DATA (MSB FIRST) COMMENTS SEQUENCE NUMBER TX RX START Bus master initiates a START condition. 1 TX RX <address, 0> Bus master sends DS620 address, R/W = 0. 2 RX TX ACK DS620 generates acknowledge bit. 3 TX RX ACh Bus master sends the address location of the MSb of the configuration register (contains the 1SHOT bit). This writes to the SRAM location corresponding the EEPROM location. RX TX ACK DS620 generates acknowledge. 5 TX RX xxxxxxx0b Bus master writes to the configuration register putting the DS620 in continuous conversion mode: 1SHOT = RX TX ACK DS620 generates acknowledge. 7 TX RX START Bus master generates a repeated start condition. 8 TX RX <address, 0> Bus master sends DS620 address, R/W = 0. 9 RX TX ACK DS620 generates acknowledge. 10 TX RX 51h Master sends START CONVERT command to DS620 to start temperature conversions. 11 RX TX ACK DS620 generates acknowledge bit and begins conversions. 12 TX RX START Bus master generates a repeated start condition. 13 TX RX <address, 0> Bus master sends DS620 address, R/W = 0. 14 RX TX ACK DS620 generates acknowledge. 15 TX RX 48h Master sends COPY DATA command to DS620 to copy data in from SRAM memory to EEPROM memory. RX TX ACK DS620 generates acknowledge. 17 TX RX STOP Bus master sends STOP condition to end communication with DS620. (The bus master could send a repeated start condition if additional communication with the DS620 is desired.)