Agilent 8474B Data Sheet

Typical values:

RV(diode video impedance) ≈ 1.5 kΩ*
C

B

(RF bypass capacitor) ≈ 27 pF nominal

TR (10 to 90% risetime) ≈ 2.2 (R

LOAD

) (RV)

(CB+ C

LOAD

) =

0.35

R

LOAD

+ R

V

BW

Agilent 8474B/C/E
Coaxial GaAs Microwave
Detectors

0.01 to 50 GHz

Data Sheet

Figure 1. Equivalent circuit for

8474A/B/C/D/E with typical parameters

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 ohm
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 SMA-compatible 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.

*@ 25˚ C and PIN ≤ 20 dBm (see Figure 7)

2

Detector performance characteristics

Figure 2. Typical transfer characteristics (Ta = 25° C).

Figure 3. Typical square law deviation.

Figure 4. Typical tangential sensitivity.

Figure 5. Typical output response with temperature. (Pin ≤20 dBm)

Figure 6. Typical video impedance variation with temperature.

Figure 7. Typical square law deviation due to frequency.

3

Specifications

8474B 8474C 8474E

Frequency range: 0.01-18 GHz 0.01-33 GHz 0.01-50 GHz
Frequency response ±0.35 dB ±0.45 dB from ±0.4 dB from

0.01 to 0.01 to

26.5 GHz 26.5 GHz
±0.7 dB from ±0.6 dB from

26.5 to 26.5 to
33 GHz 40 GHz

±1.0 dB from
40 to 50 GHz

SWR: <1.3 <1.4 .01- <1.2 .01-

26.5 GHz 26.5 GHz
<2.2 26.5- <1.6 26.5­33 GHz 40GHz

<2.8 40-50 GHz

Low-level sensitivity: >0.4 mV/µW >0.4 mV/µW >0.4 mV/µW

>0.34 mV/µW

40-50 GHz
Max. operating inputs: 200 mW 200 mW 200 mW
Typical short- 0.75 watt 0.75 watt 0.75 watt
Term max. input: (<1 min.) (<1 min.) (<1 min.)
Noise: <50 µV <50 µV <50 µV
(µV peak-to-peak

with CW power
applied to produce
100 MV output,
400 kHz BW)
STD output polarity: negative negative negative
Note: Above specifications are at 25° C and ≤20 dBm unless otherwise specified.

Mechanical information

8474B 8474C 8474E

Dimensions 20.82 (0.82) 7.9 (0.31) 7.9 (0.31)
mm (inches) 59.86 (2.36) 41.15 (1.62) 37.36 (1.47)

18.68 (0.74) 9.7 (0.38) 7.6 (0.30)

Input connector: Type N (m) 3.5 mm (m) 2.4 mm (m)

SMA 1.85 min

compatible compatible
Output connector: BNC (f) SMC (m) SMC (m)
Net weight: 85.3 grams 13.9 grams 9.1 grams

(3 oz.) (0.49 oz.) (0.32 oz.)

8474B Options 002 004 008 012 018

Frequency range (GHz): .01-2 2-4 4-8 8-12.4 12.4-18
Frequency response (dB): ±0.25 ±0.25 ±0.25 ±0.25 ±0.35
SWR: <1.09 <1.1 <1.2 <1.3 <1.31

8474C Options 004 008 012 018 026 033

Frequency range (GHz): 2-4 4-8 8-12.4 12.4-18 18-26.5 26.5-33
Frequency response (dB): ±0.2 ±0.2 ±0.25 ±0.3 ±0.3 ±0.3
SWR: <1.1 <1.16 <1.2 <1.3 <1.41 <2.2

Environmental

*Operating temperature: -65 to 100° C
Temperature cycling (non-operating): MIL-STD 883, method 1010.1:

(-65 to 100° C)

Vibration: MIL-STD 883, method 2007: (0.6” D.A. 20 to 80 Hz, 20g, 80 to 200 Hz)
Shock: MIL-STD 883, method 2002.1: (500g, 0.5 msec)
Acceleration: MIL-STD 883, method 2001: (500g)
Altitude: MIL-STD 883, method 1001: (50,000 ft, 15,240 m)
Salt atmosphere: MIL -STD 883, method 1009.1: (48 hr, 5% solution)
Moisture resistance: MIL-STD 883, method 1004.1: (25 to 40° C, 95% RH)
RFI: MIL-STD 461B
ESD: 10 hits at 25kV to the body, not the center conductor.

Figure 8. Typical frequency response.

* 8474A/B specified for 0° C - 75° C.

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Copyright © 2001, 2006
Agilent Technologies, Inc.
Printed in U.S.A. May 30, 2006
5952-0801