HSMS-286R-TR1G Avago Technologies US Inc., HSMS-286R-TR1G Datasheet - Page 8

• Manufacturer Part Number: HSMS-286R-TR1G
• Description: DIODE SCHOTTKY DETECT HF SOT-363
• Manufacturer: Avago Technologies US Inc.

Specifications of HSMS-286R-TR1G

• Diode Type: Schottky - 2 Pair Series Connection
• Voltage - Peak Reverse (max): 4V
• Capacitance @ Vr, F: 0.25pF @ 0V, 1MHz
• Package / Case: SC-70-6, SC-88, SOT-363
• Diode Case Style: SOT-363
• No. Of Pins: 6
• Peak Reflow Compatible (260 C): Yes
• Leaded Process Compatible: Yes
• Forward Voltage: 350mV
• Repetitive Reverse Voltage Vrrm Max: 4V
• Forward Current If: 1mA
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Max: -
• Power Dissipation (max): -
• Resistance @ If, F: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

915 MHz Detector Circuit
Figure 11 illustrates a simple impedance matching network
for a 915 MHz detector.
Figure 11. 915 MHz Matching Network for the HSMS-286x Series at 3 µA Bias.
A 65 nH inductor rotates the impedance of the diode to
a point on the Smith Chart where a shunt inductor can
pull it up to the center. The short length of 0.065” wide
microstrip line is used to mount the lead of the diode’s
SOT‑323 package. A shorted shunt stub of length <λ/4
provides the necessary shunt inductance and simul‑
taneously provides the return circuit for the current
generated in the diode. The impedance of this circuit is
given in Figure 12.
Figure 12. Input Impedance.
The input match, expressed in terms of return loss, is
given in Figure 13.
Figure 13. Input Return Loss.
As can be seen, the band over which a good match is
achieved is more than adequate for 915 MHz RFID ap‑
plications.
8
INPUT
RF
-10
-15
-20
FREQUENCY (GHz): 0.9-0.93
-5
0
0.9
HSMS-285A/6A fig 15
65nH
TRANSMISSION LINE
DIMENSIONS ARE FOR
MICROSTRIP ON
0.032" THICK FR-4.
HSMS-285A/6A fig 16
WIDTH = 0.015"
LENGTH = 0.600"
HSMS-285A/6A fig 14
WIDTH = 0.050"
LENGTH = 0.065"
FREQUENCY (GHz)
0.915
100 pF
VIDEO
OUT
0.93
The HSMS‑282x family is a better choice for 915 MHz ap‑
plications—the foregoing discussion of a design using
the HSMS‑286B is offered only to illustrate a design
approach for technique.
Figure 14. 2.45 GHz Matching Network.
Figure 15. Physical Realization.
2.45 GHz Detector Circuit
At 2.45 GHz, the RF impedance is closer to the line of
constant susceptance which passes through the center
of the chart, resulting in a design which is realized
entirely in distributed elements — see Figure 14.
In order to save cost (at the expense of having a larger
circuit), an open circuit shunt stub could be substituted
for the chip capacitor. On the other hand, if space is at a
premium, the long series transmission line at the input
to the diode can be replaced with a lumped inductor. A
possible physical realization of such a network is shown
in Figure 15, a demo board is available from Avago.
Figure 16. Test Detector.
INPUT
0.030" PLATED THROUGH HOLE,
RF IN
RF
0.094" THROUGH, 4 PLACES
CHIP CAPACITOR, 20 TO 100 pF
3 PLACES
HSMS-285X fig 20 was 17
TRANSMISSION LINE
DIMENSIONS ARE FOR
MICROSTRIP ON
0.032" THICK FR-4.
WIDTH = 0.078"
LENGTH = 0.165"
HSMS-2860 fig 15
WIDTH = 0.017"
LENGTH = 0.436"
HSMS-2860
FINISHED
BOARD
SIZE IS
1.00" X 1.00".
MATERIAL IS
1/32" FR-4
EPOXY/
FIBERGLASS,
1 OZ. COPPER
BOTH SIDES.
100 pF
VIDEO OUT
VIDEO
OUT