DC and Bias Point Simulations > BJT I-V Curves, Class A Power, Eff., Load, Gm vs. Bias

Description

This simulation setup generates the I-V curves of a BJT. Various data dependent on the I-V curves, such as transconductance, class A output power, and efficiency are also shown. Both the base current and the collector-to-emitter voltage are swept.

Needed to Use Schematic

Nonlinear BJT model

Main Schematic Settings

Sweep ranges for base current and collector voltage

Data Display Outputs

BJT_IV_Gm_PowerCalcs.dds, "ClassA_calcs" page:

• Device I-V curves
• Load line set by placing a marker on the I-V curves at the knee, and by a user-specifiable maximum VCE.
• Maximum allowed DC power dissipation curve, with maximum dissipation set by user.
• Given the load line specified by the knee of the I-V curves and the maximum VCE:
  • Optimum collector voltage and collector current, for maximum power delivered to the load while in Class A operation
  • Corresponding load resistance
  • Corresponding maximum output power
  • Corresponding DC power consumption
  • Corresponding DC-to-RF efficiency
• Given a different bias point, specified by a different marker:
  • Load line between that marker and the marker at the knee of the I-V curve
  • Resistance of this load line
  • DC power consumption at this bias point
  • Output power, assuming the device remains in Class A operation (AC voltage does not exceed user-specified VCE, and does not enter the knee region)
  • DC-to-RF efficiency at this bias point
• Device beta versus base current at the VCE specified by one of the markers

Note The estimate of DC-to-RF efficiency and output power are only approximate, since no high-frequency effects are modeled in this simulation.

BJT_IV_Gm_PowerCalcs.dds, "IV and Gm vs. Bias" page:

• • Device I-V curves
  • DC transconductance (Gm) versus VCE
  • DC transconductance (Gm) versus IBB and VCE
  • DC transconductance (Gm) versus collector current
  • Collector current versus base current at one VCE
  • Table of transconductance values

Schematic Name

BJT_IV_Gm_PowerCalcs

Data display name

BJT_IV_Gm_PowerCalcs.dds