Unicore UM980 User Manual

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Foreword

This document describes the information of the hardware, package, specification and the use of Unicore UM980 modules.

Target Readers

This document applies to technicians who possess the expertise on GNSS receivers.

Contents

1 Introduction

• 1.1 Key Features
• 1.2 Key Specifications
• 1.3 Block Diagram

2 Hardware

• 2.1 Pin Definition
• 2.2 Electrical Specifications
• 2.3 Dimensions

3 Hardware Design

• 3.1 Recommended Minimal Design
• 3.2 Antenna Feed Design
• 3.3 Power-on and Power-off
• 3.4 Grounding and Heat Dissipation
• 3.5 Recommended PCB Package Design

4 Production Requirement

5 Packaging

• 5.1 Label Description
• 5.2 Product Packaging

1 Introduction

UM980 is a new generation of GNSS high precision RTK positioning module from Unicore. It supports all constellations and all frequencies, and can simultaneously track GPS, BDS, GLONASS, Galileo, QZSS, NavIC and SBAS. The module is mainly used in surveying and mapping, precise agriculture, UAVs, and autonomous robots.

UM980 is based on NebulasIV™, a GNSS SoC which integrates the RF-baseband and high precision algorithm. Besides, the SoC integrates a dual-core CPU, a high speed floating point processor and an RTK co-processor with 22 nm low power design, and it supports 1408 super channels. All these above enable stronger signal processing.

With the built-in JamShield adaptive anti-jamming technology, UM980 can fulfill a strengthening RTK engine solution of multi-mode multi-frequency, which ensures a good performance on RTK initialization speed, measurement accuracy and reliability even in the most challenging environments such as urban canyons and tree shades.

Furthermore, UM980 supports abundant interfaces such as UART, I²C*, SPI*, as well as 1PPS, EVENT, CAN*, which meets the customers' needs in different applications.

* I2C, SPI, CAN: reserved interfaces, not supported currently

1.1 Key Features

• Based on the new generation GNSS SoC -NebulasIV™, with RF-baseband and high precision algorithm integrated
• All-constellation multi-frequency RTK engine and advanced RTK processing technology
• Instantaneous RTK initialization technology
• 60 dB narrowband anti-jamming and jamming detection
• Heading2 technology to provide orientation information
• STANDALONE single-station high-precision positioning technology
• Supports B2b-PPP and E6-HAS

1.2 Key Specifications

Table 1-1 Technical Specifications

¹ Test results may be biased due to atmospheric conditions, baseline length, GNSS antenna type, multipath, number of visible satellites, and satellite geometry

² The measurement uses a 1 km baseline and a receiver with good antenna performance, regardless of possible errors of antenna phase center offset

³ After 20 minutes of convergence under open sky without jamming

Physical Characteristics

Environmental Specifications

Functional Ports

• UART × 3
• I²C* x 1
• SPI* x 1 Slave
• CAN* x 1 Shared with UART3

* I2C, SPI, CAN: reserved interfaces, not supported currently

1.3 Block Diagram

RF Part

The receiver gets filtered and enhanced GNSS signal from the antenna via a coaxial cable. The RF part converts the RF input signals into the IF signals, and converts IF analog signals into digital signals required for NebulasIV™ chip (UC9810).

NebulasIV™ SoC (UC9810)

NebulasIV (UC9810) is Unicore's new generation high precision GNSS SoC with 22 nm low power design, supporting all constellations all frequencies and 1408 super channels. It integrates a dual-core CPU, a high speed floating point processor and an RTK co-processor, which can fulfill the high precision baseband processing and RTK positioning independently.

2 Hardware

2.1 Pin Definition

⁷ Not recommended to take VCC_RF as ANT_BIAS to feed the antenna. See section 3.2 for more details.

2.2 Electrical Specifications

2.2.1 Absolute Maximum Ratings

2.2.2 Operating Conditions

⁸ The voltage range of VCC (3.0 V ~ 3.6 V) has already included the ripple voltage.

⁹ Since the product has capacitors inside, inrush current occurs during power-on. You should evaluate in the actual environment in order to check the effect of the supply voltage drop caused by inrush current in the system.

2.2.3 IO Threshold

2.2.4 Antenna Feature

2.3 Dimensions

Table 2-6 Dimensions

3 Hardware Design

3.1 Recommended Minimal Design

L1: 68 nH RF inductor in 0603 package is recommended

C1: 100 nF + 100 pF capacitors connected in parallel is recommended

C2: 100 pF capacitor is recommended

C3: N * 10 µF + 1 * 100 nF capacitors connected in parallel is recommended, and the total inductance should be no less than 30 μF

R1: 10 kΩ resistor is recommended

3.2 Antenna Feed Design

UM980 just supports feeding the antenna from the outside of the module rather than from the inside. It is recommended to use devices with high power and that can withstand high voltage. Gas discharge tube, varistor, TVS tube and other high-power protective devices may also be used in the power supply circuit to further protect the module from lightning strike and surge.

If the antenna feed supply ANT_BIAS and the module's main supply VCC use the same power rail, the ESD, surge and overvoltage from the antenna will have an effect on VCC, which may cause damage to the module. Therefore, it is recommended to design an independent power rail for the ANT_BIAS to reduce the possibility of module damage.

Notes:

• L1: feed inductor, 68 nH RF inductor in 0603 package is recommended
• C1: decoupling capacitor, recommended to connect two capacitors of 100 nF/100 pF in parallel
• C2: DC blocking capacitor, recommended 100 pF capacitor
• It is not recommended to take VCC_RF as ANT_BIAS to feed the antenna (VCC_RF is not optimized for anti-lightning strike, anti-surge and over current protection due to the compact size of the module)
• D1: ESD diode, choose the ESD protection device that supports high frequency signals (above 2000 MHz)
• D2: TVS diode, choose the TVS diode with appropriate clamping specification according to the requirement of feed voltage and antenna withstand voltage

3.3 Power-on and Power-off

VCC

• The VCC initial level when power-on should be less than 0.4 V.
• The VCC ramp when power-on should be monotonic, without plateaus.
• The voltages of undershoot and ringing should be within 5% VCC.
• Power-on time interval: The time interval between the power-off (VCC < 0.4 V) to the next power-on must be larger than 500 ms.

V_BCKP

• The V_BCKP initial level when power-on should be less than 0.4 V.
• The V_BCKP ramp when power-on should be monotonic, without plateaus.
• The voltages of undershoot and ringing should be within 5% V_BCKP.
• Power-on time interval: The time interval between the power-off (V_BCKP < 0.4 V) to the next power-on must be larger than 500 ms.

3.4 Grounding and Heat Dissipation

The 48 pads in the rectangle in Figure 3-3 are for grounding and heat dissipation. In the PCB design, the pads should be connected to a large sized ground to strengthen the heat dissipation.

3.5 Recommended PCB Package Design

See the following figure for the recommended PCB package design.

Notes:

For the convenience of testing, the soldering pads of the pins are designed long, exceeding the module border much more. For example:

• The pads denoted as detail C are 1.79 mm longer than the module border.
• The pad denoted as detail A is 0.50 mm longer than the module border. It is relatively short as it is an RF pin pad, so we hope the trace on the surface is as short as possible to reduce the impact of external interference on the RF signals.

4 Production Requirement

Recommended soldering temperature curve is as follows:

Temperature Rising Stage

• Rising slope: Max. 3 °C/s
• Rising temperature range: 50 °C ~ 150 °C

Preheating Stage

• Preheating time: 60s ~ 120 s
• Preheating temperature range: 150 °C ~ 180 °C

Reflux Stage

• Over melting temperature (217 °C) time: 40s ~ 60 s
• Peak temperature for soldering: no higher than 245 °C

Cooling Stage

• Cooling slope: Max. 4 °C / s

In order to prevent falling off during soldering of the module, do not solder it on the back of the board during design, and it is not recommended to go through soldering cycle twice.

The setting of soldering temperature depends on many factors of the factory, such as board type, solder paste type, solder paste thickness etc. Please also refer to the relevant IPC standards and indicators of solder paste.

Since the lead soldering temperature is relatively low, if using this method, please give priority to other components on the board.

The opening of the stencil needs to meet your design requirement and comply with the examine standards. The thickness of the stencil is recommended to be 0.15mm.

5 Packaging

5.1 Label Description

5.2 Product Packaging

The UM980 module uses carrier tape and reel (suitable for mainstream surface mount devices), packaged in vacuum-sealed aluminum foil antistatic bags, with a desiccant inside to prevent moisture. When using reflow soldering process to solder modules, please strictly comply with IPC standard to conduct temperature and humidity control on the modules. As packaging materials such as the carrier tape can only withstand the temperature of 55 degrees Celsius, modules shall be removed from the package during baking.

Note:

• The cumulative tolerance of 10 side holes should not exceed ±0.2 mm.
• Material of the tape: Black antistatic PS (surface impedance 10⁵-10¹¹) (surface static voltage <100 V), thickness: 0.35 mm.
• Total length of the 13-inch reel package: 6.816 m (Length of the first part of empty packets: 0.408 m, length of packets containing modules: 6 m, length of the last part of empty packets: 0.408 m).
• Total number of packets in the 13-inch reel package: 284 (Number of the first part of empty packets: 17; actual number of modules in the packets: 250; number of the last part of empty packets: 17).
• All dimension designs are in accordance with EIA-481-C-2003.
• The maximum bending degree of the carrier tape within the length of 250 mm should not exceed 1 mm (see the figure below).

Before surface mounting, make sure that the color of the 30% circle on the HUMIDITY INDICATOR is blue (see Figure 5-4). If the color of the 20% circle is pink and the color of the 30% circle is lavender (see Figure 5-5), you must bake the module until it turns to blue. The UM980 is rated at MSL level 3. Please refer to the IPC/JEDEC J-STD-033 standards for the package and operation requirements. You may also access to the website www.jedec.org to get more information.

The shelf life of the UM980 module packaged in vacuum-sealed aluminum foil antistatic bags is one year.