The active device is M1. In Chapter 8 we explored the transistor and you should recall that the BJT device is a current amplifier of sorts (current controlled current source) in that the collector current is β times the base current. Current mirrors have relatively high, sometimes nonlinear input impedance, so they must be fed by a current from a high-impedance current source (sometimes known as a stiff current source). The current mirror is created as a part of the major MOSFET structure with common drain (D) and gate (G) terminals and separated source terminals (S and CS). MP . The current mirror is used to provide bias currents and active loads to circuits.

Because the source-to-drain voltage of M2 is larger than 6. VBN • Relative to 3 Current Mirror OTA • Same G m, GBW, and SR • A v increased by cascode g mc r oc factor • Approximately same noise The high effective collector load provided by the current mirror enables voltage gains of 5000 or more to be achieved provided there is …

Simple current mirror Two implementations exist for the simple current mirror: BJT and MOSFET. Its load consists of a current-mirror active load consisting of M2 and M3.ThecurrentsourceIREFsets the drain current in M3 which is mirrored into the drain of M2. 2. Current mirror circuit. A Wilson current mirror is a three-terminal circuit (Fig. BJT The BJT implementation of the simple current mirror is used as a block in the operational amplifier. 1) that accepts an input current at the input terminal and provides a "mirrored" current source or sink output at the output terminal. Figure 5. T1 and T2 are PNP transistors and form together a current mirror. Conceptually, an ideal current mirror is simply an ideal current amplifier with a gain of -1. A current mirror circuit, mirror or copy the input current of one active device to the other active devices output. It may be used as a Wilson current source by applying a constant bias current to the input branch as in Fig. T3 acts as a regulating valve which increases the current through the current mirror as Input A gets more power while T4 kind of does the opposite by draining current from the mirror with increasing input B power. MN . The internal current mirrors convey this input current to the compensation node, allowing fast charging and discharging-theoretically, in proportion to input step size. Op-amp current mirror. O . So where is R SET for this mirror?

1 : 1 . 1 : B . Current mirror as differential amplifier. 2 BI TAIL VBP . I am reading about common source amplifier with a current-mirror active load from the book Analog Integrated Circuit Design by Tony Chan Carusone, David Johns, Kenneth Martin. For the analysis, we assume β→∞and VA→∞for each bjt so that the output current from each mirror is equal to the input current. The circuit consists of an input diffamp and four Wilson current mirrors. To minimize errors related to the voltage drop on bounding wires from the source current of the major device, two separate terminals, one for a current mirror current return (SR) and •We thus prefer to employ a “unit” transistor and create copies by repeating such a device.

•Direct scaling of the width also faces difficulties.

3 Current Mirror OTA w/ Cascode Output 9 V- V+ . •Current mirrors usually employ the same length for all of the transistors. An example application of the current mirror is the transconductance op amp. An ideal current mirror circuit is an ideal current amplifier with the inverting configuration that can reverse the current direction. An op amp is required if the input current must have a low-impedance sink. i. o .

M1 v. M1 .

Well, in this case I REF is determined not by a resistor in the active-load mirror but by the I BIAS current source (which, in real life, would be a current mirror with a current-setting resistor).

With a current-feedback amplifier, the low-impedance input allows higher transient currents to flow into the amplifier as needed. The circuit is shown in Fig. The mirrored current is a precise copy of the input current. Conceptually, an ideal current mirror is simply an ideal inverting current amplifier that reverses the current direction as well or it is a current-controlled current source (CCCS). •Current ratioing is achieved by only scaling the width of transistors. The reference current, in turn, is determined by a resistor (i.e., the current-setting resistor, R SET). Transistor long tailed pair with a current mirror . B : 1 .

I am confused by the yellow sentence below: For a fixed bias drain current,ID , the effective overdrive voltage is reduced by increasing the device width W. FET Current-Mirror Examples Common-Source Amplifier Figure 1 shows a common-source amplifier. I TAIL.