ADT7461AR-REEL7 ON Semiconductor, ADT7461AR-REEL7 Datasheet

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FEATURES On-chip and remote temperature sensor 0.25°C resolution/1°C accuracy on remote channel 1°C resolution/3°C accuracy on local channel Automatically cancels kΩ (typ) of resistance in series with remote diode to allow noise filtering Extended, switchable temperature measurement ...

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... Series Resistance Cancellation ....................................................9 Temperature Measurement Method...........................................9 Temperature Measurement Results ..........................................10 Temperature Measurement Range............................................10 Temperature Data Format..........................................................10 REVISION HISTORY 12/07- Rev 1: Conversion to ON Semiconductor 7/05—Rev Rev. B Changes to Features Section .............................................................1 Changes to Applications Section......................................................1 Changes to General Description Section........................................1 Changes to Addressing the Device Section ...................................14 Updated Outline Dimensions..........................................................21 Changes to the Ordering Guide ......................................................22 10/04— ...

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SPECIFICATIONS T = −40°C to +120° 5.5 V, unless otherwise noted Table 1. Parameter POWER SUPPLY Supply Voltage Average Operating Supply Current Undervoltage Lockout Threshold Power-On-Reset Threshold TEMPERATURE-TO-DIGITAL CONVERTER ...

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ADT7461 SMBus TIMING SPECIFICATIONS Table 2. SMBus Timing Specifications Parameter Limit at T and T MIN MAX f 400 SCLK t 1.3 LOW t 0.6 HIGH t 300 R t 300 F t 600 SU; STA 2 t 600 HD; ...

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ABSOLUTE MAXIMUM RATINGS Table 3. Parameter Positive Supply Voltage ( GND DD D+ D− to GND SCLK, SDATA, ALERT THERM Input Current, SDATA, THERM Input Current, D− ESD Rating, All Pins (Human Body Model) Maximum Junction Temperature (T ...

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ADT7461 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Table 4. Pin Function Descriptions Pin No. Mnemonic Description 1 V Positive Supply 5 Positive Connection to Remote Temperature Sensor. 3 D− Negative Connection to Remote Temperature ...

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TYPICAL PERFORMANCE CHARACTERISTICS GND 20 0 – –40 –60 – LEAKAGE RESISTANCE (MΩ) Figure 4. Temperature Error vs. Leakage Resistance 0 –0.1 –0.2 –0.3 –0.4 –0.5 –0.6 –0.7 ...

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ADT7461 5 40mV NO FILTER 60mV NO FILTER 40mV WITH FILTER 4 60mV WITH FILTER –1 0 100 200 300 FREQUENCY (MHz) Figure 10. Temperature Error vs. Common-Mode Noise Frequency (With and Without R-C-R Filter of ...

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FUNCTIONAL DESCRIPTION The ADT7461 is a local and remote temperature sensor and over/under temperature alarm, with the added ability to auto- matically cancel the effect of 3 kΩ (typical) of resistance in series with the temperature monitoring diode. When the ...

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ADT7461 C1* REMOTE SENSING TRANSISTOR *CAPACITOR C1 IS OPTIONAL. IT SHOULD ONLY BE USED IN NOISY ENVIRONMENTS. TEMPERATURE MEASUREMENT RESULTS The results of the local and remote temperature measurements are stored in the local and remote temperature value registers and ...

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The user can switch between measurement ranges at any time. Switching the range also switches the data format. The next temperature result following the switching is reported back to the register in the new format. However, the contents of the ...

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ADT7461 Table 8. Conversion Rate Register Codes Code Conversion/Second 0x00 0.0625 0x01 0.125 0x02 0.25 0x03 0.5 0x04 1 0x05 2 0x06 4 0x07 8 0x08 16 0x09 32 0x0A 64 0x0B to 0xFF Reserved Limit Registers The ADT7461 has ...

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Offset Register Offset errors may be introduced into the remote temperature measurement by clock noise or by the thermal diode being located away from the hot spot. To achieve the specified accuracy on this channel, these offsets must be removed. ...

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ADT7461 Table 10. Sample Offset Register Codes Offset Value 0x11 −128°C 1000 0000 −4°C 1111 1100 −1°C 1111 1111 −0.25°C 1111 1111 0°C 0000 0000 +0.25°C 0000 0000 +1°C 0000 0001 +4°C 0000 0100 +127.75°C 0111 1111 One-Shot Register The ...

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SERIAL BUS INTERFACE Control of the ADT7461 is carried out via the serial bus. The ADT7461 is connected to this bus as a slave device, under the control of a master device. After a conversion sequence completes, there should be ...

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ADT7461 1 SCLK A6 A5 SDATA START BY MASTER SERIAL BUS ADDRESS BYTE Figure 17. Writing a Register Address to the Address Pointer Register, then Writing Data to the Selected Register 1 SCLK SDATA A6 A5 START BY MASTER SERIAL ...

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ALERT OUTPUT This is applicable when Pin 6 is configured as an ALERT output. The ALERT output goes low whenever an out-of-limit measurement is detected the remote temperature sensor is open circuit open-drain output and ...

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ADT7461 the high temperature limits. THERM is reset automatically when the temperature falls back within the THERM limit. The external limit is set by default to 85° the local THERM limit. A hysteresis value can be programmed so ...

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APPLICATION INFORMATION Noise Filtering For temperature sensors operating in noisy environments, the industry standard practice was to place a capacitor across the D+ and D− pins to help combat the effects of noise. However, large capacitances affect the accuracy of ...

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ADT7461 thermal, contact with a PCB and may also forced airflow. How accurately the temperature of the board and/or the forced airflow reflects the temperature to be measured also affects the accuracy. Self-heating due to the power ...

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APPLICATION CIRCUIT Figure 25 shows a typical application circuit for the ADT7461 using a discrete sensor transistor connected via a shielded, twisted pair cable. The pull-ups on SCLK, SDATA, and ALERT are required only if they are not already provided ...

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ADT7461 OUTLINE DIMENSIONS 5.00 (0.1968) 4.80 (0.1890 6.20 (0.2440) 4.00 (0.1574) 5.80 (0.2284) 3.80 (0.1497 1.27 (0.0500) BSC 1.75 (0.0688) 1.35 (0.0532) 0.25 (0.0098) 0.10 (0.0040) 0.51 (0.0201) COPLANARITY 0.25 (0.0098) 0.31 (0.0122) SEATING 0.10 0.17 ...

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... ORDERING GUIDE Model Temperature Range ADT7461AR −40°C to +125°C ADT7461AR-REEL −40°C to +125°C ADT7461AR-REEL7 −40°C to +125°C 1 ADT7461ARZ −40°C to +125°C 1 ADT7461ARZ-REEL −40°C to +125°C 1 ADT7461ARZ-REEL7 −40°C to +125°C ADT7461ARM −40°C to +125°C ADT7461ARM-REEL − ...