Is This Circuit a D Flip-Flop or an Inverter?

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In summary, the conversation discusses a component from an example of a frequency divider by 2 design guide. The speaker is struggling to understand how the component works, specifically when D=0 and CLK=1. They believe that in this state, the two leftmost BJTs with collector resistors may be working as inverters. They also question the purpose of the circuit and wonder who labeled the inputs. The other speaker suggests that CLK and NCLK may be a select between a normal differential amplifier and one with both inputs tied high. They also discuss the bias and resistors in the circuit and realize that it is not an integrated circuit. The purpose of the circuit is still unclear to them.
  • #1
genxium
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This component is from the ADS 2008 example(in Frequency Divider by 2, Design Guide), I don't quite understand how it works clearly.

By far I think that if D=0&CLK=1 , then the collector current Ic of BJT1 is small, resulting in that Vc of BJT1 is High, hence Vb of BJT14 is High and BJT14 is active, so [itex]\bar{Q}[/itex]=1.

But I have no idea how to figure out Q when D=0&CLK=1, can anyone give me a hint? I want to ask if the 2 left most BJTs with collector resistor are working as inverters?
 

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  • #2
I can't see how this circuit would hold a value as the tail current is shared between the diff amps. One of them has to loose their bias depending on the state of clk. If I am right and it cannot hold a value it is not a flop.

Who labeled the inputs? My guess is that this is a comparator with an offset trim and hysteresis.

I only looked at this really fast so I could be totally off base though.
 
  • #3
Actually, you know what. I think clk and nclk are supposed to be a select. You either select between a normal diff amp or a diff amp with both its inputs tied high.

I was thinking the other structure was for calibration or something but then I realized the bias is 1mA and the resistors and it dawned on me that this is not an IC.

I have no idea why one would do this though.
 

FAQ: Is This Circuit a D Flip-Flop or an Inverter?

What is a D flip-flop circuit?

A D flip-flop circuit is a type of sequential logic circuit that stores a single bit of data and can change its output based on a clock signal. It has two stable states, 0 and 1, and is commonly used in digital electronics to store and transfer data.

How does a D flip-flop circuit work?

A D flip-flop circuit consists of two inputs - a data input (D) and a clock input (CLK) - and two outputs - Q (the current state) and Q̅ (the opposite state). When the clock input transitions from 0 to 1, the data input is transferred to the output. If the clock input transitions from 1 to 0, the output maintains its current state. This allows for the storage and transfer of a single bit of data.

What are the applications of a D flip-flop circuit?

D flip-flop circuits are commonly used in digital electronics for applications such as data storage, data transfer, and frequency division. They are also essential components in synchronous sequential circuits, which are used in microprocessors, computer memory, and other digital systems.

How is a D flip-flop circuit different from other types of flip-flops?

There are several types of flip-flops, including D, JK, T, and SR flip-flops. The main difference between them is the number of inputs and the behavior of their outputs. D flip-flops have a single data input and are sensitive to the clock signal, whereas other flip-flops may have multiple inputs and different output behaviors.

How is a D flip-flop circuit implemented in a circuit design?

A D flip-flop circuit can be implemented using basic logic gates such as AND, OR, and NOT gates. It can also be built using specialized integrated circuits (ICs) designed specifically for flip-flops. The implementation will vary depending on the specific design and application requirements.

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