Locosys MC-1612 Hardware Design Manual page 2

1 General Rules for Design-in
In order to obtain good GPS performances, there are some rules which require attentions for using
MC-1612 GPS module.
2 Circuit Design
2.1 Power supply VCC
It is necessary to provide a clean and stable power supply for our GPS module in order to obtain
good performances. Unstable power source may have a significant negative impact on the GPS
performance. To achieve this, the Vcc ripple must be controlled under 50mVpp. In addition, there
are also some suggestions for main power circuit design:
(1). Add a ferrite bead, power choke or low pass filter for power noise reduction
(2). linear regulator is better than switch DC/DC power supplier in ripple
(3). Use enough decoupling capacitors beside VCC for stable voltage.
2.2 V_BCKP backup battery
Backup power is used for keeping RTC running and navigation data after the main power was turn
off. For a short term VCC off, with backup power, the GPS module can have a faster TTFF, Time to
First Fix, or hot start when next power on.
It is recommended to connect the module V_BCKP to a sustained power source (ex: Li-Ion
rechargeable coin battery, super cap) for backup power. See figure for reference.
Using Coin Battery for GPS module
Note: 1. The V_BCKP pin must be supplied power to make the module function-able.
2. The sequence of V_BCKP and VCC power supply must comply with the following
conditions:
V_BCKP priority than VCC power is supplied.
V_BCKP and VCC's power is supplied at the same time.
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LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi Dist., New Taipei City 221, Taiwan
886-2-8698-3698
886-2-8698-3699
www.locosystech.com