Describe the connection required to program the device gain to 46dB. Hence determine the bandwidth at this setting given the Unity-Gain Frequency of the device is 25MHz in ad624.
To program the device gain to 46dB in ad624, the device needs to be connected according to the following specifications:
1. Connect Pin 5 (GAIN) to the positive supply voltage (V+) to set the gain to 1000.
2. Connect Pin 6 (REF) to GND to set the reference voltage to the inverting input voltage.
3. Connect Pin 7 (IN+) to the signal source.
4. Connect Pin 8 (IN-) to the input voltage reference.
5. Connect Pin 9 (OUT) to the load resistor or amplifier circuit.
To determine the bandwidth at this setting, we need to use the formula:
Unity-Gain Frequency = (Gain x Bandwidth) / (2 x π x Capacitance)
Rearranging the formula, we get:
Bandwidth = (Unity-Gain Frequency x 2 x π x Capacitance) / Gain
Substituting the given values, we get:
Bandwidth = (25MHz x 2 x π x 20pF) / 1000
Bandwidth = 1.57MHz
Therefore, the bandwidth at the setting of 46dB gain is 1.57MHz.
To program the device gain to 46dB on the AD624, you will need to connect the gain-setting pins of the device to the desired configuration. The AD624 has three gain-setting pins: G1, G2, and G3.
To program a specific gain, you need to connect either G1, G2, or G3 to the REF pin, while leaving the other gain pins open (floating) or connected to the common pin (COM). In this case, to set the gain to 46dB, G2 and G3 should be connected to the REF pin.
Now, let's move on to determining the bandwidth at this gain setting, given that the unity-gain frequency of the device is 25MHz.
The bandwidth of an amplifier is typically given by the formula:
Bandwidth = Unity-Gain Frequency / Gain
In this case, the unity-gain frequency is 25MHz, and the gain is 46dB.
First, let's convert the gain from dB to a linear scale. The formula for converting dB to a linear scale is:
Gain (linear scale) = 10^(Gain (dB) / 20)
Converting 46dB to a linear scale:
Gain (linear scale) = 10^(46 / 20) = 10^2.3 ≈ 199.53
Now, let's calculate the bandwidth:
Bandwidth = 25MHz / 199.53 ≈ 125.31kHz
Therefore, the bandwidth at a gain setting of 46dB is approximately 125.31kHz.