Logic level refers to the output voltage levels of digital logic, which is often 3.3 V or 5 V.
1
vote
3answers
164 views
What design decisions must I make to select a suitable P-Channel MOSFET
I need a PFET with a logic level gate to trigger a power connection to a hobby servo that pulls more current than my MCU pin can handle.
The requirement is simple but I'm trying to understand how to ...
0
votes
2answers
61 views
analog level conversion in ADC circuit
I'm trying to feed a 3.3V ADC from a gas sensor that operates at 5V. I know I can use a voltage divider, but am a bit confused how it would apply here.
Datasheet: https://cdn.sparkfun.com/datasheets/...
2
votes
2answers
83 views
Logic family for 3.3 V microcontroller interface
I need to generate a bunch of chip selects for a SPI bus that I want to use on a project. I will use a 36 position (similar to PCIExpress = cheap) card edge connector and etc.
The bus is simple :
<...
0
votes
1answer
45 views
What characteristics of a MOSFET should I be looking at? [duplicate]
I'm trying to determine a MOSFET for a circuit I'm building which will drive the gate of an N-channel MOSFET at 3.3v with an available current 40mA (**this will be driven using PWM at 4MHz), the ...
9
votes
1answer
572 views
What's the purpose of this diode in this level-shifter?
look at this circuit:
I don't get that what's the usage/purpose of the BAS316 in this circuit?
1
vote
1answer
65 views
How to turn a DIP switch into an array of logical values
Is there a better way to turn a open/closed switch into a logical value (capable or sinking or sourcing current) other than:
simulate this circuit – Schematic created using CircuitLab
I'...
0
votes
1answer
89 views
Interfacing 12V logic with 5V circuitry
I'm trying to build a simple circuit to control a church lampadary for an escape room game. I don't know if you've seen these but they're fairly common in catholic churches where I live: You input ...
-1
votes
1answer
69 views
Question about Logic Level MOSFET's [closed]
In this schematic i thought i was connecting the 19v in to Q1 the source of the MOSFET and continue out the drain. however in eagle the default connection shows it supposed to connect the 19v in to ...
0
votes
1answer
47 views
How to connect a CD40109BE Voltage Level Shifter
I have a circuit requirement using a Texas Instrument CD40109BE Voltage Level Shifter. This chip incorporates 4 low to high level shifting circuits. I plan to use two of these circuits, A and B with ...
0
votes
2answers
94 views
How to drive power MOSFET by logic level signal without inverting phase?
I struggle yet another day with very simple problem (circuit).
This challenge seems to be very common, but nowhere I can find a complete solution:
I have a heavy load (12v / 1 Ohm peltier = 12A max) ...
0
votes
1answer
47 views
Upper and lower bound - Digital electronics
A logic signal is transmitted in a logic circuit with positive logic, where \$V_{IL}=2.3 V\$, \$V_{IH}=4.5 V\$, \$V_{OL}=1.4 V\$, and \$N_{MH}= 1.8 V\$ . Recall that when using positive logic, the ...
0
votes
1answer
51 views
Multiple SPI devices with different logic levels
I'm going to use one of the PIC32MX795F512L SPI peripherals (master), 1 to 4MHz, to communicate with multiple devices (slaves):
Wi-Fi module MRF24WG0MA (3.3V);
uSD card (3.3V);
9 modules with ...
3
votes
3answers
202 views
Interfacing open-collector optoisolator to 3.3V microcontroller
I have a bit of a puzzle on my hands trying to interface a Fairchild MID400 optoisolator (popular "logic level" optoisolator for mains detection) to a 3.3V GPIO pin. The MID400 is a 5V part [*] and ...
0
votes
2answers
42 views
2 state converter, from -24VDC [ON] - +5VDC [OFF] to 5VDC [ON] - 0VDC [OFF]
So as the header says, I would like to take a 2 state signal (ON/OFF) where the on state is -24VDC and it's off state is +5VDC and make that/convert to a 0-5VDC 2 state signal, where 0 is the ...
1
vote
2answers
72 views
MOSFET-N as a switch for several ICs
I want to use MOSFET-N (MTM232270LBF) as a power switch for several ICs in my project. It should poweron the devices when logic level is high (3.3V) and poweroff when 0V.
I want to ask you if ...
0
votes
1answer
88 views
why use 2 diodes when shifting from 3.3 to 5v? [closed]
for the question "how do I go from 3.3 to 5v" people point to the microchip cheat sheet.
The Diode option has one between the data line and 5V so it pulls it almost to zero, the other one seems to ...
1
vote
1answer
51 views
Large range input single level shifter
I have an application where I will be taking serial signals will need to level shift the signal to 3.3V. The input signal will be from 15 to 5V for a high input and I need them all shifted down to 3....
0
votes
1answer
76 views
What is the explanation with shorting vcc and gnd to power up the whole circuit in a breadboard? [closed]
I was building a logic circuitry that performs 8 bit multiplier 16 bit divider using decoders as finite state machine in breadboards. the circuit is a bit large and i wonder why grounds or low voltage ...
0
votes
2answers
230 views
How to output 5V from 3.3V MCU?
Big picture: I want to control a LUXdrive 3023 BuckPuck LED driver (3023-D-E-1000) from a Particle Photon (essentially an ARM Cortex M3 microcontroller). The MCU runs at 3.3V. I have tried a few ...
1
vote
3answers
54 views
MOSFETS +/- Voltages? Which to use?
I've been trying to get into some low level electronics to explore to "Internet of Things" and still struggling a little with MOSFETS.
I'm trying to make a single push button act as a latching power ...
0
votes
1answer
45 views
Level Shifter Issue with Ground
I am using this level shifter spark fun breakout board: https://learn.sparkfun.com/tutorials/using-the-logic-level-converter
My goal is to interface a 5V logic SPI LCD with a 3.3V logic micro ...
0
votes
1answer
51 views
Whats happenning with my logic levels?
I'm using a 3.3 MCU and a 5v logic RS-485 IC. I'm trying to send out some data to another controller. I don't have a logic level shifter as of now. So I decided to use resistor divider, to get it to a ...
1
vote
2answers
400 views
7400 series CMOS vs 4000 series logic IC
I understand the traditional difference between the 7400 series and the 4000 series logic ICs, but since there are CMOS versions of the 7400 series, is there an advantage to use the 7400 CMOS version ...
0
votes
3answers
110 views
Does powering a module with 5v instead of 3.3v affect it's logic level? [closed]
I bought a NEO-6 u-blox 6 GPS Module (datasheet, pages 9 and 14), which has a standard serial connection. I have a USB to serial converter, which is 5v logic. This board says it can be supplied 3v-5v, ...
0
votes
3answers
67 views
Do bi-directional level converters connect either input directly to ground?
So I have the following circuit, which is a bi-directional level converter:
I am using it to convert a 5v logic signal (which at high is actually 4.2v and low is ~0.2v) to a 3v3 logic signal. I ...
0
votes
4answers
104 views
Logic-level switching 12v
I implemented the following schematic trying to follow Jon Watte's reply to this question.
There are two things I don't understand:
Why is the probe Q14 showing 4.34 volts? Why is it not closer ...
1
vote
1answer
89 views
What's wrong with my simulation for Bi-directional logic level converter?
I am trying to make a simulation by using Multisum 14 for i bi-directional channel for Logic level circuit from SparkFun which use Philips AN97055 IC as a Bi-directional level shifter...
The ...
0
votes
1answer
50 views
Comparator with latch as trigger
I was hoping to use a Linear Comparator with a latch such as LT1016 as a trigger for the Register output clock for a 74HC590.
The 74HC590 is going to be cascaded with it's RCO going to several more ...
0
votes
1answer
71 views
Do I need a level shifter with an open drain output
I'm currently doing a schematic that has an IC that operates at 3.3V (HDC1000 for those curious), and the rest of my digital operates at 1.8V. I have a level shifter for the I2C lines, but there is an ...
1
vote
2answers
113 views
-5/0 volt to 0/5 volt logic levels?
Does anyone know a good way to convert -5/0 volt logic to 0/5 volt? I'm using a chip as seen in the diagram below, but I'm not sure what to do about the inverted logic levels. Basically, I need to add ...
0
votes
2answers
91 views
Set multiplexer inputs to a logic 1 state
How can I set, in Orcad, all the entries of multiplexer(in the picture) (except: 1, 13), to logic state '1' (for example, I understand that if I place 'ground' to some entry, then it will be ...
0
votes
1answer
147 views
How to PWM-drive a N-channel non-logic level power MOSFET with a 3.3V signal?
Follow-up of Using IR21531 as a simple 1 channel gate driver
After doing the above question (I'm very sorry, beacuse my question seems a XY one), I'll try to explain better what I believe that I want ...
0
votes
1answer
86 views
Using IR21531 as a simple 1 channel gate driver
I've bought the only gate driver I've found on the local hardware store (IR21531). I want to use it only to drive a IRF630 with a PWM 3.3V signal.
How should I do the wiring? As you can see on the ...
4
votes
1answer
184 views
Power Path Controlling with GPIO and MOSFET
I'm not particularly well acquainted with MOSFET logic design and need some verification on a few things to make sure I've got them correct, and to see if there's any better ways of doing it. I need ...
0
votes
1answer
69 views
Where is the ground/earth used in the Sparkfun Logic Level Converter
I am studying the Sparkfun Logic Level converter and the basic aim of this is to understand how these BSS138 transistors are used in logic level conversion. I have used transistors before in driving ...
3
votes
3answers
176 views
Switch (Relatively) High Voltage from Logic Level
The Situation:
Basically, I would like to switch a load that requires 30v using a switch that cannot have more than 5v across it. More descriptively, I am trying to drive the anode of a VFD segment ...
0
votes
1answer
52 views
uni directional logic level conversion with active drive current
I'm trying to connect an EM4095 to a cortex m0. The EM4095 requires an active high drive voltage of min 4V and has an internal pull down of 50K. Additionally it must be low during boot, otherwise it ...
1
vote
2answers
44 views
Why is Vtyp less than Vmin on a CMOS chip
Regarding the chip 74HC08
On the table describing Static Characteristics (Section 9). Why is the typical VIH lower than the minimum value.
And vice versa for VIL
0
votes
1answer
54 views
Rotary Switches - 4 Positions, Two Outputs - How to determine the selected “mode”?
My apologies for not such a great description.. so I will clarify here.
I have a rotary switch from an old aircraft panel that has 4 positions and two outputs.
Using my voltmeter's resistance mode I ...
0
votes
2answers
146 views
Noisy Logic Level Converter for SD Card
I have designed a Arduino shield that is designed to be placed in the field and log data from a sensor which it then saves to an SD card. In order to log this data, I must convert 5v SPI to 3v3 of ...
0
votes
1answer
53 views
Low voltage PWM to logic level PWM
I have a sensor which constantly outputs serial data at very low voltages (in the milli-volt range), however I need to read this serial data using a PIC micro controller. How can i convert this data ...
0
votes
1answer
44 views
Do any flip-flops use separate clock levels for “sample” and “propagate” events
Many kinds of sequential logic require that the output of one register be fed into the input of another register which is strobed by the same clock. In such logic, it's necessary to ensure that a ...
0
votes
1answer
58 views
How does a bipolar transistor work on logical level?
When does a BJT conduct electricity and from where to where does it flow?
I thought a BJT is off when the base is low and ...
0
votes
1answer
225 views
Driving MOSFET gate using PIC
I would like to drive a MOSFET gate using 12V (in order to reduce the drain-source resistance). Using the answer from a few post i've read I have come up with the following circuit. Will this circuit ...
0
votes
2answers
164 views
MOSFET driving MOSFET for reduced reduced Rds [duplicate]
I am using a PIC to drive the gate of a logic level MOSFET. Although the 5V logic output of the pic is sufficient to exceed the threshold voltage I would like to drive the gate using 12V to reduce the ...
0
votes
1answer
169 views
How does this logic level converter on the Adafruit HUZZAH work
I am busy with a project where I am connecting a 5V(Amtel ATMega328) MCU to an 3V(ESP8266) via the serial port. Obviously I need some logic levels converted. I looked at the schematics of several open-...
0
votes
3answers
65 views
CMOS Logic system
When I was practicing logic circuit design using PMOS and NMOS , It's said that we have to use all PMOS for Pull Up Network (PUN ) and NMOS for Pull Down Network (PDN). But we know that for input ...
5
votes
3answers
237 views
Ignore Pulses Less than a Given Width in a Pulse Train
Let's say I have a 5V pulse train that varies between 0 and 75000 pulses per second. Pulse width, let's say, is 5 microseconds. How could I calculate or determine the best way to filter out all pulses ...
0
votes
2answers
112 views
Is noise a problem when using a logic level shifter?
Good morning everyone,
I'm building a device that uses several bidirectional logic level translators to interface 3.3V microcontroller to 5V, 2.5V and 1.8V sensors (via I2C lines).
But I wonder if ...
0
votes
2answers
54 views
Measuring Switch State using PIC
What is the best way to measure the state of a latching switch using a micro controller?
Keeping in mind the voltage level of the input to the switch is higher then the maximum voltage input to a MCU ...
