N_Diode_N4 - Diodes (04) Reference: Microelectronic...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Diodes (04) Reference: Microelectronic Circuits: 5 th Edition By Adel S. Sedra & Kenneth C. smith
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 REAL DlODE OR SILICON DIODE In this section we study the characteristics of real diodes, specifically, semiconductor junction diodes made of silicon . The physical processes that give rise to the diode terminal characteristics, and to the name "junction diode," may be revised / studied in Section 3.7 of the book: relevant revision of semiconductor physics. Figure 3.7 shows the i-v characteristic of a silicon junction diode. 3.2 TERMINAL CHARACTERISTICS OF JUNCTION DIODES Figure 3.7 The i–v characteristic of a silicon junction diode.
Background image of page 2
3 REAL DlODE OR SILICON DIODE The same characteristic is shown in Fig. 3.8 with some scales expanded and others compressed to reveal details. Note that the scale changes have resulted in the apparent discontinuity at the origin. 3.2 TERMINAL CHARACTERISTICS OF JUNCTION DIODES … Figure 3.8 The diode i–v relationship with some scales expanded and others compressed in order to reveal details.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 REAL DlODE OR SILICON DIODE As indicated, the characteristic curve consists of three distinct regions : 1. The forward-bias region, determined by v > 0 2. The reverse-bias region, determined by v < 0 3. The breakdown region, determined by v < -V zk Figure 3.8 The diode i–v relationship with some scales expanded and others compressed in order to reveal details.
Background image of page 4
5 REAL DlODE OR SILICON DIODE 3.2.1 The Forward-Bias Region The forward-bias-or simply forward- region of operation is entered when the terminal voltage v is positive. In the forward region the i-v relationship is closely approximated by equation 3.1 In this I s is a constant for a given diode at a given temperature. A formula for I s in terms of the diode's physical parameters and temperature is given in Section 3.7. 3.2 TERMINAL CHARACTERISTICS OF JUNCTION DIODES …
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6 REAL DlODE OR SILICON DIODE 3.2.1 The Forward-Bias Region The current I S , is usually called the saturation current . Another name for I S , used occasionally, is the scale current . This name arises from the fact that I S is directly proportional to the cross- sectional area of the diode. Thus doubling of the junction area 3.2 TERMINAL CHARACTERISTICS OF JUNCTION DIODES …
Background image of page 6
7 REAL DlODE OR SILICON DIODE 3.2.1 The Forward-Bias Region For "small-signal" diodes, which are small-size diodes intended for low-power applications, I s is on the order of 10 -15 A. The value of I S is, however, a very strong function of temperature . As a rule of thumb, I s doubles in value for every 5°C rise in temperature . The voltage V T in Eq. (3.1) is a constant called the thermal voltage and is given by 3.2 TERMINAL CHARACTERISTICS OF JUNCTION DIODES …
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
8 REAL DlODE OR SILICON DIODE 3.2.1 The Forward-Bias Region 3.2 TERMINAL CHARACTERISTICS OF JUNCTION DIODES … where k = Boltzmann's constant = 1.38 x 10 -23 joules / kelvin T = the absolute temperature in kelvins = 273 + temperature in "C q = the magnitude of electronic charge = 1.60 x 10
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 32

N_Diode_N4 - Diodes (04) Reference: Microelectronic...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online