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MN1818 Design Guidelines
1
Introduction
This document contains important technical information, design notes and helpful hints to assist the
designer in achieving first time success in bringing up a design using the MN1818 GPS Receiver
module. It contains design examples and suggestions on a wide variety of topics, including power
supply connections, special reset circuit requirements, RF interface, shielding and filtering
requirements, antenna considerations and other important subjects.
2
Power Supply
The MN1818 GPS Receiver Module is designed to operate from a single 3V power supply. Either a
switching power supply or a linear supply can be used to provide the 3V power. Sufficient decoupling
on the power supply is necessary to ensure good performance. It is recommended that the 3V power
supply be filtered by a 10uF tantalum capacitor. The decoupling capacitor should be placed as close
as possible to the module's power supply pin.
If a switching power supply is used, it may be necessary to increase the value of the tantalum
capacitor to eliminate switching power supply ripple.
It should be noted that the DC supply must be clean. If there is any coupled AC noise (particularly
centered around L1), it is carried directly into the input of the MN1818 and could reduce the
sensitivity.
2.1
Ground Plane
To ensure optimal RF performance, the user should provide a solid ground plane underneath the
module. Sufficient via holes on this ground plane should be used to connect to the main board
ground plane.
The module does not use separate grounding for RF, power and digital signals. It is NOT
recommended that the user split the ground plane connecting the module to the power supply. This
is because if the user may introduce unwanted ground loops if separate RF ground and power
ground is used.
3
Reset Circuit Requirements
¯ ¯ ¯ ¯ ¯ ¯ pin must be held low until 10 milliseconds after the 3-volt power supply has stabilized to
The RESET
within proper tolerance. The RESET
or on power down to prevent corruption of flash memory contents.
Micro Modular Technologies Pte. Ltd.
No. 3, Ubi Avenue 3, #05-01 Crocodile House 408857 Singapore
Tel: 65-6745-8832 Fax: 65-6293-0661 Email: sales@micromodular.com.sg
¯ ¯ ¯ ¯ ¯ ¯ pin must be pulled low before power drops below specification
www.micro-modular.com
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Table of Contents
Summary of Contents for Micro Modular Technologies MN1818
- Page 1 Power Supply The MN1818 GPS Receiver Module is designed to operate from a single 3V power supply. Either a switching power supply or a linear supply can be used to provide the 3V power. Sufficient decoupling on the power supply is necessary to ensure good performance.
- Page 2 The antenna supply voltage is not switched during sleep mode. The MN1818 will awaken from sleep mode whenever a transition occurs on the RX0 or RX1 input pin. Thus it is possible to send a NMEA command to waken the MN10818, but as the first character is lost (the first transition is actually lost to the software), the receiver will awaken, but not respond to the command.
- Page 3 The internal RTC does not maintain time when the RESET it maintain time when power is removed to the MN1818. If either of these conditions is a requirement to maintain time, the MN1818 also supports the addition of an external RTC circuit as shown in Figure 3.
- Page 4 27 pF capacitor to ground. Shielding and Filtering Requirements The MN1818 is designed to receive a GPS signal that can be as low as -150 dBm. Any source of interference near in frequency to the GPS signal could potentially jam the MN1818 and disrupt reception of the signal.
- Page 5 In this case, a suitable filter must be placed on the output of the power amplifier of the collocated transmitter to avoid this case. Layout Considerations In order to get the optimal performance from the MN1818 GPS receiver module there are a few points that the user should note when designing the layout. Solid Ground Plane It is necessary to provide a solid ground plane below the module.
- Page 6 The antenna vendor can tune the antenna to compensate for this detuning. Micro Modular Technologies Pte. Ltd. Page 6 of 8 No.
- Page 7 The antenna vendor can provide assistance in this area and can possibly tune the chip for a specific application. Figure 6 – Chip Antenna Micro Modular Technologies Pte. Ltd. Page 7 of 8 No. 3, Ubi Avenue 3, #05-01 Crocodile House 408857 Singapore www.micro-modular.com...
- Page 8 Micro Modular Technologies Pte. Ltd. assumes no liability resulting from errors or omissions in these, or any document, or from the use of the information contained herein. Micro Modular Technologies Pte.
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