CMOS stands for Complementary MOS, most digital logic is made in CMOS.
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Voltage regulator device selection
I intend to design a CMOS voltage regulator that takes 2.5V supply and outputs 1.2V. I am starting off with an opamp+pass transistor design.
Will there be a specific advantage to using an NMOS ...
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2answers
243 views
Question about mosfet gate resistor
I have n mosfet gate connected to 4043 logic and Id is about 100mA. Both 4043 and mosfet has +5v. I have plan to use 2N7000 mosfet
Questions are:
How large gate resistor i need between 4043 and ...
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1answer
49 views
ReRAM CMOS compatibility (vs phase change memory)
When ReRAM is described as having good compatibility with CMOS processes, it means that ReRAM can be constructed with "standard" manufacturing processes, correct? Meaning that it can be grown with ...
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2answers
86 views
What is the basic principle for a cmos vcc detector circuit?
Most systems that have any controller/firmware need to know when to start powering up. I would imagine this might need a powerup circuit or a detector that trips when we are at an acceptable voltage. ...
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Mosfet Circuits Voltage
So let's take a simple cmos circuit like this:
So I get that for DC analysis \$V_G = 12 \frac{R_2}{R_1+R_2} \$ and then \$ V_{GS} \$ makes sense to me...because there is a constant \$ V_G \$ value ...
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What should be considered when sizing trace widths for digital logic signals?
For traces that carry a static DC current, it's pretty easy to calculate the minimum trace width based on the required ampacity of the trace. However, I'm not sure what should be considered when ...
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129 views
Q-Point of a circuit
In a BJT or MOSFET circuit we have this curve:
What is that q-point? From my research I have the following information:
The operating point of a device, also known as bias point or quiescent ...
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78 views
Accessing an SRAM Array?
As im learning about Computer Architecture im trying to understand it from the ground up (Transistors in CMOS in particular)
I came across the simple 6T schematic for SRAM (2 inverters)
Mostly ...
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1answer
311 views
XOR gate; transistor level design [duplicate]
What would a transistor level design of an XOR gate look like?
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163 views
CMOS Inverter Voltage Transfer Function
So let's say I have a perfectly symmetrical Voltage transfer function curve for my CMOS inverter. The curve looks like this:
The question is, how would this curve change if the size of the NMOS ...
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1answer
301 views
Specifications of NMOS and PMOS transistors for 90nm technology?
What are the length and width specifications for PMOS and NMOS transistors and capacitor ranges for 90 nm CMOS technology? I'd like to design a low power full adder cell using majority charge ...
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3answers
209 views
Raw access to CMOS image sensor?
I am interested in developing an idea using CMOS sensors, and I was wondering if I could get some pointers (I don't know much about image sensors)
First, my understanding is that CMOS image sensors ...
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233 views
Driving LEDs / other small loads with a 74HC06 or similar inverter
I was recently reverse-engineering some firmware (and other bits) from a router, and spotted that the front panel LEDs were driven from a 74HC06 hex inverter gate chip rather than a proper LED driver.
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281 views
what happens when transistors are interchanged in CMOS?
A basic cmos inverter will have a P-transistor upside and N-transistor down side. what happens if we reverse the p and n transistors?
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99 views
Clock conversion from 3.3v CMOS to 2.5v
I need to convert a bunch of data signals from an FPGA coming out at 3.3V CMOS into 2.5V for an LCD display. I've found the SN74CB3T16210 and the SN74AVCBH164245 and they both seem like they'll do the ...
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2answers
116 views
Briefly flash LED on low/high change
I've got the output of a CMOS IC (74HC4017 1-of-10 decade counter). It's output pins are either 0V or VCC.
The counter is driven by a slow clock (say, 1Hz). Now I want an LED on one of the output ...
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151 views
How do I find a “pin readout” equivalent for this omnivision cameracube?
I need to know how to connect this omnivision cameracube to a pcb but I don't know what any of the connections on the bottom of the camera correspond to. How can I figure this out?
...
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118 views
Can I slow a CMOS output through an RC filter?
Is it good practice to slow down the slew rate of a CMOS output by putting an RC filter on it? What happens with impedance matching after I do this? Or can I just set the RC filter with such a low ...
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3answers
183 views
Gate array propagation delay times
This is kind of a simple question I haven't been able to find an answer for.
According to my notes, propagation delay increases as supply voltage decreases. While intuitively I would think it would ...
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2answers
140 views
Application of buffer chip in serial communication
On a microcontroller board that I am working on, there is a buffer chip between the microcontroller TI msp430 F1611 and USB interface ...
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2answers
430 views
CMOS vs TTL Logic Gates?
This is probably a simple question but how come CMOS Logic Gates built from Only Transistors is completely different from one that uses TTL Logic (Like BJT's). I know BJT aren't really used anymore ...
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2answers
267 views
Interfacing 3V TI MSP430 to PC serial port
I am scratching my head to figure out a possible soloution for this scenario:
I am developing a simple application using TI MSP430 microcontroller. The microcontrol part is powered by 2xAA batteries. ...
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2answers
187 views
Working of a CMOS inverter
I'm new to this concept and parts of it are a little confusing. I understood the part when a 5V signal is applied as input, a channel is formed in the NMOS device, as the positive voltage attracts ...
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1answer
164 views
How a Cmos not gate works
This is a very newbie question, but i don't understand it well, and i'm studying a lot! =(
I have a Cmos not gate, and I don't understand well how it works.
Dividing in cases:
case X = 0V: the ...
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2answers
217 views
HEF4060B counter doesn't count
I'm building (on a breadboard) a 16Mhz oscillator (part of another circuit) with the HEF4060B using an external xtal.
Schematic I'm using is
that's not so different from the example on the ...
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1answer
314 views
homemade camera with CMOS module SEN-08667 recording video [duplicate]
Possible Duplicate:
develop webcamera with battery and memory to SELF RECORDING (Disc Processing System)
im trying to build an own camera that have the following things and record video to ...
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4answers
659 views
Using CMOS IC in a TTL circuit
Is it safe to use a CMOS IC? For instance I'll be using a CD4017 in this circuit:
http://www.555-timer-circuits.com/police-lights.html
Will it still function correctly? Any further modifications ...
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2answers
570 views
CMOS inverter with gate of PMOS transistor always grounded
If there is a CMOS inverter such that the gate of the PMOS transistor is always attached to the ground and the input voltage is only applied to the gate of NMOS, then how would the inverter behave, as ...
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1answer
237 views
MOS Capacitance and Performance
I was learning about the advantages and challenges in scaling down MOS transistors. I came across this statement in Wikipedia :
...
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764 views
Power consumed by a CPU
I think the power for a CPU with current I and voltage U is I · U.
I wonder how the following conclusion from Wikipedia is derived?
The power consumed by a CPU, is approximately ...
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3answers
130 views
Mixing NMOS and CMOS
I have an old system board for a pinball machine that I'm fixing up. One of the ROMs is failing post. The reason is because the 27S256 EPROM never had the sticker applied to the window, and due to a ...
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2answers
284 views
Strange behavior from a 4017 Johnson counter
I'm using a HEF4017BP connected to LEDs and a pusbutton to control some LEDs.
Here's the schematic:
So I'm using the pushbutton to drive the clock, the capacitor is there to help with debouncing ...
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3answers
530 views
Cascaded logic inverters
In this datasheet the logic diagram shows three cascaded inverters to get a simple inverting function.
So that would mean that you have three PMOS-NMOS pairs in succession. Why is this better ...
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697 views
How are CPUs designed?
I've started playing with electronics a while ago and making simple logic gates using transistors. I know modern integrated circuits use CMOS instead of transistor-transistor logic. The thing I can't ...
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What' so great about CMOS?
I've read lot of topics here ,
I read some people saying I prefer to "have CMOS characteristics " & so on
, Also in some data sheets (like AVR ) , they say it have CMOS characteristics .... etc
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1answer
254 views
Safely connecting 4056 and MSP430
I'm using MSP430G2553IN20 microcontroller on LaunchPad to drive an 4056 chip (HCF4056B to be precise) and a 7 segment display. The 4056 is set to sink current.
I've connected the port 2 pins, set as ...
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1answer
613 views
What is the fastest 7400 series family? Is 74VHC faster than 74AHC?
What is the fastest 7400 series logic family?
Is 74VHC* faster than 74AHC*?
This list does not seem to be in any particular order:
http://en.wikipedia.org/wiki/7400_series
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1answer
472 views
Silicon Controlled Switches: applications&suppliers
I came across this description of what are called "silicon controlled switches." I always look to balance n/p-channel electronics for stability, and using these silicon controlled switches seemed like ...
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2answers
640 views
Atmega8 input impedance
What is the Atmega8 input impedance. I want to add a push button to an Atmega8 and my configuration would look something like this:
A +5V source, resistor, push button not pressed goes to Atmega8, ...
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3answers
518 views
Differential amplifier - what is the differences between CMRR and CMR?
i know that CMRR is Common-mode rejection ratio, but what is it CMR?
\$CMRR = \dfrac{A_{dm}}{A_{CM}}\$
i didn't find any mention of it in Sedra & Smith bible.
does anyone know what CMR is?
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334 views
How do I set the speed of a 4060B chip?
Apologies if this is a bit simple, but I'm new to this!
How do I set the speed for a 4060B chip? I want it to trigger every 5 minutes (fairly accurately).
I've looked at the instructions here: ...
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285 views
Is this buffer for protecting 3.3v logic from 9v power sane?
there. I'm playing with the idea of making a multi-interface for classic game controllers. I realize this is foolish, but I'm doing it anyway.
The interface connector between the system and the ...
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4answers
311 views
Reliability of anti-static packaging
OK, DILs are on the way out, but from time to time you still can see CMOS DILs packaged like this as ESD protection:
That's aluminium foil on EPS (expanded polystyrene). The EPS isn't conductive, ...
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3answers
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Going from Transistors to Gates to…IC's?
So I am trying to understand I guess what is probably a basic concept of computers.
I was taking a look at this previous question:
From Transistor to Gates
And it's accompanying link:
...
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3answers
253 views
Will cutting power to a CMOS chip effectively remove it from the circuit?
I have some designs that require several 4017 ICs to be switched in and out of the circuit intermittently, for counting circuits that require more than 10 outputs.
The way I am currently designing ...
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3answers
273 views
Do I need to duplicate the 4th “substrate” connection when building CMOS gates out of discrete transistors?
All CMOS digital integrated circuits I've ever seen connect all the nFET substrates together to GND.
In particular, the IC CMOS NAND gate has one nFET that has its substrate connected to GND, but its ...
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Understanding CMOS performance and complexity for ASIC : 350nm to 45nm process
I am trying to build an ASIC chip with the help of the MOSIS project. (They make it cheaper by combining multiple small project into a single fab). I have a choice between 350nm to 45nm, and ...
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Equal rise time and fall time in CMOS circuits
For the design of digital CMOS circuits, there is a need to ratio the PMOS and NMOS transistors so that the worst case rise time and fall time on the output are equal. Why is this a crucial ...
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2answers
200 views
Why do MOFET need so many contact windows?
I don't understand these sentences from Razavi's book, Design of CMOS Integrated Analog Circuit,
'the gate polysilicon and the source and drian terminals are typically tied to metal(aluminum) that ...
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Voltage at what Amperage
I've often seen devices with power requirements specified only in Volts (e.g. 7-12V) but never the amperage. I've wanted to run various embedded devices of wall warts and batteries (the devices have ...
