MLX90215 Datasheet, PDF (4/10 Pages) List of Unclassifed Manufacturers – Precision Programmable Linear Hall Effect Sensor

MLX90215
Precision Programmable
Linear Hall Effect Sensor
Temperature Compensation
Temperature compensation (TC) is defined as the
change in sensitivity over temperature. Expressed in
(Parts Per Million per Degree Celcius) ppm/^oC.
TC
=
Sens _{T 1} − Sens _{T 2}
Sens ₂₅
∗ ¹ ∗10 ⁶
T1−T 2
ppm
o_C
Sens_T1 = Sensitivity measured at Temperature 1 (T1)
Sens_T2 = Sensitivity measured at Temperature 2 (T2)
Sens₂₅ = Initial Sensitivity measured at 25^oC
Table 3 - Temperature Compensation
TC Code Min Typical Max
Units
0
-700
-550
-350
ppm/^oC
1
-625
-450
-275
ppm/^oC
2
-525
-375
-175
ppm/^oC
3
-450
-300
-100
ppm/^oC
4
-350
-200
-25
ppm/^oC
5
-275
-125
50
ppm/^oC
6
-200
-50
125
ppm/^oC
7
-100
25
225
ppm/^oC
8
125
275
425
ppm/^oC
9
225
350
525
ppm/^oC
10
300
425
600
ppm/^oC
11
375
525
700
ppm/^oC
12
450
600
775
ppm/^oC
13
525
675
850
ppm/^oC
14
600
775
950
ppm/^oC
15
675
850
1025 ppm/^oC
16
975
1300
1550 ppm/^oC
17
1025
1375
1650 ppm/^oC
18
1125
1470
1750 ppm/^oC
19
1200
1550
1825 ppm/^oC
20
1275
1650
1950 ppm/^oC
21
1325
1725
2025 ppm/^oC
22
1425
1800
2125 ppm/^oC
23
1475
1900
2200 ppm/^oC
24
1500
2000
2425 ppm/^oC
25
1550
2100
2525 ppm/^oC
26
1600
2200
2625 ppm/^oC
27
1675
2275
2700 ppm/^oC
28
1750
2375
2825 ppm/^oC
29
1825
2450
2925 ppm/^oC
30
1900
2550
3025 ppm/^oC
31
1950
2650
3125 ppm/^oC
Programming the Temperature Compensation
The MLX90215 has a 5-bit (32 step) programmable
adjustment that changes it’s sensitivity drift over a given
temperature range. By adjusting the TC code the
sensitivity can be programmed to increase as
temperature increases to counteract the decrease in
magnetic flux most magnets display over temperature.
For example a SmCo (Samarium Cobalt) magnet has a
temperature coefficient of approximately -300 ppm/^oC.
The MLX90215 can be programmed with a TC of 300
ppm/^oC to counteract the TC of the magnet and greatly
improve linearity in the application over temperature.
Table 3 (left) illustrates the way the TC code affects the
sensitivity temperature drift. Also note in Table 3, the
overlap in TC codes. The numbers in the table represent
typical results and are for reference only. For accurate
results the TC code must be determined experimentally.
This TC code map applies to MLX90215’s with a first
line brand showing “215DB”
Special Note
The MLX90215 programmed with a zero TC code
(default) has a typical TC value between the range of –
300 to –600 ppm/^oC. This means sensitivity will
decrease slightly as temperature increases. The slightly
negative initial TC value allows the MLX90215 to be
accurately programmed up to 0 TC. Almost all magnets
have a naturally negative TC code. The natural TC of a
magnet added with the initial negative TC value of the
MLX90215 could degrade linearity over a large
temperature span. Using a TC code of 6, 7, or 8 will
give the MLX90215 a slightly positive TC code.
Previous revisions of the MLX90215 with second line
brand of “15AXX” or “15DXX” should refer to factory
for TC code maps.
Diagnostic Characteristics
Condition
VOUT Shorted to VDD
VOUT Shorted to VSS
VOUT open with pull up load
VOUT open with pull down load
VSS open with pull up load
VSS open with pull down load
> 10 K Ohms
VDD open with pull up load
> 4.7 K Ohms
VDD open with pull down load
Output Level
VOUT = VDD
VOUT = VSS
VOUT = VDD
VOUT = VSS
VOUT = VDD
VOUT = VDD
or 94% VDD
VOUT = VSS
or 3% VDD
VOUT = VSS
3901090215
Rev 007
Page 4
9/09/03