Keysight 8474B/C/E
Planar-Doped Barrier Diode Detectors
0.01 to 50 GHz
Data Sheet
Introduction
Features and Description
–
–
–
–
Exceptional flatness
Broadband from 0.01 to 50 GHz
Extremely temperature stable
Environmentally rugged
The 8474 series of coaxial detectors are specifically designed for use in microwave instrumentation
and systems. These detectors utilize a GaAs diode matched to a 50
Ω
transmission line with a
miniature thin film circuit.
The diodes are a Planar-Doped Barrier (PDB) structure fabricated by use of Molecular Beam Epitaxy
technology. This combination yields a device which has superior characteristics to point-contact and
low-barrier Schottky devices. These characteristics are reflected in frequency response specification
and in square law response vs. frequency (Figure 7) with PDB detectors showing a maximum square
law response variation of 3% from 2 to 18 GHz vs. 9.5% for Schottky detectors.
These detectors are extremely rugged with high resistance to ESD damage and are less sensitive to
temperature change than either point-contact or Schottky diodes. These products offer 10 MHz to
50 GHz performance with the 2.4 mm connector (8474E) or narrower frequency coverage with APC-7
Type N or SMAcompatible 3.5 mm and 2.92 mm connectors. There is no need to order matched pairs
because the frequency tracking is better than the original matched pair specifications.
Equivalent diode
R
V
, diode video
impedance
C
B
, RF bypass
capacitor
Video out
V
RF in
50 Ω
Figure 1. Equivalent circuit for 8474A/B/C/D/E with typical parameters
Typical values:
R
V
(diode video impedance) ~ 1.5 kΩ*
C
B
(RF bypass capacitor) ~ 27 pF nominal
TR (10 to 90% risetime) ~ 2.2
(R
LOAD
) (R
V
)
R
LOAD
+ R
V
(C
B
+ C
LOAD
) =
0.35
BW
*@ 25 °C and PIN ≤ –20 dBm (see Figure 7)
03 | Keysight | 8474B/C/E Planar-Doped Barrier Diode Detectors – Data Sheet
Detector Performance Characteristics
50 kΩ 1 kΩ
2
Sensitivity change (dB)
1V
Output voltage
100 m
10 m
1m
0.1 m
0.01 m
–40
–30
–20
0
–2
–4
–6
–8
30 Ω
200 Ω
R
L
= 50 kΩ
R
L
= 10 kΩ
R
L
= 1 kΩ
R
L
= 100 Ω
–10
0
10
20
30
40
–10
–80 –60 –40 –20
0
20
40
60
80
100
Input power (dBm)
Figure 2. Typical transfer characteristics (T
a
= 25 °C)
Temperature (°C)
Figure 5. Typical output response with temperature (Pin ≤ –20 dBm)
100 k
Data taken at 25 ° –25 ° –100 °C
Deviation from square law
2
0
–2
–4
–6
–8
–10
–12
–20
–10
0
P
in
(dBm)
Figure 3. Typical square law deviation
Video resistance (Ω)
R
L
= 0.5 kΩ
R
L
= 0.5 kΩ
R
L
= 2 kΩ
R
L
= 50 kΩ
10 k
R
L
= 0.5 kΩ
R
L
= 50 kΩ
1k
10
20
0
–60
–20
20
60
100
140
Temperature (°C)
Figure 6. Typical video impedance variation with temperature
0
Tangential sensitivity (dBm)
–10
–20
–30
–40
–50
–60
–70
–80
10
2
10
3
10
4
10
5
10
6
10
7
10
8
Ta = 100 °C
dB
Ta = 60 °C
Ta = 25 °C
5
0
–5
–10
10
2 GHz
8 GHz
12 GHz
18 GHz
% variation in dB from output at –20 dBm RF input
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Bandwidth (Hz)
Figure 4. Typical tangential sensitivity
RF power (dBm)
Figure 7. Typical square law deviation due to frequency
04 | Keysight | 8474B/C/E Planar-Doped Barrier Diode Detectors – Data Sheet
Specifications
8474B
Frequency range
Frequency response
0.01 to 18 GHz
± 0.35 dB
8474C
0.01 to 33 GHz
± 0.45 dB from 0.01 to 26.5 GHz
± 0.7 dB from 26.5 to 33 GHz
SWR
< 1.3
< 1.4 .01 to 26.5 GHz
< 2.2 26.5 to 33 GHz
> 0.4 mV/µW
200 mW
0.75 watt (< 1 min.)
< 50 µV
8474E
0.01 to 50 GHz
± 0.4 dB from 0.01 to 26.5 GHz
± 0.6 dB from 26.5 to 40 GHz
± 1.0 dB from 40 to 50 GHz
< 1.2 .01 to 26.5 GHz
< 1.6 26.5 to 40 GHz
< 2.8 40 to 50 GHz
> 0.4 mV/µW
> 0.34 mV/µW 40 to 50 GHz
200 mW
0.75 watt (< 1 min.)
< 50 µV
Low-level sensitivity
Maximum operating inputs
Typical short-term maximum input
Noise
(µV peak-to-peak with CW power applied
to produce 100 MV output, 400 kHz BW)
Standard output polarity (default)
> 0.4 mV/µW
200 mW
0.75 watt (< 1 min.)
< 50 µV
Negative
Negative
Negative
Notes:
Above specifications are at 25 °C and ≤ –20 dBm unless otherwise specified.
Negative polarity (Option 301) is a default option. Select Option 103 for positive polarity.
Mechanical Information
8474B
Dimensions mm (inches)
20.82 (0.82)
59.86 (2.36)
18.68 (0.74)
Type N (m)
BNC (f)
85.3 grams (3 oz.)
8474C
7.9 (0.31)
41.15 (1.62)
9.7 (0.38)
3.5 mm (m)
SMA compatible
SMC (m)
13.9 grams (0.49 oz.)
8474E
7.9 (0.31)
37.36 (1.47)
7.6 (0.30)
2.4 mm (m)
1.85 min compatible
SMC (m)
9.1 grams (0.32 oz.)
Input connector
Output connector
Net weight
8474B options
Frequency range (GHz)
Frequency response (dB)
SWR
8474C options
Frequency range (GHz)
Frequency response (dB)
SWR
001
0.01 to 18
± 0.35
< 1.31
001
0.01 to 33
± 0.3
< 2.2
002
0.01 to 2
± 0.25
< 1.09
008
4 to 8
± 0.2
< 1.16
004
2 to 4
± 0.25
< 1.1
012
8 to 12.4
± 0.25
< 1.2
008
4 to 8
± 0.25
< 1.2
033
26.5 to 33
± 0.3
< 2.2
05 | Keysight | 8474B/C/E Planar-Doped Barrier Diode Detectors – Data Sheet
Environmental
Operating temperature* –65 to 100 °C
Temperature cycling
(non-operating)
Vibration
Shock
Acceleration
Altitude
Salt atmosphere
Moisture resistance
RFI
ESD
*
MIL-STD 883, method 1010.1: (–65 to 100 °C)
MIL-STD 883, method 2007: (0.6” D.A. 20 to 80 Hz, 20 g, 80 to 200 Hz)
MIL-STD 883, method 2002.1: (500 g, 0.5 msec)
MIL-STD 883, method 2001: (500 g)
MIL-STD 883, method 1001: (50,000 ft, 15,240 m)
MIL-STD 883, method 1009.1: (48 hr, 5% solution)
MIL-STD 883, method 1004.1: (25 to 400 °C, 95% RH)
MIL-STD 461B
10 hits at 25 kV to the body, not the center conductor
8474A/B specified for 0 to 75 °C.
Ordering Information
Model
8474B
Option number
002
004
008
102
1
103
301
8474C
008
012
033
103
301
1.
Option description
0.01 to 2 GHz octave only
2 to 4 GHz octave only
4 to 8 GHz octave only
Square law load
Positive polarity
Negative polarity
4 to 8 GHz octave only
8 to 12.4 GHz octave only
26.5 to 33 GHz octave only
Positive polarity
Negative polarity
Option 102 external square law load extends the square law region of the detector with deviation of
± 0.5 dB from the ideal square law response.
Frequency response (dB)
1
8474B
0
8474C
8474E
–1
0
10
20
30
40
50
Frequency
Figure 8. Typical frequency response
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