Urgently looking for chip model

RF-刘海石

Urgently looking for chip model [Copy link]

 

Hello everyone, I work in RF, I don't know much about digital aspects, and I use few chips. Recently I am working on a project that requires using logic circuits to control the on and off of the RF switch.

The circuit I designed is an 8-way switch. High level turns on and low level turns off. Only one way is turned on at a time, so one way is high level and the other 7 ways are low level. I have chosen a 38 decoder, 74HC138, but the function of this chip is exactly the opposite. See the truth table.

To use this chip, you must add a NOT gate circuit to convert it, so I would like to ask everyone if there is a chip that does not require conversion to complete it.

The current PCB has limited space, so I added a NOT gate. Maybe there is not enough space. I can add MOS tubes and transistors. I can make the circuit work, but the size is limited and 8 channels cannot be placed.

Please consult everyone, thank you!!!

topwon

74HC238

wsmysyn

74HC238 should be able to meet the requirements,,,

RF-刘海石

wsmysyn posted on 2019-6-21 09:32 74HC238 should be able to meet the requirements,,,

Man, I really appreciate it. , . . .

constant

It feels like making a multi-channel filtering circuit and switching the RF module. . . . . . . . . . . .

wsmysyn

RF-Liu Haishi posted on 2019-6-21 09:41 Brother, I really appreciate it. , . . .

RF-刘海石

constant posted on 2019-6-21 09:56 I feel like I’m making a multi-channel filtering circuit and switching RF modules. . . . . . . . . . . . .

Yes, almost, but this time it is multi-beam antenna switching. The front end is 8 antennas, and then the switch is made of PIN tube, which switches every 10us and switches in a cycle.

btty038

constant posted on 2019-6-21 09:56 I feel like I’m making a multi-channel filtering circuit and switching RF modules. . . . . . . . . . . . .

8 antennas, wide frequency band?

topwon

btty038 posted on 2019-6-21 10:28 8 antennas, wide frequency band?

The number of antennas and the dynamic switching function should have little to do with the frequency band. It should be used for directional applications, such as direction finding and positioning.

shihuntaotie

Are you making a pin switch?

btty038

topwon posted on 2019-6-21 11:06 The number of antennas and the dynamic switching function should have little to do with the frequency band. It should be used for directional applications, such as direction finding and positioning.

I misunderstood. I am also right. The direction finding, positioning and interference methods are different. I misunderstood.

RF-刘海石

Shihuntaotie posted on 2019-6-21 11:08 Are you making a pin switch?

Yes.

RF-刘海石

btty038 posted on 2019-6-21 10:28 8 antennas, wide frequency band?

Does not require a wide frequency band, TDD mode, alternate transmission and reception.

topwon

Using discrete devices to make MIMO control circuits?

RF-刘海石

topwon posted on 2019-6-21 13:24 Using discrete devices to make MIMO control circuits?

I don't know the specific project, and the customer didn't tell me, but I guess it's mimo, and the baseband is AD9361. The customer just gave me the RF part, that is, it was made according to the customer's requirements. I used a switch before. Some indicators were not ideal, and the power bearing was not good, so I planned to use PIN tube to try it again.

zhuyebb

74HC238 should be able to meet the requirements,,, image

Plutor

I would like to ask if you can still predict the topic of the National Electrical Engineering Competition this year?

RF-刘海石

Plutor posted on 2019-7-5 11:01 I would like to ask if the OP still predicts the topic of the National Electrical Engineering Competition this year

Waiting for the device list and instrument list to come down.