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LEON-G100/G200 - System Integration Manual

GSM.G1-HW-09002-C Preliminary Design-In

Page 51 of 75

2 Design-In

This section provides a design-in checklist.

2.1 Schematic design-in checklist

The following are the most important points for a simple design-in check:

 VCC supply should be capable of delivering 2.5 A current bursts with low voltage drop.

 VCC supply should be clean, with very low ripple and noise.

 Do no connect DC/DC regulator output and Battery Pack on VCC, they are mutually exclusive.

 V_CHARGE and CHARGE_SENSE must be externally shorted (LEON-G200 only).

 The DC supply used as charger must be current limited as specified (LEON-G200 only).

 Do no leave POWER_ON floating: add a pull-up resistor.

 Insert a series inductor on each microphone lines and a 27 pF bypass capacitor on each audio line.

 Capacitance must be limited on each SIM signal to match the SIM specifications.

 Check that voltage level of connected digital pins does not exceed operating range.

 Check UART signals direction, since the signal names follow the ITU-T V.24 Recommendation.

 Add a proper pull-up resistor on each line of the DDC interface.

 Capacitance must be limited on each line of the DDC interface.

 Check the matching of the digital audio interface specifications to connect a proper device (LEON-G200

only).

 For debug purposes, add a test point on each I2S pin and on GPIO1 also if they are not used.

 To avoid an increase of module current consumption in power down mode, any external signals

connected to the module digital pins (UART interface, Digital Audio Interface, HS_DET, GPIOs) must be

set low or tri-stated when the module is in power down mode.

Layout:

 Check 50 Ω impedance of ANT line.

 Ensure no coupling occurs with other noisy or sensitive signals.

 VCC line should be wide and short.

 Route VCC supply line away from sensitive analog signals.

 Avoid coupling of any noisy signals to microphone inputs lines.

 Ensure proper grounding.

 Consider “No-routing” areas for the Data Module footprint.

 Optimize placement for minimum length of RF line and closer path from DC source for VCC.

Antenna:

 Antenna should have 50 Ω impedance, V.S.W.R less then 3:1, recommended 2:1 on operating bands in

deployment geographical area.

 Antenna should have built in DC resistor to ground to get proper Antenna detection functionality.

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MaxTech NXP-16 Dokumentacja Strona 51