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Last Updated on : 2021-11-19 06:23:08download
GUC400 is a GNSS positioning module that Tuya has developed. It applies to car navigation, outdoor positioning, and survey and mapping products.
GUC400 is a positioning module with the ceramics passive antenna meeting the industry standard of 15 mm×15 mm×4 mm. It includes a highly integrated GNSS chip UFirebird-UC6226NIS and peripheral circuits. Besides, it is further built-in with a SAW filter, an LNA, a 26-MHz TCXO, an SPDT, and other components. The GUC400 module can detect the working status of the external active antenna, has a short-circuit protection mechanism, and can automatically switch between the passive antenna and the active antenna, to ensure fast and precise positioning. It supports both the GPS and Beidou system, to offer users efficient and convenient positioning experiences.
|Update date||Updated content||Version after update|
|11/12/2021||This is the first release.||V1.0.0|
GUC400 has 2 lines of pins with a 1.54-mm pin spacing. Each line has 12 pins.
The dimensions of GUC400:
Thickness of PCB: 0.8±0.1 mm
|Pin number||Symbol||Signal type||Description|
|1||RXD||I||Serial interface for receiving data, which is used to input PMTK/PQ commands and upgrade firmware|
|2||TXD||O||Serial interface for transmitting data, which is used to output NMEA sentences|
|4||VCC||PI||The interface of the main power supply|
|5||V_BCKP||PI||The interface of the backup power supply|
|6||1PPS||O||PPS stands for Pulse Per Second|
|8||ADET_N||O||The interface for detecting the working status of the external active antenna. If not used, disconnected.|
|10||RST||I||Reset pin. Low active.|
|11||EX_ANT||I||The interface for inputting RF signals of the external active antenna. If not used, disconnected.|
Note: P indicates a power supply pin and I/O indicates an input/output pin.
|Parameter||Description||Minimum value||Maximum value||Unit|
|ESD voltage (human body model)||TAMB-25℃||–||TBD||KV|
|ESD discharge voltage (machine model)||TAMB-25℃||–||TBD||KV|
|Parameter||Description||Minimum value||Typical value||Maximum value||Unit|
|Operating mode||Type||Average value||Peak value (typical value)||Unit|
Note: The test voltage for
VDCDC_INis 3.3 V and the latest firmware version R22.214.171.124 Build 6582. A built-in ceramics antenna is adopted.
|CN0||The signal strength of the stimulator: -130 dBm (AVG)||40±2||dBc|
|TTFF (the module is static state in the open environment)||Cold boot/hot start/recapture||30/1.2/2||s|
|Sensitivity test||Capture sensitivity/tracking sensitivity||-145/-158||dBm|
|Positioning precision||Remain static in the open area CEP50||2.5||m|
|Internal passive ceramics antenna||Characteristic impedance of 50 Ω, a gain of 1.5dB, VSWR≤1.5||–||–|
|External active antenna||Antenna provided by the third party with the characteristic impedance of 50Ω||–||–|
By default, the GUC400 module receives signals in the frequency band GPS L1 (1575.42 Mhz) and frequency band BDS B1 (1561 MHz). The module has a passive ceramics antenna of 15 mm×15 mm×4 mm. Meanwhile, it also supports the external active antenna. The module can automatically switch between the two antennas with the internal SPDT.
The GUC400 module has a passive ceramics antenna with the specifications of 15 mm×15 mm×4 mm. Its performance is critical to the reception sensitivity of the whole GNSS. The specifications of the antenna of module GUC400 are as follows:
|Frequency range of receiving||1561-1575 ± 2.5 MHz||Central frequency1568 ± 3 MHz|
|Characteristic impedance||50 Ω||–|
|Band width||Min. 20 MHz||Return loss ≤ -10 dB|
|Frequency temperature coefficient||0 ± 10 ppm /℃||-40 ℃ to 85 ℃|
|Polarization||RHCP||Right hand circular polarization|
|Gain||Typ. 1.5 dBi||–|
|Axial ratio||Max. 5 dB||–|
The test results of the antenna are as follows:
The radiation performance of the antenna is easily affected by various factors, such as the size and shape of the PCB, and the dielectric constant of the components near the antenna. Please follow the following advice during the layout of the PCB:
The module should be at least 5mm away from the edge of the mother board. You’d better put it at the centre of the mother board.
It is recommended that you make a hole at the connection point of the mother board and the antenna of the module. The diameter of the hole should be not less than 2.5 mm.
It must be ensured that the antenna faces the sky without shading.
The performance of the ceramics passive antenna is affected by the size of the ground around it. So you’d better maintain a complete ground with the size of 30 mm × 30 mm under the antenna, which is shown below: Moreover, you should not put another component (especially a large component or a component that has the radiation and interference capability) and make another hole in the ground.
The distance between the antenna and elements that have a metal housing and are high enough should not be less than 10 mm.
The MCU, crystal, LCD, camera, and other high-speed components and interfaces should be placed in the opposite direction of the module and kept away from the module as much as possible.
The wiring of the USB, LCD, camera, and crystal and the hole should be at the inner layer of the mother board and separated from the module with the ground. That is, keep away from the module as much as possible.
The DCDC must keep away from the module.
The housing of devices (especially the materials around the antenna) should be made of non-metal materials, and the distance between it and the antenna should be at least 3 mm.
As the RF part of the GNSS module is sensitive to temperature, the module should keep away from the heating source.
The connection between the external active antenna and the GUC400 module is designed as below: The DC in the EX_ANT pin of the module can be directly supplied to the external active antenna. In this design, the RF link should be as short as possible, and the characteristics impedance should be strictly controlled at 50 Ω. R1, C1, and C2 are reserved for impedance matching. By default, C1 and C2 are NC, and R1 is 0R. It should be noted that R1 mustn’t be a capacitor, because the current flows to the antenna via R1; and the C1 and C2 cannot be inductance or resistance, to avoid short circuit.
|Active antenna||Recommended specifications|
|Operating frequency||L1: 1575.42±1.023 MHz; B1: 1561±2.046 MHz|
|Band width||> 20 MHz|
|Characteristic impedance||50 Ω|
|Noise factor||≤ 1.5|
|Gain (Ceramics antenna)||5 dBic (Put onto a test mother board of 70 mm×70 mm)|
|Gain (Internal LNA)）||28±3 dB|
|Current consumption||9±3 mA (3.3V)|
The GUC400 module can detect the status of the external active antenna, and switch between the internal and external antennas according to the status of the external antenna. You can query the status of the external active antenna by sending $ANTSTAT sentences to the module via the UART interface.
|Status of the external antenna||OPEN_DET||SHORT_DET||Level of Pin ADET_N (Control via SPDT)||Message returned by the module|
|Open circuit||1||0||1 (Switch to the internal antenna)||$ANTSTAT,1,0|
|Short circuit||0||1||1 (Switch to the internal antenna)||$ANTSTAT,0,1|
|Normal||0||0||0 (Switch to the external antenna)||$ANTSTAT,0,0|
- If the module returns the sentence of $ANTSTAT,1,0, it indicates that the external antenna is not connected or falsely soldered, and the module will automatically switch to the internal ceramics passive antenna.
- If the module returns the sentence of $ANTSTAT,0,1, it indicates that the external antenna is short-circuited, and the module will automatically switch to the internal ceramics passive antenna and cut off the power supplied from the EX_ANT pin.
- If the module returns the sentence of $ANTSTAT,0,0, it indicates that the external antenna is normal and the module will automatically switch to the external antenna.
Mechanical dimensions of GUC400 (unit: mm)
Note: The default outline dimension tolerance is ±0.35 mm, and the critical dimension tolerance is ±0.1 mm. If you have specific requirements on dimensions, make them clear in the module datasheet after communication.
Bottom view of GUC400 (unit: mm)
Recommended footprint (unit: mm)
The moisture-proof bag must be placed in an environment where the temperature is below 40°C and the relative humidity is lower than 90%.
The shelf life of a dry-packaged product is 12 months from the date when the product is packaged and sealed.
There is a humidity indicator card (HIC) in the packaging bag.
Set oven temperatures according to the following temperature curve of reflow soldering. The peak temperature is 245°C.
A: Temperature axis
B: Time axis
C: Liquidus temperature: 217 to 220°C
D: Ramp-up slope: 1 to 3°C/s
E: Duration of constant temperature: 60 to 120s; the range of constant temperature: 150 to 200°C
F: Duration above the liquidus: 50 to 70s
G: Peak temperature: 235 to 245°C
H: Ramp-down slope: 1 to 4°C/s
Note: The above curve is just an example of the solder paste SAC305. For more details about other solder pastes, please refer to Recommended oven temperature curve in the solder paste specifications.
|Product model||MOQ (pcs)||Shipping packaging method||The number of modules per reel||The number of reels per carton|
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