10-Bit Digital Temperature Sensor 6-Lead SOT-23 AD7814 BANDGAP TE

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10-Bit Digital Temperature Sensor 6-Lead SOT-23 AD7814 BANDGAP TE

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FEATURES 10-Bit Temperature-to-Digital Converter +125 Operating Temperature Range Accuracy SPI- DSP-Compatible Serial Interface Shutdown Mode Space-Saving SOT-23 Package APPLICATIONS Hard Disk Drives Personal Computers Electronic Test Equipment Office Equipment Domestic Appliances Process Control
10-Bit Digital Temperature Sensor 6-Lead SOT-23 AD7814
BANDGAP TEMPERATURE SENSOR 10-BIT ANALOG/DIGITAL CONVERTER
AD7814
TEMPERATURE VALUE REGISTER
SERIAL INTERFACE
SCLK DOUT
GENERAL DESCRIPTION
PRODUCT HIGHLIGHTS
AD7814 complete temperature monitoring system SOT-23 package 8-lead µSOIC package. contains bandgap temperature sensor 10-bit monitor digitize temperature reading resolution +0.25°C. AD7814 flexible serial interface that allows easy interfacing most microcontrollers. interface compatible with SPITM, QSPI MICROWIREprotocol also compatible with DSPs. part features standby mode that controlled serial interface. AD7814's wide supply voltage range, supply current SPI-compatible interface, make ideal variety applications, including personal computers, office equipment domestic appliances.
AD7814 on-chip temperature sensor that allows accurate measurement ambient temperature. measurable temperature range -55°C +125°C, with temperature accuracy. Supply voltage +2.7 +5.5 Space-saving 6-lead SOT-23 package 8-lead µSOIC package. 10-bit temperature reading +0.25°C resolution. AD7814 features standby mode that reduces current consumption
trademark Motorola, Inc. MICROWIRE trademark National Semiconductor, Inc.
REV.
Information furnished Analog Devices believed accurate reliable. However, responsibility assumed Analog Devices use, infringements patents other rights third parties which result from use. license granted implication otherwise under patent patent rights Analog Devices. Technology Way, P.O. 9106, Norwood, 02062-9106, U.S.A. Tel: 781/329-4700 World Wide Site: http://www.analog.com Fax: 781/326-8703 Analog Devices, Inc., 1999
AD7814-SPECIFICATIONS1,
TMAX, +2.7 +5.5 unless otherwise noted)
Units Test Conditions/Comments
Parameter
TEMPERATURE SENSOR Accuracy
Resolution Update Rate, Temperature Conversion Time SUPPLIES Supply Voltage Supply Current Normal Mode Shutdown Mode Power Dissipation Power Dissipation DIGITAL INPUT Input High Voltage, Input Voltage, Input Current, Input Capacitance, DIGITAL OUTPUT Output High Voltage, Output Voltage, Output Capacitance, COUT
Bits
+85°C. +5.5 -40°C 0°C. +5.5 -55°C +125°C. +5.5
Specified Performance
Using Normal Mode Using Shutdown Mode
Digital Inputs ISOURCE ISINK
NOTES specifications apply -55°C +125°C unless otherwise stated. Guaranteed design characterization, production tested. +2.7 -40°C +85°C, typical temperature error 2°C. Specifications subject change without notice.
TIMING CHARACTERISTICS1,
TMAX, +2.7 +5.5 unless otherwise noted)
Parameter
Limit
Units
Comments SCLK Setup Time SCLK High Pulsewidth SCLK Pulsewidth Data Access Time After SCLK Falling Edge Data Setup Time Prior SCLK Rising Edge Data Hold Time After SCLK Rising Edge SCLK Hold Time DOUT High Impedance
NOTES Guaranteed design characterization, production tested. input signals specified with (10% timed from voltage level Figure Measured with load circuit Figure
REV.
AD7814
ABSOLUTE MAXIMUM RATINGS*
-0.3 Digital Input Voltage -0.3 Digital Output Voltage -0.3 Operating Temperature Range -55°C +125°C Storage Temperature Range -65°C +150°C Junction Temperature +150°C SOT-23, Power Dissipation Thermal Impedance 240°C/W Lead Temperature, Soldering Vapor Phase sec) +215°C Infrared sec) +220°C µSOIC Package, Power Dissipation Thermal Impedance 206°C/W Lead Temperature, Soldering Vapor Phase sec) +215°C Infrared sec) +220°C
*Stresses above those listed under Absolute Maximum Ratings cause permanent damage device. This stress rating only; functional operation device these other conditions above those indicated operational section this specification implied. Exposure absolute maximum rating conditions extended periods affect device reliability.
OUTPUT
+1.6V 50pF
Figure Load Circuit Data Access Time Relinquish Time
ORDERING GUIDE
Model AD7814ART AD7814ARM
Temperature Range -55°C +125°C -55°C +125°C
Temperature Error*
Package Description 6-Lead SOT-23 8-Lead µSOIC
Branding Information
Package Options RT-6 RM-8
*Temperature error over +85°C temperature range.
CAUTION (electrostatic discharge) sensitive device. Electrostatic charges high 4000 readily accumulate human body test equipment discharge without detection. Although AD7814 features proprietary protection circuitry, permanent damage occur devices subjected high energy electrostatic discharges. Therefore, proper precautions recommended avoid performance degradation loss functionality.
WARNING!
SENSITIVE DEVICE
REV.
AD7814
FUNCTION DESCRIPTION
Mnemonic
SOT-23
SOIC
Description Analog Digital Ground. Serial Data Input. Serial data loaded part's control register provided this input. Data clocked into control register rising edge SCLK. Positive Supply Voltage, +2.7 +5.5 Serial Clock Input. This clock input serial port. serial clock used clock data temperature value register AD7814 also clock data into control register part. Chip Select Input. Logic Input. device selected when this input low. SCLK input disabled when this high. Serial Data Output. Logic output. Data clocked temperature value register this pin. Data clocked falling edge SCLK. connect.
SCLK
DOUT
CONFIGURATIONS SOT-23
SOIC
DOUT SCLK
DOUT
AD7814
VIEW (Not Scale)
VIEW (Not Scale)
AD7814
SCLK
CONNECT
REV.
AD7814
CIRCUIT INFORMATION Table Temperature Data Format
AD7814 10-bit digital temperature sensor. part houses on-chip temperature sensor, 10-bit converter, reference serial interface logic functions SOT-23 package. converter section consists conventional successive-approximation converter based around capacitor DAC. parts capable running +2.7 +5.5 power supply. on-chip temperature sensor allows accurate measurement ambient device temperature made. working measurement range AD7814 -55°C +125°C.
CONVERTER DETAILS
Temperature -128°C -125°C -100°C -75°C -50°C -25°C -0.25°C +0.25°C +10°C +25°C +50°C +75°C +100°C +125°C +127°C
SERIAL INTERFACE
Digital Output 0000 0000 0000 1100 0111 0000 1101 0100 0011 1000 1001 1100 1111 1111 0000 0000 0000 0001 0010 1000 0110 0100 1100 1000 0010 1100 1001 0000 1111 0100 1111 1100
conversion clock part internally generated external clock required except when reading from writing serial port. normal mode, internal clock oscillator runs automatic conversion sequence. conversion initiated every this time, part wakes performs temperature conversion. This temperature conversion typically takes which time part automatically shuts down. result most recent temperature conversion available serial output register time. AD7814 placed shutdown mode, Control Register, which case, on-chip oscillator shut down further conversions initiated until AD7814 taken shutdown mode. conversion result from last conversion prior shutdown still read from AD7814 even when shutdown mode. automatic conversion mode, every time read write operation takes place, internal clock oscillator restarted read write operation. result conversion available, typically later. Similarly, when part taken shutdown mode, internal clock oscillator restarted conversion result available, typically later. Reading from device again before conversion complete will again provide same data.
TEMPERATURE VALUE REGISTER
serial interface AD7814 consists four wires, SCLK, DOUT. interface operated 2-wire mode with tied Ground, which case interface read-only capability, with data being read from data register DOUT line. line used write part into standby mode, required. line used select device when more than device connected serial clock data lines. part operates slave mode requires externally applied serial clock SCLK input access data from data register. serial interface AD7814 designed allow part interfaced systems that provide serial clock that synchronized serial data, such 80C51, 87C51, 68HC11, 68HC05 PIC16Cxx microcontrollers well processors. read operation from AD7814 accesses data from Temperature Value Register while write operation part writes data Control Register.
temperature value register read-only register that stores temperature reading from 10-bit twos complement format. temperature data format shown Table This shows full theoretical range from -128°C +127°C, practice temperature measurement range limited operating temperature range device (-55°C +125°C).
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AD7814
SCLK
DOUT LEADING ZERO
DON'T CARE DON'T CARE
POWERDOWN
Figure Serial Interface Timing Diagram
Read Operation
Figure shows timing diagram serial read from AD7814. line enables SCLK input. bits data transferred during read operation. Read operations occur during streams clock pulses. serial data accessed number bytes bits data being read. read operation, DOUT line remains state last data clocked AD7814 until returns high, which time DOUT line goes into three-state.
Write Operation
serial data transfer from AD7814 requires 16bit read operation. Many 8-bit microcontrollers have 8-bit serial ports this 16-bit data transfer handled 8-bit transfers. Other microcontrollers processors transfer bits data serial data operation.
AD7814 MC68HC11 Interface
Figure also shows timing diagram serial write AD7814. write operation takes place same time read operation. Data clocked into Control Register part rising edge SCLK. Only third data stream provides user-controlled function. This third power-down which puts AD7814 into shutdown mode. first bits data stream don't cares while other bits data stream other, than power-down bit, should ensure correct operation AD7814. Data loaded Control Register fifteenth falling SCLK edge data takes effect this time i.e., part programmed into shutdown, does this point. brought high before this fifteenth SCLK edge, Control Register will loaded power-down status part will change.
MICROPROCESSOR INTERFACING
Figure shows interface between AD7814 MC68HC11 microcontroller. MC68HC11 configured master mode with CPOL logic CPHA logic one. When MC68HC11 configured like this, SCLK line idles high between data transfers. Data transferred from AD7814 8-bit serial data operations. diagram shows full (four-wire) interface. MC68HC11 configured output used drive input.
AD7814*
SCLK DOUT MC68HC11* SCLK MISO MOSI
*ADDITIONAL PINS OMITTED CLARITY
Figure AD7814 MC68HC11 Interface
AD7814 8051 Interface
AD7814's serial interface allows easy interface most microcomputers microprocessors. Figures through show some typical interface circuits. serial interface AD7814 consists four wires: DIN, DOUT SCLK. interface circuits shown utilize four interface lines. However, depending application possible operate interface with either three wires. SCLK line that comes AD7814 shared with other devices issue with spurious clocks outlined previously concern, possible leave line AD7814 tied permanently low. application does require power-down facility offered AD7814, line tied permanently low. Thus, interface operated from just wires, SCLK DOUT.
interface circuit between AD7814 microcontroller shown Figure 8xC51 configured Mode serial interface mode. serial clock line 8xC51 P3.1) idles high between data transfers. Data transferred from AD7814 8-bit serial data operations. AD7814 outputs data stream first valid while 8xC51 expects first. Thus, data read into serial buffer needs rearranged before correct data word from AD7814 available accumulator.
REV.
AD7814
example shown, AD7814 connected serial port 8051. Because serial interface 8xC51 contains only data line, line AD7814 tied interface example given Figure applications that require power-down feature AD7814, serial interface should implemented using data port lines 8051. This allows full-duplex serial interface implemented. method involves `bitbanging' port line generate serial clock while using other port lines shift data with fourth port line connecting Port lines through (with P1.1 configured input) used connect SCLK, DOUT, respectively, implement this scheme.
AD7814*
SCLK DOUT P3.1 P3.0 P1.2 P1.3 8051*
interface requires inverter between SCLK line ADSP-21xx SCLK input AD7814. ADSP21xx SPORT tied together with output input. operates Alternate Framing Mode SPORT Control Register described above.
AD7814*
SCLK DOUT
ADSP-21xx*
*ADDITIONAL PINS OMITTED CLARITY
Figure AD7814 ADSP-21xx Interface
MOUNTING AD7814
*ADDITIONAL PINS OMITTED CLARITY
Figure AD7814 8051 Interface
AD7814 PIC16C6x/7x Interface
Figure shows interface circuit between AD7814 PIC16C6x/7x microcontroller. PIC16C6x/7x Synchronous Serial Port (SSP) configured master with Clock Polarity logic one. this mode, serial clock line PIC16C6x/7x idles high between data transfers. Data transferred from AD7814 8-bit serial data operations. example shown, port line being used generate AD7814.
AD7814*
SCLK DOUT PIC16C6x/7x*
AD7814 used surface air-temperature sensing applications. device cemented surface with thermally conductive adhesive, temperature will within about 0.1°C surface temperature, thanks device's power consumption. Care should taken insulate back leads device from air, ambient temperature different from surface temperature being measured. ground provides best thermal path die, temperature will close that printed circuit ground track. Care should taken ensure that this good thermal contact with surface being measured. with AD7814 associated wiring circuits must kept free from moisture prevent leakage corrosion, particularly cold conditions where condensation more likely occur. Water-resistant varnishes conformal coatings used protection. small size AD7814 package allows mounted inside sealed metal probes, which provide safe environment device. AD7814 should decoupled with ceramic capacitor between GND. This particularly important AD7814 mounted remote from power supply.
SUPPLY DECOUPLING
*ADDITIONAL PINS OMITTED CLARITY
Figure AD7814 PIC16C6x/7x Interface
AD7814 ADSP-21xx Interface
Figure shows interface between AD7814 ADSP-21xx processor. ensure correct operation interface SPORT Control Register should follows: TFSW RFSW Alternate Framing INVRFS INVTFS Active Framing Signal DTYPE Right Justify Data SLEN 1111, 16-Bit Data Words ISCLK Internal Serial Clock TFSR Frame Every Word IRFS Configured Input ITFS Configured Output
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AD7814
OUTLINE DIMENSIONS
Dimensions shown inches (mm).
6-Lead Plastic Surface Mount SOT-23 (RT-6)
0.122 (3.10) 0.106 (2.70)
0.071 (1.80) 0.059 (1.50)
0.118 (3.00) 0.098 (2.50)
0.037 (0.95) 0.075 (1.90) 0.051 (1.30) 0.035 (0.90) 0.059 (0.15) 0.000 (0.00) 0.057 (1.45) 0.035 (0.90) 0.020 (0.50) SEATING 0.010 (0.25) PLANE 0.009 (0.23) 0.003 (0.08) 0.022 (0.55) 0.014 (0.35)
8-Lead Mini/Micro SOIC (RM-8)
0.122 (3.10) 0.114 (2.90)
0.122 (3.10) 0.114 (2.90)
0.199 (5.05) 0.187 (4.75)
0.0256 (0.65) 0.120 (3.05) 0.112 (2.84) 0.006 (0.15) 0.002 (0.05) 0.018 (0.46) SEATING 0.008 (0.20) PLANE 0.043 (1.09) 0.037 (0.94) 0.011 (0.28) 0.003 (0.08) 0.120 (3.05) 0.112 (2.84)
0.028 (0.71) 0.016 (0.41)
REV.
PRINTED U.S.A.
C3599-8-4/99

10-Bit Digital Temperature Sensor 6-Lead SOT-23 AD7814 BANDGAP TE

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