MLX90277EGOSR0-0 MELEXIS [Melexis Microelectronic Systems], MLX90277EGOSR0-0 Datasheet - Page 13

• Manufacturer Part Number: MLX90277EGOSR0-0
• Description: Dual Programmable Linear Hall Effect Sensor
• Manufacturer: MELEXIS [Melexis Microelectronic Systems]

The value of TempCo is often determined by the magnet. In the application the TempCo is adjusted to
compensate for the temperature coefficient of the magnet. To adjust the value the look up table is read from
the device. The parameters are then calculated to match the desired value. The Melexis PTC hardware and
software tools contain built in functions for programming the TempCo.
Table 12: TempCo Accuracy
Note: The budget error of the whole system, the compensation mismatch (system vs. IC) tolerance should be
taken into consideration during the design. Table 11 is valid for Rough Gain within the specified option code.
See section 10.4 for information on selecting the option code.
The MLX90277 sensors' EEPROM memory content is secured through a parity check. This self-diagnostic
feature brings the output to a defined range in case of a parity error. The parameter, FAULTLEV, is used to
define the parity error diagnostic state. With the FAULTLEV set to 0 a parity error event will result in an
output diagnostic voltage low. With the FAULTLEV set to 1 a parity error event will result in an output
diagnostic voltage high. To get rid of the output load influence the output diagnostic voltage level can be
fixed to either Ground (to be used with pull-down load) or V
software and hardware tools have built in functions for calculating and programming the parity.
Note: The MLX90277 sensors' EEPROM is also redundant. Each parameter bit is written in three separate
cells and a “majority voting” is applied to determine its status. A parity error is detected only if two out of the
three cells unexpectedly change state. The bits available for the customer ID are not redundant.
The memory cells of the EEPROM are arranged in a table of four columns and one hundred twenty eight
rows. This configuration gives redundancy to the parameters stored in the EEPROM. Each parameter bit is
written in three separate cells in an individual row. A majority voting applied to the three cells determines the
logic status of the bit.
A parameter bit only toggles state in error if two out of three memory cells, within a row, unexpectedly
change. If this happens the feature, PARITY, forces the output voltage to the FAULTLEV diagnostic level.
This ensures the device does not operate with a critical memory fault.
The remaining memory cells are used for data storage. The status of these cells does not effect the device
operation. For example the Customer ID, CUSTID, is stored in this area. Melexis stores the device ID
information, TempCo look-up table and CRC bits in the extra cells. The CRC bits ensure the integrity of the
Melexis data.
Note: To avoid parity and CRC errors, the entire contents of the EEPROM must be read before
programming. Melexis PTC software and hardware tools have built in functions for reading the EEPROM and
handling parity.
3901090277
Rev 004
TempCo Range (ppm / ° C)
0 to 500
500 to 1200
1200 to 2000
10.9 Diagnostic Output Level (FAULTLEV)
10.10 The EEPROM, Parity and Melexis CRC
Accuracy (ppm / ° C)
± 100
± 150
± 200
Page 13 of 21
Dual Programmable Linear Hall Effect Sensor
DD
(to be used with pull-up load). Melexis PTC
MLX90277
Data Sheet
Nov/06