ECLLQFP32EVB datasheet(5/22 Pages) ONSEMI

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ECLLQFP32EVB

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Evaluation Board Assembly Instructions

The 32-lead LQFP evaluation board is designed for

characterizing devices in a 50

W laboratory environment

using high bandwidth equipment. Each signal trace on the

board has a via, which has an option of placing a termination

resistor depending on the input/output configuration (see

Table 1, Configuration List). Table 17 contains the Bill of

Materials for this evaluation board.

Solder the Device on the Evaluation Board

The soldering can be accomplished by hand soldering or

soldering re-flow techniques. Make sure pin 1 of the device

is located next to the white dotted mark and all the pins are

aligned to the footprint pads. Solder the 32-lead LQFP

device to the evaluation board.

Connecting Power and Ground Planes

For standard ECL lab setup and test, a split (dual) power

supply is required enabling the 50

W internal impedance in

the oscilloscope to be used as a termination of the ECL

signals (VTT = VCC – 2.0 V, in split power supply setup, VTT

is the system ground, VCC is 2.0 V, and VEE is –3.0 V or

–1.3 V; see Table 2, Power Supply Levels).

Table 2. Power Supply Levels

Power Supply

VCC

VEE

GND

5.0 V

2.0 V

-3.0 V

0.0 V

3.3 V

2.0 V

-1.3 V

0.0 V

2.5 V

2.0 V

-0.5 V

0.0 V

Connect three banana jack sockets to VCC, VEE, and GND

labeled holes. Wire bond the appropriate device pin pad on

the bottom side of the board to VCC and VEE power stripes.

(Device specific, please see configuration for each desired

device. See Figure 5)

It is recommended to solder 0.01

mF capacitors to C4 and

C5 to reduce the unwanted noise from the power supplies.

C1, C2, and C3 pads are provided for 0.1

mF capacitor to

further diminish the noise from the power supplies. Adding

capacitors can improve edge rates, reduce overshoot and

undershoot.

Termination

All ECL outputs need to be terminated to VTT (VTT = VCC

–2.0 V = GND) via a 50

W resistor. 0402 chip resistor pads

are provided on the bottom side of the evaluation board to

terminate the ECL driver (More information on termination

is provided in AN8020). Solder the chip resistors to the

bottom side of the board between the appropriate input of the

device pin pads and the ground pads. For ease of assembly,

it is advised to place and solder termination resistors on its

vertical (side) position, instead of its original or flat position.

Installing the SMA Connectors

Each configuration indicates the number of SMA

connectors needed to populate an evaluation board for a

given configuration. Each input and output requires one

SMA connector. Attach all the required SMA connectors

onto the board and solder the connectors to the board on J1

through J32. Please note that alignment of the signal

connector pin of the SMA can influence the lab results. The

reflection and launch of the signals are largely influenced by

imperfect alignment and soldering of the SMA connector.

Validating the Assembled Board

After assembling the evaluation board, it is recommended

to perform continuity checks on all soldered areas before

commencing with the evaluation process. Time Domain

Reflectometry (TDR) is another highly recommended

validation test.

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