Evaluation Printed Circuit Board

The AFBR-775BxxxZ/785BxxxZ transmit/receive pair are high-performance fiber optic modules manufactured for parallel data communication applications over 50/125 mm MM optical fiber. At data rates from 1 to 6.25 Gbps per channel these modules are suitable for applications requiring up to 75 Gbps aggregate bandwidth. Each transmitter/receiver pair completes a robust communication link across 150 meters of optical fiber useful in many datacom and telecom switch and router back-plane connections. 

This application note is intended for use in conjunction with the device data sheet for the respective transmit/receive pair, which is available from your Avago Technologies representative. The data sheet provides a detailed description of the modules operation, signal descriptions and maximum ratings. It is recommended that the block diagrams, pin definitions, and maximum ratings from the data sheet be reviewed prior to testing.

Recommended Equipment List
Test Equipment Included in Sample Kit:

• 12-Channel Pluggable Tx Evaluation Board
  
• 12-Channel Pluggable Rx Evaluation Board
  
• Avago Technologies AFBR-775BxxxZ/785BxxxZ Data Sheet
  
• Application Note 5304

Test Equipment Not Included in Sample Kit:

• 3.3 V dc -Power Supply(s) 2.5 V dc -Power Supply(s)
• 12-fiber Multimode Fiber Optic Ribbon Cable with MTP® Connectors
• 12-fiber Multimode Fiber Optic Breakout-Cable with MTP®-to-SC connectors
• 86100A Agilent Digital Communications Analyzer (DCA)
• Agilent 83487A Opt H21 DCA Plug-In (or equivalent)
• Agilent ParBERT 81250 (or equivalent Bit Error Rate Tester)
• Variable Fiber Optic Attenuator
• Optical Power Meter (multimode, 850nm capable)
• 81002FF Integrating Sphere Adapter (recommended High-frequency coaxial cables with SMA connectors (x48) 

Evaluation Board Description
Top views of the evaluation printed circuit boards are shown in Figures 9 and 10 near the end of this document. Descriptions of the test access points including the high-speed I/O connections and control and sense outputs are listed in Table 1 for the Transmitter and Table 2 for the Receiver. The evaluation boards are 6.4 x 5.15 in.(16.3 x 13.1cm) and are 4-layer PCB with Rogers on top layer dielectric.

Electrical connections from the modules to their respective evaluation PCB are achieved through a 100 pin (10x10) MEG-Array® plug-receptacle [4]. This high-density connector enables the user to easily interchange modules allowing testing of many device pairs using only one set of evaluation boards. The robust design of these pluggable modules allows for repeated plugging and unplugging of the modules up to 50 times without degradation in the receptacle electrical integrity.

Please note that these modules are electrically sensitive devices and are NOT intended for “hot-plug” applications. The power supply to the evaluation boards should be turned OFF prior to plugging or unplugging the devices. “Hot plugging” these devices is not recommended and may result in excessive voltage and or inrush current that exceeds the device limits and may cause damage.

These evaluation boards provide access to all transmit and receive high-speed I/O’s through straight PCB mount SMA connectors. All of the high-speed differential data I/O have 100 nF ac-coupling capacitors on the evaluation boards (ac-coupling is recommended for these modules). The power supplies (2.5V and 3.3V) can be applied through BNC connectors on each board.

Mating Directions

• Ensure the connector assemblies are clean and free of contaminants prior to mating. Locate and match the connector’s position marking (D) for both the Plug and Receptacle. Also ensure that the power (both 3.3V and 2.5V) are not turned on. This will result in the correct orientation of the modules with regard to the evaluation boards. Rough alignment is required prior to connector mating as misalignment of > 0.8 mm could damage the connector contacts. The receptacle is keyed for rough alignment. Application of mating forces should originate from one side of the connector then proceed to the other side of the connector. See Figure 1.

Figure 1  Mating Forces

Unmating Directions

• Release any fasteners holding the assembly together.
• Turn off the voltage to the module (both 2.5V and 3.3V ).
• Force applied during connector unmating needs to originate from the alignment slot/key end of the assembly.
• Unmating the connector perpendicular to the alignment slot/key may cause damage to the terminal contacts. See Figure 2. 

Figure 2  Un-Mating Forces

It should be noted that the transmitter and receiver modules are keyed in such a way that connecting a transmitter module to a receiver footprint or evaluation board and vice-versa is prevented.

To learn more about Evaluation Printed Circuit Board, click here.

Truck/Bus Harness Protection in 24V Battery Systems

TE Circuit Protection has developed overcurrent protections that can also be used as a protection for truck/bus harness. This application note discusses how overcurrent protection products of TE helps protect the wiring-harness architecture found in trucks, buses and other vehicles with electrical systems based on 24 V technology.

Optimized vehicle harness architecture has a hierarchical structure resembling that of a tree with its main power trunks dividing into smaller and smaller branches that use overcurrent protection at each node. Because a hierarchical architecture can use smaller wires and relays on its “smaller branches,” the resulting harness is smaller and lighter, resulting in a cost savings — both in materials and fuel. In addition, a hierarchical or distributed architecture can provide system protection together with fault isolation, thereby reducing warranty costs and increasing customer satisfaction.

Figure 1 shows a simplified version of a partially distributed architecture with each junction box either directly feeding a module or feeding another nodal module which supplies peripheral loads. Unfortunately the sheer number of circuits found in today’s vehicles has made the optimized system hard to realize in practice. With many tens of circuits emanating from the primary power distribution center, it has become almost impossible to position all the subsequent junction boxes so that they are readily accessible and close to the electronics they are intended to feed. 

Figure 1: In a partially distributed architecture, where a module supplies a number of peripheral loads, PPTC devices can allow shorter and smaller wires to be used. Door and HVAC module examples are shown here.

As a result, system designers have resorted to harness design solutions that negate some of the desired end-benefits, such as:

1. (1)  sacrificing wire size optimization and fault isolation by combining loads into one circuit;
   
2. (2)  locating electrical centers where they are only accessible by trained service personnel, at increased cost; and
   
3. (3)  routing back and forth between various functional systems, increasing wiring length, size and cost.

For example, due to the necessity for fuse accessibility, a conventional door module would have separate power feeds for windows, locks, LEDs (light emitting diodes) and mirror functions, each protected by a separate fuse in the junction box. By incorporating PolySwitch resettable PPTC (polymeric positive temperature coefficient) devices in the door module itself, a single power feed can be used. This helps save wire and reduce the cost and size of the junction box. 
 
Using a resettable circuit protection design that does not need to be driver accessible offers a number of solutions that can be used separately or in combination to better optimize harness designs. For example, a single junction box located in the instrument panel can still be employed. Instead of positioning the PPTC devices close to the conventional fuses on the front panel, they can be located inside the box, close to the connectors or on the bottom face of the box. This saves both frontal area as well as reducing the box’s volume, as shown in Figure 2. 

Figure 3 illustrates yet another advantage of replacing conventional fuses with resettable PolySwitch devices. Indeed, using a PPTC device in a dedicated manner (delocalized or not) can allow wire and relay downsizing, thus helping save cost, space and weight. 

To learn more about Truck/Bus Harness Protection, click here.

App Guide for Flat-Panel TV Sets

Your partner for flat-panel TV sets

NXP Semiconductors offers a wide portfolio of advanced solutions for flat-panel TV sets. All are built on our deep understanding of the needs of set designers and manufacturers, and of market requirements.

We can deliver application-specific solutions for reception, drawing on a complete range of silicon tuners that cover all the major standards for hybrid terrestrial, cable and satellite reception. We also support peripheral functions, such as advanced audio and HDMI interfaces, and provide an extensive portfolio of standard products for TVs.

We use next-generation packaging to save space, lower costs, and improve AV content security, and we reduce energy consumption with low-power technologies that dramatically increase efficiency. We design for ruggedness, supplying devices that stand up to intensive use, and we deliver the high integration needed to simplify development, lower BOM and production costs, and reduce time-to-market.

We are known for innovation and our ability to introduce new technologies that set the standard for performance, efficiency, and size. Our new chip-scale package (CSP) devices, for example, have an exceptionally compact footprint yet achieve a new benchmark in mechanical robustness.

We support our customers with a cost-efficient supply chain, and an enterprise-wide commitment to the highest standards of security, quality, and reliability. We also help our customers prepare for the future, by working with them to implement new features, such as 3D, that will drive growth. In short, our customers have the confidence that comes from working with a world-class partner.

 
Primary AC/DC controllers

<75 W flyback controller TEA1738 for primary control of small flat-panel TVs
The TEA1738 supports high-end regulation schemes. For designs that need less sophisticated flyback control, the TEA1733 is recommended.

Features:

• SMPS controller IC enabling low-cost applications
• Large input voltage range (12 to 30 V)
• Integrated OverVoltage Protection (OVP) on pin VCC
• Very low supply current during start-up and restart (typically 10 μA)
• Low supply current during normal operation (typically 0.55 mA without load)
• Overpower or high/low line compensation
• Adjustable overpower time-out
• Adjustable overpower restart timer
• Fixed switching frequency with frequency jitter to reduce EMI
• Frequency reduction at medium power operation to maintain high efficiency
• Frequency reduction with fixed minimum peak current
• Frequency increase at peak power operation
• Slope compensation for CCM operation
• Low and adjustable OverCurrent Protection (OCP) trip level
• Adjustable soft-start operation
• Two protection inputs (e.g. for input UVP and OVP, OTP and output OVP)
• IC overtemperature protection

Silicon tuners

Our portfolio supports compatibility with legacy transmission formats, by covering hybrid analog and digital terrestrial reception. We also support the latest digital standards, along with cable and free-to-air satellite reception. We offer the high performance required by TV set manufacturers, and our software drivers simplify design work even further.

All our tuners deliver excellent performance and are suitable for high-end analog/digital applications. Also, our products have been validated against major standards worldwide.


To learn more about this application guide, click here.

Class-Leading 16-bit Sensor Signal Conditioner

ZMDI is pleased to introduce a class-leading 16-bit sensor signal conditioner (SSC) IC for calibrating resistive sensor modules. The ZSSC3026 combines high-accuracy amplification, 16-bit precision analog-to-digital conversion and an 18-bit DSP for linearization and calibration functions. This high-resolution sensor interface application-specific standard product provides special features for battery-driven low-power devices, an ultra-low standby current and intelligent power-saving technology to ensure lowest overall current consumption. Designed initially for high resolution altimeter module applications, the ZSSC3026 is ideal for use in any device that requires high accuracy and low power consumption.

“Energy-efficiency is what we do best. We enhanced the basic ZSSC30×6-family to provide our customers with the resolution and accuracy required for their next generation products,” stated Frank Schulze, Business Line Manager for Sensing and Automotive at ZMDI. “Unlike many available products today, the ZSSC3026 includes internal signal correction and allows customers to minimize engineering efforts and costs.”

Well-suited for applications in mobile devices, the ZSSC3026 also supports high accuracy industrial and medical applications; e.g., ambient assisted living and industrial pressure sensors. Extended temperature range, 4kV ESD protection and an outstanding power supply rejection ratio (PSR) enable a wide range of products in harsh environments.



To learn more about ZSSC3026, click here.

Introducing the ZL8801 Digital Power Controller

ZL8800/ZL8801
PMBus™ ChargeMode™ Control DC/DC Digital PWM Controllers

The ZL8800 is a dual channel/dual phase controller that utilizes a ChargeMode™ control loop technology to deliver fast transient response without the need for compensation, reducing design time. It provides best-in-class transient response for digital Point of Loads (POLs), saving on output capacitance and board space, important benefits for the advanced power systems found in the latest generation of base-stations, routers, and similar infrastructure designs.

The ZL8801 digital power controller is a dual phase only version of the ZL8800, with added support for DDC current share (up to 4 devices, or 8 phases).

Used in conjunction with Intersil’s easy-to-use PowerNavigator™ GUI, the ZL8800 and ZL8801 digital controllers simplify system power conversion and speed the design process.


To learn more about ZL8800/ZL8801, click here.