the driver ability of the chip of TL7705

chenping song

Now, i use the RESET/ pin of TL7705 to dirver seven AND-Gate Logic chip's input, i want to know if this can work well? you can see the picures below, we use the pin-5 of TL7705 to driver the pin-1,pin-4,pin-9,pin-12 of IC27 and pin-1,pin-4,pin-9 of IC29 derictly. if this connection can work?

over 11 years ago

0 Darwin Fernandez over 11 years ago

TI__Mastermind 40670 points

Hi Chenping,

The recommended output current for the TL7705 is 16mA. As long as you don't exceed this, you can expect the RESET logic high and low shown in the electrical characteristics table. The 74HCT08 are low current devices so I do not see an issue. Be sure your VCC is high enough such that the TLV7705 VOH can be considered a logic high for the 74HCT08.

Regards,

Darwin

0 chenping song over 11 years ago in reply to Darwin Fernandez

Prodigy 60 points

hello Darwin:

thanks for your reply, now i have another question: if the connection between the TL7705 AND 74HCT08 is O.K. we want to use the output of 74HCT08 to control the directiong signal of the RS485 chips. i want to know we should add a pull-up or a pull-down resistor at the output pin of 74HCT08? you can see the pictures below:

0 Ron Michallick over 11 years ago in reply to chenping song

TI__Guru**** 151276 points

Chenping,

Is the supply voltage for the TL7705 and the 74HCT gate set to 5V?
Add a 10k resistor to ground on pin 6 (RESET) of the TL7705 to ground. Both outputs need to be loaded.

There are many logic timers listed here that could replace the TL7705 is the supervisor function is not needed..
http://www.ti.com/lsds/ti/logic/monostable-multivibrator-products.page

The ~R/D1 node does not need a pull up or pull down resistor.

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the driver ability of the chip of TL7705