Typical at T

INSTALLATION

AND OPERATION

WIRING PRECAUTIONS

The OPA600 is a wideband, high frequency operational

amplifier with a gain-bandwidth product exceeding 5GHz.

This capability can be realized by observing a few wiring

precautions and using high frequency layout techniques. In

general, all printed circuit board conductors should be wide

to provide low resistance, low impedance signal paths and

should be as short as possible. The entire physical circuit

should be as small as is practical. Stray capacitances should

be minimized, especially at high impedance nodes, such as

the input terminals of the amplifier and compensation pins.

Stray signal coupling from the output to the input should be

minimized. All circuit element leads should be as short as

possible and low values of resistance should be used. This

will give the best circuit performance as it will minimize the

time constants formed with the circuit capacitances and will

eliminate stray, unwanted tuned circuits.

Grounding is the most important application consideration

for the OPA600, as it is with all high frequency circuits.

Ultra-high frequency transistors are used in the design of the

OPA600 and oscillations at frequencies of 500MHz and

above can be stimulated if good grounding techniques are

not used. A ground plane is highly recommended. It should

connect all areas of the pattern side of the printed circuit that

are not otherwise used. The ground plane provides a low

resistance, low inductance common return path for all signal

and power returns. The ground plane also reduces stray

signal pickup.

Point-to-point wiring is not recommended. However, if

point-to-point wiring is used, a single-point ground should

be used. The input signal return, the load signal return and

the power supply common should all be connected at the

same physical point. This eliminates common current paths

or ground loops which can cause unwanted feedback.

Each power supply lead should be bypassed to ground as

near as possible to the amplifier pins. A 1

µF CS13 tantalum

capacitor is recommended. A parallel 0.01

µF ceramic may

be added if desired. This is especially important when

driving high current loads. Properly bypassed and modula-

tion-free power supply lines allow full amplifier output and

optimum settling time performance.

OPA600 circuit common is connected to pins 1 and 13; these

pins should be connected to the ground plane. The input

signal return, load return, and power supply common should

also be connected to the ground plane.

The case of the OPA600 is internally connected to circuit

common, and as indicated above, pins 1 and 13 should be

connected to the ground plane. Ideally, the case should be

mechanically connected to the ground plane for good ther-

mal transfer, but because this is difficult in practice, the

OPA600 should be fully inserted into the printed circuit

board with the case very close to the ground plane to make

the best possible thermal connection. If the case and ground

plane are physically connected or are in close thermal

proximity, the ground plane will provide heat sinking which

will reduce the case temperature rise. The minimum OPA600

pin length will minimize lead inductance, thereby maximiz-

ing performance.

BANDWIDTH

1.4

1.2

1.0

0.8

0.6

Temperature (°C)

–75

–50

–25

0

25

50

75

100

125

G = –10V/V

OPEN-LOOP GAIN AND QUIESCENT

CURRENT vs TEMPERATURE

1.2

1.1

1.0

0.9

0.8

Temperature (°C)

–75

–50

–25

0

25

50

75

100

125

I

Q

I

Q

A

VS