Agilent 33330B/C
Coaxial Detectors for OEM and Systems Use
Product Overview
General Information
The Agilent Technologies 33330B/C
series of broadband coaxial detectors
are specifically designed for use in
microwave instrumentation and sys-
tems applications such as the detect-
ing element in leveling loops, power
monitoring, and as wideband video
detectors.
These detectors utilize a Low Barrier
Schottky (LBS) diode that requires no
bias, has exceptional broadband flat-
ness and low SWR, and is environ-
mentally rugged. For measurement
accessory applications, Agilent offers
similar RF performance with a vari-
ety of input and output connectors in
the Model 423B, 8470B, and 8472B
series.
The Low Barrier Schottky diode detector
The 33330B/C detectors consist of a
Low Barrier Schottky (LBS) diode
and a miniature thin film circuit that
matches the diode to a 50-ohm trans-
mission line. The diode is a specially
fabricated Schottky diode using met-
alization designed to achieve low ori-
gin resistance, thus eliminating the
need for bias. In addition to superior
RF characteristics, the LBS detector
offers significant advantages over
other types of detectors. For example,
a typical Schottky requires bias for
proper operation; a tunnel diode
detector has a limited power range
because of its negative resistance
region; and the point contact diode,
because of its fragile construction, is
unsuitable for many field applications.
Frequency Range
• Broadband (0.01 to 26.5 GHz)
• Excellent flatness (±0.6 dB
to 18 GHz)
• Low SWR (<1.5 to 18 GHz)
• Environmentally rugged
(MIL-STD-883 tests)
• Field replaceable diode
modules
• APC 3.5-mm connector
(reliable, SMA compatible)
• Low Barrier Schottky diode
(no bias required)
Since only metallurgical bonds are
used with the diode, the detectors are
extremely rugged. As noted on page
4, the detectors have undergone
extensive environmental testing to
MIL-STD 883 procedures, an impor-
tant factor in military systems appli-
cations. The detector can also with-
stand high RF power levels for short
durations without burnout, important
for power monitoring applications.
For example, it can typically with-
stand 1 watt CW for a minute without
permanent damage.
The equivalent circuit and pulse
response equations for the 33330B/C
detectors are shown in Figures 1 and
2, and extensive data on the perform-
ance of the detectors is given on page
3. Using this information, the user
can select a load to extend the square
law region to higher power levels or
to minimize the output variation over
a given temperature range.
Excellent broadband flatness
The thin film input matching circuit
was optimized for flat frequency
response and low SWR, which yields
improved performance in leveling
loops and power monitoring applica-
tions. Use of thin film fabrication
techniques for the circuit and diode
results in excellent unit-to-unit
repeatability of performance, and
thus matched pairs will track within
a few tenths of a dB over the entire
frequency range (see Figure 2). This
feature is especially important in the
20 to 26.5 GHz frequency range where
diode capacitance causes the sensitiv-
ity to decrease by 3.3 dB, yet this
“roll off” characteristic is very repeat-
able and matched pairs will track
within ±0.5 dB.
Low SWR
The miniature thin film circuit used
provides an excellent 50-ohm match
to the transmission line, which mini-
mizes reflections that cause frequency
response ripple and power measure-
ment inaccuracies. Such errors can be
significant. For example, using a
detector with an SWR of 2.5:1 in an
application with a 2:1 source match
can result in more than a ±1.3 dB rip-
ple. For the same source match of 2:1,
a typical 33330B detector with SWR
less than 1.25 would have less than
±0.4 dB ripple.
APC 3.5-mm connector improves perform-
ance and extends frequency range
The Agilent 33330B/C detectors use
the APC-3.5 connector, which is com-
patible with the industry standard
SMA but is more rugged and offers
improved repeatability over hundreds
of connections. Use of this connector
extends the frequency range of the
33330C to 26.5 GHz.
Figure 2. Typical frequency response of
the Agilent 33330B/C detectors
Figure 1. Equivalent circuit for the Agilent 33330B/C detectors with typical
parameter values
2
Detector Performance Characteristics
Typical transfer characteristics
Typical temperature characteristics
Figure 3. Typical transfer characteristics (Ta = 25˚ C)
Figure 6. Typical output response with temperature
(P in <–20 dBm)
Figure 4. Typical square law deviation
Figure 7. Typical video impedance variation with temperature
Figure 5. Typical tangential sensitivity
Figure 8. Typical frequency response variation with temperature
3
Specifications
1
33330B
Frequency range
2
Frequency response
Octave band flatness
Broadband flatness
0.01 to 18 GHz
Field replaceable diode modules
33330C
0.01 to 26.5 GHz
SWR
Low level sensitivity
Maximum operating input
Typical short-term maximum
input (less than 1 minute)
1 watt (typical)
Noise (µV peak to peak with
<50 µV
CW power applied to
produce 100 mV output,
400 kHz BW)
Output polarity
Negative
3
Option 001
Matched pair
0.01 to 12.4 GHz: ±0.2 dB
0.01 to 12.4 GHz: ±0.2 dB
0.01 to 18 GHz: ±0.3 dB
0.01 to 18 GHz: ±0.3 dB
0.01 to 26.5 GHz: ±0.5 dB
Option 003
Positive output
4
Environmental capabilities
Operating temperatures
5
–65˚ C to 100˚ C
Temperature cycling
MIL-STD 883. Method 1010.1: ( –65˚ C to ±100˚ C)
Vibration
MIL-STD 883. Method 2007 0.6’’ D.A. (20 to 80 Hz)
and 20 G (80 to 2000 Hz)
Shock
MIL-STD 883. Method 2002.1 (500 G. 0.5 ma)
Acceleration
MIL-STD 883. Method 2001 (5000 G)
6
Altitude
MIL-STD 883. Method 1001: (50,000 ft. 15 240 m)
Salt atmosphere
7
MIL-STD 883. Method l009.1: (48 hr. 5% solution)
Moisture resistance
With epoxy coating
7
MIL-STD 883. Method 1004.1: (25˚ C to 65˚ C, 95% RH)
Without coating
25˚ C to 40˚ C, 95% RH
±0.2 dB over any octave to 8 GHz ±0.2 dB over any octave to 8 GHz
0.01 to 12.4 GHz: ±0.3 dB
0.01 to 12.4 GHz: ±0.3 dB
0.01 to 18 GHz: ±0.6 dB
0.01 to 20 GHz: ±0.6 dB
20 to 26.5 GHz: ±1.5 dB from a–3.3 dB
linear slope
0.01 to 4 GHz: 1.2
0.01 to 4 GHz: 1.2
0.01 to 18 GHz: 1.5
4 to 18 GHz: 1.5
18 to 26.5 GHz: 2.2
>0.5 mV/µW
0.01 to 18 GHz: >0.5 mV/µW
18 to 26.5 GHz: >0.18 mV/µW
200 mW
In the event of diode burnout, the
detector module can be replaced in
the field. Since the replacement mod-
ule includes the tested and sealed
assembly of diode and thin-film
matching circuit, the user is assured
of performance to specifications. This
offers an advantage over detector
designs where only the diode is
replaced and not tested in its final
assembly.
Outline drawing
1. Measured at 25˚ C and <–20 dBm unless otherwise
specified.
2. Below 1 GHz RF may leak through the video connec-
tor. If objectionable, this may be eliminated with a
low pass filter.
3. Quantity two (2) must be ordered for each matched
pair.
4. Additional information available upon request.
5. Typical variations with temperature are shown on
page 3.
6. Tested only to 50,000 ft (15,240 m), capable of much
higher performance.
7. Use of an epoxy coating is required for meeting
these requirements. Contact your Agilent
Components Field Engineer for details.
4
Model number
33330B
33330B Option 001
33330B Option 003
33330C
33330C Option 001
33330C Option 003
Mechanical information
RF connector
Output connector
Net weight
Description
Negative polarity
Matched pair (negative)
Positive polarity
Negative polarity
Matched pair (negative)
Positive polarity
Replacement module
part number
33330-80003
33330-80004
33330-80005
33330-80006
33330-80007
33330-80008
APC-3.5 male (SMA compatible)
SMC (male center conductor)
14 g (0.5 oz)
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Product specifications and descriptions in
this document subject to change without notice.
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