MAX7474EVKIT+;中文规格书,Datasheet资料

General Description

The MAX7474 evaluation kit (EV kit) is a fully assem-bled and tested printed-circuit board (PCB) that config-ures the MAX7474 IC for automatically equalizing a baseband composite video input signal from low-cost,unshielded twisted pair (UTP) such as Category 5e (Cat 5e) cable.

The MAX7474 EV kit operates from a single 5V DC power supply. The EV kit accepts differential video input signals and provides a single-ended output. The EV kit features loss-of-sync and loss-of-burst outputs and also provides an option to set the video output sig-nal’s back-porch DC level.

Features

?Single 5V DC Power-Supply Operation

?Differential Video Input

?Single-Ended AC- or DC-Coupled Output ?Fully Equalized for Up to 300m of Cat 5e Cable ?Improved Signal Quality for Up to 600m of Cat 5e Cable ?Fixed Cable-Length Equalization in the Absence of Burst ?Adjustable Back-Porch DC Level

?Loss-of-Burst (LOB) and Loss-of-Sync (LOS)Outputs ?Evaluates the MAX7474 IC in 16-Pin SSOP Package

?Fully Assembled and Tested

Evaluates: MAX7474

MAX7474 Evaluation Kit

19-4040; Rev 0; 2/08

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,or visit Maxim’s website at https://www.sodocs.net/doc/478074422.html,.

Ordering Information

+Denotes lead-free and RoHS-compliant.

E v a l u a t e s : M A X 7474

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Quick Start

Required Equipment

Before beginning, the following equipment is needed:?5V, > 100mA DC power supply

?Video signal generator (e.g., Tektronix TG -700 or equivalent)

?Video measurement equipment (e.g., Tektronix VM-700T or equivalent)?Active differential cable driver

Procedure

The MAX7474 EV kit is fully assembled and tested.Follow the steps below to verify board operation.Caution: Do not turn on the power supply until all connections are completed.

1)Install a shunt across pins 2-3 of jumper JU1 and a

shunt across pins 1-2 of jumper JU2 (for ≥225m manual cable length equalization).2)Install a shunt across pins 1-2 of jumper JU3

(back-porch DC level set by R4).3)Verify that no shunt is installed on jumper JU4 (AC-coupled video output).

4)Connect the differential video input signal to the

VIN connector or the V_INP and VINN test points.5)Connect the VOUT BNC connector on the EV kit to

the input of the video measurement equipment.6)Connect the power-supply ground to the GND pad

on the EV kit.

7)Connect the 5V DC power supply to the VCC pad

on the EV kit.8)Set the video signal generator for the desired video

input signal.

9)Turn on the power supply and enable the video

signal generator output.

10)Analyze the video output signal with the video

measurement equipment.

Detailed Description of Hardware

The MAX7474 EV kit is designed to evaluate the MAX7474 in a 16-pin SSOP package. The MAX7474 is an adaptive equalizer for video over UTP cable. The EV kit circuit is designed on a 2-layer, 1oz copper PCB and all components are installed on the top layer. The MAX7474 EV kit operates from a 5V DC power supply that can deliver at least 100mA of current.

The MAX7474 EV kit accepts differential video input signals and provides a single-ended output nominal 1V P-P . A differential video input signal can be connect-ed to the VIN RJ-45 connector (pins 7-8), or the V_INP and V_INN test points on the MAX7474 EV kit. See Table 4 in the Jumper Selection section for the VIN RJ-45 connector pin configuration.

The MAX7474 EV kit automatically equalizes the base-band composite video signal from a low-cost UTP cable,and provides an option to set the fixed equalization level to compensate for different input cable lengths up to 300m in the absence of a burst signal. The MAX7474fixed equalization level is jumper selectable. See the Jumper Selection section for more details.

The MAX7474 EV kit provides an option to set the back-porch DC level for the video output signal. The video output’s back-porch DC level can be set by an on-board voltage reference (U2) or by an external volt-age source connected to the BP_LVL BNC connector.U2 is a MAX6037 voltage reference that provides an on-board 0 to 2.5V voltage reference for the back-porch DC level. Potentiometer R4 is used to set the back-porch DC level. The back-porch DC level is set to 1.4V at the factory. See the Jumper Selection section for more detail.

Jumper Selection

Fixed Equalization Level (FEQ0, FEQ1)

The MAX7474 EV kit provides an option to set the fixed equalization level for the video input signal to compen-sate for different cable lengths in the absence of burst.Jumpers JU1 and JU2 set the fixed equalization level pins (FEQ0 and FEQ1) of the MAX7474 IC. When using cable lengths greater than 75m, set the fixed equaliza-tion level according to Table 1.

Table 1. JU1 and JU2 Jumper Selection

Evaluates: MAX7474

MAX7474 Evaluation Kit

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Back-Porch DC Level (BPLVL)

The MAX7474 EV kit provides an option to set the back-porch DC level for the video output signal.Jumper JU3 selects the voltage source that sets the back-porch DC level for the MAX7474 BPLVL pin. See Table 2 for shunt positions.

Output Coupling (VOUT)

The MAX7474 EV kit provides an option to select the output coupling of the video output signal on the MAX7474 EV kit for AC- or DC-coupling. Jumper JU4selects the output coupling for the MAX7474 output.See Table 3 for shunt positions.

RJ-45 Connector Pin Configuration (VIN)

The MAX7474 EV kit provides an RJ-45 connector to accept a differential video input signal at the VIN RJ-45 connector. Table 4 lists the RJ-45 connector pin configuration.

The MAX7474 EV kit provides a 3-pin header to access the LOB and LOS status output signals and GND. The LOB outputs a logic-high when the color burst portion of the video signal is not detected at the input.Similarly, the LOS outputs a logic-high when the sync signal of the video signal is not detected at the input.Table 5 lists the header J1 pinout.

Table 2. JU3 Jumper Selection (BPLVL)

Table 5. Header J1 Pinout (LOB, LOS,GND)

Table 4. RJ-45 Connector Pin

E v a l u a t e s : M A X 7474

MAX7474 Evaluation Kit 4

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Figure 1. MAX7474 EV Kit Schematic

Evaluates: MAX7474

MAX7474 Evaluation Kit

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Figure 2. MAX7474 EV Kit Component Placement Guide—Component Side

Figure 3. MAX7474 EV Kit PCB Layout—Component Side

E v a l u a t e s : M A X 7474

MAX7474 Evaluation Kit Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

6_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600?2008 Maxim Integrated Products

is a registered trademark of Maxim Integrated Products, Inc.

Figure 4. MAX7474 EV Kit PCB Layout—Solder Side

分销商库存信息: MAXIM

MAX7474EVKIT+