EVB90615 Datasheet, PDF (9/30 Pages) Melexis Microelectronic Systems – Infra Red Thermometer

MLX90615
Infra Red Thermometer
8.3.2 Power-On-Reset (POR)
The Power On Reset (POR) is connected to the Vdd supply. The on-chip POR circuit provides an active level
of the POR signal when the Vdd voltage rises above approximately 0.5V and holds the entire MLX90615 in
reset until the Vdd is higher than the specified POR threshold V_POR. During the time POR is active, the POR
signal is available as a weak open drain (active high) at the SDA pin. After the MLX90615 exits the POR
state, the functions programmed in the EEPROM take control of that pin.
8.3.3 EEPROM
A limited number of addresses in the EEPROM memory are of interest for the customer. The whole EEPROM
can be read and written with the SMBus interface.The entire EEPROM content between addresses 4h and
Dh must be kept unaltered or the factory calibration of the device will be lost.
EEPROM (16X16)
Name
SMBus slave address (SA) / PWM T min
PWM T range
Config
Emissivity
Melexis reserved (factory calibration)
…
Melexis reserved (factory calibration)
ID number
ID number
Address
0h
1h
2h
3h
4h
…
Dh
Eh
Fh
Write acces
Yes
Yes
Yes
Yes
Yes
…
Yes
No
No
SMBus slave address: 7 LSBs (6..0) contains the SMBus slave address that the MLX90615 will respond to.
Note that all MLX90615 will respond to SA 00h and therefore this value is useless in a network. Factory
default is 5Bh.
PWM T min: 15 bit limit for the PWM signal minimum temperature – right justified (factory default is 355Bh,
which corresponds to +0.03°C)
PWM T range: 15 bit range for the PWM signal temperature (Tmax – Tmin) – right justified (factory default is
09C3h, which corresponds to a PWM range +0.03…+50.01°C).
The Config register consist of control bits to configure the thermometer at POR:
Bit number
Factory default value
Bit 0
1
Function
SMBus/ PWM mode select
Bit 1
0
PWM frequency (doesn’t
matter in SMBus mode)
Bit 2
0
PWM output temperature
Bit [11:3]
Device specific
Factory calibration do not alter
Bits [14:12] 001b
IIR settings*
Bit [15]
0
Must be kept 0
1 – SMBus 0 - PWM
1 - Low
0 - High
1 - Ta
0 - To
IIR setting at
EEPROM address 02h
[binary]
001
010
011
100
101
110
111
*Note: IIR setting 000b must be avoided
Settling time
[samples]
1
10
18
24
31
38
45
Spike response
%
100
50
33.(3)
25
20
16.(6)
14.286
3901090615
Rev 001
Page 9 of 30
Data Sheet
28/Aug/2008