### Q

I have got some questions about the output short circuit capability ofAD713JR-16.

In the datasheet (Rev. C) it is not clear said if the outputs are short circuit

protected.

The absolute maximum ratings say, output short circuit duration for one

amplifier is indefinite.

1. Does this mean, there is no time limit, if only one output is shorted to

ground?

2. What happens, if all four outputs are shorted to ground at the same time? Is

the device destroyed, does it depend on the thermal characteristics of the SOIC

package?

3. Is there a thermal overload protection or thermal shutdown?

In the specifications the output current at short circuit condition is typical

25mA.

4. Is this the typical value of the short circuit current limit?

5. What is the (aproximate) maximum value of the short circuit current limit?

### A

1. We only guarantee indefinite short circuit capability if one output isshorted. Permanently shorting 2 or more outputs may damage or destroy the AD713.

2. If all four outputs are shorted to ground , then the device will dissipate

power P = 4 x 25mA x Vs = 100mA x Vs = 100mA x 15V = 1.5W. This will cause a

temperature rise of around 150 degrees above ambient, if the device has no heat

sink attached, which will almost certainly destroy the device at temperatures

above 0degC.

3. Figure 8 of the datasheet shows how the short circuit current limit varies

with temperature. It automatically reduces the short circuit current limit when

the junction temperature rises, as shown.

4. & 5. See figure 3 on the datasheet. At +/-15V supplies and high output

impedance (>2k) the voltage swing is more or less constant with load

resistance. As one moves from right to left, in the direction of decreasing the

load resistance, the curve becomes an exponential shape. This corresponds to a

region of CONSTANT CURRENT. If the x axis was linear then it would be a

straight line, but since the x-axis is logarithmic, the constant current as R

decreases is an exponential. The constant current is around 25mA, but this can

vary with temperature, supply voltage and each device will have a different

value. It's not possible to guarantee a maximum short circuit current limit,

since only a typical is given in the datasheet.