Please tell me about the TI timer IC TLC555.
The 5pin CONT terminal allows voltage input from the outside, but are there any restrictions on the voltage range that can be input?
Our customer would like to be able to vary the frequency of the square wave output from the OUT terminal by inputting voltage.
Regards,
kura
Hello Kura,
Ideally the voltage applied to the CONT pin should range from 0V to 66.67% of VDD, but the absolute minimum is -0.3V and absolute maximum is VDD.
Kind regards,
Alex Curtis
Hi Kura,
The CONT pin voltage must be kept within the absolute maximum ratings, as Alex pointed out. This to prevent damage to the device.
You may be interested in figure 5-9 and figure 5-8 from the TLC555 datasheet, which shows that if the CONT voltage is less than ~0.8V, the propagation delay increases drastically. For consistent timing, you may want to keep the minimum CONT voltage above 0.8V.
Regards,
Zach
