MLX90614_15 Datasheet, PDF (11/51 Pages) Melexis Microelectronic Systems – Single and Dual Zone Infra Red Thermometer in TO-39

MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39
8.3 Block description
8.3.1 Amplifier
A low noise, low offset amplifier with programmable gain is used for amplifying the IR sensor voltage.
By carefully designing the input modulator and balanced input impedance, the max offset of the system is
0.5µV.
8.3.2 Supply regulator and POR
The module can operate from 3 different supplies:
VDD = 5V MLX90614Axx
VDD = 3.3V MLX90614Bxx (battery or regulated supply)
VDD = 8…16V MLX90614Axx few external components are necessary please refer to “Applications
information” section for information about adopting higher voltage supplies.
The Power On Reset (POR) is connected to Vdd supply. The on-chip POR circuit provides an active (high) level
of the POR signal when the Vdd voltage rises above approximately 0.5V and holds the entire MLX90614 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 an open drain at the PWM/SDA pin. After the MLX90614 exits the POR condition, the
function programmed in EEPROM takes precedence for that pin.
8.3.3 EEPROM
A limited number of addresses in the EEPROM memory can be changed by the customer. The whole
EEPROM can be read through the SMBus interface.
Name
Tomax
Tomin
PWMCTRL
Ta range
Emissivity correction coefficient
Config Register1
SMBus address (LSByte only)
ID number
ID number
ID number
ID number
EEPROM (32X16)
Melexis reserved
…
Melexis reserved
Melexis reserved
Melexis reserved
…
Melexis reserved
Melexis reserved
Melexis reserved
Melexis reserved
Address
0x00
0x01
0x02
0x03
0x04
0x05
0x06
…
0x0D
0x0E
0x0F
0x10
…
0x18
0x19
0x1A
0x1B
0x1C
0x1D
0x1E
0x1F
Write access
Yes
Yes
Yes
Yes
Yes
Yes
No
…
No
Yes
Yes
No
…
No
Yes
No
No
No
No
No
No
Table 5: EEPROM table
The addresses To_max, To_min and Ta range are for customer dependent object and ambient temperature
ranges. For details see section 8.5.3 below in this document
The address Emissivity contains the object emissivity (factory default 1.0 = 0xFFFF), 16 bit.
ε Emissivity = dec2hex[ round( 65535 x ) ]
Where dec2hex[ round( X ) ] represents decimal to hexadecimal conversion with round-off to nearest value (not
ε truncation). In this case the physical emissivity values are = 0.1…1.0.
Erase (write 0) must take place before write of desired data is made.
3901090614
Rev 009
Page 11 of 52
Data Sheet
June 29, 2015