Composite Transistor Research Articles

Low-voltage BICMOS and vertical OTA

A linear BICMOS operational transconductance amplifier (OTA) with low voltage supply requirements is presented. Two versions of this circuit using stacked and folded BICMOS composite transistors are discussed. Simulations and experimental results using transistor arrays are shown that verify the operating principle of the proposed structures.

Floating gate effects in high-power semiconductor-metal eutectic composite transistors

Novel field-effect transistors (FETs) with unusual high-power capabilities have been demonstrated previously. They are fabricated using the grown-in metal-semiconductor junctions of semiconductor-metal eutectic composite materials. Here, computer modeling has been used to examine the relation between their exceptional resistance to avalanche breakdown and the effects of floating gate junctions between the gate and drain. Calculations are presented that show how composite geometry and materials parameters could be optimized to give extremely large off-state blocking voltages combined with low series resistance. These transistors should, in principle, be capable of an on-state power dissipation lower than that of any conventional high-voltage FET device.

Electrical microcharacterization of Si-TaSi2 eutectic composite transistors by three-terminal electron-beam-induced conductivity

A new three-terminal electron-beam-induced conductivity technique, which images microscopic current characteristics, has been used to examine the effects of device and material microstructure on macroscopic performance of Si-TaSi2 eutectic composite transistors. Image contrast arising from current-limiting electron velocity saturation regions shows that current control is not microscopically uniform due to the somewhat irregular distribution of active gate elements. Macroscopically, these nonuniformities result in delayed saturation in the I-V characteristics and excess leakage current when the device is pinched off. Furthermore, the effects of the uncontacted floating gate elements, which are responsible for the unique high-voltage capability of these transistors, are graphically observed.

Applications of composite BICMOS transistors

The concept of the composite CMOS transistor is generalised and extended to include both, composite bipolar and composite BICMOS transistors. Two versions of the BICMOS device and its applications in some linear circuits to reduce supply voltage requirements and increase effective transconductance are discussed. Experimental results using transistor arrays are presented.

Switching characteristics of MINPN devices

The I– V characteristics of the MINPN devices have been studied with the focus on the physical processes in the switchings. The study consists of computer simulation and experimental measurements, both of which show that these devices can exhibit one-state as well as two-state switchings. Such switchings are attributed to the regenerative process of the avalanche of the reverse PN junction with one or multiple current gains of the two composite NPN and MINP transistors. The MIS minority injection plays an important role in determining the switching characteristics of the device. Experimentally the breakover voltage and the hold-on voltage of this device are observed to be adjustable by applying base voltages. This can be considered as another evidence for the increased minority injection of the MIS structure.

1-V operational amplifier with rail-to-rail input and output ranges

A bipolar operational amplifier (OA) with rail-to-rail input and output ranges which can operate at supply voltages down to 1 V is presented. At this supply voltage, the input offset voltage is typically 1.0 mV in an input common-mode voltage range that extends beyond both supply rails for about 300 mV, with a common-mode rejection ratio (CMRR) between 38 and 100 dB, depending on conditions. The output voltage can reach both supply rails within 100 mV, the output current is limited to +or-10 mA, the voltage gain is 100 dB, and the bandwidth is 450 kHz. The die is 2.5*5.5 mm/sup 2/. Qualities such as offset, input-bias current, and CMRR are improved when the supply voltage is increased and the dynamic level shift is autonomically turned off. The OA has been protected against unintentional reversal of the output signal when the inputs are substantially overdriven. The output stage of the circuit consists of two full complementary composite transistors, whose HF characteristics have been improved by internal Miller compensation and linearization of the transconductance.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Stability factors of Darlington transistors†

Expressions giving the change in quiescent collector current due to variations in collector reverse saturation current. and base-emitter voltage have previously been derived for the Darlington composite transistor. In this paper these expressions arc used to obtain stability ratios that directly compare the stability of the Darlington composite transistor with that of a single transistor. A relationship is developed. incorporating these stability ratios, which shows that the Darlington composite is more stable than a single transistor to changes in Ic Bo.but with respect to changes in VBE, it is less stable. Furthermore, because these stability parameters are in opposition, their overall effect is to make the composite transistor about. 25% ( ± 10%) less stable than a single transistor when a proper choice of biasing resistors is made.

Inductive Characteristics of Composite Transistors

Inductive characteristics of the composite transistors have been theoretically investigated. It has been found that the impedance (Z12) consists of two parts i.e. negative resistance and inductance. This inductance has special features such as (i) no magnetic field (ii) high Q (iii) capability of amplification. The area where this inductance finds wide application has also been painted out.

Properties of the super-alpha composite transistor at high frequencies

The equivalent circuit of the composite transistor, the input impedance and the current gain have been developed by analysing its equivalent circuit, in terms of the various parameters of the individual transistors in the common base and common emitter configuration. It is found that in the C.E. configuration, the short-circuit input impedance hie has a negative resistance component over a frequency range in which the current gain in the C.B. configuration h/b is greater than 1.

An accurate integrated voltage-to-current converter

Presents a monolithic integrated differential voltage-to-current converter. The transconductance of the converter is determined accurately by one external resistor. A total error in the conversion factor as low as /spl plusmn/0.5 percent is obtained by using composite transistors and by using the mutual equality of integrated resistors. The transconductance has a nonlinearity of 0.02 percent and a temperature coefficient of 4/spl times/10/SUP -5///spl deg/C. The output impedance is 5 M/spl Omega/. The voltage-to-current converter is a versatile building block. It can be applied as an instrumentation amplifier, a universal current mirror or current follower, etc.

Thermal Variation of Emitter Base Voltage of Composite Transistor

Thermal variation of emitter base voltage of composite transistor has been computed for a wide dynamic range. At the outset a postulate is given in terms of its essential temperature dependent linear and non-linear properties. The conjoint occurrence of fundamental equation is derived. Numerical results which are relevant for the interpretation of existence of symmetries in change of emitter base voltage and effect of high emitter series resistance of inverse transistor, are briefly discussed.

Correspondence: Discussion on ‘Gain and stability of a new composite transistor’†

Correspondence: Discussion on ‘Gain and stability of a new composite transistor’†

Analysis of Darlington composite transistor amplifier in the super-alpha configuration

The paper presents the analysis of a Darlington composite transistor amplifier in the super-alpha configuration. Equations have been developed to study the variations of voltage gain, current gain, power gain input impedance with load resistance and frequency. Calculations have heen made using the IBM 1130 computer for the case of a typical transistor working under typical operating conditions. Graphs representing these variations have been presented and discussed in detail. This Darlington composite transistor amplifier is found to offer some interesting possibilities for applications at low frequencies up to 1 MHz. Simple, although approximate, empirical formulae have been suggested for making ready calculations of voltage gain and power gain in this frequency range in the useful range of load resistances up to 1 kohm in the case of 1 MHz and 10 kohms in the case of 100 kHz. The maximum voltage and power gains obtainable are about 10 with 1 MHz and 1 kohm limitation and about 100 with 100 kHz and 10 kohms limitation.

Harmonic distortion of the Darlington composite transistor

Based on the current-voltage transfer characteristic, equations were derived relating this distortion levels, the operating conditions mid the characteristic parameters of a transistor amplifier, The characteristic of the Darlington composite transistor was determined experimentally, and its harmonic distortion was analysed and compared with its component, transistors, Compensation of harmonic distortion by load and source resistances was discussed.

Comments on ‘ Investigations of the variation of voltage gain with stability factor and biasing resistances in Darlington composite transistors ’

Comments on ‘ Investigations of the variation of voltage gain with stability factor and biasing resistances in Darlington composite transistors ’

Frequency properties of a Darlington composite transistor

Abstract In this paper the analysis of frequency properties of a Darlington composite transistor is given and such of its frequencies as alpha cut-off frequency, beta cut-off frequency and high-frequency power gain are obtained. It is shown that in the CB configuration the | α(ƒ)| function of this device has an extremum value greater than one

Gain and stability of a new composite transistor†

Abstract A new composite system of transistors has been proposed in which three transistors, two p-n-p and one n-p-n, have been used. The combination operates like a p-n-p junction transistor. The expression for the current gain of the system in the common base has been obtained in terms of the current gain of the individual transistors and it has been found that the current gain exceeds unity (1 ·49). A mathematical analysis, however, indicates that the stability of such a system is appreciably increased if the current gain of one of the transistors (n-p-n) in common base is 0·5. It has been further shown that by the addition of such a transistor to the system, the current gain of the composite transistor system remains unaltered.

Effect of variation of load resistance on amplifier characteristics of complementary composite transistors. II

Effect of variation of load resistance on amplifier characteristics of complementary composite transistors. II

Effect of variation of generator resistance on output resistance of complementary composite transistors †

Abstract An expression for the output resistance of a complementary composite transistor has been obtained by analysing its equivalent circuit in terms of the various parameters of the individual transistors. Further, the expression obtained has been simplified by assuming that the parameters of the two transistors are of the same type. The effect of variation of generator resistance on the output resistance has also been investigated and it has been found that the output resistance of a complementary composite transistor is leas than half in value to that of a single transistor and nearly double in value to that of the Darlington composite transistor. It decreases as the value of generator resistance is increased with much higher rate than in the single or Darlington composite transistor.

Characteristics of the composite transistors

The expressions for the current amplification, voltage amplification, input resistance and output, resistance of the composite junction transistor in terms of The resistance parameters of the individual transistor in the common base, common emitter and common collector configurations are derived. It. is found that the composite arrangement, in general, has (i) a much higher current gain and input resistance, and (ii) smaller voltage gain and output. resistance in all the three configurations. The characteristics of the composite system are greatly modified when the second junction transistor is replaced by a point contact, type. This is discussed and practical applications pointed out.