HSMS-286F Datasheet, PDF (11/18 Pages) Broadcom Corporation. – Surface Mount Microwave Schottky Detector Diodes

120
INPUT POWER = –30 dBm
100
3.0 µA
80
1.0 µA
10 µA
60
0.5 µA
40
-55 -35 -15 5
25 45 65 85
TEMPERATURE (°C)
Figure 25. Output Voltage vs. Temperature and Bias Current
in the 915 MHz Voltage Doubler using the HSMS-286C.
in a single package, such as the SOT-143 HSMS‑2865 as
shown in Figure 29.
In high power differential detectors, RF coupling from
the detector diode to the reference diode produces a
rectified voltage in the latter, resulting in errors.
Isolation between the two diodes can be obtained
by using the HSMS-286K diode with leads 2 and 5
grounded. The difference between this product and the
conventional HSMS-2865 can be seen in Figure 29.
3
4
6 54
35
INPUT POWER = – 30 dBm
3.0 µA
25
10 µA
1.0 µA
15
0.5 µA
5
-55 -35 -15 5 25 45 65 85
TEMPERATURE (°C)
Figure 26. Output Voltage vs. Temperature and Bias Current
in the 5.80 GHz Voltage Detector using the HSMS-286B Schottky.
Six Lead Circuits
The differential detector is often used to provide temper‑
ature compensation for a Schottky detector, as shown in
Figures 27 and 28.
bias
matching
network
differential
amplifier
Figure 27. Differential Detector.
PA
detector
diode
Vs
to differential
amplifier
HSMS-2865 _{reference diode}
Figure 28. Conventional Differential Detector.
These circuits depend upon the use of two diodes
having matched V_f characteristics over all ­operating
temperatures. This is best achieved by using two diodes
1
2
HSMS-2865
SOT-143
12 3
HSMS-286K
SOT-363
Figure 29. Comparing Two Diodes.
The HSMS-286K, with leads 2 and 5 grounded, offers
some isolation from RF coupling between the diodes.
This product is used in a differential detector as shown
in Figure 30.
PA
detector
diode
Vs
to differential
amplifier
HSMS-286K
reference diode
Figure 30. High Isolation Differential Detector.
In order to achieve the maximum isolation, the designer
must take care to minimize the distance from leads 2
and 5 and their respective ground via holes.
Tests were run on the HSMS-282K and the conventional
HSMS-2825 pair, which compare with each other in the
same way as the HSMS-2865 and HSMS-286K, with the
results shown in Figure 31.
Frequency = 900 MHz
5000
1000
RF diode
Vout
Square law
100
response
10
1
0.5
-35
37 dB
HSMS-2825
ref. diode _HSMS-282K
ref. diode
47 dB
-25 -15 -5
5
15
INPUT POWER (dBm)
Figure 31. Comparing HSMS-282K with HSMS-2825.
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