Avtech 14258, Instructions Manual, Page: 22 / 48

BASIC AMPLITUDE CONTROL
The basic test arrangement for the AVR-EB4-B-NXPB-SOD123W is shown in the figure
below. The PULSE output on the instrument mainframe is connected to the PULSE
input on the test jig (model AVX-TRR-NXPB-SOD123W, or a customized variant) using
the supplied coaxial cables, and the control cable is connected using the supplied DB-9
cable.
The total effective resistance of resistors R
A
and R
C
in the diagram above is 50Ω / 2 =
25Ω. Thus, the voltage at the jig output is simply given by:
VOUT = IDUT × (R
A
|| R
C
)
VOUT = IDUT × 25 Ω
where I
DUT
is the current through the device under test. This is the key equation for
relating the observed voltage waveform to the DUT current.
22
AVR-EB4-B-NXPB
MAINFRAME
OUT
SYNC
CONNECTOR
CONTROL
AVX-TRR-NXPB
TEST JIG (OR VARIANT)
SAMPLING
OSCILLOSCOPE
(BW > 2 GHz)
TRIG
CONNECTOR
R
A
,
50Ω
CONTROL
IN2
DUT
OUT
R
C
,
50Ω
I
DUT
V
OUT
= I
DUT
× 25Ω
2m DB-9
CABLE
TWO 2m SMA-to-SMA
COAXIAL CABLES
V
1
V
2
R
1
, 175Ω
C
2
,
0.33uF
User-supplied attenuator,
to limit sampling scope
input to safe values.
Typically 20 dB.
60 cm
SMA-to-SMA
COAXIAL
CABLE
R
2
,
25Ω
IN1