What are the disadvantages of differential amplifier?

Answer 1

It has low input resistance

Answer 2

A:from a single ended none main concern is offset voltages and current offset and for some latch-up

Further explanation:

A differential amplifier is actually a very advanced (and good!) amplifier - it (at a minimum) consists of two transistors and biasing schemes, and in a basic form has two inputs and two outputs - one output is inverting, the other is non inverting, thus the two outputs can be used together to provide a 3dB (2 x) gain over using a single output.

From a signal to noise ratio, a differential amplifier is also a cut above if implemented correctly and designed well. For the best results, a positive and negative signal should be transmitted to the amplifier. One goes to either input of the amplifier, with the other to the other input. Noise inherently will be added onto both of these lines, but the noise will tend to be in the same direction for both. A differential amplifier has a high "common mode rejection", which means if the same voltage is applied to both inputs, the output will not change (it only amplifies the difference between the inputs). This is why sound boards and a lot of other A/V equipment use differential amplifiers.

If these features are not important for your design, then the added complexity of circuitry (usually requiring a positive and negative voltage, multiple transistors, etc.) becomes a disadvantage. Also, if you are just starting out, designing one well may be a bit over your head (a clear disadvantage when you don't know what's going on in the circuit - it becomes very difficult to trouble shoot).

Answer 3

it take more current