View ADT7302ART-REEL7_674908.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

Preliminary Technical Data
FEATURES
13-bit temperature-to-digital converter -40C to +125C operating temperature range 2C accuracy 0.03125C temperature resolution Shutdown current of 1 A Power dissipation of 0.631 mW at VDD = 3.3 V SPI- and DSP-compatible serial interface Shutdown mode Space-saving SOT-23 and MSOP packages
2C Accurate, MicroPower Digital Temperature Sensor in 6-Lead SOT-23 ADT7302
FUNCTIONAL BLOCK DIAGRAM
BAND GAP TEMPERATURE SENSOR GND 13-BIT ANALOG/DIGITAL CONVERTER VDD
ADT7302
TEMPERATURE VALUE REGISTER
DOUT
APPLICATIONS
Medical equipment Automotive: Environmental controls Oil temperature Hydraulic systems Cell phones Hard disk drives Personal computers Electronic test equipment Office equipment Domestic appliances Process control
Figure 1. Functional Block Diagram
GENERAL DESCRIPTION
The ADT7302 is a complete temperature monitoring system available in SOT-23 and MSOP packages. It contains a band gap temperature sensor and a 13-bit ADC to monitor and digitize the temperature reading to a resolution of 0.03125C. The ADT7302 has a flexible serial interface that allows easy interfacing to most microcontrollers. The interface is compatible with SPI(R), QSPITM, and MICROWIRETM protocols as well as DSPs. The part features a standby mode that is controlled via the serial interface. The ADT7302's wide supply voltage range, low supply current, and SPI compatible interface make it ideal for a variety of applications, including personal computers, office equipment, automotive, and domestic appliances.
PRODUCT HIGHLIGHTS
1. The ADT7302 has an on-chip temperature sensor that allows an accurate measurement of the ambient temperature. The measurable temperature range is -40C to +125C. Supply voltage of 2.7 V to 5.5 V. Space-saving 6-lead SOT-23 and 8-lead MSOP packages. Temperature accuracy of 2C. 13-bit temperature reading to 0.03125C resolution. The ADT7302 features a shutdown mode that reduces the power consumption to 4.88 W with VDD = 3.3 V @ 1 SPS.
2. 3. 4. 5. 6.
Rev. PrE
Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. www.analog.com Tel: 781.329.4700 (c) 2004 Analog Devices, Inc. All rights reserved. Fax: 781.326.8703
04662-C-001
SERIAL BUS INTERFACE
CS SCLK DIN
ADT7302 TABLE OF CONTENTS
Specifications.....................................................................................3 Timing Characteristics.................................................................4 Absolute Maximum Ratings............................................................5 ESD Caution..................................................................................5 Pin Configurations and Function Descriptions............................6 Typical Performance Characteristics..............................................7 Circuit Information ..........................................................................8 Converter Details..........................................................................8
Preliminary Technical Data
Temperature Value Register ........................................................ 8 Serial Interface .............................................................................. 9 Microprocessor Interfacing....................................................... 10 Mounting The ADT7302........................................................... 12 Supply Decoupling ..................................................................... 12 Outline Dimensions ....................................................................... 13 Ordering Guide............................................................................... 14
REVISION HISTORY
Revision PrE: Preliminary Version
Rev. PrE | Page 2 of 14
Preliminary Technical Data SPECIFICATIONS
ADT7302
TA = TMIN to TMAX, VDD = 2.7 V to 5.5 V, unless otherwise noted. All specifications apply for -40C to +125C, unless otherwise stated Table 1.
Parameter TEMPERATURE SENSOR AND ADC Accuracy Min Typ TBD TBD TBD 0.03125 1 2 2 2.7 1.6 190 1.6 280 0.2 0.2 631 1.41 4.88 7.4 42.9 65 423 641 2.5 0.8 1 10 VDD - 0.3 V 0.4 50 V pF Max 2 2.5 3 Unit C C C C sec ms sec V mA A mA A A A W mW W W W W W W V V A pF Test Conditions/Comments VDD = +3.3 V (10%) and 5 V (10%) TA = 0C to 70C. TA = -20C to +85C. TA = -40C to +125C. Temperature measurement every 1 second
Temperature Resolution Auto Conversion Update Rate, tR Temperature Conversion Time Thermal Time Constant1 SUPPLIES Supply Voltage Supply Current Normal Mode
5.5 2.2 300 2.2 400 1 1
For Specified performance. VDD = 3.3 V. Powered up and converting VDD = 3.3 V. Powered up and not converting VDD = 5 V. Powered up and converting VDD = 5 V. Powered up and not converting VDD = 3.3 V. VDD = 5 V. VDD = 3.3 V. Auto conversion update, tR. VDD = 5 V. Auto conversion update, tR. VDD = 3.3 V VDD = 5 V VDD = 3.3 V VDD = 5 V VDD = 3.3 V VDD = 5 V
Shutdown Mode Power Dissipation Normal Mode (Average) Shutdown Mode (Average)2 1 SPS 10 SPS 100 SPS DIGITAL INPUT3 Input High Voltage, VIH Input Low Voltage, VIL Input Current, IIN Input Capacitance, CIN DIGITAL OUTPUT3 Output High Voltage, VOH Output Low Voltage, VOL Output Capacitance, COUT
VIN = 0 V to VDD All digital inputs ISOURCE = ISINK = 200 A IOL = 200 A
1
Thermal Time Constant is the time it takes for a starting temperature difference to change to 36.8% of it's starting value. For example if the ADT7302 experienced a thermal shock from 0C to 100C, it would take typically 2 secs for the ADT7302 to reach 63.2C. The ADT7302 is taken out of shutdown mode and a temperature conversion is immediately performed after this write operation. Once the temperature conversion is complete, the ADT7302 is put back into shutdown mode. 3 Guaranteed by design and characterization, not production tested.
2
Rev. PrE | Page 3 of 14
ADT7302
Preliminary Technical Data
TIMING CHARACTERISTICS
Guaranteed by design and characterization, not production tested. All input signals are specified with tr = tf = 5 ns (10% to 90% of VDD) and timed from a voltage level of 1.6 V. See Figure 3. TA = TMIN to TMAX, VDD = 2.7 V to 5.5 V, unless otherwise noted. Table 2.
Parameter t1 t2 t3 t4 1 t5 t6 t7 t81 Limit 5 25 25 35 20 5 5 40 Unit ns min ns min ns min ns max ns min ns min ns min ns max Comments CS to SCLK Setup Time SCLK High Pulse Width SCLK Low Pulse Width Data Access Time after SCLK Falling Edge Data Setup Time prior to SCLK Rising Edge Data Hold Time after SCLK Rising Edge CS to SCLK Hold Time CS to DOUT High Impedance
1
Measured with the load circuit of Figure 2.
200A IOL
TO OUTPUT PIN
1.6V CL 50pF
02884-0-002
200A
IOH
Figure 2. Load Circuit for Data Access Time and Bus Relinquish Time
Rev. PrE | Page 4 of 14
Preliminary Technical Data ABSOLUTE MAXIMUM RATINGS
Table 3. ADT7302 Stress Ratings
Parameter VDD to GND Digital Input Voltage to GND Digital Output Voltage to GND Operating Temperature Range Storage Temperature Range Junction Temperature 6-Lead SOT-23 (RJ-6) Power Dissipation1 Thermal Impedance JA, Junction-to-Ambient (Still Air) 8-Lead MSOP (RM-8) Power Dissipation1 Thermal Impedance3 JA, Junction-to-Ambient (Still Air) JC, Junction-to-Case IR Reflow Soldering Peak Temperature Time at Peak Temperature Ramp-up Rate Ramp-down Rate Rating -0.3 V to +7 V -0.3 V to VDD + 0.3 V -0.3 V to VDD + 0.3 V -40C to +125C -65C to +150C 150C WMAX = (TJMAX - TA2)/JA
MAXIMUM POWER DISSIPATION (W)
ADT7302
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability
1.2
190.4C/W WMAX = (TJMAX - TA2)/JA 205.9C/W 43.74C/W +220C (-0/+5C) 10 s to 20 s 2C/s to 3C/s -6C/sec
1.0
0.8 SOT-23 0.6
0.4
MSOP
0.2
TEMPERATURE (C)
1
Values relate to the package being used on a standard 2-layer PCB. Reference Figure 3 for a plot of maximum power dissipation versus ambient temperature (TA). 2 TA = ambient temperature 3 Junction-to-case resistance is applicable to components featuring a preferential flow direction, e.g., components mounted on a heat sink. Junction-to-ambient resistance is more useful for air-cooled, PCB mounted components.
Figure 3. Plot of Maximum Power Dissipation vs. Temperature
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.
Rev. PrE | Page 5 of 14
02884-0-003
0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
ADT7302 PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
GND 1 DIN 2 6 DOUT
Preliminary Technical Data
NC 1
04662-C-004
8 NC
SCLK 4
Figure 4. SOT-23
5 VDD
Figure 5. MSOP
Table 4. Pin Function Description
Mnemonic GND DIN VDD SCLK CS DOUT SOT-23 Pin No. 1 2 3 4 5 6 Description Analog and Digital Ground. Serial Data Input. Serial data to be loaded to the part's control register is provided on this input. Data is clocked into the control register on the rising edge of SCLK. Positive Supply Voltage, 2.7 V to 5.5 V. Serial Clock Input. This is the clock input for the serial port. The serial clock is used to clock data out of the ADT7302's temperature value register and to clock data into the ADT7302's control register. Chip Select Input. Logic input. The device is selected when this input is low. The SCLK input is disabled when this pin is high. Serial Data Output. Logic output. Data is clocked out of the temperature value register at this pin. Data is clocked out on the falling edge of SCLK.
Rev. PrE | Page 6 of 14
04662-C-005
TOP VIEW 5 CS (Not to Scale) 4 SCLK VDD 3
ADT7302
DOUT 2 CS 3
ADT7302
TOP VIEW (Not to Scale)
7 GND 6 DIN
Preliminary Technical Data TYPICAL PERFORMANCE CHARACTERISTICS
-000
500E-9 450E-9 400E-9 350E-9 300E-9 250E-9 200E-9 150E-9 100E-9 50E-9
ADT7302
ALL CAPS (Initial caps)
-000
-000
TBD
-000 -000 ALL CAPS (Initial caps) -000 -000
-000
-000 -000
Shutdown Current (A)
000E+0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 Supply Voltage (V)
Figure 6. Temperature Accuracy @ 3.3 V and 5 V Figure 9. Shutdown Current vs. Supply Voltage @ 30C
215.0E-6 210.0E-6
5.5 V
20 250 mv p-p ripple @ Vdd = 5 V 15 Temperature Error (C)
205.0E-6 200.0E-6
Current (A)
10
195.0E-6 190.0E-6
3.3 V
5
185.0E-6 180.0E-6 175.0E-6 170.0E-6 -45 5 55
Temperature (C)
0 10E+3 -5
100E+3
1E+6
10E+6
100E+6
-10 Frequency (Hz)
105
155
Figure 10. Temperature Accuracy vs. Supply Ripple Frequency
140
Figure 7. Average Operating Supply Current vs. Temperature
120
205E-6
100
Temperature (C)
200E-6
80
195E-6 Current (A)
60
40
190E-6
20
185E-6
0 0 5 10 15 20 25 Time (sec) 30 35 40 45 50
180E-6
Figure 11. Response to Thermal Shock
175E-6 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 Supply Voltage (V)
Figure 8. Average Operating Supply Current vs. Supply Voltage @ 30C
Rev. PrE | Page 7 of 14
ADT7302 CIRCUIT INFORMATION
The ADT7302 is a 13-bit digital temperature sensor with a 14th bit that acts as a sign bit. The part houses an on-chip temperature sensor, a 13-bit A/D converter, a reference circuit, and serial interface logic functions in SOT-23 and MSOP packages. The A/D converter section consists of a conventional successive-approximation converter based around a capacitor DAC. The parts are capable of running on a 2.7 V to 5.5 V power supply. The on-chip temperature sensor allows an accurate measurement of the ambient device temperature to be made. The specified measurement range of the ADT7302 is -40C to +125C. The structural integrity of the device starts to deteriorate when operated at voltage and temperature maximum specifications.
Preliminary Technical Data
TEMPERATURE VALUE REGISTER
The temperature value register is a 14-bit read-only register that stores the temperature reading from the ADC in 13-bit twos complement format plus a sign bit. The MSB (DB13) is the sign bit. The ADC can theoretically measure a 255C temperature span. The internal temperature sensor is guaranteed to a low value limit of -40C and a high limit of +125C. The temperature data format is shown in Table 5, which shows the temperature measurement range of the device (-40C to +125C). A typical performance curve is shown in Figure 6. Table 5. Temperature Data Format
Temperature -40C -30C -25C -10C -0.03125C 0C +0.03125C +10C +25C +50C +75C +100C +125C Digital Output DB13...DB0 11, 1011 0000 0000 11, 1100 0100 0000 11, 1100 1110 0000 11, 1110 1100 0000 11, 1111 1111 1111 00, 0000 0000 0000 00, 0000 0000 0001 00, 0001 0100 0000 00, 0011 0010 0000 00, 0110 0100 0000 00, 1001 0110 0000 00, 1100 1000 0000 00, 1111 1010 0000
CONVERTER DETAILS
The conversion clock for the part is internally generated; no external clock is required except when reading from and writing to the serial port. In normal mode, an internal clock oscillator runs an automatic conversion sequence. During this automatic conversion sequence, a conversion is initiated every 1 second. At this time, the part powers up its analog circuitry and performs a temperature conversion. This temperature conversion typically takes 800 s, after which time the analog circuitry of the part automatically shuts down. The analog circuitry powers up again when the 1 second timer times out and the next conversion begins. The result of the most recent temperature conversion is always available in the serial output register because the serial interface circuitry never shuts down. The ADT7302 can be placed in a shutdown mode via the control register, in which case the on-chip oscillator is shut down and no further conversions are initiated until the ADT7302 is taken out of shutdown mode. The ADT7302 can be taken out of shutdown mode by writing all zeros into the control register. The conversion result from the last conversion prior to shutdown can still be read from the ADT7302 even when it is in shutdown mode. In normal conversion mode, the internal clock oscillator is reset after every read or write operation. This causes the device to start a temperature conversion, the result of which is typically available 800 s later. Similarly, when the part is taken out of shutdown mode, the internal clock oscillator is started and a conversion is initiated. The conversion result is available 800 s later, typically. Reading from the device before a conversion is complete causes the ADT7302 to stop converting; the part starts again when serial communication is finished. This read operation provides the previous result.
Temperature Conversion Formula 1. Positive Temperature = ADC Code(d)/32
2. Negative Temperature = (ADC Code*(d) - 16384)/32
*Using all 14 bits of the data byte, includes the sign bit.
Negative Temperature = (ADC Code(d)* - 8192)/32
*DB13 (sign bit) is removed from the ADC code
01, 0010, 1100, 0000
DIGITAL OUTPUT
00, 1001, 0110, 0000
75C
00, 0000, 0000, 0001 -0.03125 C -40C -30C
11, 1111, 1111, 1111
TEMPERATURE (C)
125C
11, 1100, 0100, 0000
04662-C-006
11, 1011, 0000, 0000
Figure 12. Temperature to Digital Transfer Function
Rev. PrE | Page 8 of 14
Preliminary Technical Data
CS
ADT7302
t1
SCLK 1 2
t2
3 4 15 16
t7
t3 t4
DOUT LEADING ZEROS DB13 DB12 DB1 DB0
t8
DIN
POWERDOWN
Figure 13. Serial Interface Timing Diagram
SERIAL INTERFACE
The serial interface on the ADT7302 consists of four wires: CS, SCLK, DIN, and DOUT. The interface can be operated in 2wire mode with CS and DIN tied to ground, in which case the inter-face has read-only capability, with data being read from the data register via the DOUT line. It is advisable to utilize CS, which improves synchronization between the ADT7302 and the master device. The DIN line is used to write the part into standby mode, if required. The CS line is used to select the device when more than one device is connected to the serial clock and data lines. The part operates in a slave mode and requires an externally applied serial clock to the SCLK input to access data from the data register. The serial interface on the ADT7302 allows the part to be interfaced to systems that provide a serial clock synchronized to the serial data, such as the 80C51, 87C51, 68HC11, 68HC05 and PIC16Cxx microcontrollers as well as DSP processors. A read operation from the ADT7302 accesses data from the temperature value register while a write operation to the part writes data to the control register.
Read Operation
Figure 13 shows the timing diagram for a serial read from the ADT7302. The CS line enables the SCLK input. Thirteen bits of data plus a sign bit are transferred during a read operation. Read operations occur during streams of 16 clock pulses. The first two bits out are leading zeros and the next 14 bits contain the temperature data. If CS remains low and 16 more SCLK cycles are applied, the ADT7302 loops around and outputs the two leading zeros plus the 14 bits of data that are in the temperature value register. When CS returns high, the DOUT line goes into three-state. Data is clocked out onto the DOUT line on the falling edge of SCLK.
Write Operation
Figure 13 also shows the timing diagram for a serial write to the ADT7302. The write operation takes place at the same time as the read operation. Only the third bit in the data stream provides a user-controlled function. This third bit is the powerdown bit, which, when set to a 1, puts the ADT7302 into shutdown mode. Besides the power-down bit, all bits in the input data stream should be zero to ensure correct operation of the ADT7302. Data is loaded into the control register on the 16th rising SCLK edge; the data takes effect at this time, i.e., if the part is programmed to go into shutdown, it does so at this point. If CS is brought high before this 16th SCLK edge, the control register is not loaded and the power-down status of the part does not change. Data is clocked into the ADT7302 on the rising edge of SCLK.
Rev. PrE | Page 9 of 14
04662-C-007
t5
t6
ADT7302
MICROPROCESSOR INTERFACING
The ADT7302's serial interface allows for easy interface to most microcomputers and microprocessors. Figure 14 through Figure 17 show some typical interface circuits. The serial interface on the ADT7302 consists of four wires: CS, DIN, DOUT and SCLK. All interface circuits shown utilize all four interface lines. However, it is possible to operate the interface with three wires. If the application does not require the powerdown facility offered by the ADT7302, the DIN line can be tied permanently low. Thus, the interface can be operated from just three wires: SCLK, CS, and DOUT. The serial data transfer to and from the ADT7302 requires a 16bit read operation. Many 8-bit microcontrollers have 8-bit serial ports, and this 16-bit data transfer is handled as two 8-bit transfers. Other microcontrollers and DSP processors transfer 16 bits of data in a serial data operation.
Preliminary Technical Data
In the example shown, the ADT7302 is connected to the serial port of the 8051. Because the serial interface of the 8051 contains only one data line, the DIN line of the ADT7302 is tied low in the interface example given in Figure 15. For applications that require the ADT7302's power-down feature, the serial interface should be implemented using data port lines on the 8051. This allows a full-duplex serial interface to be implemented. The method involves "bit-banging" a port line to generate a serial clock while using two other port lines to shift data in and out with the fourth port line connecting to CS. Port lines 1.0 through 1.3 (with P1.1 configured as an input) can be used to connect to SCLK, DOUT, DIN, and CS, respectively, to implement this scheme.
ADT7302 to MC68HC11 Interface
Figure 14 shows an interface between the ADT7302 and the MC68HC11 microcontroller. The MC68HC11 is configured in master mode with its CPOL and CPHA bits set to a Logic 1. When the MC68HC11 is configured like this, its SCLK line idles high between data transfers. Data is transferred to and from the ADT7302 in two 8-bit serial data operations. The diagram shows the full (4-wire) interface. PC1 of the MC68HC11 is configured as an output and is used to drive the CS input.
ADT7302*
SCLK DOUT DIN CS P3.1 P3.0
8051*
P1.3
*ADDITIONAL PINS OMITTED FOR CLARITY
Figure 15. ADT7302 to 8051 Interface
ADT7302 to PIC16C6x/7x and PIC16F873 Interface
Figure 16 shows an interface circuit between the ADT7302 and the PIC16C6x/7x microcontroller. The PIC16C6x/7x synchronous serial port (SSP) is configured as an SPI master with the clock polarity bit set to a Logic 1. In this mode, the serial clock line of the PIC16C6x/7x idles high between data transfers. Data is transferred to and from the ADT7302 in two 8-bit serial data operations. In the example shown, port line RA1 is being used to generate the CS for the ADT7302.
ADT7302*
SCLK DOUT DIN CS
MC68HC11* SCLK MISO
04662-C-008
MOSI PC1
*ADDITIONAL PINS OMITTED FOR CLARITY
Figure 14. ADT7302 to MC68HC11 Interface
ADT7302*
PIC16C6x/7x* SCK SDO
04662-C-010
ADT7302 to 8051 Interface An interface circuit between the ADT7302 and the microcontroller is shown in Figure 15. The 8051 is configured in its Mode 0 serial interface mode. The serial clock line of the 8051 (on P3.1) idles high between data transfers. Data is transferred to and from the ADT7302 in two 8-bit serial data operations. The ADT7302 outputs the MSB of its data stream as the first valid bit while the 8051 expects the LSB first. Thus, the data read into the serial buffer needs to be rearranged before the correct dataword from the ADT7302 is available in the accumulator.
SCLK DOUT DIN CS
SDI RA1
*ADDITIONAL PINS OMITTED FOR CLARITY
Figure 16. ADT7302 to PIC16C6x/7x Interface
The following software program shows how to program an PIC16F873 to communicate with the ADT7302. The PIC16F873 is configured as an SPI master with the PortA.1 pin used as CS. Any Microchip microcontroller can use this program by simply exchanging the include file for the device that's being used.
Rev. PrE | Page 10 of 14
04662-C-009
P1.2
Preliminary Technical Data
#include <16F873.h> #device adc=8 #use delay(clock=4000000) #fuses NOWDT,XT, PUT, NOPROTECT, BROWNOUT, LVP #BIT CKP = 0x14.4 #define CS PIN_A1 void main(){ int MSByte,LSByte; long int ADC_Temp_Code; float TempVal,ADC_Temp_Code_dec;
ADT7302
setup_spi(spi_master); CKP = 1; do{ delay_ms(10); Output_low(CS); delay_us(10); MSByte = SPI_Read(0); LSByte = SPI_Read(0); delay_us(10); Output_High(CS); MSByte = 0x03; LSByte = 0x20; ADC_Temp_Code = make16(MSByte,LSByte); ADC_Temp_Code_dec = (float)ADC_Temp_Code; if ((0x2000 & ADC_Temp_Code) == 0x2000) { TempVal = (ADC_Temp_Code_dec - 16384)/32; } else { TempVal = (ADC_Temp_Code_dec/32); } }while(True); }
//Pic is set up as Master device. //Idle state of clock is high.
//Allow time for conversions. //Pull CS low. //CS to SCLK setup time. //The first byte is clocked in. //The second byte is clocked in. //SCLK to CS setup time. //Bring CS high.
//16bit ADC code is stored ADC_Temp_Code. //Covert to float for division. //Check sign bit for negative value. //Conversion formula if negative temperature.
//Conversion formula if positive temperature.
//Temperature value stored in TempVal.
Rev. PrE | Page 11 of 14
ADT7302
ADT7302 to ADSP-21xx Interface
Preliminary Technical Data
MOUNTING THE ADT7302
The ADT7302 can be used for surface- or air-temperature sensing applications. If the device is cemented to a surface with thermally conductive adhesive, the die temperature will be within about 0.1C of the surface temperature, thanks to the ADT7302's low power consumption. Care should be taken to insulate the back and leads of the device from the air if the ambient air temperature is different from the surface temperature being measured. The ground pin provides the best thermal path to the die, so the temperature of the die will be close to that of the printed circuit ground track. Care should be taken to ensure that this is in good thermal contact with the surface being measured. As with any IC, the ADT7302 and its associated wiring and circuits must be kept free from moisture to prevent leakage and corrosion, particularly in cold conditions where condensation is more likely to occur. Water-resistant varnishes and conformal coatings can be used for protection. The small size of the ADT7302 allows it to be mounted inside sealed metal probes, which provide a safe environment for the device.
Figure 17 shows an interface between the ADT7302 and the ADSP-21xx DSP processor. To ensure correct operation of the interface, the SPORT control register should be set up as follows: TFSW = RFSW = 1, alternate framing INVRFS = INVTFS = 1, active low framing signal DTYPE = 00, right justify data SLEN = 1111, 16-bit data-words ISCLK = 1, internal serial clock TFSR = RFS = 1, frame every word IRFS = 0, RFS configured as input ITFS = 1, TFS configured as output The interface requires an inverter between the SCLK line of the ADSP-21xx and the SCLK input of the ADT7302. The ADSP21xx has the TFS and RFS of the SPORT tied together, with TFS set as an output and RFS set as an input. The DSP operates in alternate framing mode, and the SPORT control register is set up as described previously.
ADT7302*
SCLK DOUT DIN CS
ADSP-21xx* SCK DR DT
04662-C-011
SUPPLY DECOUPLING
The ADT7302 should be decoupled with a 0.1 F ceramic capacitor between VDD and GND. This is particularly important if the ADT7302 is mounted remote from the power supply.
RFS TFS
*ADDITIONAL PINS OMITTED FOR CLARITY
Figure 17. ADT7302 to ADSP-21 Interface
Rev. PrE | Page 12 of 14
Preliminary Technical Data OUTLINE DIMENSIONS
2.90 BSC
6 5 4
ADT7302
1.60 BSC
1 2 3
2.80 BSC
PIN 1 0.95 BSC 1.30 1.15 0.90 1.90 BSC
1.45 MAX
0.22 0.08 10 4 0 0.60 0.45 0.30
0.15 MAX
0.50 0.30
SEATING PLANE
COMPLIANT TO JEDEC STANDARDS MO-178AB
Figure 18. 6-Lead Small Outline Transistor Package [SOT-23] (RJ-6) Dimensions shown in millimeters
3.00 BSC
8
5
3.00 BSC
4
4.90 BSC
PIN 1 0.65 BSC 1.10 MAX 8 0 0.80 0.60 0.40
0.15 0.00 0.38 0.22 COPLANARITY 0.10
0.23 0.08 SEATING PLANE
COMPLIANT TO JEDEC STANDARDS MO-187AA
Figure 19. 8-Lead Mini Small Outline Package [MSOP] (RM-8) Dimensions shown in millimeters
Rev. PrE | Page 13 of 14
ADT7302 ORDERING GUIDE
Model ADT7302ART-500RL7 ADT7302ART-REEL7 ADT7302ART-REEL ADT7302ARM ADT7302ARM-REEL7 ADT7302ARM-REEL ADT7302ARTZ-500RL72 ADT7302ARTZ-REEL72 ADT7302ARTZ-REEL2 ADT7302ARMZ2 ADT7302ARMZ-REEL72 ADT7302ARMZ-REEL2
1 2
Preliminary Technical Data
Temperature Accuracy1 2C 2C 2C 2C 2C 2C 2C 2C 2C 2C 2C 2C Package Description 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23 8-Lead MSOP 8-Lead MSOP 8-Lead MSOP 6-Lead SOT-23 6-Lead SOT-23 6-Lead SOT-23 8-Lead MSOP 8-Lead MSOP 8-Lead MSOP Samples Branding Information T01 T01 T01 Package Option RJ-6 RJ-6 RJ-6 RM-8 RM-8 RM-8 RJ-6 RJ-6 RJ-6 RM-8 RM-8 RM-8
Temperature Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C
Temperature accuracy is over 0C to 70C temperature range. Z = Pb-free.
(c) 2004 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners.
PR04662-0-8/04(PrE)
Rev. PrE | Page 14 of 14
This datasheet has been download from: www..com Datasheets for electronics components.

▲Up To Search▲

Price & Availability of ADT7302ART-REEL7

	To Download ADT7302ART-REEL7 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .