Other Parts Discussed in Thread: LM13700
Hi Team
I would like to be able to teach you the following points regarding the TL026C.
The circuit is designed using TL026C as shown in Figure 1.
・ Input: Connect a signal of amplitude 40mVp-p to IN + with a capacitor, and terminate with a resistor. IN- connects to GND.
・ Output: Control AGC terminal so that the signal is output at 1.2 Vp-p from OUT +. OUT- is open.
・ Power supply: Connect Vcc + to 4.5V and Vcc- to -4.5V.
・ Operating temperature: 0 ° C to 85 ° C
In this circuit, the voltage at the AGC pin is changed in a 25 ° C environment, and the gain of the TL026C is measured from the output of the OUT + pin, as shown in the graph in Figure 2.
① Due to the relationship between AGC voltage and Gain, the graph of the specification document (Figure 3) reads that Gain up to 85 times can be obtained at 25 ° C environment, but in measurement Gain(Figure 2) is obtained only up to 35 times. (Maximum Gain 70 times, even considering differential) Please explain the reason why Gain can not be obtained according to the specifications.
② From the relationship between the “AVD Large-signal differential voltage amplification (MIN 55 to MAX 115 [V / V])] in the specification sheet and the graph in Figure 2, the TL026C output Gain 30 times of our circuit is Are there any problems as a condition for using TL026C? If you have a problem, please tell us "What concerns do you have?" And "How much gain should I use?"
③ In our circuit, when the output gain of the TL026C is designed to be 10 times, the change in gain at a frequency of about 10 Hz and noise of a frequency of 50 kHz appear in the output signal of the TL026C.
Can you give me some advice to remove these noise components? (Figure 4)
④ In our circuit, when the output gain of the TL026C is designed to be 10, 25 or 30 times, undershoot / overshoot appears in the output signal as the gain becomes higher.
The undershoot / overshoot becomes larger as the gain is higher. Can you give me some advice for removing these undershoots /overshoots?
⑤ What is the proper range of use for the TL026C REF OUT pin output current?
Thanks
Best regards
Nagura