7

expected ambient temperature of 85°C, the total allowable

power dissipation for the SO8 package would be:

At 12V total supply voltage each amplifier draws a maximum

of 10mA and dissipates 12V * 10mA = 120mW or 240mW for

the dual amplifier. Which leaves 121mW of increased power

due to the load. If the load were 150

Ω connected to the most

+1V the load current would be 6.67mA. Then an extra

146mW ((12V - 1V) * 6.67mA * 2) would be dissipated in the

EL2210 or EL2211. The total dual amplifier power

dissipation would be 146mW + 240mW = 386mW, more than

the maximum 361mW allowed. If the total supply difference

were reduced to 10V, the same calculations would yield

200mW quiescent power dissipation and 120mW due to

loading. This results in a die temperature of 143°C (85°C +

58°C).

In the above example, if the supplies were split ±6V and the

150

Ω loads were connected to ground, the load induced

power dissipation would drop to 66.7mW (6.67mA * (6 - 1) *

2) and the die temperature would be below the rated

maximum.

Video Performance

Following industry standard practices (see EL2044

applications section) these six devices exhibit good

differential gain (dG) and good differential phase (dP) with

±5V supplies and an external 820

Ω resistor to the negative

supply, in a gain of 2 configuration. Driving 75

Ω back

terminated cables to standard video levels (1.428V at the

amplifier) the EL2210, EL2310, and EL2410 have dG of

0.1% and dP of 0.2°. The EL2211, EL2311, and EL2411

have dG of 0.04% and dP of 0.15°.

Due to the negative swing limitations described above,

inverted video at a gain of 2 is just not practical. If swings

below ground are required then changing the extra 820

Ω

resistor to 500

Ω will allow reasonable dG and dP to

approximately -0.75mV. The EL2211, EL2311, and EL2411

will achieve approximately 0.1%/0.4° between 0V and

-0.75V. Beyond -0.75V dG and dP get worse by orders of

magnitude.

Differential gain and differential phase are fairly constant for

all loads above 150

Ω. Differential phase performance will

improve by a factor of 3 if the supply voltage is increased to

±6V.

Output Drive Capability

None of these devices have short circuit protection. Each

output is capable of more than 100mA into a shorted output.

Care must be used in the design to limit the output current

with a series resistor.

Printed-Circuit Layout

The EL2210/EL2211/EL2310/EL2311/ EL2410/EL2411 are

well behaved, and easy to apply in most applications.

However, a few simple techniques will help assure rapid,

high quality results. As with any high-frequency device, good

PCB layout is necessary for optimum performance. Ground-

plane construction is highly recommended, as is good power

supply bypassing. A 0.1µF ceramic capacitor is

recommended for bypassing both supplies. Lead lengths

should be as short as possible, and bypass capacitors

should be as close to the device pins as possible. For good

AC performance, parasitic capacitances should be kept to a

minimum at both inputs and at the output. Resistor values

should be kept under 5k

Ω because of the RC time constants

associated with the parasitic capacitance. Metal-film and

carbon resistors are both acceptable, use of wire-wound

resistors is not recommended because of their parasitic

inductance. Similarly, capacitors should be low-inductance

for best performance.

P

D

150

85

–

160

°C/W

-------------------------

361mW

=

=

EL2210/11, EL2310/11, EL2410/11