ADT75 Analog Devices, Inc., ADT75 Datasheet
ADT75
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ADT75 Summary of contents
Page 1
... Supply voltage Space-saving, 8-lead MSOP and 8-lead SOIC. 4. Temperature accuracy is ±1°C maximum. 5. Temperature resolution is 0.0625°C. 6. Shutdown mode reduces the current consumption to 3 μA typical. 7. Connect up to eight ADT75s to a single SMBus/I FUNCTIONAL BLOCK DIAGRAM 12-BIT DECIMATOR LPF 1-BIT + – ...
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... ADT75 TABLE OF CONTENTS Features .............................................................................................. 1 Applications....................................................................................... 1 Product Highlights ........................................................................... 1 Functional Block Diagram .............................................................. 1 General Description ......................................................................... 3 Specifications..................................................................................... 4 A Grade.......................................................................................... 4 B Grade .......................................................................................... 5 Timing Specifications and Diagram .......................................... 6 Absolute Maximum Ratings............................................................ 7 ESD Caution.................................................................................. 7 Pin Configuration and Function Descriptions............................. 8 Typical Performance Characteristics ............................................. 9 Theory of Operation ...................................................................... 10 Circuit Information.................................................................... 10 Converter Details........................................................................ 10 Functional Description.............................................................. 10 REVISION HISTORY 10/05— ...
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... ADC to monitor and digitize the temperature to a resolution of 0.0625°C. The ADT75 is pin and register compatible with the LM75 and AD7416. The ADT75 is guaranteed to operate at supply voltages from 5.5 V. Operating at 3.3 V, the average supply current is typically 200 μA. ...
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... ADT75 SPECIFICATIONS A GRADE 3 5.5 V. All specifications for −55°C to +125°C, unless otherwise noted. A MIN MAX DD Table 1. Parameter TEMPERATURE SENSOR AND ADC Accuracy 3 5 Accuracy 3 3 Accuracy 4 5 ADC Resolution Temperature Resolution ...
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... Part converting and I C interface inactive Part converting and interface inactive Supply current in shutdown mode Supply current in shutdown mode V = 3.3 V, normal mode at 25°C DD Average power dissipated for V = 3.3 V, shutdown DD mode at 25°C Average power dissipated for V = 5.0 V, shutdown DD mode at 25°C ADT75 ...
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... ADT75 TIMING SPECIFICATIONS AND DIAGRAM Measure the SDA and SCL timing with the input filters turned on to meet the fast mode I improves the transfer rate but has a negative affect on the EMC behavior of the part +2 +5.5 V, unless otherwise noted. ...
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... Figure 3. MSOP Maximum Power Dissipation vs. Ambient Temperature 3°C/sec maximum –6°C/sec maximum 6 minutes maximum 260°C (+0°C) 20 sec to 40 sec 3°C/sec maximum –6°C/sec maximum 8 minutes maximum Rev Page 1.2 1.0 0.8 0.6 0.4 0.2 MAX PD = 3.4mW AT 150°C 0 TEMPERATURE (°C) ADT75 ...
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... SDA SMBus Serial Data Input/Output. Serial data that is loaded into and read from the ADT75 registers is provided on this pin. Open-drain configuration; needs a pull-up resistor. 2 SCL Serial Clock Input. This is the clock input for the serial port. The serial clock is used to clock in and clock out data to and from any register of the ADT75. Open-drain configuration ...
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... SUPPLY RIPPLE FREQUENCY (MHz) Figure 9. Temperature Accuracy vs. Supply Ripple Frequency 0.025 0.020 0.015 0.010 MSOP PACKAGE 0.005 0 –0.005 SOIC PACKAGE –0.010 –0.015 –0.020 –0.025 RECOVERY TIME AT 25°C (Hours) Figure 10. Response to Thermal Shock ADT75 5.0 5.5 PIN. DD 4.0 4.5 5 ...
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... Overall accuracy for the ADT75 A Grade is ±2°C from −25°C to +100°C and accuracy for the ADT75 B Grade is ±1°C from 0°C to +70°C. Both grades have excellent transducer 2 linearity ...
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... One LSB of the ADC corresponds to 0.0625°C. The ADC can theoretically measure a temperature range of 255°C (−128°C to +127°C ), but the ADT75 is guaranteed to measure a low value temperature limit of −55° high value temperature limit of +125°C. The temperature measurement result is stored in the ...
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... Bit D3 and Bit D4 of the configuration register are used to set up a fault queue six faults are provided to prevent false tripping of the OS/ALERT pin when the ADT75 is used in a noisy temperature environment. The number of faults set in the queue must occur consecutively to set the OS/ALERT output. ...
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... REGISTERS The ADT75 contains six registers: four are data registers, one is the address pointer register, and the final register is the one-shot register. The configuration register is the only data register that is 8 bits wide while the rest are 16 bits wide. The temperature value register is the only data register that is read only ...
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... D12 D11 Configuration Register This 8-bit read/write register stores various configuration modes for the ADT75. These modes are shutdown, overtemperature interrupt, one-shot, SMBus alert function enable, OS/ALERT pin polarity, and overtemperature fault queues. Table 10. Bit Configuration Mode D7 OS/SMBus alert D6 ...
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... Normal mode; powered up and converting every 100 ms 1 One-shot mode D6 Reserved. Write 0 to this bit. Reserved D7 Interrupt Mode Only. Enable SMBus alert function mode. This bit can enable the ADT75 to support the SMBus alert function when the interrupt mode is selected (D1 = 1). OS/SMBus Alert D7 OS/SMBus Alert Mode Mode 0 Disable SMBus alert function ...
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... Like all SMBus/I C-compatible devices, the ADT75 has a 7-bit serial address. The four MSBs of this address for the ADT75 are set to 1001. Pin A2, Pin A1, and Pin A0 set the three LSBs. These pins can be configured two ways, low and high, to give eight different address options. Table 12 shows the different bus address options available. Recommended pull-up resistor value on the SDA and SCL lines is 10 kΩ ...
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... WRITING DATA Depending on the register being written to, there are two different writes for the ADT75. Writing to the Address Pointer Register for a Subsequent Read In order to read data from a particular register, the address pointer register must contain the address of that register does not, the correct address must be written to the address pointer register by performing a single-byte write operation, as shown in Figure 14 ...
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... START BY MASTER SERIAL BUS ADDRESS BYTE READING DATA Reading data from the ADT75 is done in a one data byte operation for the configuration register and a two data byte operation for the temperature value register, T register, and the T HYST Figure 17. Reading back the contents of the temperature value register is shown in Figure 18. Reading back from any register first requires a single-byte write operation to the address pointer register to set up the register address of the register that is going to be read from ...
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... POLARITY = ACTIVE HIGH Interrupt Mode In the interrupt mode, the OS/ALERT pin goes inactive when any ADT75 register is read. The OS/ALERT pin can only return to active status if the temperature measured is below the limit stored in the T reset, it goes active again only when the temperature has gone ...
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... The device whose SMBus alert output is low responds to the SMBus alert response address and the master reads its device address. As the device address is seven bits long, the ADT75’s LSB is free to be used as an indicator as to which temperature limit was exceeded. The LSB is high if the temperature is ...
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... Using the power-down mode can reduce the current dissipated through the ADT75 subsequently reducing the self-heating affect. When the ADT75 is in power-down mode and operating at 25°C, static dissipation in the ADT75 is typically 78.6 μW with V = 3.3 V and the power-up/conversion rate is 1 SPS DD (sample per second) ...
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... ADT75 die is discharged via the copper tracks, the package pins, and the bond pads. Of the pins on the ADT75, the GND pin transfers most of the heat. Therefore, to measure the temperature of a heat source it is recommended that the thermal resistance between the ADT75 GND pin and the GND of the heat source is reduced as much as possible. For example, use the ADT75’ ...
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... ADT75ARZ –55°C to +125°C 1 ADT75ARZ-REEL7 –55°C to +125°C 1 ADT75ARZ-REEL –55°C to +125°C 1 ADT75BRMZ –55°C to +125°C 1 ADT75BRMZ-REEL7 –55°C to +125°C 1 ADT75BRMZ-REEL –55°C to +125° Pb-free part grade temperature accuracy is over the −25°C to +100°C temperature range. ...
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... ADT75 NOTES 2 Purchase of licensed I C components of Analog Devices or one of its sublicensed Associated Companies conveys a license for the purchaser under the Philips I 2 Rights to use these components system, provided that the system conforms to the I © 2005 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners ...