MLX90365 Datasheet, PDF (6/35 Pages) Melexis Microelectronic Systems – Triaxis® Position Sensor IC

MLX90365
Triaxis® Position Sensor IC
5. Absolute Maximum Ratings
Parameter
Supply Voltage, VDD (overvoltage)
Reverse Voltage Protection
Positive Output Voltage
Output Current (IOUT)
Reverse Output Voltage
Reverse Output Current
Operating Ambient Temperature Range, TA
Storage Temperature Range, TS
Magnetic Flux Density
Value
+ 24 V
− 12 V (breakdown at -14 V)
+ 18 V (breakdown at 24 V)
+ 30 mA (in breakdown)
− 0.3 V
− 50 mA (in breakdown)
− 40°C … + 150°C
− 40°C … + 150°C
±1T
Exceeding the absolute maximum ratings may cause permanent damage. Exposure to absolute
maximum rated conditions for extended periods may affect device reliability.
6. Description
As described on the block diagram the three vector components of the magnetic flux density (B_X, B_Y and
B_Z) applied to the IC are sensed through the sensor front-end. The respective Hall signals (V_X, V_Y and V_Z)
are generated at the Hall plates and amplified.
The analog signal processing is based on a fully differential analog chain featuring the classic offset
cancellation technique (Hall plate 2-Phases spinning and chopper-stabilized amplifier).
The conditioned analog signals are converted through an ADC (15 bits) and provided to a DSP block for
further processing. The DSP stage is based on a 16 bit RISC micro-controller whose primary function is
the extraction of the position from two (out of three) raw signals (after so-called front-end compensation
steps) through the following function:
α = ∠(V₁, k ⋅V₂ )
where alpha is the magnetic angle ∠(B1, B2), V₁ = V_X or V_Y or V_Z , V₂ = V_X or V_Y or V_Z and k is a
programmable factor to match the amplitude of V₁ and k V₂.
The DSP functionality is governed by the micro-code (firmware − F/W) of the micro-controller which is
stored into the ROM (mask programmable). In addition to the magnetic angle extraction, the F/W controls
the whole analog chain, the output transfer characteristic, the output protocol, the programming/calibration
and also the self-diagnostic modes.
The magnetic angular information is intrinsically self-compensated vs. flux density variations. This feature
allows therefore an improved thermal accuracy vs position sensor based on conventional linear Hall
sensors.
In addition to the improved thermal accuracy, the realized position sensor features excellent linearity
performances taking into account typical manufacturing tolerances (e.g. relative placement between the
Hall IC and the magnet).
MLX90365
Rev. 5.7
Page 6 of 35
Datasheet
Jan. 22, 16