Agilent Technologies 4395A - Page 254

Typical
Impedance
Measurement
Techniques
Setting
the Upper
Limit for
DC
Bias
The
4395A can
control
DC
bias
so
that
a
user-specied
upper
limit
(current
or
voltage) is
not
exceeded.
This feature
ensures
that
the
device
under
DC
bias
is
protected
from
excessively
high
voltage or
current.
DC
bias can
be
applied
in
one
of
two
modes:
current
control
and
voltage
control. Y
ou can
set
the
upper
limit
voltage
for
current
control
mode
,
or
the
upper
limit
current
for voltage
control
mode
.
Caution
Before
applying DC
bias,
you must
set
the
upper
limit
to
protect
the
DUT
.
To
set the
DC
bias
upper
limit,
follow
these
steps:
1.
Press
4
Source
5
.
2.
Select
one
of
the
following
two
options:
T
o
apply
DC
bias in
voltage
control
mode
,
toggle
N
N
N
N
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
DC
SRC
[CURRENT]
to
N
N
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
DC
SRC
[VOLTAGE]
.
T
o
apply
DC
bias
in
current
control
mode
,
toggle
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
NN
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
NN
DC
SRC
[VOLTAGE]
to
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
N
N
N
N
N
N
DC
SRC
[CURRENT]
.
3.
Set
the
upper
limit
voltage
or
current.
F
or
voltage
control
mode
,
choose
N
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
DC
CURRENT
LIMIT
and
enter
the
upper
limit
current
using
the
numeric
keys
.
F
or
current
control
mode
,
choose
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
DC
VOLTAGE
LIMIT
and
enter
the
upper
limit
voltage
using
the
numeric
keys
.
Setting
up
and
Applying
Output
V
oltage/Current
1.
Press
4
Source
5
.
2.
Press
NN
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
NN
N
N
N
DC
VOLTAGE
(for
voltage
control
mode)
or
NN
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
NN
N
N
N
DC
CURRENT
(for
current
control
mode),
and
enter
output
DC
voltage
or
current
using
the
numeric
keys
.
3.
T
oggle
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
NN
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
DC
OUT on
OFF
to
N
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
ON
off to
apply
the
DC
voltage
or
current
to
the
DUT
.
8-52 Analyzing the Measurement Results