APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL prodlit@apexmicrotech.com

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NOTE: Refer to HS11 Heatsink in Accessories section

INTRODUCTION

This easy-to-use kit provides a platform for the evaluation

of power op amps that use the PA74 pin-out configuration. It

can be used to analyze a multitude of standard or proprietary

circuit configurations. In addition, it is flexible enough to do most

standard amplifier test configurations.

The schematic for 1/2 of the PC board is shown in Figure 2.

The schematic for the other half is identical except part refer-

ence designators are primed (i.e. R1 = R1'). Note that all of

the components shown on the schematic will probably not be

used for any single circuit. The component locations on the PC

board (See Figure 3) provide maximum flexibility for a variety

of configurations. Also included are loops for current probes as

well as connection pads on the edge of the PC board for easy

interconnects.

The hardware required to mount the PC board and the device

under evaluation to the heatsink are included in the kit. Because

of the limitless combination of configurations and component

values that can be used, no other parts are included in this kit.

However, generic formulas and guidelines are included in the

APEX DATABOOK and this evaluation kit documentation.

BEFORE YOU GET STARTED

• All Apex amplifiers should be handled using proper ESD

precautions!

• Initially set all power supplies to the minimum operating levels

allowed in the device data sheet.

• Check for oscillations.

• Always use the heatsink included in this kit with thermal grease

or a TW03 and torque the part to the specified 4-7 in-lbs

(.45-.79 N•M).

• Do not change connections while the circuit is under pow-

er.

• Never exceed any of the absolute maximums listed in the

device data sheet.

• Always use adequate power supply bypassing.

• Remember that internal power does not equal load power.

• Do not count on internal diodes to protect the output against

sustained, high frequency, high energy kickback pulses.

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Figure 1

PARTS LIST

Part #

Description

Quantity

HS11

Heatsink

1

EVAL02

PC Board

1

MS03

Mating Socket

2

HWRE01

Hardware Kit

1

TW03

Thermal Washer

1 Box/10

HWRE01 contains the following:

4 #8 Panhead Screw

4 #6 x 1.25" Panhead Screw

4 #8 .375" Hex Spacer

4 #6 x 5/16" Hex Nut

4 #8 1.00" Hex Standoff

2 #6 x 1/4" Hex Nut

ASSEMBLY HINTS

The mating sockets included with this kit have recessed

nut sockets for mounting the device under evaluation. This

allows assembly from one side of the heatsink, making it easy

to swap devices under evaluation. The sizes of the stand-offs

were selected to allow proper spacing of the board-to-heatsink

and allow enough height for components when the assembly

is inverted.

ASSEMBLY

1. Insert a #6 x 5/16" hex nut in each of the nut socket recesses

located on the bottom of the mating socket.

2. Insert the socket into the pc board until it is firmly pressed

against the ground plane side of the pc board.

3. Solder the socket in place (see Figure 1). Be sure the nuts

are in the recesses prior to soldering.

4. Mount the PC board assembly to the heatsink using the

stand-offs and spacers included.

5. Apply thermal grease or a TW03 to the bottom of the device

under evaluation. Insert into the mating socket through the

heatsink.

6. Use the #6 x 1.25" panhead screws to mount the amplifier to

the heat sink. Do not overtorque. Recommended mounting

torque is 4-7 in-lbs (.45-.79 N•M).

Mounting precautions, general operating considerations,

and heatsinking information may be found in the APEX DATA

BOOK.

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