12-Bit Sign Temperature Sensor with SPI-Compatible Serial Interface

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12-Bit Sign Temperature Sensor with SPI-Compatible Serial Interface

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19-2121; 7/01
12-Bit Sign Temperature Sensor with SPI-Compatible Serial Interface
MAX6662 12-bit sign temperature sensor combined with programmable overtemperature alarm 3-wire (SPITM-compatible) serial interface single package. converts temperature into digital values using internal analog-to-digital converter (ADC). temperature data stored temperature register 13-bit word, which allows 0.0625°C resolution. temperature data readable time through serial interface. operating temperature range -55°C +150°C. MAX6662 provides programmable watchdog interrupt outputs. ALERT used lower temperature warning functions, while used higher temperature-critical functions, such power-supply shutdown. MAX6662 features shutdown mode that saves power disabling everything except serial interface. temperature sensor available 8-pin package. 12-Bit Sign, 0.0625°C Resolution Accuracy ±1°C (+30°C +50°C) ±1.6°C (0°C +70°C) ±2.5°C (-20°C +85°C) ±2.5 (+150°C) Extended Temperature Measurement Range -55°C +150°C Average Supply Current, 125µA (typ) Shutdown Mode Minimize Power Consumption Portable Applications Programmable Temperature Fault Outputs Switchable Fault Queue Eliminate False Tripping Noisy Environments
Features
MAX6662
Applications
HVAC Refrigeration Automotive Test Equipment
PART MAX6662MSA
Ordering Information
TEMP. RANGE -55°C +150°C PIN-PACKAGE
Typical Operating Circuit
+5.5V
Configuration
VIEW
0.1µF HEAT SOURCES MAX6662 ALERT SCLK SCLK ALERT
MAX6662
SYSTEM CONTROLLER
trademark Motorola, Inc. Maxim Integrated Products
pricing, delivery, ordering information, please contact Maxim/Dallas Direct! 1-888-629-4642, visit Maxim's website www.maxim-ic.com.
12-Bit Sign Temperature Sensor with SPI-Compatible Serial Interface MAX6662
ABSOLUTE MAXIMUM RATINGS
Voltages Referenced .-0.3V ALERT, OT.-0.3V SIO, SCLK, CS.-0.3V (VCC 0.3V) Current .-10mA +50mA Continuous Current into (except NC).10mA Continuous Power Dissipation +70°C) 8-Pin (derate 5.9mW/°C above +70°C).471mW Operating Temperature Range (Note .-55°C +150°C Junction Temperature .+150°C Storage Temperature Range .-65°C +150°C Lead Temperature (soldering, 10s) .+300°C
Note MAX6662 recommended operate above +125°C extended period time.
Stresses beyond those listed under "Absolute Maximum Ratings" cause permanent damage device. These stress ratings only, functional operation device these other conditions beyond those indicated operational sections specifications implied. Exposure absolute maximum rating conditions extended periods affect device reliability.
ELECTRICAL CHARACTERISTICS
(VCC +5.5V, -55°C +125°C, unless otherwise noted. Typical values +25°C +3.3V.)
PARAMETER SYMBOL CONDITIONS +30°C +50°C, +3.3V +70°C, +3.3V Accuracy -20°C +85°C, +3.3V -40°C +100°C, +3.3V -55°C +125°C, +3.3V +150°C, +3.3V Power-Supply Rejection Ratio Resolution Supply Voltage Range Average Operating Current +5.5V +3.0V +5.5V +3.0V +5.5V +3.0V Power-On-Reset Threshold Power-On-Reset Threshold Hysteresis Conversion Time Temperature Update Frequency SERIAL INTERFACE (SIO, SCLK, ALERT, Input Voltage Input High Voltage Input/Output Leakage Current Input Capacitance Output Sink Current Output High Voltage Output Voltage ILEAK ALERT, 0.6V ISIO 1.6mA source ISIO 1.6mA sink tCONV VPOR 0.25 PSRR -1.0 -1.6 -2.5 -3.0 -4.0 ±0.4 ±0.7 ±1.0 ±1.2 ±1.5 ±2.5 0.0625 °C/V +1.0 +1.6 +2.5 +3.0 +4.0 UNITS
TEMPERATURE DIGITAL-CONVERTER CHARACTERISTICS
Peak Operating Current (Note
Shutdown Supply Current
12-Bit Sign Temperature Sensor with SPI-Compatible Serial Interface
ELECTRICAL CHARACTERISTICS (continued)
(VCC +5.5V, -55°C +125°C, unless otherwise noted. Typical values +25°C +3.3V.)
PARAMETER SERIAL INTERFACE TIMING Serial Clock Frequency SCLK High Pulse Width SCLK Pulse Width High Pulse Width SCLK Fall Output Data Valid Fall SCLK Rise Rise Output Disable SCLK Hold Time SCLK Setup Time SCLK Hold Time Output Fall Time fSCLK tCSW tCSS tCSH CLOAD 100pF CLOAD 100pF SYMBOL CONDITIONS UNITS
MAX6662
Note Peak operating current measured during conversion.
Typical Operating Characteristics
(VCC +3V, +25°C, unless otherwise noted.)
TEMPERATURE ERROR TEMPERATURE
MAX6662 toc01
TEMPERATURE ERROR DISTRIBTUTION
PERCENTAGE SAMPLES NOTE: DEVICES TRIMMED +30°C SAMPLES
MAX6662 toc02
SUPPLY CURRENT TEMPERATURE
AVERAGE OVER SUPPLY CURRENT (µA) +5.0V
MAX6662 toc03
+5.0V +3.3V +3.0V
TEMPERATURE ERROR (°C)
+30°C
+3.3V +3.0V
TEMPERATURE (°C) -0.45-0.35 -0.25 -0.15 0.05 0.15 0.25 0.35 0.45 TEMPERATURE ERROR (°C)
TEMPERATURE (°C)
12-Bit Sign Temperature Sensor with SPI-Compatible Serial Interface MAX6662
Typical Operating Characteristics (continued)
(VCC +3V, +25°C, unless otherwise noted.) SHUTDOWN CURRENT TEMPERATURE
MAX6662 toc04
SHUTDOWN CURRENT (µA) +5.0V +3.0V TEMPERATURE (°C) +3.3V
Description
NAME SCLK ALERT Serial-Clock Input Chip Select Input. enable serial interface data input/output. Serial-Data Input/Output. Bidirectional data input output serial interface. Ground Overtemperature Output. Open-drain output requires pullup resistor VCC. Alert Output. Open-drain output requires pullup resistor VCC. Connection. make connection this pin. Supply Voltage Input. Bypass with 0.1µF capacitor close possible. FUNCTION
Detailed Description
MAX6662 continuously converts temperature into digital value using integrated ADC. Temperature data updated twice second. resulting data readable time through SPIcompatible serial interface. Figure shows simplified functional diagram MAX6662. internal current sources force 100µA 10µA currents through diode (diode-connected transistor), while integrating measures voltage difference. difference voltage corresponds temperature. result stored Temperature register. control logic unit compares temperature temperature limit settings stored registers determine whether fault condition occurred.
Temperature Fault Alert
ALERT open-drain active-low (default, also programmable active-high) output used alert system temperature faults. ALERT programmed operate either modes: comparator interrupt mode. Interrupt Mode interrupt mode, MAX6662 ALERT asserts alarm undertemperature (TLOW) fault, well overtemperature (THIGH) fault. Once either fault occurred, remains active indefinitely, regardless condition. ALERT unconditionally deasserted (even Temperature still limits) reading temperature register. ALERT only asserts again temperature crosses hysteresis, thereby corresponding fault (TLOW THIGH) that initially ALERT.
12-Bit Sign Temperature Sensor with SPI-Compatible Serial Interface MAX6662
-BIT SIGN ALERT
TEMPERATURE TLOW SCLK
THIGH
TMAX
THYST CONFIGURATION
SERIAL INTERFACE
Figure MAX6662 Simplified Functional Diagram
example: THIGH 100°C THYST 20°C, ALERT does assert until temperature exceeds 100°C. temperature then read through serial interface, ALERT deasserts. ALERT asserts again when temperature less than 80°C (Figure Comparator Mode comparator mode, ALERT asserted when temperature exceeds value THIGH register, lower than value register. ALERT deasserts when temperature less than THIGH THYST greater than TLOW THYST. Reading registers does deassert ALERT. example: THIGH 100°C TLOW 80°C, ALERT does assert until temperature exceeds 100°C, below 80°C. Then, ALERT only deasserts temperature less than THIGH THYST greater than TLOW THYST.
Overtemperature Alert
operates only comparator mode. asserted when temperature exceeds TMAX, deasserted when temperature drops below TMAX THYST. read operation does reset open-drain active-low (default) output, programmed active-high.
THIGH THIGH THYST TEMPERATURE
TLOW THYST TLOW ALERT
TEMPERATURE READ
LAST INTERRUPT MISSED, THRESHOLD STILL CHANGES THIGH.
Figure Example ALERT Operation Interrupt Mode
12-Bit Sign Temperature Sensor with SPI-Compatible Serial Interface MAX6662
Temperature Fault Queue
activation ALERT subject depth fault queue. Fault Queue Configuration register enabled, ALERT does assert until four consecutive temperature conversions fault. example: THIGH 100°C, THYST 20°C, ALERT interrupt mode, fault queue enabled, ALERT does assert until four consecutive conversions exceed 100°C. temperature then read through serial interface, ALERT deasserts. ALERT asserts again when four consecutive conversions less than 80°C.
Serial Interface Protocol
serial interface consists three signal lines: chip select (CS), bidirectional data line (SIO), serial clock (SCLK). Only master (external) drives SCLK. Both master MAX6662 drive SIO. When high, MAX6662 does respond activity clock data lines. When goes low, transaction begins. valid transaction clock cycles provided from SCLK after goes low-no more fewer. communication with more fewer than exactly clocks ignored. Data clocked MAX6662 rising edge SCLK when master writing. Data clocked falling edge SCLK when master reading. Both command byte data word clocked out) with most-significant (MSB) first. first eight clock cycles dedicated command byte cycle). This command byte input MAX6662 through SIO. Sixteen cycles data follow. cycles data either driven master MAX6662, depending command byte. MAX6662 driving SIO, starts driving falling edge eighth clock until rising edge Data available falling edge eighth clock cycle. Figure depicts valid serial interface transaction Figure serial interface timing diagram.
tCSW
Shutdown Mode
MAX6662 features programmable shutdown mode. Shutdown Configuration register shut down. shutdown mode, everything disabled except power-on reset (POR) serial interface. shutdown mode, information stored registers retained. Temperature register retains temperature from last conversion result.
SCLK COMMAND BYTE BITS) DATA WORD BITS)
tCSS SCLK
tCSH
Figure MAX6662 Serial Interface Operation
Figure Detailed Serial Interface Timing Diagram
Table Descriptions Configuration Register
Reserved. Writing these bits ignored. Fault Queue bit. enable queue. ALERT polarity bit. active-high ALERT output. Default ALERT output active-low. polarity bit. active-high output. Default output active-low. Interrupt Mode bit. enable interrupt mode. Default comparator mode. Shutdown bit. shut down MAX6662. Reserved. Writing these bits ignored. DESCRIPTION
12-Bit Sign Temperature Sensor with SPI-Compatible Serial Interface
Table Command Codes Temperature Limit Registers
COMMAND DESCRIPTION Temperature register read Configuration register read THYST register read TMAX register read TLOW register read THIGH register read Configuration register write THYST register write TMAX register write TLOW register write THIGH register write
first command byte always high signify Start, second bit, high read write. There total valid commands. temperature conversion runs continuously asynchronously from serial interface. When Temperature register read, conversion progress aborted data output from previous conversion. conversion started each time serial interface accessed.
MAX6662
MAX6662 Registers
MAX6662 registers: Temperature, Configuration, THYST, TMAX, TLOW, THIGH registers. They bits (Figure Temperature register read only; other registers read from written Temperature Register Temperature register sign bit. next bits temperature data. digital temperature data most recent temperature conversion
TEMPERATURE REGISTER (COMMAND C1H) Label State Sign Data Data TOVER THIGH TLOW Flag Flag Flag
Label State
CONFIGURATION REGISTER (COMMAND READING; COMMAND WRITING) Fault ALERT Interrupt Shutdown Queue Polarity Polarity Mode Mode
TEMPERATURE LIMIT REGISTERS (THYST, TMAX, TLOW, THIGH) (TABLE Label State
Reserved (not used). Writing this ignored. THYST register: 0000 0001 0000 0000b (2°C) TMAX register: 0010 1000 0000 0000b (+80°C) TLOW register: 0000 0101 0000 0000b (+10°C) THIGH register: 0010 0000 0000 0000b (+64°C)
Sign
Data
Data
Figure Assignment MAX6662 Registers
12-Bit Sign Temperature Sensor with SPI-Compatible Serial Interface MAX6662
Table Output Code Temperature
TEMPERATURE (°C) +150.0000 +125.0000 +25.0000 +0.0625 0.0000 -0.0625 -25.0000 -55.0000 BINARY CODE 0100 1011 0000 0xxx 0011 1110 1000 0xxx 0000 1100 1000 0xxx 0000 0000 0000 1xxx 0000 0000 0000 0xxx 1111 1111 1111 1xxx 1111 0011 0111 0xxx 1111 1100 0111 0xxx
MAX6662 supply current typically 125µA when serial interface active. When driving high-impedance loads, devices dissipate negligible power; therefore, temperature essentially same package temperature. accurate temperature monitoring good thermal contact between MAX6662 package monitored device circuit. Heat flows plastic packages primarily through leads. Short, wide copper traces leading temperature monitor ensure that heat transfers quickly reliably. rise temperature self-heating given following formula: PDISSIPATION where DISSIPATION power dissipated MAX6662, package's thermal resistance. typical thermal resistance +170°C/W 8-pin package. limit effects self-heating, minimize output currents. example, MAX6662 sinks with maximum ALERT voltage specification 0.8V, additional 3.2mW power dissipated within This corresponds 0.54°C rise temperature.
stored Temperature register using two's-complement format with 1LSB corresponding 0.0625°C (Table three least-significant bits (LSBs) temperature status (flag) bits. Temperature register read only. command byte reading Temperature register. Configuration Register Configuration register uses only bits, bits Table describes function. shutdown should shut down entire MAX6662 except serial interface POR. fault queue bit. When Fault Queue ALERT outputs asserted four consecutive temperature faults occurred. Configuration register read written Writing unused bits ignored. command byte reading from this register; command byte writing this register. Temperature-Limit Registers High-Temperature HIGH Low-Temperature (TLOW), Hysteresis (THYST) registers temperature limit triggering ALERT (Figure Maximum-Temperature (TMAX) Hysteresis registers temperature threshold output. These temperature-limit registers 9MSB bits bits sign) setting temperature values two's complement format with resolution. 7LSBs ignored. These registers read written Table shows command bytes reading writing these registers.
Chip Information
TRANSISTOR COUNT: Bipolar: MOS: 10177 PROCESS: BiCMOS
Applications Information
12-Bit Sign Temperature Sensor with SPI-Compatible Serial Interface
Package Information
MAX6662
Maxim cannot assume responsibility circuitry other than circuitry entirely embodied Maxim product. circuit patent licenses implied. Maxim reserves right change circuitry specifications without notice time.
Maxim Integrated Products, Gabriel Drive, Sunnyvale, 94086 408-737-7600 2001 Maxim Integrated Products Printed registered trademark Maxim Integrated Products.
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12-Bit Sign Temperature Sensor with SPI-Compatible Serial Interface

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