LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual
UBX-14054794
Production Information
Design-in
Page 29 of 85
The following block schematic specifies the A/D converter and temperature sensor for the LEA-6R.
The LTC1860 and LM70-5 function at 5 V. A level translation with open-drain buffers and pull-up
resistors on the outputs is required.
LEA-6R
Turn Rate Sensor
(MOSI)
22K
10R
leave open
Gyro
SCK
MISO
SPI_SCS2_N
+5V
REF
100nF
GND
GND
CONV
SCK
VCC
SC
CS
V
REF
IN
+
IN
-
12-Bit
A/D Converter
Linear LTC1860
Temperature
Sensor
National LM70-5
SDO
SI/O
V
+
GND
GND
GND
100nF
RATE
100nF
GND
100K
SPI_SCS1_N
10uF
220nF
+5V
+5V
+5V
+5V
+3V
+3V
+3V
+5V
+3V
Figure 23: Attaching A/D converter and temperature sensor using the SPI
Add appropriate coupling capacitances according to the recommendations in the data sheets of the illustrated
semiconductor products. All shown resistors shall have 5% accuracy or better. All shown capacitors (X7R types)
shall have 10% accuracy or better.
For correct operation with the LEA-6R firmware, this circuit must be adopted without making any
modifications such as, but not limited to, using different types of semiconductor devices and changing
signal assignment.
LEA-6R default SPI clock is 870 kHz. As LEA-4R default value is 460 kHz, migrating from LEA-4R to LEA-6R
will require a bandwidth verification of the SPI circuits and shall be designed for a bandwidth of 4 MHz.
2.2.3.2
Gyroscope requirements
Gyroscopes should meet the requirements listed below:
Parameter
Specification
Supply Voltage
5.0 V ± 0.25 V
Zero Point
2.5 V ± 0.4 V
Scale Factor
25 mV/(°/s) ± 5 mV/(°/s)
Dynamic Range
±60 °/s to ±125 °/s
Linearity
±0.5 % (full scale)
Recommended operating temperature range
-40 to +85°C
Table 9: Requirements for gyroscopes
Follow the gyroscope manufacturer design recommendations for proper analog signal conditioning.
