ADAF1080 (Rev.A)
Document overview
- Manufacturer or author: Analog Devices, Inc.
- PDF pages: 38
Technical content
Integrated 8 mT AMR Magnetic Field Sensor and Signal Conditioner Rev. A DOCUMENT FEEDBACK TECHNICAL SUPPORT
FEATURES
►Single-axis, high-precision, AMR magnetic field sensor ►Maximum magnetic field strength on the sense field axis for linear operation up to ±8 mT ►DC and AC magnetic field measurements ►Output noise (noise density magnetic field equivalent): 6 nT/√Hz ►>100 dB dynamic range ►Flip coil to calibrate electrical offset over life and temperature ►Temperature compensated output ►Integrated precision instrumentation amplifier ►Up to 2.2 MHz bandwidth at gain = 20 ►Programmable chopping for precision measurements ►Synchronization features for wide bandwidth applications ►Ratiometric output capability to improve PSRR ►Programmable gain for 1.8 V to 5 V ADC range ►Analog output optimized to drive ADC ►Ease of use features ►Wide and user-selectable output common-mode voltage ►Integrated electrical offset cancellation ►Integrated diagnostics ►Temperature range: –40°C to +125°C ►Supply voltage range: 4.5 V to 5.5 V ►Available in a 20-Lead LFCSP with an exposed pad
APPLICATIONS
►Isolated and contactless current sensing ►Handheld current clamp meters ►Motor control current sense ►AC and DC power applications ►Precision magnetic field sensing applications ►Precision linear encoders ►Low-noise, precision magnetometers PRODUCT HIGHLIGHTS 1. Contactless current measurement 2. Precise measurement of magnetic field strength in a single axis 3. Low-noise analog front end 4. Negligible hysteresis 5. High-bandwidth, wide-range magnetic field sensor 6. Electrical offset cancellation over life and temperature FUNCTIONAL BLOCK DIAGRAM Figure 1. Functional Block Diagram driver for precise measurement of magnetic fields up to ±8 mT. mode of half the voltage set on the external VSET input pin. offset cancellation in the presence of a constant magnetic field. a magnetic saturation event.
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REVISION HISTORY
5/2026—Rev. 0 to Rev. A 1/2023—Revision 0: Initial Version
Table 1. Magnetic Characteristics VSET is the voltage on the VSET pin and is tied to VDD, unless otherwise stated. Table 2. Magnetic Range ±2 mT 1 Ideal sensitivity, factory trimmed and calculated with the linear best-fit, is measured from the following points: ±2 mT, ±1 mT, and ±0.5 mT. 2 Production tested at ±1 mT. Full range guaranteed by design and/or characterization. 3 Ideal coefficient, factory trimmed and calculated with the third-order best-fit, is measured from the following points: ±2 mT, ±1 mT, and ±0.5 mT. Table 3. Magnetic Range ±4 mT
Table 3. Magnetic Range ±4 mT (Continued) 1 Ideal sensitivity, factory trimmed and calculated with the linear best-fit, is measured from the following points: ±4 mT, ±3 mT, ±2 mT, ±1 mT, and ±0.5 mT. 2 Production tested at ±1 mT. Full range guaranteed by design and/or characterization. 3 Ideal coefficient, factory trimmed and calculated with the third-order best-fit, is measured from the following points ±4 mT, ±3 mT, ±2 mT, ±1 mT, and ±0.5 mT. Table 4. Magnetic Range ±8 mT 2 Production tested at ±1 mT. Full range guaranteed by design and/or characterization.
and is tied to VDD, unless otherwise stated. Table 5. General Characteristics
Table 5. General Characteristics (Continued) 1 Output referred. Divide by 2 if G = 40, and divide by 4 if G = 20. 2 Calculated equivalent magnetic field. 3 The stability of VOFFSETwFLIP is the calculated offset with the flipping functionality. The sensor is flipped 200 times and standard deviation of the 100 offsets calculated.
Table 6. Flipping Functionality Specifications Figure 2. Flip Coil Driver Timing Diagram with Output Voltage Status
Table 7. Diagnostic Coil Specifications Table 8. Temperature Sensor Specifications Table 9. Synchronization and Chopping Specifications
Figure 3. Synchronization Timing Diagram
Table 10. Absolute Maximum Ratings ing conditions for extended periods may affect product reliability. Table 11. Thermal Resistance sitive devices in an ESD protected area only. Charged device model (CDM) per ANSI/ESDA/JEDEC JS-002. Table 12. ADAF1080, 20-Lead LFCSP devices and circuit boards can discharge without detection. taken to avoid performance degradation or loss of functionality.
Figure 4. Pin Configuration Table 13. Pin Function Descriptions 1 VDD Supply Voltage. The VDD pin must be connected to the other VDD supply voltage pin (Pin 6). 2 VOUT Output Voltage Proportional to the Magnetic Field Sensed. Output ratiometric to VDD. 3 VSET VSET Input. The VSET pin sets the common-mode voltage of the OUT pin to VSET/2. 4 A0 Gain Setting LSB. When A0 is not in use, it is internally pulled high to VDD. 5 A1 Gain Setting MSB. When A1 is not in use, it is internally pulled high to VDD. 6 VDD Supply Voltage. Connect a 1 µF capacitor to GND as close to the VDD pin as possible. this pin. VTEMP is proportional to the die junction temperature. 8 DIAG+ Positive Input of the Diagnostic Coil. If DIAG+ is not in use, connect it to GND. SYNC_EN is not in use, it is internally pulled to GND. 12 NC No Connect. The NC pin can be left open or connected to GND. 14 GND_FLIP Ground of the Flip Coil Driver, Attach to System Ground. VDD_FLIP and VDD as close as possible to the VDD_FLIP pin. 16 GND_FLIP Ground of the Flip Coil Driver, Attach to System Ground. is not in use, internally pulled it high. open or connected to the EPAD. 19 NC No Connect. The NC pin can be left open or connected to GND. 20 NC No Connect. The NC pin can be left open or connected to GND. used as the diagnostic coil and is internally connected between the DIAG+ and DIAG− pins.
Figure 41. PSRR vs. Frequency, BSENSE = 8 mT
Figure 42. Sense Field Axis and Cross Field Axis 25°C, as shown in Figure 42. for each of the three ranges shown in Table 2, Table 3, and Table 4. ity of the output of the ADAF1080. magnetic fields are applied in the application. offset error, sensitivity error, temperature related errors, or noise. in plane with, the sense field axis of the sensor. axis relative to the ADAF1080 package. nearby ferromagnetic material, or the magnetic field of the earth.
analog.com Rev. A | 20 of 38 Output Error due to a Cross Field SERROC_BC is the error due to the presence of a cross field. SER- ROC_BC is defined as the percentage change of the output voltage in the presence of a cross field compared to the output voltage with no cross field. S ERR OR _ BC = V OU T B CR OSS − V O U T B C RO SS = 0 V OU T B C ROSS = 0 × 100 where: VOUT(BCROSS) is the measured output voltage of the device with a cross field present. VOUT(BCROSS = 0) is the measured output voltage of the device with no cross field present.
Figure 45. Sense Field Axis of the ADAF1080 measuring small magnetic fields in the nT range.
Figure 50. Sense Field Axis
Figure 55. Synchronization of the ADAF1080 and the ADC Sampling for Slow performance with and without chopping. Table 15. SYNC Pin Functionality
1.6 MHz
calibrated out of the sense magnetic field measurement. VOUTFn is the output of the ADAF1080 when FLIP_DRV is GND. VOUTFp is the output of theADAF1080 when FLIP_DRV is VDD. VSET is the voltage on the VSET pin. shown in the Flip Coil and Measurement Timing section. ADAF1080 as shown in Figure 48.
dependency on the sense field. BCALC is the calculated field measured by the ADAF1080. VOUT is the measured output of the ADAF1080. VOFFSET is the output voltage when BSENSE = 0 mT. time, tSETTLING, is required for the output to settle. behavior that has a time constant of approximately 10 μs. regardless of the signal chain used in the application. IFLIP_ON is the peak current required to flip the sensor. the recommended RFLIP and CFLIP for different flipping frequencies. Table 16. Recommended RFLIP and CFLIP Values for Different FLIP_DRV CFLIP must be carefully chosen to obtain a capacitance of 10 µF. capacitance to supply the flip current required for the flip coil. maximize the usable input range of the ADC. configuration coupled with a 3.3 V and a 5 V ADC, respectively.
inputs without the need for additional active components. requirements into account for determining these values. dulation distortion, using the SYNC pin set according to Table 15. Table 17. Recommended ROUT and COUT Values for Different Filter Bandwidth on the VOUT Pin and Recommended Amplifier Modes
1 MHz 200 Ω 750 pF Chopping disabled: SYNC_EN = GND and SYNC = VDD
2 MHz 200 Ω 330 pF Chopping disabled: SYNC_EN = GND and SYNC = VDD
TVTEMP is the calibrated temperature of the sensor. VTEMP is the output of the VTEMP pin. TCAL is the temperature at which the calibration was performed. VTEMP must be left disconnected when not in use. Figure 58. Circuit Diagram for Temperature Measurements Using VTEMP
Figure 59. Design Example with 5 V ADC and 20 kHz Filter Table 18. Component Values for the Design Example with 5 V ADC and 20 kHz Filter
nearby magnetic field interference. Figure 60. Design Example with the EVAL-ADAF1080-3EBZ Evaluation Board Table 19. Component Values for the Design Example with the EVAL-ADAF1080-3EBZ
Figure 65. Alternative Layout for a 3-Layer PCB
Figure 66. Mechanical Drawing of the ADAF1080 Including Placement Tolerances
Figure 67. 20-Lead Lead Frame Chip Scale Package [LFCSP] Table 20. Evaluation Boards