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Rohm make one called BU70013TL but I'm not sure of it's exact characteristics. I think it may be for use in consumer water, gas and electricity meters so they retain the usage count if the power fails. Other than that, you can quite easily emulate the 4017 with an MCU containing EEPROM or you can use battery back-up for a real 4017. Their current
If you don't have any unusual requirements like cold-sparing (i.e. output does not leak back when VDD=0) then the usual CMOS digital ESD schemes could be applied. If you need "power off high impedance" on the outputs then probably need to use a GGNMOS clamp per output (possibly with a back diode). Verifying ESD (...)
Sorry for the long and dull post...please by all means just skim read and hit back with anything you suspect may be remotely relevant..:-|:-|:-P:-P:lol::lol: We are providing 1V5, 173A to a processor load by way of a 28V input. This means using a cascaded network of off-the-shelf power modules by as in the JPEG attached here. S
Hi, I?m trying to build a midterm system between a costly and highly custom VPX and a platform where each board interfaces with one another by cables. for example: imagine I have an off the shelf mini-itx motherboard, a switch, and 2 network video encoders my idea is to have a back plane that would supply power, serial communication (...)
hi dear friend I'm working with sim900 (sim 900 doesn't answer my at command just reply every thing that I send, back) and when I turning the sim900 off send "NORMAL power DOWN" on hyper terminal:bang::bang::bang::bang: (cry cry cry) help me please
Take the back off, switch it on in a dark room and look for light around the back of the display. If you can see light it means the backlights are working and you have a video fault. If no light is 'leaking' out, the problem is almost certainly the high voltage inverters or the power supply to them. They (...)
Hi group, Hope this is the right group? I have a Raspberry Pi running Wheezy with an external hard drive that is powered by an external power supply. It fails to reboot because the Pi turns off the hard drive while coming down and fails to turn it back on. I have researched this problem to no avail. So I was thing of (...)
Hello, I have a problem with the operation of power supply (buck topology) using LNK306 chip as when the current exceeds 100mA the power supply seems to switch off and then switches back on when the current drops by releasing the load ( using speakers as load ) , it seems that there is a component that reaches saturation (...)
Hi guys, my ups broke down - a Mustek powerMust 600VA offline. Learned is made by Centralion and is marketed also as a Ippon back office 600va. Obviously first checked the SLA batt- discharged but ok(chargeable), then the fuse - ok also. Then i suspected off the DPDT relay, i replaced it and nothing. (...)
Linear operation is possible if you set Vgg to 3.5V, maybe even 4V for very linear amplification. And because 64QAM has about 7dB peak-to-average (and 16QAM about 4dB) might need to back-off few dB's the output power, to get minimum signal distortions and lowest ACPR.
Dear All, I am designing an AC DC which requires switching the AC power on and off to the inductor. The power of the inductor will then be fed to the other circuit for AC DC conversion. I would like to know if there is any way to switch on and off the back to back mosfets consider the (...)
Problem is due to physical layout. Make ground connection of FET from near the supply. Post some pics of wiring and front and back of board. Pulses on scope can also be picked from air if probes are not rightly connected.
If you can meet timing/power in prelayout, use all HVT then. Otherwise use mix mode, some time back end would be pissed off if you give them netlist not meeting timing.
The LDMOS transistors BLS6G2731-6G or BLS6G2735L-30 from NXP are specified for Class-AB pulsed RF operation in 2.7GHz - 3.1GHz range. Most probably if you back-off the output power (and losing efficiency) you can use the transistors for a Class-A PA design.
back in the "good old days", you could salvage stuff from electronics (I still have old vacuum tubes laying around that I expect to use 'any day now'). Nowadays I think you are probably better off just buying things new. Maybe you can find a usable power transformer or something like that, but everything else is just so (...)
I would use back to back mosfets for switching THE AC power. You could drive them via a pulse trafo, or a gate driver supplied from an isolated high side supply.
Dear forum members, How to get the peak to average ratio of PA and how is it related to modulation technique. what is meant by back off power of it related to peak to avg ratio. Also please give me an idea how constellation symbols relate to peak to avg ratio.
Hi guys. I need some help designing a Normal/Alternate DC uninterruptable power supply with battery back-up to illuminate a 14v lighting circuit. I will be using Locktronics to build the circuit and it needs to be as simple as possible. SPECS: Normal Alternative supplies to be rated @ 14v Battery back-up
Hi Techs, Cansomeone help with some tips on this tv. On powering up tv the screen comes on blue color. and whenever i press the chanel buttons up and down it only goes to ch. 4, 3, and 67, but still remain in full blue color, there is no raster,. I would power off the set and imediately power on back (...)
Hello all. I am using Allegro PCB Editor 15.2. I had three GND planes and a power plane created with dynamic copper pours. Naturally, once I created them I turned off their visibility. At some point, when I turned them back on I noticed that the planes were making full contact with vias that they were not electrically connected to. This (...)
Hello experts, Our RS485 bus connects 10 nodes together. But one of the nodes might be shut down(power off) from time to time. I am wondering if the current flowing on RS485 bus might revert the current back into the powered off transceiver and do damage to the transceiver. Any explicit specification that (...)
I want design a 3W(35dBm) WCDMA PA adopting back-off method , and amplifier is MRF21060.driver amplifer is MHPA21010. I dont know if the above choice is ok ? please help me ? thank you!! if you have better choices ,please tell me ! thank you !! parameters are as following: output power :35dBm Gain: 50dB ACPR: ?5MHz &
Is about 3dB back-off of the output power. P1dB is the compression point of the output power.
hi is there anybody who is familiar with power amplifier designs? would you please upload an ADS file on designing power amps? how can we determine the nonlinear characteristic of the PA with respect some data like input back off and IP3 level? thanks
This goes back to the 1940s and magnetrons. Frequency variations caused by the power supply being off were called pushing. The ones for the load not being exactly 50 +j0 were called pulling. They had smith chart diagrams with lines of constant frequency on them.
You have to put the question in a different way: What modulations can be amplified with less distortions by a Class-AB PA? The answer is: Most of the constant and non-constant envelope modulations. For modulations with high-peak to average is necessary more back-off of the input power.
Sorry I haven't been back with a reply earlier. I bookmarked it on my phone so I could look later on my computer and only just noticed the bookmark. My understanding is that when the power is off C1 discharges mostly through R2 and the load Rlamp. The charging of C1 is then through R3 but the potential divider with R2 means that it (...)
hi . i have a dell vostro 1500 notebook . it is completely dead . when i plug the power cable , the LED on the charger turns off . and it won't turn on until i unplug the charger and back on . the charger is OK . i have tested it . and it does not boot up with battery too . i checked on web and this seems to be a common issue in this model (...)
Attached is a picture of the power supply off of a monitor I'm trying to repair. I changed out all of the CAPS that were defective, still no picture. I know it's a problem with the power supply because when I switch out a good one for this one the monitor fires up. When the bad PS is put back in, there's absolutely no (...)
I have to design a PA/LNA for a Zigbee application, which uses OQPSK modulation. I heard that we have to handle a back off value to avoid using a linear PA into saturation but I did not succeed in finding the back off value for OQPSK modulation. Thanks
If you back-off the power of a 10W (40 dBm) transistor with 12.5dB, means the output power will be 0.56W (27.5 dBm). To get 1W (30dBm) linear output power for OFDM communication you need a transistor with greater linear output power than 10W. A normal efficiency of linear PA’s (...)
It depends from the signal you have to amplify. I mean: is it a CW or it's a signal requiring the amplifier to have back-off enough to manage the crest factor (f.i: high order modulation schemes, CDMA, OFDM) ? Furthermore what about gain ?
Hey I'm working on a wireless battery charger design. So far, i have inductive coupling to power up a PLL based battery charging circuit. each circuit works fine in isolation. but when together and when the whole circuit is off, the battery back powers the rest of the circuit rendering it ON even when its supposed to be (...)
When the Monitor is first powerd up the image is great, but after about 15min or so horizontal lines start to scroll up the screen. If I power off the monitor for about 30 sec of more they go away, but will come back in minutes. Could it be over heating? or is it something easy to fix?? I have tried it on 3 (...)
Hello Mashur, I don't think that the formula OBO = log(Pout/Pin) is correct: Gain = Pout/Pin. Said that, output back off means setting the working point of power amplifier at a gain OBO dB below its Gmax value. This is done to avoid that the intermodulation products originating from the input multicarrier signal raise over a certain (...)
Hi kspalla Your explanation is good but I think that someone who doesn't know what does back-off mean is not going to understand P1dB, PAR and IMD acronyms. For passerby: You should follow vfone's advice: Cripps book rules :-)
My monitor will work fine for the first 15 minutes and then it will turn off the screen but keep the power light on. If I turn it off and back on I can get about 3 more seconds out of it until I let it rest. I have been looking over other threads and I have checked to see if it is the monitor and it is. I have checked the (...)
My monitor will work fine for the first 15 minutes and then it will turn off the screen but keep the power light on. If I turn it off and back on I can get about 3 more seconds out of it until I let it rest. I have been looking over other threads and I have checked to see if it is the monitor and it is. I have checked the (...)
provide enough reserve power such that the motor pointer can be brought back to zero position This job requires a lot of current, even a 10,000mfd is not enough i think. Try some other method, use your main source till proper shutdown is done. MicroCon
OBO=Output power back off
Your problem is the invertor for the back lights . The problem is usauly a bad cap check for bulging or swollen caps
In this case use BLF542 which allows you to back-off the output power, to avoid the high peaks of the modulation. IMD3 at maximum output power (5W) is approximately -30dBc, and better than this at 3W.
Tune the bias point, and tune the matching output (Lo, Co, Cac) for maximum available output power (shall be more than 4dBm) and after that, back-off the input power to find the sweet-spot for IM3. Sweet spot is a deep in the IM3 vs P_inp/output curve, which depends by the bias, AM-AM and AM-PM characteristics of the (...)
They remain on to supply the 5 V-standby voltage to USB ports (if enabled). But that is just for convenience - you can turn it totally off with the switch in the back. /Ram
Hi everyone, I am doing a 3.8G low power pre-amp which also bandstop 900M,1.8M and 5.8M everything is ok when using a network analyzer to check. Figure 1 (power = -10dBm), 15dB gain at 3.8G and there is already back off from P1dB However, once i use Signal generator + spectrum analzyer to check the gain. I (...)
There is a second meaning: Some PA's a programmable output power range. So there are more efficient for more backoff to there maximum output power. But these programming is stable over a full frame typical. So the distortion induced effects the backoff to the peak power (...)
i have any lg 32lc56 tv and it keeps turning itself off and then wont turn back on again. i have contacted lg customer sevices but to be honest there useless.... they informed me they would pick the tv up 3 months ago and i have contacted them on several occasions and was told the same thing. basically the power cord is fine, the on (...)
I have a JVC HR-S9800U Super VHS deck. We had a storm overnight with lots of lightning and the power went out. Now, when I try to turn power on to the deck, it comes on for 2 or 3 seconds, and then powers itself back off. The surge protector shows that a surge came through, but everything else plugged into (...)
A reflective switch is one in which the incident power at the ?off? port is reflected back to the source as a result of the impedance mismatch presented at its input. The non-reflective switch is designed to present a 50-ohm impedance in the ?off? state, and to absorb incident power. Usually the (...)
becuase your problem disapperared after u have taken off some hardware and put it back, i suggest you 1st to check if the antivirus is enabled in the bios boot and disable it. if its not enabled, i suppose u had some dust in a free memory slot as about the cap, it ll explode dont worry (just kidding, but a good day it will not filter some IC pow