Keithley S530 - Beta2

S530 Parametric Test System Test Subroutine Library User's Manual Section 3: Test subroutine library reference
S530-907-01 Rev. A / September 2015 3-3
beta2
This subroutine calculates beta () and base-emitter voltage (V
BE
) at a specified collector current (I
C
) and
collector-emitter bias (V
CE
).
Usage
double beta2(int e, int b, int c, int sub, double ice, double vce, double *vbeout,
double *icout, char type);
e
Input
The emitter pin of the device
b
Input
The base pin of the device
c
Input
The collector pin of the device
sub
Input
The substrate pin of the device
ice
Input
The targeted collector current, in amperes
vce
Input
The forced collector-emitter voltage, in volts
type
Input
Type of transistor: "N" or "P"
vbeout
Output
The measured base voltage
icout
Output
The measured collector current
Returns
Output
The calculated beta:
 -1.0 = TYPE not "N" or "P"
 -2.0 = SMU2 overload
 -3.0 = Divide by 0, or  < 0.01
 -4.0 =  > 10 K
 -5.0 = Too many iterations
 -6.0 = Emitter voltage limit reached; developed emitter voltage is
within 98 % of the 3 V voltage limit
Details
If a positive substrate pin is specified, the substrate is grounded. If a positive substrate pin is not
specified, the substrate is left floating.
A delay is incorporated into the beta2 subroutine; this delay is the calculated time required for stable
forcing of emitter current with a 3 V voltage limit.
A faster and simpler subroutine to use is beta2a (on page 3-4).
V/I polarities
The polarities of V
CE
and I
E
are determined by device type.
Source-measure units (SMUs)
 SMU1: Forces I
E
, 3 V voltage limit
 SMU2: Forces V
CE
, maximum current limit, measures I
CE
 SMU3: Forces 0.0 V, measures base current (I
B
)