In this paper we present a comparative study of three topology to design push pull amplifier for wide band amplification, and also analysis among these and verify who is best for wide band application is use of radio & wireless communications, we examine topology at different parameters like frequency band width, transients’ analysis, power consumption’s, noise figure temperature stability etc and their uses.
Introduction
I. INTRODUCTION
Inany radio frequency communication system, power amplifier plays very important role, the main function of power amplifier is provided larger output power at the load to derive all output power devices.1 For this work push pull amplifier is very popular between researcher and designer and in electronic field because it provided high efficiency without any distortion and larger band width. Push pull amplifier work on the principle of class B amplifier2. Last few decades CMOS technology play very effective role in designing R F communications electronics devices because
Low power consumptions
High efficiency
Cost Effective
Minimum feature size
Number of gates on a chip
High noise immunity3
In modern time latest demand in electronic field amplification at very minimum power consumptions provided better output without any detorsion with high frequency band. To achieve this goal researcher, use many topologies like Darlington pair, Szikali pair, RKTG pair, NMOS and NPN transistor pair, NMOS and PMOS compounds pair and so many other pair which are possible4.
Among all these possible pair here, we have presented a comparative study among RKTG pair, NMOS and NPN transistor pair and NMOS& PMOS compounds pair, these pair are simulated in 180 nm meter cadence virtuoso software and parameters are same2.
II. COMPARISONS AMONG THEIR PAIR
RKTG Pair:This pair worked on the principle of complementary compound pair using CMOS technology, RKTG pair is designed with the help of two PMOS and TWO NMOS. It worked on principle that if a complimentary pair consist OF PMOS deriver and NMOS output devices, then the driver act as simple NMOs transistor. And its vice-versa1.
2. NMOS and NPN Pair:This pair is designed with the help of NMOS and NPN transistors pair, in this pair NMOS transistor is in driver position and NPN transistor is in it fallower position this combination provided high speed at low power consumptions, their connection model is given below.
3. NMOS and PMOS Combinations Or MRKTAN Pair:This pair designed just opposite of RKTG pair and designing principle is same as like RKTG pair, in this pair we change the place of both MOS transistor i.e., where in RKTG pair place PMOS tis is replace with NMOS and vice versa. Is can being easily under stood by below ray diagram.
4. Comparisons Among Their Circuits& Simulations Results:Since all these above-mentioned topologies simulated on cadence virtuoso 180 nm technology. If we put all values like input voltage biased resistance input capacitance inductor value at output load resistance output capacitance are same and then we draw a comparison table among their simulation result as shown in below6-8
Parameter
RKTG pair
NMOS and NPN transistor
MRKTAN pair
Input frequency
50Hz
50Hz
1000Hz
Input amplitude
1mV
1mV
1mV
Bandwidth
100KHz-6.25ZHz
75Hz-127 PHz
177Hz-77 YHz
Voltage gain
14.8db
36.8db
Less than 1
Power gain
-
-
36.8db
Current gain
-
-
-
Power consumptions
69 mW
36mW
63pW
III. DISCUSSION AND RESULT
By the examine the above result it is found that in radio frequency communication system if want larger voltage gain with bandwidth, we prefer to use design amplifier with the combination of NMOS and NPN transistor but if we focus extra bandwidth with slightly less voltage gain, we use to design amplifier BY RKTG pair but again we find without voltage gain double extra bandwidth we chose MRKTAN pair.
IV. FUTURE WORK
we focus to modify the MRKTAN pair to increase the voltage gain without disturbing the bandwidth and minimize the power loss and tends to zero.
V. ACKNOWLEDGMENT
This work is supported by the grant from the Major Research Project of University Grant Commission (UGC) New Delhi (Project ID.MRP-MAJOR-ELEC-2013-31956). Authors are thankful to University Grant Commission to provide financial support.10