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± Limit Voltage (V)

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7 1.8

1.9

2.0

-40

-50

-60

-70

-80

-90

3rd-Harmonic

2nd-Harmonic

V

f = 5MHz

R

G019

Output Drive

Thermal Considerations

P

DO

+ (10 V

15.5 mA)

+ 155 mW

P

DL +

4

(100 W ø 804 W)

+ 70 mW

P

D

+ 155 mW ) 70 mW + 225 mW

T

J

125

(4)

OPA698M

SGLS287A – MAY 2005 – REVISED MARCH 2006

Figure 67. Harmonic Distortion Near Limit Voltages

The OPA698 has been optimized to drive 500-

Ω loads, such as ADCs. It still performs well driving 100-Ω loads;

the specifications are shown for the 500-

Ω load. This makes the OPA698 an ideal choice for a wide range of

high-frequency applications.

Many high-speed applications, such as driving ADCs, require op amps with low output impedance. As shown in

the typical performance curve Output Impedance vs Frequency, the OPA698 maintains low closed-loop output

impedance over frequency. Closed-loop output impedance increases with frequency, since loop gain decreases

with frequency.

The OPA698 does not require heat sinking under most operating conditions. Maximum desired junction

temperature sets a maximum allowed internal power dissipation as described below. In no case should the

maximum junction temperature be allowed to exceed 150°C.

resistive load, and equal bipolar supplies, it is at maximum when the output is at 1/2 either supply voltage. In this

stage and not in the load, that determines internal power dissipation.

as:

25

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