Download presentation

1
**Professor Ronald L. Carter ronc@uta.edu http://www.uta.edu/ronc/**

Semiconductor Device Modeling and Characterization – EE5342 Lecture 16 – Spring 2011 Professor Ronald L. Carter

2
SPICE Diode Temp. Eqs.1 ©rlc L16-07Mar2011

3
**Corrections in some versions of SPICE**

©rlc L16-07Mar2011

4
**SPICE Diode Temp. Pars.1 PARAMETER definition and units default value**

XTI IS temperature exponent 3.0 TIKF ikf temperature coefficient (linear) °C TRS1 rs temperature coefficient (linear) °C TRS2 rs temperature coefficient (quadratic) °C TBV1 bv temperature coefficient (linear) °C TBV2 bv temperature coefficient (quadratic) °C T_ABS absolute temperature °C T_MEASURED measured temperature °C T_REL_GLOBAL relative to current temperature °C T_REL_LOCAL Relative to AKO model temperature °C ©rlc L16-07Mar2011

5
Thermal Resistance ©rlc L16-07Mar2011

6
**Self-Heating Effects Id (A) Vd,ext = Vd + Id*RS**

348K < TNOM < 300K 10 mW 20 mW 30 mW 40 mW 50 mW 60 mW 70 mW 80 mW Rth = 0 K/W , RS = 0.32 W Rth = 600 K/W, RS = 1 W ©rlc L16-07Mar2011

7
Self-Heating Effects SPICE models the IS, etc. the same for all power dissipations. The effect of diode self-heating is to increase the current at all voltages. In this case, an Rth of 600K/W gave nearly the same simulation as re-setting RS from 1 Ohm to 0.32 Ohm. The diode Tj is different at all curr. ©rlc L16-07Mar2011

8
**PiN Diode PiN: Na >> Nint (= N-) & Nint << Nd**

Wi = Intrinsic region (metall.) width Em,P-T = Peak field mag. when xn = Wi Vbi = fi = Vtln(NaNd/ni2) Vbi,int = fi,int = Vtln(NaNint/ni2) VHL = Vtln(Nd/Nint), the offset at N+N- Vbi = Vbi,int + VHL VPT = applied voltage when xn = Wi ©rlc L16-07Mar2011

9
**PiN Diode Depletion Fields**

Normalized Position, x’ = x/Wi Normalized Field, E/Em,P-T dx’p dx’n x’n -x’p ©rlc L16-07Mar2011

10
**PiN Diode Depletion Conditions**

©rlc L16-07Mar2011

11
**CV data and N(x) calculation**

©rlc L16-07Mar2011

12
**Diode Switching Consider the charging and discharging of a Pn diode**

(Na > Nd) Wd << Lp For t < 0, apply the Thevenin pair VF and RF, so that in steady state IF = (VF - Va)/RF, VF >> Va , so current source For t > 0, apply VR and RR IR = (VR + Va)/RR, VR >> Va, so current source ©rlc L16-07Mar2011

13
**Diode switching (cont.)**

VF,VR >> Va F: t < 0 Sw RF R: t > 0 VF + RR D VR + ©rlc L16-07Mar2011

14
Diode charge for t < 0 pn pno x xn xnc ©rlc L16-07Mar2011

15
**Diode charge for t >>> 0 (long times)**

pn pno x xn xnc ©rlc L16-07Mar2011

16
Equation summary ©rlc L16-07Mar2011

17
**Snapshot for t barely > 0**

pn Total charge removed, Qdis=IRt pno x xn xnc ©rlc L16-07Mar2011

18
**I(t) for diode switching**

ID IF ts ts+trr t - 0.1 IR -IR ©rlc L16-07Mar2011

19
References 1Semiconductor Device Modeling with SPICE, 2nd ed., by Massobrio and Antognetti, McGraw Hill, NY, 1993. **OrCAD Pspice A/D Reference Guide, Copyright 1999, OrCAD, Inc. ***MicroSim OnLine Manual, MicroSim Corporation, 1996. ©rlc L16-07Mar2011

Similar presentations

OK

Semiconductor Device Modeling and Characterization – EE5342 Lecture 35 – Spring 2011 Professor Ronald L. Carter

Semiconductor Device Modeling and Characterization – EE5342 Lecture 35 – Spring 2011 Professor Ronald L. Carter

© 2018 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google