Ublox LENA-R8 Series, Руководство по системной интеграции

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LENA-R8 series - System integration manual
UBX-22015376 - R02 Design-in Page 83 of 116
C1-Public
Reference Description Part number - manufacturer
R1
47 k  Resistor
Various Manufacturers
R2, R4, R5 10 k  Resistor Various Manufacturers
R3 100 k  Resistor Various Manufacturers
T1 P-Channel MOSFET Low On-Resistance IRLML6401 - International Rectifier or
NTZS3151P - ON Semi
T2 NPN BJT Transistor BC847 - Infineon
C1 100 nF Capacitor Ceramic Various Manufacturers
Table 44: Components for connecting LENA-R8 series modules to u-blox 1.8 V GNSS receivers using V_INT as supply
For additional guidelines regarding the design of applications with u-blox 1.8 V GNSS receivers, see
the Integration Manual of the selected u-blox GNSS receiver. It is recommended to consider and
implement all the possible measures for proper RF coexistence of the Cellular and the GNSS systems.
Connection with u-blox 3.0 V GNSS receivers (LENA-R8001 modules only)
Figure 64 shows an application circuit for connecting the module to a u-blox 3.0 V GNSS receiver:
•
The 1.8 V pins SDA and SCL of the cellular module are connected to the related pins of the u-blox
3.0 V GNSS receiver using a proper I2C-bus Bidirectional Voltage Translator (as the TI TCA9406),
with pull-up resistors where appropriate.
• The GPIO2 is connected to the active-high enable pin of the voltage regulator that supplies the
u-blox 3.0 V GNSS receiver providing the “GNSS supply enable” function. A pull -down resistor is
provided to avoid a switch-on of the positioning receiver when the cellular module is switched off.
• The 1.8 V pin GPIO3 of the cellular module is connected to the related pin of the u-blox 3.0 V GNSS
receiver implementing the “GNSS Tx data ready” function using a proper Unidirectional Voltage
Translator (as the TI SN74AVC2T245).
u-blox M10 GNSS
3.0 V receiver
24
GPIO3
1V8
B1 A1
GND
U3
B2 A2
VCCB VCCA
Unidirectional
Voltage Translator
C4 C5
3V0
TxD
R1
IN OUT
LDO Regulator
SHDNn
R2
VMAIN 3V0
U1
23
GPIO2
26
SDA
27 SCL
1V8
SDA_A SDA_B
GND
U2
SCL_A SCL_B
VCCA VCCB
I2C-bus Bidirectional
Voltage Translator
4 V_INT
C1
C2 C3
R3
SDA
SCL
VCC
DIR1
DIR2 OEn
OE
GNSS Tx data ready
GNSS supply enabled
GND
LENA-R8001
GND GND
R4 R5
Figure 64: Application circuit for connecting LENA-R8001 modules to u-blox 3.0 V GNSS receivers
Reference Description Part number - manufacturer
R1, R2, R4, R5 10 k  Resistor Various Manufacturers
R3 47 k  Resistor Various Manufacturers
C2, C3, C4, C5 100 nF Capacitor Ceramic Various Manufacturers
U1, C1 Voltage Regulator for GNSS receiver and related
output bypass capacitor See GNSS receiver Hardware Integration Manual
U2 I2C-bus Bidirectional Voltage Translator TCA9406DCUR 11 - Texas Instruments
U3 Unidirectional Voltage Translator
SN74AVC2T245 11 - Texas Instruments
Table 45: Components for connecting LENA-R8001 modules to u-blox 3.0 V GNSS receivers
11 Voltage Translator providing the partial power down feature for back-drive protection.