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I am designing a MCU controlled open-collector digital output (MCU control the base of transistor as a switch, output low). The output is assumed max. 26Vdc, 85mA. As transistor has max. reverse Vce of about 5V, I would like to add a reverse polarity protection for the output. In the other words, my device has no problem even the user (...)
In the old days of 40 years ago this served a useful purpose. One was making the OR function by putting all of the open collectors to one node with a resistor pullup. Back then a DIP logic IC cost one hour of salary of an average factory worker, so saving one DIP in a design was economically rewarding. The open collectors (...)
Similar to what the others have mentioned, open collector (or open-drain outputs for CMOS) are used for level-conversion and/or wired-AND. An example of the first feature is when you want to interface 5V to 3.3V circuits, or if you want to drive circuits with a high Vcc. The second application is used in shared buses, where there are (...)
Does an open-drain or open-collector ouput pin can supply Vol if external pullup is not added? ---- have got the answer One more new question: Do I need to add two pullups to both side of the buffer if I connected a open-drain or open-collector signal to that buffer?
If you're interfacing to an external connection that requires open collector characteristics (e.g., PS/2 interface), then you can simulate open collector buffers with 3-state buffers: out_signal <= '0' when in_signal = '0' else 'Z';
As a matter of fact, it is open DRAIN, not open collector .. Historically speaking, early microcontrollers didn't have much inside and they had to relay on external devices such as memories .. To connect external memory one needs bi-directional port and the simplest way to obtain bi-directional line is to use an open (...)
If the open-configuration (OC or OD) doesn't exist you can't "arrange" it .. Regards, IanP
goto: and follow link(s) .. rgds, ianp
Hi, please help me, i want the schematic for convert from open collector output to line driver output. how to do that?? i want to use it to control servo motor with line driver input CW and CCW?? any body have opinion for this problem?? Any open colector is a line driver as long the load is at the end of the line. Wh
hi frens. i need an open collector buffer. please can you provide a list of such chips so that i can found one of them in my local market. thanks
1. simply the manufacturing of the device has to be different, the lower voltage ones are cheaper to produce. It is a trade off between cost and need to use the higher voltage. 2. The maximum voltage should be in the data sheet. For devices that do not have open collector pins, the pin produces the voltage so it is set by the device, usually ve
Hi, The attached code has three 1-axis accelerometers sending data to an Atmega32, which interfaces with the PS/2 port of the computer. I have some questions about this: (1) At the beginning of the code: #define CLK_OUT PORTC.1 #define DATA_OUT PORTC.6 #define CLK_IN PINC.3 #define DATA_IN PINC.4 I'd like to know
Hi There, I'm looking at doing something where I'll have a remote photoelectric switch with an NPN open collector output situated ~300m from my power source (18Vdc) and microcontroller. I'm not sure the best way to go about this and was wondering if the following approach would be ok? I'm contemplating running a light, cheap 3 or 4 core wire
In open collector TTL it is necessary that you should have a pull up resistor for proper operation. It is also said that if you are connecting one TTL to another TTL, even if you don't connect the pull up resistor it work properly. How is that so? I mean when the output transistor is saturated (or ON in other words) the output capacitor voltage wil
What is the difference in open collector outputs VS non-open collector in TTL?
See . The purpose of the pull-up resistor (resistor between output and positive supply) is to get high output voltage when the open collector NPN transistor is in the off state. A well-known open collector comparator is the LM 339. The datasheet contains the internals, so you can see the NPN open co
Hi all I am new in Hardware design . I have seen open Drain pin in a controller ,so what does it mean . Can i use it as input or output . how to use it .Some of documents say it should be pull up with a Vcc ,why should be so , if i connect it with GND . Thanks in Advnace
assume my sensor is operated at 5v and it is open collector output, how to connect open collector output to micro controller, i must use any pull up resistor?
in my panasonic drive the encoder output is a differential signal A+ A- B+ B- Z+ Z- HOW TO CONVERT DIFFERENTIAL SIGNAL TO open collector OUTPUT
The only difference is the type of the transistor: if you have a BJT, then the circuit si open-collector; if you have a MOSFET, then it becomes open-drain/
HI, Using ATmega169, I can't find in the Datasheet if IO port are open collector. I think they 're because they have internal Pull up but I'm not sure. Can anyone confirm me ? Have a nice day ZE_DIB
Any references with detailed explanation of push-pull, open-drain, open-collector and other electronics interfacing logics? Thanks in advance ! mogwai.
sometime i see the ic datasheet show the push-pull port or the open-drain port. What different for this?
Hai Guys: In one of the journal on VCO design, by Hajimiri, it is stated that an open drain transistors are used as drivers and are designed to drive a 50 Ohms load at 0dBm, What it is meant by an open drain configuration?. Rgds
Hello! I am using microcontroller to collect data from car. I have input channels for digital and analog sensors and I would need to protect those channels in some way. Digital channels should accept both, DHE and inductive sensor outputs, so the input circuit should be capable to trigger approx 100Vpp sine-wave with +2V offset and with no modi
Hello! I am using microcontroller to collect data from car. I have input channels for digital and analog sensors and I would need to protect those channels in some way. Digital channels should accept both, DHE and inductive sensor outputs, so the input circuit should be capable to trigger approx 100Vpp sine-wave with +2V offset and with no modi
Hello! I have spent last couple of days using Multisim and Google and trying to design input circuit to microcontroller (AVR) with following requirements: 1. Incoming signals: TTL-level pulse sensor, open-collector Hall-sensor and automotive switch-type input (+13,6V - open circuit) 2. Frequency range would be from discrete input (...)
One clamp diode can use for the open drain structure pin. And the ESD current path of this pin to VDD is first from pin to vss, then from vss to vdd.
1st hit when you google "open drain" : If you just check out the first page of hits, you'll get a good idea of what the advantages are.
The caliper uses a very small battery. I would try to avoid using the battery power to run the rest of the circuitry if at all possible. Check if caliper put out power on line (1.55 Volt = silver oxide battey ?) via (MOS) transistor or pullup or have simple open collector output. If caliper feeds power out to datalin
Hi, May i know what is open-drain output buffer? what is the purpose of using it? I always read it from paper. It always used to match 50ohm instrument load. How it can match to 50ohm? Thanks.
The relay can be powered with 24V at the gate, and the signal can be interfaced to transistor base that is connected as an open collector switch, this will switch this relay, it is a standerd MCD apps.
If you use an old computer, parallel data line will have something like TTL 374 latch with ≈2.5mA sourcing and ≈20mA sinking capabilities; controll lines inputs will be of TTL 244 type and outputs TTL 05 OC (open collector) with ≈4.7kΩ pullups .. In the above case I can't see any reason why you should add any pullups at all
Usually the output stage of Digital circuits are Transistors working as a switch... In open collector and open Drain types there would not be any Pull up resistor internally at this output stage. They could be use by using an external pull up resistor connected to their outputs...
Hello In some pull up configurations (open collector/drain), if you connect more than one of these configurations to the same supply, you connect capacitor between collector/drain (signal line) and GND (aka Wired AND/OR). This is mainly for signal integrity and higher noise immunity. lets say it is easy and cheap way of (...)
Ope drain or open collector are nromally active low types of output.
Hello, Can open drain output be used as led driver,without requiring extra pullup resistor other than the led current limiting resistor. lets say the led power voltage is 5v and its cathode is connected to the open drain o/p and there is a current limiting resistor.Now when the ouput goes to high impedance state,will the output get pulled up
Assuming you are using a 3V3 Micro, these chips normally have an open collector output pin? Feed your pwm output into an unused input pin, then translate those levels to your open collector pin, which you have pulled up to 10 Volts. Job Done!
The best test circuit to use is the one in the data sheet in Figure 2. Are you running a parametric test of just trying to find a use for it? Parametric testing requires sampling equipment fast enough to measure the signal rise and fall times and possibly a special testing jig to ensure the input and output impedance are known and matched. If y
Clamp diodes on CMOS are connected to all inputs and to Vdd & Vss. The Schottky diode drop protects the CMOS inputs from see a voltage outside the rails by this diode drop. The only risk is that ESD has been known to be in the order of pico seconds and if the ESD rise time is faster than that of the diode, the diode will not protect. Th
hello, Do you think the below implementation of a NAND latch is OK? .....or will the circuit blow up if the "forbiddden" condition ever occurs? NAND latch giving latching overvoltage shutdown protection ...the open collector comparator "MCP65R" comparator feeds into the latch, and the comparator trip
Hi All, I doing some study on op-amp with open drain output. i.e Simulation items on this type of op-amp. however, I cannot find any related information so far. Can anyone provide me the information or direct me to where can I obtained information about this type of op-amp design and simulation? Thank you in advance~
Hello, I've got the MCP65R46 open collector comparator pulling up to 12V with a 330K resistor. Is this OK...? The datasheet appears to say that 10V is the maximum? Vdd pin is 3V3 MCP65R46 datasheet:
The high and low on this pin are logic levels. No. CHRG is a 40V rated open collector output, otherwise the circuit won't work.
This is called a wired-OR configuration. Only the LOW condition is an active output, where the open drain sink the signal to 0V. This way there is no danger for a collision between HIGH and LOW, resulting in a short Circuit. Reading the status there is also no problem With a logical collision, since the unit expecting a HIGH, will know there is a
It depends a lot on what remote resources you expect or can insist upon. If you want minimal wiring and no opportunity for supply integrity problems, you might make the signals more like open/short to the return/ground; this would be active low open drain / open collector. If you want to push a positive voltage or current (...)
OVP is to limit the output voltage. Use a P MOSFET switch to pass the input to output with no voltage drop. Then use a PNP transistor to turn off the switch. It can be regulated using a comparator with a 2.5V reference and divider on the output. the open collector driver can now drive the PNP base for a precision 40V series pass switch with a regu
I think that a power driver IC would be much more able to withstand ESD-type abuse than any discrete device, and since your lashups involve multiple discretes you might end up money ahead using one of the lower-drive-current ones. Now whether the open-collector type drive is necessary or just simplicity, I couldn't say, nor whether using a driver
Ok... Let's see.. First of all power your mouse or keyboard from another power supply independent from the micro and that alone might solve you problem. If not you will have to put some open collector drivers on the output from the Keyb. or mouse and you can try a cmos schimtt trigger on the input but even that might not solve the problem and y
Try the DP8311 , open collector