DS1631 MAXIM | Alldatasheet
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Technical content
FEATURES
DS1631 and DS1631A Provide ±0.5°C Accuracy over a 0°C to +70°C Range DS1731 Provides ±1°C Accuracy over a -10°C to +85°C Range DS1631A Automatically Begins Taking Temperature Measurements at Power-Up Operating Temperature Range: -55°C to Temperature Measurements Require No External Components Output Resolution is User-Selectable to 9, 10, 11, or 12 Bits Wide Power-Supply Range (+2.7V to +5.5V) Converts Temperature-to-Digital Word in 750ms (max) Multidrop Capability Simplifies Distributed Temperature-Sensing Applications Thermostatic Settings are User-Definable and Nonvolatile (NV) Data is Read/Written Through 2-Wire Serial Interface (SDA and SCL Pins) All Three Devices are Available in 8-Pin μSOP Packages and the DS1631 is Also Available in a 150mil SO package—see Table 1 for Ordering Information PIN CONFIGURATIONS
DESCRIPTION
The DS1631, DS1631A, and DS1731 digital thermometers provide 9, 10, 11, or 12-bit temperature readings over a -55°C to +125°C range. The DS1631 and DS1631A thermometer accuracy is ±0.5°C from 0°C to +70°C with 3.0V ≤ VDD ≤ 5.5V, and the DS1731 accuracy is ±1°C from -10°C to +85°C with 3.0V ≤ VDD ≤ 5.5V. The thermostat on all three devices provides custom hysteresis with user-defined trip points (TH and TL). The TH and TL registers and thermometer configuration settings are stored in NV EEPROM so they can be programmed prior to installation. In addition, the DS1631A automatically begins taking temperature measurements at power-up, which allows it to function as a stand-alone thermostat. Communication with the DS1631/DS1631A/DS1731 is achieved through a 2-wire serial interface, and three address pins allow up to eight devices to be multidropped on the same 2-wire bus. Pin descriptions for the DS1631/DS1631A/DS1731 are provided in Table 2 and user-accessible registers are summarized in Table 3. A functional diagram is shown in Figure 1. DS1631/DS1631A/DS1731 High-Precision Digital Thermometer and Thermostat www.maxim-ic.com SO (150mil and 208mil) (DS1631Z+, DS1631S+) SCL VDD A2 GND TOUT SDA μSOP (DS1631U+, DS1631AU+, DS1731U+) SCL VDD A2 GND TOUT SDA See Table 2 for Pin Descriptions
APPLICATIONS
Network Routers and Switches Cellular Base Stations Portable Products Any Space-Constrained Thermally Sensitive Product
Table 1. ORDERING INFORMATION Table 2. DETAILED PIN DESCRIPTION 1 SDA Data Input/Output Pin for 2-Wire Serial Communication Port. Open-Drain. 2 SCL Clock Input Pin for 2-Wi re Serial Communication Port. 3 T OUT Thermostat Output Pin. Push-Pull.
4 GND Ground Pin
5 A 2 Address Input Pin
6 A 1 Address Input Pin
7 A 0 Address Input Pin
8 V DD Supply Voltage Pin. +2.7V to +5.5V Power-Supply Pin.
Figure 1. FUNCTIONAL DIAGRAM maximum rating conditions for extended periods of time may affect reliability.
DC ELECTRICAL CHARACTERISTICS (VDD = 2.7V to 5.5V; TA = -55°C to +125°C.) PARAMETER SYMBOL CONDITION MIN MAX UNITS NOTES Supply Voltage V DD 2.7 5.5 V 1 0°C to +70°C, 0°C to +70°C, 2.7V ≤ VDD < 3.0V ±1 DS1631, DS1631A Thermometer Error TERR -55°C to +125°C ±2 °C 2 -10°C to +85°C, 3.0V ≤ VDD ≤ 5.5V ±1 -10°C to +85°C, DS1731 Thermometer Error TERR -55°C to +125°C ±2 °C 2 Low-Level Input Voltage VIL -0.5 0.3 x V DD V High-Level Input Voltage VIH 0.7 x VDD VDD + 0.3 V VOL1 3mA sink current 0 0.4 SDA Low-Level Output Voltage VOL2 6mA sink current 0 0.6 V Input Current Each I/O Pin 0.4 < V I/O < 0.9VDD -10 +10 µA Temperature conversion -55°C to +85°C Temperature conversion +85°C to +125°C 1.25 mA E2 write 400 Active Supply Current IDD Communication only 110 µA Standby Supply Current ISTBY 0°C to +70°C 800 nA 4 VOH 1mA source current 2.4 V 1 TOUT Output Logic Voltage VOL 4mA sink current 0.4 V 1
AC ELECTRICAL CHARACTERISTICS (VDD = 2.7V to 5.5V; TA = -55°C to +125°C.) PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS NOTES 9-bit resolution 93.75 10-bit resolution 187.5 11-bit resolution 375 Temperature Conversion Time tTC 12-bit resolution 750 ms SCL Frequency f SCL 0 400 kHz Bus Free Time Between a STOP and START Condition t BUF 1.3 µs 5 START and Repeated START Hold Time from Falling SCL t HD:STA 0.6 µs 5, 6 Low Period of SCL t LOW 1.3 µs 5 High Period of SCL t HIGH 0.6 µs 5 Repeated START Condition Setup Time to Rising SCL t SU:STA 0.6 µs 5 Data-Out Hold Time from Falling SCL tHD:DAT 0 0.9 µs 5 Data-In Setup Time to Rising SCL tSU:DAT 100 ns 5 Rise Time of SDA and SCL tR 20 + 0.1C B 1000 ns 5, 7 Fall Time of SDA and SCL tF 20 + 0.1C B 300 ns 5, 7 STOP Setup Time to Rising SCL tSU:STO 0.6 µs 5 Capacitive Load for Each Bus Line CB 400 pF I/O Capacitance C I/O 10 pF Input Capacitance C I 5 pF Spike Pulse Width that can be Suppressed by Input Filter t SP 0 50 ns NOTES: 1) All voltages are referenced to GND. 2) See Figure 2 for Typical Operating Curves. 3) Specified with TOUT pin open; A0, A1, A2 = 0V or VDD; and fSCL ≥ 2Hz. 4) Specified with temperature conversions stopped; TOUT pin open; SDA = VDD; SCL = VDD; and A0, A1, A2 = 0V or VDD. 5) See Timing Diagram in Figure 3. All timing is referenced to 0.9 x VDD and 0.1 x VDD. 6) After this period the first clock pulse is generated. 7) For example, if CB = 300pF, then tR[min] = tF[min] = 50ns.
Table 3. REGISTER SUMMARY
1 SRAM,
6 MSbs = SRAM
2 LSbs (POL and 1SHOT bits) = EEPROM
temperature measurement and ADC sequence. mode determined by the configuration register’s 1SHOT bit. state until a single temperature conversion is again initiated by a Start Convert T command. configuration register. Note that the conversion time doubles for each additional bit of resolution.
Table 5. CONFIGURATION REGISTER BIT DESCRIPTIONS DONE = 0. Temperature conversion is in progress. DONE = 1. Temperature conversion is complete. a Software POR command is issued. Software POR command is issued. NVB = 0. NV memory is not busy. H, and TL resolution (see Table 6). H, and TL resolution (see Table 6). Power-up state = last value written to this bit. Factory setting = 0. POL = 1. TOUT is active high. POL = 0. TOUT is active low. Power-up state = last value written to this bit. Factory setting = 0. command initiates continuous temperature conversions. Table 6. RESOLUTION CONFIGURATION
interface to the bus through their SCL input pins and open-drain SDA I/O pins. device generates the SCL signal and START and STOP conditions. high by a pullup resistor (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. indicate that the master will perform another operation. 8). After the STOP is issued, the master releases the bus to its idle state.
2 A1 A0, where A2, A1, and A0 are user-selectable through
to be multidropped on the same bus. 1, and if the master is going to write data to the slave device then R/W¯¯ = 0. SET section of this data sheet. Figure 7. CONTROL BYTE
Figure 8. START, STOP, AND ACK SIGNALS All data is transmitted MSb first over the 2-wire bus. One bit of data is transmitted on the 2-wire bus each SCL period. takes one SCL period. Therefore, nine clocks are required for every one-byte data transfer. an ACK after receiving the command byte.
The master can read data from the DS1631/DS1631A/DS1731 by issuing an Access Config, Access TH, Access TL, or Read Temperature command following the control byte (see Figures 9c and 9e). After receiving an ACK in response to the command, the master must generate a repeated 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 DS1631/DS1631A/DS1731 that a “read” is being performed. After the DS1631/DS1631A/DS1731 send an ACK in response to this control byte, it begins transmitting the requested data on the next clock cycle. One byte of data will be transmitted when reading from the configuration register after which the master must respond with a NACK followed by a STOP. For two- byte reads (i.e., from the Temperature, TH, or TL register), the master must respond to the first data byte with an ACK and to the second byte with a NACK followed by a STOP. If only the most significant byte of data is needed, the master can issue a NACK followed by a STOP after reading the first data byte. COMMAND SET The DS1631/DS1631A/DS1731 command set is detailed below: Start Convert T [ 51h ] 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 T command is issued. Stop Convert T [ 22h ] Stops temperature conversions when the device is in continuous conversion mode (1SHOT = 0). Read Temperature [ AAh ] Reads last converted temperature value from the 2-byte temperature register. Access TH [ A1h ] Reads or writes the 2-byte TH register. Access TL [ A2h ] Reads or writes the 2-byte TL register. Access Config [ ACh ] Reads or writes the 1-byte configuration register. Software POR [ 54h ] 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.
Figure 9 (a, b, c, d, e). 2-WIRE INTERFACE TIMING THERM = DS1631, DS1631A, or DS1731 a) Issue a "Start Convert T” or “Stop Convert T” Command S 11 00 A2 A1 A0 W AC 7 C 6 C 5 C 4 AC3 C1 C0 P Control Byte Command ByteSTART STOPACK (THERM) SCL SDA ACK (THERM) d) Write to the TH or TL Register A2 A1 A0 C2 SCL SDA S 1 10 0W A Control ByteSTART ACK (THERM) AC7 C6 C5 C4 C3 C1 C0 Command Byte ACK (THERM) D4D6 D5 D3 D2 D0D7D6 D5 D4 D3 D2 D1 D0D7 AD1 P LS Data Byte (from Master) A MS Data Byte (from Master) STOPACK (THERM) ACK (THERM) e) Read From the Temperature, TH, or TL Register AD 2 D 1 D 0D6 D5 D4 D3D7A2 A1 A000AC4 C3 C2 C1C7 C6 C5A2 A1 A0 A ACK (THERM) Repeat START A SCL SDA S 11 00 W Control ByteSTART Command Byte S 11 R Control Byte MS Data Byte (from THERM) ACK (THERM) ACK (THERM) ACK (Master) D5 ND6 D4 D3 D2 D1 D0 P LS Data Byte (from THERM) STOP NACK (Master) (THERM) (THERM) AD2D6 D5 D4 D3 D1 D0A0 W AA1 1 0 1 0 1 100A D 7A2 b) Write to the Configuration Register S1 1 00 Control ByteSTART SCL SDA ACK Command Byte P Data Byte (from Master) STOPACK ACK (THERM) NA1S1 1 00 A2 A1 A0 W 010 A 1 100 D6 D5 D4 D3 D2 D1 D0 PD7S1 100 A2 A1 A0 R A c) Read From the Configuration Register ACK (THERM) Repeat START SCL SDA Control ByteSTART Command Byte Data Byte (from THERM) STOPNACK (Master) Control ByteACK (THERM) ACK (THERM)
In this example, the master c onfigures the DS1631/DS1631A/DS1731 (A 1A2A3 = 000) for continuous conversions and thermostatic function. MASTER MODE THERMETER* MODE DATA (MSb first) COMMENTS TX RX START START condition from MASTER. TX RX 90h MASTER sends control byte with R/W¯¯ = 0. RX TX ACK Acknowledge bit from THERMOMETER. TX RX ACh MASTER sends Access Config command. RX TX ACK Acknowledge bit from THERMOMETER. TX RX 02h MASTER writes a data byte to the configuration register to put the THERMOMETER in continuous conversion mode and set the TOUT polarity to active high. RX TX ACK Acknowledge bit from THERMOMETER. TX RX STOP STOP condition from MASTER. TX RX START START condition from MASTER. TX RX 90h MASTER sends control byte with R/W¯¯ = 0. RX TX ACK Acknowledge bit from THERMOMETER. TX RX A1h MASTER sends Access TH command. RX TX ACK Acknowledge bit from THERMOMETER. TX RX 28h MASTER sends most significant data byte for T H = +40°C. RX TX ACK Acknowledge bit from THERMOMETER. TX RX 00h MASTER sends least significant data byte for T H = +40°C. RX TX ACK Acknowledge bit from THERMOMETER. TX RX STOP STOP condition from MASTER. TX RX START START condition from MASTER. TX RX 90h MASTER sends control byte with R/W¯¯ = 0. RX TX ACK Acknowledge bit from THERMOMETER. TX RX A2h MASTER sends Access TL command. RX TX ACK Acknowledge bit from THERMOMETER. TX RX 0Ah MASTER sends most significant data byte for T L = +10°C. RX TX ACK Acknowledge bit from THERMOMETER. TX RX 00h MASTER sends least significant data byte for T L = +10°C. RX TX ACK Acknowledge bit from THERMOMETER. TX RX STOP STOP condition from MASTER. TX RX START START condition from MASTER. TX RX 90h MASTER sends control byte with R/W¯¯ = 0. RX TX ACK Acknowledge bit from THERMOMETER. TX RX 51h MASTER sends Start Convert T command. RX TX ACK Acknowledge bit from THERMOMETER. TX RX STOP STOP condition from MASTER. *THERMOMETER = DS1631, DS1631A, or DS1731