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DRV425
Current Sense IC with Integrated Magnetic Sensor and Readout
Features
Benefits
•
• High sensor sensitivity (100x hall sensors),
low offset and drift
• Sensor integration for small size and lower
system cost and better EM robustness
• Unique sensor feedback loop enables
exceptional linearity and gain accuracy
• Gain / range adjustable by a single resistor
• Fast detection and indication of input and
overload conditions
•
•
•
•
•
•
•
•
Precision Integrated Magnetic Sensor:
2µT Offset, 5nT/C Drift (typ)
Adjustable Sensor Range: up to ±2mT
High Gain Accuracy: 0.3%,5ppm/C (max)
Wide Signal Bandwidth: 47 kHz (typ)
Precision Reference: 50 ppm/C (max)
Over-Range and Error Flags
Power Supply 3 V to 5.5 V
Temperature Range: -40 to +125C
Packages: 4x4mm QFN
Current
Conductor
Rshunt
COMP1
COMP2
VDD
COIL1
GND
COIL2
AINP
AINN
DRV425
IM
Internal
Compensation
Coil
Applications
VOUT
•
Current monitoring
•
Magnetic field sensing
•
Magnetic field gradient sensing
Magnetic
Field
REFIN
Sensor
Readout
Magnetic
Sensor
Integrator / Filter
H-Bridge
Driver
Device Control & Degaussing
OR
ERROR DEMAG GSEL0 GSEL1
1.65 V or 2.5 V
Voltage Reference
RSEL0
RSEL1
1
DRV425 – How it works
Compensation
Coil
Sense Coil
The shunt sense
amplifier (G=4)
provides an output
proportional to the
magnetic field.
High precision fluxgate
magnetic sensor
detects the magnetic
field vector in its axis.
Signal is amplified and
used to drive a
compensating current
that keeps the sensor
operating with 0 field.
The current driving the
compensation coil is
proportional to the
magnetic field to be
measured with a very
stable gain factor.
The shunt resistor
converts the current
into voltage and sets
the amplification factor.
 The precision sensor provides low offset, low noise measurement
 The unique feedback configuration provides accurate and stable gain.
 Input and output overload conditions are detected by error flags.
2
Magnetic Field inside Bus Bar Hole
 Field gradient inside the hole is
proportional to the current through
busbar
 The gradient is measured by two
DRV425 sensors on the opposite
sides of a PCB
 Common mode fields are rejected
3
DRV425 - Value for High-Current Measurements
Today
New
approach
Benefits
 Sensor integrated into the BusBar for isolated measurement up to 1000s of Amps
 Differential measurement inside the bus bar further increases immunity to stray
fields and to frequency effects and to overcurrent conditions
 Lower power than shunt based solutions
 Compact module design and ease of installation
 High SNR by replacing discrete hall sensors
 High accuracy over a wide dynamic range
 Lower complexity and single temperature calibration
4
Isolated Current Measurement Portfolio
Isolated shunt: 0 – 80A
AMC1304L25
AMC1304M05
AMC1304L05
AMC1304M25
LVDS Interface
20MHz CLK, 1-Ch
Current Shunt, LDO
7kV Isolation
CMOS Interface
20MHz CLK, 1-Ch
Current Shunt, LDO
7kV Isolation
LVDS Interface
20MHz CLK, 1-Ch
Current Shunt, LDO
7kV Isolation
CMOS Interface
20MHz CLK, 1-Ch
Current Shunt, LDO
7kV Isolation
AMC1203
AMC1204
AMC1204B
10MHz Modulator
Current Shunt
4kV Digital Isolation
20MHz Modulator
Current Shunt
4kV Digital Isolation
20MHz Modulator
Current Shunt
4.25kV Digital Isolation
AMC1100
AMC1200
AMC1200B
100kHz Amplifier
E-metering
4.25kV Digital Isolation
100kHz Amplifier
Current Shunt
4kV Digital Isolation
100kHz Amplifier
Current Shunt
4.25kV Digital Isolation
High
Q-100
MEASUREMENT
ACCURACY
Q-100
AMC1305M05
AMC1305M25
CMOS Interface
20MHz CLK, 1-Ch
Current Shunt
7kV Isolation
CMOS Interface
20MHz CLK, 1-Ch
Current Shunt
7kV Isolation
AMC1305L25
LVDS Interface
20MHz CLK, 1-Ch
Current Shunt
7kV Isolation
Closed-loop Magnetic: 10A – 1000A
DRV401
DRV411
DRV421
Fluxgate Sensor Signal
Conditioner IC
Hall Sensor Signal
Conditioner IC
Fluxgate Integrated Sensor
Signal Conditioner IC
Low
Open-loop Magnetic: 5A – 1000A
Low
ADS1208
ADS1205
ADS1209
ADS1204
DRV425
Single Input
Hall Effect Sensor
2-Ch
Hall Effect Sensor
2-Ch
Hall Effect Sensor
4-Ch
Hall Effect Sensor
Fluxgate Integrated
Magnetic Sensor IC
High
PRIMARY CURRENT
Q1 Qualified
EXISTING
NEW
ROADMAP
DRV425
Fully Integrated Precision Magnetic Field Sensor and Readout
• Why were these parts developed?
The DRV425 with the integrated fluxgate is the highest precision magnetic sensor IC in the
market.
Diverse applications such as linear position measurement, torque and current sensing, metal detection
and magnetic field mapping today are limited by existing sensors accuracy or form factor. Although Hall
plates are widely used, they are limited in terms of their offset, noise, gain stability and achievable
linearity.
DRV425 helps overcome all such challenges in a precision measurement world. DRV425 has a higher
sensitivity, lower offset voltage, offset drift, and noise than integrated Hall sensors and enables highly
accurate measurements with greater gain stability & Sensitivity
• What differentiates this part?
Dynamic range, sensor precision and gain accuracy.
The DRV425 is designed for open loop Current sensing and magnetic field sensing applications. It has
100x higher sensitivity as well as lower offset, offset drift and noise than integrated Hall sensors. The
very low hysteresis, the incorporation of feedback via an on chip compensation coil provides 10-50x
better precision than designs with competing Magneto-Resistive technology. Its unique magnetic core
design provides higher sensitivity and signal bandwidth, along with lower power dissipation and higher
dynamic range. The sensing range is optimized from less than 1uT to 2mT and is therefore is
complimentary to TI’s Hall technology.
• What problem does DRV425 solve for customers/application?
DRV425 will improve customer system’s resolution, offer higher sensitivity and accuracy, reduce
assembly constraints and allow using less sensors or simpler cheaper magnets.
Who to Sell To…
Application Area #1
Application Area #2
Example
End
Equipment
• Torque Measurement
in motion control
• E-Bike, Power Tools
• Motor Drives
• Position Sensing
(Linear-Rotational)
• Industrial Process
Control
• Motion Sensing
• Magnetic Field Sensing
• Metal Detection
• Bus bar Current
measurement for
High Voltage
applications
• Electric Panels
• Wind Power
Key Market
Differentiat
ors
•
•
• Offset, Offset Drift
• Accuracy
• Sensitivity
•
•
•
•
•
Offset Drift
Accuracy, Gain
Stability, Non
Linearity
Low Noise
Application Area # 3
Sensitivity
Gain Stability
Gain Accuracy
Large Dynamic
Range
DRV425 – Features & Benefits
Fully Integrated Precision Magnetic Field Sensor and Readout

- Offset & Offset Drift : ±2uT, ±5nT/°C
 The high sensor sensitivity, low offset and noise allows measurement of
small magnetic fields and field gradients.
Features

Discovery
Questions
High Gain Accuracy
- Gain Error : ±0.04% (typ), Gain error Drift : ±7ppm/°C (typ)
 Eliminate the need for gain calibration over temperature
 Gain accuracy with unique feedback structure allows precise measurement
of small magnetic fields and widest dynamic range

Sensor Range : ± 2mT


Pricing &
Availability
Highly Sensitive & Precise Integrated Fluxgate Sensor
Ability to measure small magnetic field as low as sub 1uT ( complimentary
to hall sensors with 2mT+ range)
Integrated Sense amplifier & Precision Reference
- Reference Accuracy : 2.0 % max, Reference Drift : 50ppm/°C max
 Enables small footprint for system solution as only external component
required is gain selection resistor

Diagnostic Features : Over Range & Error Flags

Fast detection and indication of input and overload conditions aid system
level decisions.
DRV425 – Discovery Questions
Fully Integrated Precision Magnetic Field Sensor and Readout
•
Features
Do you need superior system precision sensing and accuracy?
 DRV425 with the integrated fluxgate is the highest precision, sensitive and accurate
magnetic sensor IC
•
Does your application need accurate small range Magnetic field
measurement or gradient sensing?
 With low offset (2uT), low noise, superior gain accuracy (0.3%) and stability it can be
used for gradient field detection.
•
Discovery
Questions
Do you face system performance limitation on account of offset and gain
accuracy and stability.
 External/Hall Sensors are limited in performance. The low offset (2uT), offset drift
(5nT/C), and noise(17nTrms) of the integrated sensor offer superior performance.
•
Is system noise an important factor for your application. Can you achieve
your system linearity?
 Low Noise @1Hz 5nT/rt (Hz), 0.1 to 10Hz, 17nTrms
•
Pricing &
Availability
Do you face system size limitation because of Discrete/external sensor and
Magnet size?
 Precise Integrated Sensor in a small 4x4mm package, reduced size & simple assembly.
•
Does your system have protection and diagnostic feature for Magnetic
sensing?
 Diagnostic features. Overload condition detection
DRV425 – Pricing & Availability
Fully Integrated Precision Magnetic Field Sensor and Readout
• Pricing 1Ku
Features
: $2.90
• Availability

Production samples available
• Resources
Discovery
Questions

Evaluation Board : DRV425EVM

Reference Designs:


Application Notes :

Pricing &
Availability

Bus Bar Current Sensing/Gradient Sensing -- Coming Soon
Coming soon
Blogs: planned on Precision Hub
DRV425 – Competitive Positioning
Sensor Type
Sensor sensitivity [@5V]
Sensitivity drift
IC sensitivity
Resistance
Range (lin / [max])
Offset
Offset drift
Noise @ 1Hz
Noise_white
IQ
Supply range
BW
Hyst
Linearity
unit
V/T
ppm/C
V/T
Ohm
mT (+/-)
uT (+/-)
uT/C
nT/rt(Hz)
nT/rt(Hz)
mA
V
kHz
uT
%
TI
Sensitec Honeywell Honeywell Sensitec
DRV425 AFF755/6 HMC1001 HMC1043 GF708
Fluxgate WF-AMR WF-AMR WF-AMR
GMR
200
60
160
50
650
20
3600
3000
2250
2400
2500
850
350
16000
2
0.3
0.2
0.6
0.5
3
40
NA
10
110
0.005
0.083
0.1
0.1
1
5
16
0.3
1
16
1.5
10
0.2
1
0.2
5
2
0
3
0.3
3-5.5
1.2-9
5 - 12
1.8-10
1.2 - 9
40
1000
5000
5000
1000
0.25
50
0.1
0.8
1
1.4
10
-40 to
125
-55 to 150 -40 to 125
2
0.3
0.2
0.6
0.5
0.42
2.34
0.05
0.22
0.48
0.25
4.17
5
5
50
2
2.4
2
8.4
50
2
54
30
67.5
60
2.9
54.3
30.5
68.2
92.7
Temp Range
0
Range
mT (+/-)
error - noise
uT
error - offset drift
uT
error - non-linearity
uT
error - sensitivity drift
uT
Detectivity (rms of total error)
uT
dB
56.9
Dynamic Range**
%FS
0.14%
Error [%FS]
1000.0
50.0
1.0
Test
Parameters
Detectivity Noise Bandwidth
[Hz]
Detectivity Temperature
Range: [C]
Detectivity Linear range:
14.9
18.09%
16.3
15.24%
18.9
11.37%
14.6
18.55%
Sensitec
NVE
Melexis
Melexis Infineon
GF705 AA005-02 MLX90215 MLX91205 TLE4997*
GMR
GMR
CMOS Hall IMC Hall Comp Hall
50
27.5
2200
2200
1000
200
5
5-140
280
300
5000
2-8 [25]
7 [30]
200
7.5
200
500
700
6000
NA
400
2.5
0.22
16
3
5
16
16
1300
125
885
0.2
0.2
1300
125
885
1
4
11
7.5
1.2 - 9
4.5-5.5
4.5-5.5
4.5-5.5
1000
1000
1.3
100
3.2
50
200
0
10
2
2
0.1
0.5
0.3
8
0.48
125
160
880
903.1
1
0.48
11
20
110
112.3
200
282.58
800
200
10000
10037.9
7.5
27.17
150
37.5
75
174.0
200
192.37
250
600
50
679.7
18.9
11.29%
19.0
11.23%
26.0
5.02%
32.7
2.32%
49.4
0.34%
* TLE4997 Special Device with In package gain drift calibration.
** The Dynamic range has been calculated with the given test parameters
Detectivity Derived from errors from noise, offset drift, gain drift and non-linearity
11
Integrated Fluxgate Key Specifications
Advantages of integrated fluxgate sensor:
 Lowest offset, offset drift and hysteresis among magnetic sensors
 High sensitivity (>100x larger than hall sensors)
 Low noise (5nT/Hz @1Hz; 1.5nT/ @1kHz)
PRECISION
Advantages of integrated feedback architecture:
 Gain accuracy (<0.3%)
 Gain drift (100x smaller than xMR sensors)
ACCURACY
Additional advantages:
INTEGRATION
Bio-Magnetic Field
Spinal Cord
Magnetic Field
fT
pT
 Fully integrated sensor readout circuitry
 On chip precision reference available
Natural Magnetic Field
Magnetic
Storm
nT
Industrial Magnetic Field
Earth
Magnetic Field
uT
Space Magnetic Field
Super-conducting
Magnetic
mT
T
kT
MT
Hall Sensor
xMR Sensor
SQUID
Fluxgate Sensor
TI Integrated Sensor
12
Integrated Fluxgate Advantages
Advantages of low offset, drift and noise and high sensitivity:




PRECISION
Can detect sub 100nT magnetic fields
Relaxes mechanical design constraints
Allows use of lower cost magnets
Allows gradient detection (stray field rejection)
Advantages of gain accuracy, stability and linearity:
ACCURACY
 Range can be adjusted via single resistor
 No gain calibration needed
 Enables open-loop current measurement
Advantages of integration:
INTEGRATION
Bio-Magnetic Field
Spinal Cord
Magnetic Field
fT
pT
 Lower EMI than discrete fluxgate sensors
 Small footprint
Natural Magnetic Field
Magnetic
Storm
nT
Industrial Magnetic Field
Earth
Magnetic Field
uT
Space Magnetic Field
Super-conducting
Magnetic
mT
T
kT
MT
Hall Sensor
xMR Sensor
SQUID
Fluxgate Sensor
TI Integrated Sensor
13