DEPARTMENT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE MASSACHUSETTS INSTITUTE OF TECHNOLOGY CAMBRIDGE, MASSACHUSETTS 02139

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1 DEPARTMENT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE MASSACHUSETTS INSTITUTE OF TECHNOLOGY CAMBRIDGE, MASSACHUSETTS 0239 Types of Diodes Diode Name Diode Symbol Used for: Special Characteristics Rectifier Diode, Converting AC to ; Can be had in very high Fast Switching Linear and switching current capacities, too Rectifier power supplies slow for hf signal use. Signal Diode HF rectification, Small t r = few ns detection Zener Diode Voltage reference, Used in reverse regulation breakdown Lightemitting Indication, 7segment s vary with color Diode [LED] displays Photodiode Light detection, mech. Reverse current is electrical conversion; increased by light; in solar cell FWD direction=solar cell Optocoupler Electrical isolation LED and photodiode in an opaque package Schottky Diode VHF rectification, No stored charges, >300 detecting small signals MHz, 0.25V [metal jn] Varactor Diode Tuning radio and Tairly linear C with V R receivers Varistor AC line spike protection 2 backback zeners Current Regulator Constant current source Steprecovery snap diode generates Exploits reversecurrent Diode harmonics, f multipliers phenomenon Back Diode Very small signal V maller than rectification Tunnel Diode High frequency Part of forward char. has oscillators negative resistance Laser Diode PIN Diode Reading, writing CD, DVD etc. RF switching diode Diode types Chart of 02/07/05

2 DIODES Type V R(max) a I R(max) b (µa) I F (ma) I F (A) Reverse recovery (ns) Capacitance (pf) Class Comments PAD 45 pa@20v 5 lowest I R Siliconix FJT very low I R pa@5v, pa@5v ID 30 pa@v 0.03 very low I R Intersil; dual N < low I R na@25v N gen purp sig diode indus std; same as N448 N Schottky: low N3062 N4305 N4002 N4007 } 0 00 < b low cap, sig diode controlled amp rect pf at 0 volts indus std; 7member fam N pwr Schottky N pwr Schottky N amp rect N83A high curr rect N83RA reverse (a) V R(max) is repetitive peak reverse voltage, 25 o C, µa leakage. (b) I R(max) is reverse leakage current at V R and 0 o C ambient temperature.

3 Input/ Basic Negative Series Clipper R pk = pk 0.7 V L V V pk = Basic Positive Series Clipper V V pk = V pk = (0.7 V) Biased Negative Series Clipper V pk = pk 0.7 V V pk = V Biased Positive Series Clipper V V pk = V V pk = (0.7 V) Diode Series Clipper Circuits.

4 Input/ Basic Negative Shunt Clipper R Vin s pk = V R in pk S V pk = 0.7 V Basic Positive Shunt Clipper R Vin s Biased Negative Shunt Clipper V in V pk = 0.7 V V pk = ( pk ) R S pk = V R in pk L R S V pk = (V ) (0.7 V) Biased Positive Shunt Clipper pk = V 0.7 V V pk = ( pk ) R S Variable Shunt Clipper R pk = R adjustable V pk = pk Zener Shunt Clipper (Clipped, Zenered) V Z pk = Z V pk = 0.7 V Zener Shunt Clipper (Clipped, Zenered) pk = 0.7 V V pk = V Z V Z Symmetrical Zener Shunt Clipper pk = V Z 0.7 V V RL V pk = (V z ) (0.7 V) Diode Shunt Clipper Circuits.

5 Input/ Negative Clamper V pk = 0.7 V V pk = pkpk V Positive Clamper V pk = in pkpk V pk = 0.7 V Diode Clamper Circuits.

P-N Diodes & Applications

P-N Diodes & Applications Outline Major junction diode applications are Electronics circuit control Rectifying (forward mode) Special break-down diodes: Zener and avalanche Switching Circuit tuning (varactor)