Datasheet

MAX31865
RTD-to-Digital Converter
7Maxim Integrated
Pin Configuration
Pin Description
PIN NAME FUNCTION
1 BIAS Bias Voltage Output (V
BIAS
)
2 REFIN+
Positive Reference Voltage Input. Connect to BIAS. Connect the reference resistor between REFIN+
and REFIN-.
3 REFIN- Negative Reference Voltage Input. Connect the reference resistor between REFIN+ and REFIN-.
4 ISENSOR Low Side of R
REF.
Connect to REFIN-.
5 FORCE+
High-Side RTD Drive. Connect to FORCE2 when using the 3-wire connection configuration. Protected to
Q50V.
6 FORCE2
Positive Input Used in 3-Wire Only. When in the 3-wire connection configuration, connect to FORCE+.
When in the 2-wire or 4-wire connection configuration, connect to ground. Protected to Q50V.
7 RTDIN+
Positive RTD Input. Protected to Q50V.
8 RTDIN-
Negative RTD Input. Protected to Q50V.
9 FORCE-
Low-Side RTD Return. Protected to Q50V.
10 GND2 Analog Ground. Connect to GND1.
11 SDI Serial-Data Input
12 SCLK Serial-Data Clock Input
13
CS Active-Low Chip Select. Set CS low to enable the serial interface.
14 SDO Serial-Data Output
MAX31865
TQFN
(5mm x 5mm)
TOP VIEW
19
20
EP
+
18
17
7
6
8
REFIN+
ISENSOR
FORCE+
9
BIAS
SDO SCLK SDI DGND
12
DRDY
45
15 14 12 11
DVDD
V
DD
FORCE-
RTDIN-
RTDIN+
FORCE2
REFIN-
CS
3
13
N.C.
16
10
GND2
GND1