XR10910 Datasheet, PDF (17/19 Pages) Exar Corporation – 16:1 Sensor Interface

Typical Application – 16:1 Bridge Sensor Interface
The XR10910 was designed to interface multiple bridge
sensors with a microcontroller or FPGA as illustrated in
Figure 6.
The bridge output signal is differential (Vo+ and Vo-).
Ideally, the unloaded bridge output is zero (Vo+ and Vo-
are identical). However, in-exact resistive values result
in a difference between Vo+ and Vo-. This bridge offset
voltage can be substantial and vary between sensors. The
XR10910 provides the ability to calibrate the bridge offset
on each of the 16 bridge sensors using the on-board DAC.
Bridge 16
Bridge 1
BRDG
VCC
LDO
IN16+
IN16-
INA /
PGA
OUT
ADC
µC
16:1
MUX
±560mV
offset trim
IN1+
10-bit
DAC
PGA
SDA
IN1-
I2C
Control
SCL
XR10910
Figure 6: 16:1 Bridge Sensor Interface
Layout Considerations
General layout and supply bypassing play major roles in
high frequency performance. Follow the steps below as a
basis for high frequency layout:
■■ Include 6.8µF and 0.1µF ceramic capacitors for power supply
decoupling
■■ Place the 6.8µF capacitor within 0.75 inches of the power pin
■■ Place the 0.1µF capacitor within 0.1 inches of the power pin
■■ Connection to the exposed pad is not required. Exposed pad
can be connected to ground (GND).
■■ Minimize all trace lengths to reduce series inductances
XR10910
© 2014-2015 Exar Corporation
17 / 19
exar.com/XR10910
Rev 1B