MULTI TECH 92U13A16858 MultiConnect xDot MTXDOT Developer Instruction Manual

MULTI TECH 92U13A16858 MultiConnect xDot MTXDOT Developer

Micro Developer Board LEDs

the top assembly diagram).

Chapter 11 Developer Board Schematics

Assembly Diagrams and Schematics
Top:
Diagram showing the top view of the developer board with various components labelled, including U8, JP1, JP2, JP3, JP5, TP1, TP2, TP3, TP4, TP5, J1, S1, S2, R30, R33, R34, R44, C30, C34, U14, LED1, LED2, LED3, LED4, F1D1, F1D2, and P30.

Note: R30 sits on L1, C34 sits on L1.

Bottom
Diagram showing the bottom view of the developer board with various components labelled, including U5, U6, U7, Y1, Y2, R1, R2, R3, R4, R5, R6, R10, R11, R12, R13, R16, R17, R18, R20, R21, R22, R23, R32, R33, R40, R41, R42, R43, C1, C2, C3, C4, C5, C6, C7, C10, C11, C12, C13, C14, C15, C18, C20, C21, C31, C32, C33, F1D1, F1D4, E1, and TP1.

Schematics

Detailed schematic diagrams of the developer board showing the connections and components. The schematics include various sections such as power supply, microcontroller, sensors, and communication interfaces.

Chapter 12 Design Considerations

Noise Suppression Design
Adhere to engineering noise-suppression practices when designing a printed circuit board (PCB). Noise suppression is essential to the proper operation and performance of the modem and surrounding equipment.

Any OEM board design must consider both on-board and off-board generated noise that can affect digital signal processing. Both on-board and off-board generated noise that is coupled on-board can affect interface signal levels and quality. Noise in frequency ranges that affect modem performance is of particular concern.

On-board generated electromagnetic interference (EMI) noise that can be radiated or conducted off-board is equally important. This type of noise can affect the operation of surrounding equipment. Most local government agencies have certification requirements that must be met for use in specific environments.

Proper PC board layout (component placement, signal routing, trace thickness and geometry, and so on) component selection (composition, value, and tolerance), interface connections, and shielding are required for the board design to achieve desired modem performance and to attain EMI certification.

Other aspects of proper noise-suppression engineering practices are beyond the scope of this guide. Consult noise suppression techniques described in technical publications and journals, electronics and electrical engineering text books, and component supplier application notes.

PC Board Layout Guideline

In a 4-layer design, provide adequate ground plane covering the entire board. In 4-layer designs, power and ground are typically on the inner layers. Ensure that all power and ground traces are 0.05 inches wide. The recommended hole size for the device pins is 0.036 in. +/-0.003 in. in diameter. Use spacers to hold the device vertically in place during the wave solder process.

Electromagnetic Interference

The following guidelines are offered specifically to help minimize EMI generation. Some of these guidelines are the same as, or similar to, the general guidelines. To minimize the contribution of device-based design to EMI, you must understand the major sources of EMI and how to reduce them to acceptable levels.

• Keep traces carrying high-frequency signals as short as possible.
• Provide a good ground plane or grid. In some cases, a multilayer board may be required with full layers for ground and power distribution.
• Decouple power from the ground with decoupling capacitors as close to the device’s power pins as possible.
• Eliminate ground loops, which are unexpected current return paths to the power source and ground.
• Decouple the telephone line cables at the telephone line jacks. Typically, use a combination of series inductors, common mode chokes, and shunt capacitors.
• Methods to decouple telephone lines are similar to decoupling power lines; however, telephone line decoupling may be more difficult and deserves additional attention.
• A commonly used design aid is to place footprints for these components and populate them as necessary during performance/EMI testing and certification.
• Decouple the power cord at the power cord interface with decoupling capacitors. Methods to decouple power lines are similar to decoupling telephone lines.
• Locate high-frequency circuits in a separate area to minimize capacitive coupling to other circuits.
• Locate cables and connectors to avoid coupling from high-frequency circuits.
• Lay out the highest frequency signal traces next to the ground grid.
• If using a multilayer board design, make no cuts in the ground or power planes and be sure the ground plane covers all traces.
• Minimize the number of through-hole connections on traces carrying high-frequency signals.
• Avoid right-angle turns on high-frequency traces. Forty-five-degree corners are good; however, radius turns are better.
• On 2-layer boards with no ground grid, provide a shadow ground trace on the opposite side of the board to traces carrying high-frequency signals.
• This will be effective as a high-frequency ground return if it is three times the width of the signal traces.
• Distribute high-frequency signals continuously on a single trace rather than several traces radiating from one point.

Electrostatic Discharge Control

Handle all electronic devices with precautions to avoid damage due to static charge accumulation. See the ANSI/ESD Association Standard (ANSI/ESD S20.20-1999) – a document “for the Development of an Electrostatic Discharge Control for Protection of Electrical and Electronic Parts, Assemblies and Equipment.” This document covers ESD Control Program Administrative Requirements, ESD Training, ESD Control Program Plan Technical Requirements (grounding/bonding systems, personnel grounding, protected areas, packaging, marking, equipment, and handling), and Sensitivity Testing.

MultiTech strives to follow these recommendations. Input protection circuitry is incorporated in MultiTech devices to minimize the effect of static buildup. Take precautions to avoid exposure to electrostatic discharge during handling. MultiTech uses and recommends that others use anti-static boxes that create a Faraday cage (packaging designed to exclude electromagnetic fields). MultiTech recommends that you use our packaging when returning a product and when you ship your products to your customers.

Chapter 13 Mounting slots and Programming External Targets

Mounting the Device on Your Board
A footprint diagram is included on the xDot Mechanical Diagram.

Solder Profile
Solder Paste: SAC NC 254
Note:  Calculate slope over 120 seconds

Graph showing the solder profile with temperature (Celsius) on the Y-axis and time (seconds) on the X-axis. The graph depicts the temperature rise, soak time, peak temperature, and cooling phases.

FAQS

Q: What is the purpose of the LED indicators on the Micro Developer Board?

 A: The LED indicators provide information about the board’s status, including power, programming status, and proximity sensor activity.

Q: What are the recommended guidelines for PC board layout to minimize EMI?

 A: Ensure adequate ground plane coverage, keep high frequency traces short, use decoupling capacitors, avoid ground loops, and follow other detailed guidelines provided in the document.

Q: How should electronic devices be handled to prevent electrostatic discharge damage?

 A: Handle devices with precautions, use anti-static packaging, and follow the ANSI/ESD Association Standard guidelines.

Q: What is the recommended solder profile for mounting xDots?

 A: Use SAC NC 254 solder paste, follow the specified temperature and time limits for rising slope, falling slope, soak time, peak temperature, and total time above 218C.

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