| Home | Terms of Use | Site Map | Contact Us |
IndustryCommunity.com > Electrical and Electronic Community > PSpice Models for Analog & Digital ICs Message Board > Message
Main Menu
Find

[ List Subjects ][ Current Board ][ Post Message ]
[ View Followups ][ Post Followup ]

Subject: 433MHz SAW oscillator did not work in PSPICE simulation

Date: 09/08/01 at 11:01 AM
Posted by: Vanadium
E-mail: vanadium@hutchcity.com
Message Posted:

Hello Experts,

I am trying to design a 433MHz oscillator using a SAW resonator and a Philips wideband transistor BFT25A connected as a Colpitts circuit. The circuit is described by the PSPICE file as attached below. According to the PSPICE simulation results, the oscillating frequency was totally controlled by the LC values. The SAW device contributed no effect to the circuit. How can I make the circuit oscillate at 433.92MHz with high stability?

Your helpful contribution will be highly appreciated.

[code]433MHz Oscillator
VCC 2 0 3V
L1 2 4 26nH
R2 2 5 150k
C3 4 6 12pF IC=3
C4 6 0 10pF IC=3
R3 6 0 3.9k
XSAW 5 0 NMR433A
XQ1 4 5 6 BFT25A
.LIB MYLIB.LIB
.TRAN 10p 500n UIC
.OPTIONS ITL5=500000
.END[/code]

The PSPICE library "MYLIB.LIB" is attached as follows:

[code]* My Own Library
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
* 433.92MHz SAW Resonator, Unloaded Q = 12,800, Ceratronics Limited.
*
.subckt NMR433A 1 2
*
rm 1 11 18
lm 11 12 86.0075uH
cm 12 2 1.56417fF
cp 1 2 1.7pF
cpar1 1 0 0.5pF
cpar2 2 0 0.5pF
.ends
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
* BFT25A SPICE MODEL
* PHILIPS SEMICONDUCTORS
* Date : September 1995
*
* PACKAGE : SOT23 DIE MODEL : BFT25A
* 1: COLLECTOR; 2: BASE; 3: EMITTER;
.SUBCKT BFT25A 1 2 3
Q1 6 5 7 7 QBFT25A
* SOT23 parasitic model
Lb 4 5 0.4n
Le 7 8 0.83n
L1 2 4 0.35n
L2 1 6 0.17n
L3 3 8 0.35n
Ccb 4 6 71f
Cbe 4 8 71f
*
* PHILIPS SEMICONDUCTORS Version: 1.0
* Filename: BFT25A.PRM Date: Feb 1992
*
.MODEL QBFT25A NPN
+ IS = 1.37749E-017
+ BF = 8.56539E+001
+ NF = 9.79900E-001
+ VAF = 5.08049E+001
+ IKF = 1.00000E+001
+ ISE = 2.19977E-015
+ NE = 1.85715E+000
+ BR = 1.69751E+001
+ NR = 9.85511E-001
+ VAR = 2.49144E+000
+ IKR = 1.88014E-001
+ ISC = 2.05160E-016
+ NC = 1.10731E+000
+ RB = 8.00000E+001
+ IRB = 1.00000E-006
+ RBM = 8.00000E+001
+ RE = 7.91100E+000
+ RC = 5.30000E+000
+ EG = 1.11000E+000
+ XTI = 3.00000E+000
+ CJE = 2.23030E-013
+ VJE = 6.69700E-001
+ MJE = 5.96638E-002
+ TF = 5.11209E-012
+ XTF = 7.90917E+000
+ VTF = 1.33880E+000
+ ITF = 5.66263E-003
+ PTF = 1.53714E+001
+ CJC = 2.29018E-013
+ VJC = 3.94786E-001
.ENDS
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
* end of library file[/code]


Follow Ups:


Post a Follow-up:

Name:
E-Mail:
Subject:

Message to Post:

 

1999-2001 Sunlit Technology Co., Ltd. All rights reserved.