HSMS-286B-TR1 [AVAGO]
SILICON, UHF-C BAND, MIXER DIODE;型号: | HSMS-286B-TR1 |
厂家: | AVAGO TECHNOLOGIES LIMITED |
描述: | SILICON, UHF-C BAND, MIXER DIODE 光电二极管 |
文件: | 总17页 (文件大小:196K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
HSMS-286x Series
Surface Mount Microwave
Schottky Detector Diodes
Data Sheet
Description
Features
Avago’sHSMS-286xfamilyofDCbiaseddetectordiodes
have been designed and optimized for use from 915
MHz to 5.8 GHz. They are ideal for RF/ID and RF Tag
applications as well as large signal detection,
modulation, RF to DC conversion or voltage doubling.
•
•
•
Surface Mount SOT-23/SOT-143 Packages
Miniature SOT-323 and SOT-363 Packages
High Detection Sensitivity:
up to 50 mV/µW at 915 MHz
up to 35 mV/µW at 2.45 GHz
up to 25 mV/µW at 5.80 GHz
Availableinvariouspackageconfigurations, thisfamily
ofdetectordiodesprovideslowcostsolutionstoawide
variety of design problems. Avago’s manufacturing
techniques assure that when two or more diodes are
mounted into a single surface mount package, they are
taken from adjacent sites on the wafer, assuring the
highest possible degree of match.
•
•
•
Low FIT (Failure in Time) Rate*
Tape and Reel Options Available
Unique Configurations in Surface Mount SOT-363
Package
– increase flexibility
– save board space
– reduce cost
•
HSMS-286K Grounded Center Leads Provide up to
10 dB Higher Isolation
Pin Connections and Package Marking
•
•
Matched Diodes for Consistent Performance
1
2
3
6
5
4
Better Thermal Conductivity for Higher Power
Dissipation
•
Lead-free Option Available
* For more information see the Surface Mount Schottky
Reliability Data Sheet.
Notes:
1. Package marking provides orientation and identification.
2. The first two characters are the package marking code.
The third character is the date code.
SOT-323 Package Lead Code Identification
(top view)
SINGLE
3
SERIES
3
SOT-23/SOT-143 Package Lead Code
Identification (top view)
1
2
1
2
B
C
COMMON
ANODE
3
COMMON
CATHODE
3
SINGLE
3
SERIES
3
1
2
1
2
1
2
1
2
#0
#2
F
E
COMMON
ANODE
3
COMMON
CATHODE
3
SOT-363 Package Lead Code Identification
(top view) HIGH ISOLATION
UNCONNECTED
UNCONNECTED PAIR
TRIO
6
1
6
1
5
4
6
1
6
1
5
4
1
2
1
2
#4
#3
UNCONNECTED
PAIR
2
3
2
3
L
K
3
4
BRIDGE
QUAD
RING
QUAD
5
4
5
4
1
2
#5
2
3
2
3
P
R
2
SOT-23/SOT-143 DC Electrical Specifications, TC = +25°C, Single Diode
Part
Number
HSMS-
Package
Marking
Code
Typical
Capacitance
CT (pF)
Lead
Code
Forward Voltage
VF (mV)
Configuration
2860
2862
2863
2864
2865
T0
T2
T3
T4
T5
0
2
3
4
5
Single
250 Min.
350 Max.
0.30
Series Pair[1,2]
Common Anode[1,2]
Common Cathode[1,2]
Unconnected Pair [1,2]
Test Conditions
IF = 1.0 mA
VR = 0 V, f = 1 MHz
Notes:
1. ∆VF for diodes in pairs is 15.0 mV maximum at 1.0 mA.
2. ∆CT for diodes in pairs is 0.05 pF maximum at –0.5V.
SOT-323/SOT-363 DC Electrical Specifications, TC = +25°C, Single Diode
Part
Number
HSMS-
Package
Marking
Code
Typical
Capacitance
CT (pF)
Lead
Code
Forward Voltage
VF (mV)
Configuration
286B
286C
286E
286F
286K
T0
T2
T3
T4
TK
B
C
E
F
Single
250 Min.
350 Max.
0.25
Series Pair[1,2]
Common Anode[1,2]
Common Cathode[1,2]
High Isolation
K
Unconnected Pair
Unconnected Trio
Bridge Quad
286L
286P
286R
TL
TP
ZZ
L
P
R
Ring Quad
Test Conditions
IF = 1.0 mA
VR = 0 V, f = 1 MHz
Notes:
1. ∆VF for diodes in pairs is 15.0 mV maximum at 1.0 mA.
2. ∆CT for diodes in pairs is 0.05 pF maximum at –0.5V.
3
RF Electrical Specifications, TC = +25°C, Single Diode
Part
Number
HSMS-
Typical Tangential Sensitivity
TSS (dBm) @ f =
Typical Voltage Sensitivity g
Typical Video
Resistance
RV (KΩ)
(mV/µW) @ f =
915 MHz
2.45 GHz
5.8 GHz
915 MHz
50
2.45 GHz
5.8 GHz
25
2860
2862
2863
2864
2865
286B
286C
286E
286F
286K
286L
286P
286R
–57
–56
–55
35
5.0
Test
Conditions
Video Bandwidth = 2 MHz
Power in = –40 dBm
RL = 100 KΩ, Ib = 5 µA
Ib = 5 µA
Ib = 5 µA
Attention:
Absolute Maximum Ratings, TC = +25°C, Single Diode
Observe precautions for
handling electrostatic
sensitive devices.
Symbol
Parameter
Unit
Absolute Maximum[1]
SOT-23/143 SOT-323/363
4.0
PIV
TJ
Peak Inverse Voltage
Junction Temperature
Storage Temperature
Operating Temperature
Thermal Resistance[2]
V
°C
4.0
150
ESD Machine Model (Class A)
150
ESD Human Body Model (Class 0)
TSTG
TOP
θjc
°C
-65 to 150
-65 to 150
500
-65 to 150
-65 to 150
150
Refer to Avago Application Note A004R:
Electrostatic Discharge Damage and Control.
°C
°C/W
Notes:
1. Operation in excess of any one of these conditions may result in permanent
damage to the device.
2. TC = +25°C, where TC is defined to be the temperature at the package pins
where contact is made to the circuit board.
4
SPICE Parameters
Equivalent Linear Circuit Model,
Diode chip
Parameter
Units
V
Value
7.0
R
j
BV
CJ0
pF
eV
A
0.18
0.69
1 E - 5
5 E - 8
1.08
6.0
R
S
EG
IBV
IS
A
C
N
j
RS
Ω
V
RS = series resistance (see Table of SPICE parameters)
Cj = junction capacitance (see Table of SPICE parameters)
PB (VJ)
PT (XTI)
M
0.65
2
8.33 X 10-5 nT
Rj =
Ib + Is
0.5
where
Ib = externally applied bias current in amps
Is = saturation current (see table of SPICE parameters)
T = temperature, °K
n = ideality factor (see table of SPICE parameters)
Note:
To effectively model the packaged HSMS-286x product,
please refer to Application Note AN1124.
5
Typical Parameters, Single Diode
10000
1000
100
100
10
100
R
= 100 KΩ
L
I
(left scale)
F
TA = –55°C
2.45 GHz
915 MHz
10
T
A = +25°C
A = +85°C
T
1
10
10
.1
∆V (right scale)
5.8 GHz
F
1
DIODES TESTED IN FIXED-TUNED
FR4 MICROSTRIP CIRCUITS.
0.1
.01
1
1
-50
-40
-30
-20
-10
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
FORWARD VOLTAGE (V)
0.05
0.10
0.15
0.20
0.25
FORWARD VOLTAGE (V)
POWER IN (dBm)
Figure 3. +25°C Output Voltage vs.
Input Power, 3 µA Bias.
Figure 1. Forward Current vs.
Forward Voltage at Temperature.
Figure 2. Forward Voltage Match.
30
40
35
10,000
R
= 100 KΩ
L
20 µA
5 µA
915 MHz
10 µA
10
1000
100
30
25
2.45 GHz
20
Frequency = 2.45 GHz
Fixed-tuned FR4 circuit
Input Power =
5.8 GHz
15
10
–30 dBm @ 2.45 GHz
Data taken in fixed-tuned
FR4 circuit
1
10
1
R
= 100 KΩ
L
DIODES TESTED IN FIXED-TUNED
FR4 MICROSTRIP CIRCUITS.
R
= 100 KΩ
L
0.3
5
-50
-40
-30
–40
–30
–20
–10
0
10
.1
1
10
100
BIAS CURRENT (µA)
POWER IN (dBm)
POWER IN (dBm)
Figure 6. Voltage Sensitivity as a
Function of DC Bias Current.
Figure 4. +25°C Expanded Output
Voltage vs. Input Power. See Figure 3.
Figure 5. Dynamic Transfer
Characteristic as a Function of DC Bias.
6
the rectified output of the diode.
CJ is parasitic junction capaci-
tance of the diode, controlled by
the thickness of the epitaxial layer
and the diameter of the Schottky
contact. Rj is the junction
resistance of the diode, a function
of the total current flowing
through it.
is determined by the saturation
current, IS, and is related to the
barrier height of the diode.
Applications Information
Introduction
Avago’s HSMS-286x family of
Schottky detector diodes has been
developed specifically for low
cost, high volume designs in two
kinds of applications. In small
signal detector applications
(Pin < -20 dBm), this diode is used
with DC bias at frequencies above
1.5 GHz. At lower frequencies, the
zero bias HSMS-285x family
should be considered.
Through the choice of p-type or
n-type silicon, and the selection of
metal, one can tailor the
characteristics of a Schottky
diode. Barrier height will be
altered, and at the same time CJ
and RS will be changed. In
general, very low barrier height
diodes (with high values of IS,
suitable for zero bias applica-
tions) are realized on p-type
silicon. Such diodes suffer from
higher values of RS than do the
n-type. Thus, p-type diodes are
generally reserved for small signal
detector applications (where very
high values of RV swamp out high
RS) and n-type diodes are used for
mixer applications (where high
L.O. drive levels keep RV low) and
DC biased detectors.
8.33 X 10-5 n T
Rj = –––––––––––– = RV – Rs
IS + Ib
0.026
= ––––– at 25°C
IS + Ib
In large signal power or gain
control applications
(Pin> -20 dBm), this family is used
without bias at frequencies above
4 GHz. At lower frequencies, the
HSMS-282x family is preferred.
where
n = ideality factor (see table of
SPICE parameters)
T = temperature in °K
IS = saturation current (see
table of SPICE parameters)
Ib = externally applied bias
current in amps
Schottky Barrier Diode
Characteristics
IS is a function of diode barrier
height, and can range from
picoamps for high barrier diodes
to as much as 5 µA for very low
barrier diodes.
Stripped of its package, a
Schottky barrier diode chip
consists of a metal-semiconductor
barrier formed by deposition of a
metal layer on a semiconductor.
The most common of several
different types, the passivated
diode, is shown in Figure 7, along
with its equivalent circuit.
Measuring Diode Linear
Parameters
The measurement of the many
elements which make up the
equivalent circuit for a packaged
Schottky diode is a complex task.
Various techniques are used for
each element. The task begins
with the elements of the diode
chip itself. (See Figure 8).
The Height of the Schottky
Barrier
The current-voltage characteristic
of a Schottky barrier diode at
room temperature is described by
the following equation:
R
S
METAL
PASSIVATION
PASSIVATION
N-TYPE OR P-TYPE EPI LAYER
R
j
V - IRS
SCHOTTKY JUNCTION
C
j
R
V
I = IS (exp
(
–––––– - 1)
)
N-TYPE OR P-TYPE SILICON SUBSTRATE
0.026
R
S
CROSS-SECTION OF SCHOTTKY
BARRIER DIODE CHIP
EQUIVALENT
CIRCUIT
C
j
On a semi-log plot (as shown in
the Avago catalog) the current
graph will be a straight line with
inverse slope 2.3 X 0.026 = 0.060
volts per cycle (until the effect of
RS is seen in a curve that droops
at high current). All Schottky
diode curves have the same slope,
but not necessarily the same value
of current for a given voltage. This
Figure 7. Schottky Diode Chip.
Figure 8. Equivalent Circuit of a
Schottky Diode Chip.
RS is the parasitic series
resistance of the diode, the sum of
the bondwire and leadframe
resistance, the resistance of the
bulk layer of silicon, etc. RF
energy coupled into RS is lost as
heat—it does not contribute to
RS is perhaps the easiest to
measure accurately. The V-I curve
is measured for the diode under
forward bias, and the slope of the
curve is taken at some relatively
7
high value of current (such as
5 mA). This slope is converted
into a resistance Rd.
In the design of such detector
circuits, the starting point is the
equivalent circuit of the diode. Of
interest in the design of the video
portion of the circuit is the diode’s
video impedance—the other
elements of the equivalent circuit
disappear at all reasonable video
frequencies. In general, the lower
the diode’s video impedance, the
better the design.
RV = Rj + RS
The sum of saturation current and
bias current sets the detection
sensitivity, video resistance and
input RF impedance of the
Schottky detector diode. Where
bias current is used, some
tradeoff in sensitivity and square
law dynamic range is seen, as
shown in Figure 5 and described
in reference [3].
0.026
RS = Rd – ––––––
If
For n-type diodes with relatively
low values of saturation current,
Cj is obtained by measuring the
total capacitance (see AN1124).
Rj, the junction resistance, is
calculated using the equation
given above.
DC BIAS
L
1
The most difficult part of the
design of a detector circuit is the
input impedance matching
network. For very broadband
detectors, a shunt 60 Ω resistor
will give good input match, but at
the expense of detection
Z-MATCH
NETWORK
VIDEO
OUT
RF
IN
The characterization of the
surface mount package is too
complex to describe here—linear
equivalent circuits can be found in
AN1124.
DC BIAS
sensitivity.
Detector Circuits
(small signal)
L
1
When maximum sensitivity is
required over a narrow band of
frequencies, a reactive matching
network is optimum. Such net-
works can be realized in either
lumped or distributed elements,
depending upon frequency, size
constraints and cost limitations,
but certain general design
principals exist for all types.[5]
Design work begins with the RF
impedance of the HSMS-286x
series when bias current is set to
3 µA. See Figure 10.
When DC bias is available,
Schottky diode detector circuits
can be used to create low cost RF
and microwave receivers with a
sensitivity of -55 dBm to
-57 dBm.[1] Moreover, since
external DC bias sets the video
impedance of such circuits, they
display classic square law
response over a wide range of
input power levels[2,3]. These
circuits can take a variety of
forms, but in the most simple case
they appear as shown in Figure 9.
This is the basic detector circuit
used with the HSMS-286x family
of diodes.
Z-MATCH
NETWORK
VIDEO
OUT
RF
IN
Figure 9. Basic Detector Circuits.
The situation is somewhat more
complicated in the design of the
RF impedance matching network,
which includes the package
inductance and capacitance
(which can be tuned out), the
series resistance, the junction
capacitance and the video
resistance. Of the elements of the
diode’s equivalent circuit, the
parasitics are constants and the
video resistance is a function of
the current flowing through the
diode.
Output voltage can be virtually
doubled and input impedance
(normally very high) can be
halved through the use of the
voltage doubler circuit[4].
5
2
0.2
0.6
1
1 GHz
2
3
4
5
[1]
6
Avago Application Note 923, Schottky Barrier Diode Video Detectors.
Avago Application Note 986, Square Law and Linear Detection.
[2]
[3]
[4]
[5]
Figure 10. RF Impedance of the
Diode.
Avago Application Note 956-5, Dynamic Range Extension of Schottky Detectors.
Avago Application Note 956-4, Schottky Diode Voltage Doubler.
Avago Application Note 963, Impedance Matching Techniques for Mixers and Detectors.
8
0.094" THROUGH, 4 PLACES
The input match, expressed in
terms of return loss, is given in
Figure 13.
915 MHz Detector Circuit
FINISHED
Figure 11 illustrates a simple
impedance matching network for
a 915 MHz detector.
BOARD
SIZE IS
1.00" X 1.00".
MATERIAL IS
1/32" FR-4
EPOXY/
0
65nH
FIBERGLASS,
1 OZ. COPPER
BOTH SIDES.
RF
INPUT
VIDEO
OUT
-5
WIDTH = 0.050"
LENGTH = 0.065"
-10
-15
-20
100 pF
WIDTH = 0.015"
LENGTH = 0.600"
0.030" PLATED THROUGH HOLE,
3 PLACES
TRANSMISSION LINE
DIMENSIONS ARE FOR
MICROSTRIP ON
Figure 15. Physical Realization.
0.032" THICK FR-4.
0.9
0.915
0.93
Figure 11. 915 MHz Matching
2.45 GHz Detector Circuit
FREQUENCY (GHz)
Network for the HSMS-286x Series
at 3 µA Bias.
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.
Figure 13. Input Return Loss.
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
simultaneously provides the
return circuit for the current
generated in the diode. The
impedance of this circuit is given
in Figure 12.
As can be seen, the band over
which a good match is achieved is
more than adequate for 915 MHz
RFID applications.
The HSMS-282x family is a better
choice for 915 MHz applications—
the foregoing discussion of a
design using the HSMS-286B is
offered only to illustrate a design
approach for technique.
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.
RF
INPUT
VIDEO
OUT
WIDTH = 0.017"
A possible physical realization of
such a network is shown in
Figure 15, a demo board is
available from Avago.
LENGTH = 0.436"
100 pF
WIDTH = 0.078"
LENGTH = 0.165"
TRANSMISSION LINE
DIMENSIONS ARE FOR
MICROSTRIP ON
0.032" THICK FR-4.
HSMS-2860
Figure 14. 2.45 GHz Matching
Network.
RF IN
VIDEO OUT
FREQUENCY (GHz): 0.9-0.93
Figure 12. Input Impedance.
CHIP CAPACITOR, 20 TO 100 pF
Figure 16. Test Detector.
9
Two SMA connectors (E.F.
Johnson 142-0701-631 or equiva-
lent), a high-Q capacitor
(ATC 100A101MCA50 or equiva-
lent), miscellaneous hardware
and an HSMS-286B are added to
create the test circuit shown in
Figure 16.
A word of caution to the designer
is in order. A glance at Figure 17
will reveal the fact that the circuit
does not provide the optimum
impedance to the diode at
2.45 GHz. The temptation will be
to adjust the circuit elements to
achieve an ideal single frequency
match, as illustrated in Figure 19.
However, bandwidth is narrower
and the designer runs the risk of a
shift in the midband frequency of
his circuit if there is any small
deviation in circuit board or diode
characteristics due to lot-to-lot
variation or change in temper-
ature. The matching technique
illustrated in Figure 17 is much
less sensitive to changes in diode
and circuit board processing.
The calculated input impedance
for this network is shown in
Figure 17.
5.8 GHz Detector Circuit
A possible design for a 5.8 GHz
detector is given in Figure 21.
2.45 GHz
RF
INPUT
VIDEO
OUT
WIDTH = 0.016"
LENGTH = 0.037"
20 pF
WIDTH = 0.045"
LENGTH = 0.073"
Figure 21. 5.8 GHz Matching Network
for the HSMS-286x Series at 3 µA
Bias.
FREQUENCY (GHz): 2.3-2.6
Figure 19. Input Impedance. Modified
2.45 GHz Circuit.
FREQUENCY (GHz): 2.3-2.6
As was the case at 2.45 GHz, the
circuit is entirely distributed
element, both low cost and
compact. Input impedance for this
network is given in Figure 22.
Figure 17. Input Impedance,
3 µA Bias.
This does indeed result in a very
good match at midband, as shown
in Figure 20.
The corresponding input match is
shown in Figure 18. As was the
case with the lower frequency
design, bandwidth is more than
adequate for the intended RFID
application.
0
-5
-10
-15
-20
0
-5
-10
-15
-20
2.3
2.45
2.6
FREQUENCY (GHz)
Figure 20. Input Return Loss.
Modified 2.45 GHz Circuit.
FREQUENCY (GHz): 5.6-6.0
Figure 22. Input Impedance.
2.3
2.45
2.6
FREQUENCY (GHz)
Figure 18. Input Return Loss,
3 µA Bias.
10
Input return loss, shown in
Figure 23, exhibits wideband
match.
with much less temperature
variation.
The “Virtual Battery”
The voltage doubler can be used
as a virtual battery, to provide
power for the operation of an I.C.
or a transistor oscillator in a tag.
Illuminated by the CW signal from
a reader or interrogator, the
Schottky circuit will produce
power sufficient to operate an I.C.
or to charge up a capacitor for a
burst transmission from an
A similar experiment was con-
ducted with the HSMS-286B
series in the 5.8 GHz detector.
Once again, reducing the bias to
some level under 3 µA stabilized
the output of the detector over a
wide temperature range.
0
-5
-10
-15
-20
It should be noted that curves
such as those given in Figures 25
and 26 are highly dependent upon
the exact design of the input
impedance matching network.
The designer will have to experi-
ment with bias current using his
specific design.
oscillator. Where such virtual
batteries are employed, the bulk,
cost, and limited lifetime of a
battery are eliminated.
5.6
5.7
5.8
5.9
6.0
FREQUENCY (GHz)
Temperature Compensation
Figure 23. Input Return Loss.
The compression of the detector’s
transfer curve is beyond the
scope of this data sheet, but some
general comments can be made.
As was given earlier, the diode’s
video resistance is given by
Voltage Doublers
120
INPUT POWER = –30 dBm
To this point, we have restricted
our discussion to single diode
detectors. A glance at Figure 9,
however, will lead to the
suggestion that the two types of
single diode detectors be
combined into a two diode
voltage doubler[4] (known also as
a full wave rectifier). Such a
detector is shown in Figure 24.
3.0 µA
100
80
-5
8.33 x 10 nT
1.0 µA
10 µA
R =
V
IS + Ib
60
40
where T is the diode’s tempera-
ture in °K.
0.5 µA
-55 -35 -15
5
25 45
65 85
TEMPERATURE (°C)
As can be seen, temperature has a
strong effect upon R , and this
Figure 25. Output Voltage vs.
V
Z-MATCH
VIDEO OUT
RF IN
Temperature and Bias Current in the
915 MHz Voltage Doubler using the
HSMS-286C.
NETWORK
will in turn affect video band-
width and input RF impedance.
A glance at Figure 6 suggests that
the proper choice of bias current
in the HSMS-286x series can
minimize variation over
35
INPUT POWER = –30 dBm
Figure 24. Voltage Doubler Circuit.
3.0 µA
Such a circuit offers several
advantages. First the voltage
outputs of two diodes are added
in series, increasing the overall
value of voltage sensitivity for the
network (compared to a single
diode detector). Second, the RF
impedances of the two diodes are
added in parallel, making the job
of reactive matching a bit easier.
Such a circuit can easily be
temperature.
25
10 µA
The detector circuits described
earlier were tested over tempera-
ture. The 915 MHz voltage
doubler using the HSMS-286C
series produced the output
voltages as shown in Figure 25.
The use of 3 µA of bias resulted in
the highest voltage sensitivity, but
at the cost of a wide variation
over temperature. Dropping the
bias to 1 µA produced a detector
1.0 µA
15
5
0.5 µA
-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.
realized using the two series
diodes in the HSMS-286C.
11
The line marked “RF diode, V
is the transfer curve for the
detector diode—both the
HSMS-2825 and the HSMS-282K
exhibited the same output
voltage. The data were taken over
the 50 dB dynamic range shown.
To the right is the output voltage
(transfer) curve for the reference
diode of the HSMS-2825, showing
37 dB of isolation. To the right of
that is the output voltage due to
RF leakage for the reference
”
out
3
4
2
Six Lead Circuits
6
1
5
4
The differential detector is often
used to provide temperature
compensation for a Schottky
detector, as shown in Figures 27
and 28.
1
2
3
HSMS-286K
SOT-363
HSMS-2865
SOT-143
bias
Figure 29. Comparing Two Diodes.
matching
network
differential
amplifier
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.
diode of the HSMS-282K, demon-
strating 10 dB higher isolation
than the conventional part.
Figure 27. Differential Detector.
Such differential detector circuits
generally use single diode
detector
diode
PA
Vs
detector
PA
V
s
diode
detectors, either series or shunt
mounted diodes. The voltage
doubler offers the advantage of
twice the output voltage for a
given input power. The two
concepts can be combined into
the differential voltage doubler,
as shown in Figure 32.
to differential
amplifier
to differential
amplifier
HSMS-286K
HSMS-2865
reference diode
reference diode
Figure 30. High Isolation
Differential Detector.
Figure 28. Conventional 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.
These circuits depend upon the
use of two diodes having matched
bias
V characteristics over all
f
operating temperatures. This is
best achieved by using two
diodes in a single package, such
as the SOT-143 HSMS-2865 as
shown in Figure 29.
differential
amplifier
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.
matching
network
In high power differential detec-
tors, RF coupling from the
detector diode to the reference
diode produces a rectified voltage
in the latter, resulting in errors.
Figure 32. Differential Voltage
Doubler, HSMS-286P.
Frequency = 900 MHz
5000
RF diode
V
out
1000
100
10
Here, all four diodes of the
HSMS-286P are matched in their
Vf characteristics, because they
came from adjacent sites on the
wafer. A similar circuit can be
realized using the HSMS-286R
ring quad.
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.
Square law
response
HSMS-2825
ref. diode
37 dB
47 dB
HSMS-282K
ref. diode
1
0.5
-35
-25
-15
-5
5
15
INPUT POWER (dBm)
Figure 31. Comparing HSMS-282K
with HSMS-2825.
12
Other configurations of six lead
Schottky products can be used to
solve circuit design problems
while saving space and cost.
Package thermal resistance for
the SOT-323 and SOT-363 pack-
age is approximately 100°C/W,
and the chip thermal resistance
for these three families of diodes
is approximately 40°C/W. The
designer will have to add in the
thermal resistance from diode
case to ambient—a poor choice
of circuit board material or heat
sink design can make this number
very high.
Diode Burnout
Any Schottky junction, be it an RF
diode or the gate of a MESFET, is
relatively delicate and can be
burned out with excessive RF
power. Many crystal video
receivers used in RFID (tag)
applications find themselves in
poorly controlled environments
where high power sources may be
present. Examples are the areas
around airport and FAA radars,
nearby ham radio operators, the
vicinity of a broadcast band
transmitter, etc. In such
environments, the Schottky
diodes of the receiver can be
protected by a device known as a
limiter diode.[6] Formerly
available only in radar warning
receivers and other high cost
electronic warfare applications,
these diodes have been adapted to
commercial and consumer
circuits.
Thermal Considerations
The obvious advantage of the
SOT-363 over the SOT-143 is
combination of smaller size and
two extra leads. However, the
copper leadframe in the SOT-323
and SOT-363 has a thermal
conductivity four times higher
than the Alloy 42 leadframe of the
SOT-23 and SOT-143, which
enables it to dissipate more
power.
Equation (1) would be straightfor-
ward to solve but for the fact that
diode forward voltage is a func-
tion of temperature as well as
forward current. The equation,
equation 3, for Vf is:
The maximum junction tempera-
ture for these three families of
Schottky diodes is 150°C under
all operating conditions. The
following equation, equation 1,
applies to the thermal analysis of
diodes:
11600 (Vf – If Rs)
nT
If = IS
e
– 1
Equation (3).
where
Tj = (VfIf + PRF)θjc + Ta
Avago offers a complete line of
surface mountable PIN limiter
diodes. Most notably, our HSMP-
4820 (SOT-23) or HSMP-482B
(SOT-323) can act as a very fast
(nanosecond) power-sensitive
switch when placed between the
antenna and the Schottky diode,
shorting out the RF circuit
temporarily and reflecting the
excessive RF energy back out the
antenna.
n = ideality factor
T = temperature in °K
Rs = diode series resistance
Equation (1).
where
and IS (diode saturation current)
is given by
Tj = junction temperature
Ta = diode case temperature
θjc = thermal resistance
2
n
)
1
T
1
298
– 4060
e
(
–
)
Vf If = DC power dissipated
T
298
Is = I0
PRF = RF power dissipated
(
Note that θjc, the thermal resis-
tance from diode junction to the
foot of the leads, is the sum of
two component resistances,
Equation (4).
Equations (1) and (3) are solved
simultaneously to obtain the
value of junction temperature for
given values of diode case
θjc = θpkg + θchip
temperature, DC power dissipa-
tion and RF power dissipation.
Equation (2).
[6]
Avago Application Note 1050, Low Cost, Surface Mount Power Limiters.
13
preheat zones. The preheat zones
increase the temperature of the
board and components to prevent
thermal shock and begin evapo-
rating solvents from the solder
paste. The reflow zone briefly
elevates the temperature suffi-
ciently to produce a reflow of the
solder.
SMT Assembly
Assembly Instructions
SOT-323 PCB Footprint
Reliable assembly of surface
mount components is a complex
process that involves many
A recommended PCB pad layout
for the miniature SOT-323 (SC-70)
package is shown in Figure 33
(dimensions are in inches).
material, process, and equipment
factors, including: method of
heating (e.g., IR or vapor phase
reflow, wave soldering, etc.)
circuit board material, conductor
thickness and pattern, type of
solder alloy, and the thermal
conductivity and thermal mass of
components. Components with a
low mass, such as the SOT
0.026
The rates of change of tempera-
ture for the ramp-up and cool-
down zones are chosen to be low
enough to not cause deformation
of the board or damage to compo-
nents due to thermal shock. The
maximum temperature in the
0.079
0.039
packages, will reach solder
reflow temperatures faster than
those with a greater mass.
0.022
reflow zone (T
) should not
MAX
Dimensions in inches
exceed 235°C.
Avago’s diodes have been quali-
fied to the time-temperature
profile shown in Figure 35. This
profile is representative of an IR
reflow type of surface mount
assembly process.
Figure 33. Recommended PCB Pad
Layout for Avago’s SC70 3L/SOT-323
Products.
These parameters are typical for a
surface mount assembly process
for Avago diodes. As a general
guideline, the circuit board and
components should be exposed
only to the minimum temperatures
and times necessary to achieve a
uniform reflow of solder.
A recommended PCB pad layout
for the miniature SOT-363 (SC-70
6 lead) package is shown in
Figure 34 (dimensions are in
inches). This layout provides
ample allowance for package
placement by automated assem-
bly equipment without adding
parasitics that could impair the
performance.
After ramping up from room
temperature, the circuit board
with components attached to it
(held in place with solder paste)
passes through one or more
250
200
TMAX
0.026
150
Reflow
Zone
0.079
100
Preheat
Zone
Cool Down
Zone
0.039
50
0
0.018
Dimensions in inches
0
60
120
180
240
300
Figure 34. Recommended PCB Pad
Layout for Avago’s SC70 6L/SOT-363
Products.
TIME (seconds)
Figure 35. Surface Mount Assembly Profile.
14
Package Dimensions
Outline 23 (SOT-23)
Outline SOT-323 (SC-70 3 Lead)
e1
e2
e1
E1
E
XXX
E1
E
XXX
e
L
B
C
e
L
D
DIMENSIONS (mm)
B
D
SYMBOL
MIN.
0.80
0.00
0.15
0.10
1.80
1.10
MAX.
1.00
0.10
0.40
0.20
2.25
1.40
C
A
A1
B
DIMENSIONS (mm)
A
SYMBOL
MIN.
0.79
0.000
0.37
0.086
2.73
1.15
0.89
1.78
0.45
2.10
0.45
MAX.
1.20
0.100
0.54
0.152
3.13
1.50
1.02
2.04
0.60
2.70
0.69
C
A
A1
B
D
A1
E1
e
A
0.65 typical
1.30 typical
1.80 2.40
C
e1
E
Notes:
D
A1
XXX-package marking
E1
e
L
0.425 typical
Drawings are not to scale
e1
e2
E
Notes:
XXX-package marking
Drawings are not to scale
L
Outline 143 (SOT-143)
Outline SOT-363 (SC-70 6 Lead)
e2
DIMENSIONS (mm)
e1
SYMBOL
MIN.
1.15
1.80
1.80
0.80
0.80
0.00
0.10
MAX.
1.35
2.25
2.40
1.10
1.00
0.10
0.40
E
D
B1
E1
HE
E
HE
A
A2
A1
Q1
e
E
XXX
0.650 BCS
e
b
0.15
0.10
0.10
0.30
0.20
0.30
c
L
D
L
B
C
e
Q1
DIMENSIONS (mm)
c
A1
A2
D
A
SYMBOL
MIN.
0.79
0.013
0.36
0.76
0.086
2.80
1.20
0.89
1.78
0.45
2.10
0.45
MAX.
1.097
0.10
0.54
0.92
0.152
3.06
1.40
1.02
2.04
0.60
2.65
0.69
A
A1
B
A
b
L
B1
C
A1
D
e
E1
e
e1
e2
E
Notes:
XXX-package marking
Drawings are not to scale
L
15
For Outlines SOT-23, -323
Device Orientation
REEL
TOP VIEW
4 mm
END VIEW
CARRIER
TAPE
8 mm
ABC
ABC
ABC
ABC
USER
FEED
DIRECTION
Note: "AB" represents package marking code.
"C" represents date code.
COVER TAPE
For Outline SOT-143
For Outline SOT-363
TOP VIEW
4 mm
END VIEW
TOP VIEW
4 mm
END VIEW
8 mm
A B C
A B C
A B C
A B C
8 mm
ABC
ABC
ABC
ABC
Note: "AB" represents package marking code.
"C" represents date code.
Note: "AB" represents package marking code.
"C" represents date code.
16
Tape Dimensions and Product Orientation
For Outline SOT-23
P
P
D
2
E
F
P
0
W
D
1
t1
Ko
13.5° MAX
8° MAX
9° MAX
B
A
0
0
DESCRIPTION
SYMBOL
SIZE (mm)
SIZE (INCHES)
CAVITY
LENGTH
WIDTH
DEPTH
PITCH
A
B
K
P
3.15 0.10
2.77 0.10
1.22 0.10
4.00 0.10
1.00 + 0.05
0.124 0.004
0.109 0.004
0.048 0.004
0.157 0.004
0.039 0.002
0
0
0
BOTTOM HOLE DIAMETER
D
1
PERFORATION
CARRIER TAPE
DIAMETER
PITCH
POSITION
D
1.50 + 0.10
4.00 0.10
1.75 0.10
0.059 + 0.004
0.157 0.004
0.069 0.004
P
E
0
WIDTH
W
8.00+0.30–0.10 0.315+0.012–0.004
THICKNESS
t1
0.229 0.013
0.009 0.0005
DISTANCE
BETWEEN
CAVITY TO PERFORATION
(WIDTH DIRECTION)
F
3.50 0.05
0.138 0.002
CENTERLINE
CAVITY TO PERFORATION
(LENGTH DIRECTION)
P
2.00 0.05
0.079 0.002
2
For Outline SOT-143
P
D
P2
P0
E
F
W
D1
t1
K
0
9° MAX
9° MAX
A0
B
0
DESCRIPTION
SYMBOL
SIZE (mm)
SIZE (INCHES)
CAVITY
LENGTH
WIDTH
DEPTH
PITCH
A
B
K
P
3.19 0.10
2.80 0.10
1.31 0.10
4.00 0.10
1.00 + 0.25
0.126 0.004
0.110 0.004
0.052 0.004
0.157 0.004
0.039 + 0.010
0
0
0
BOTTOM HOLE DIAMETER
D
1
PERFORATION
DIAMETER
PITCH
POSITION
D
1.50 + 0.10
4.00 0.10
1.75 0.10
0.059 + 0.004
0.157 0.004
0.069 0.004
P
E
0
CARRIER TAPE
DISTANCE
WIDTH
THICKNESS
W
t1
8.00+0.30–0.10 0.315+0.012–0.004
0.254 0.013
0.0100 0.0005
CAVITY TO PERFORATION
(WIDTH DIRECTION)
F
3.50 0.05
0.138 0.002
CAVITY TO PERFORATION
(LENGTH DIRECTION)
P
2.00 0.05
0.079 0.002
2
Tape Dimensions and Product Orientation
For Outlines SOT-323, -363
P
P
D
2
P
0
E
F
W
C
D
1
t
(CARRIER TAPE THICKNESS)
T (COVER TAPE THICKNESS)
t
1
K
An
An
0
A
B
0
0
DESCRIPTION
SYMBOL
SIZE (mm)
SIZE (INCHES)
CAVITY
LENGTH
WIDTH
DEPTH
PITCH
A
B
K
P
2.40 0.10
2.40 0.10
1.20 0.10
4.00 0.10
1.00 + 0.25
0.094 0.004
0.094 0.004
0.047 0.004
0.157 0.004
0.039 + 0.010
0
0
0
BOTTOM HOLE DIAMETER
D
1
PERFORATION
DIAMETER
PITCH
POSITION
D
1.55 0.05
4.00 0.10
1.75 0.10
0.061 0.002
0.157 0.004
0.069 0.004
P
E
0
CARRIER TAPE
COVER TAPE
DISTANCE
WIDTH
THICKNESS
W
8.00 0.30
0.254 0.02
0.315 0.012
0.0100 0.0008
t
1
WIDTH
TAPE THICKNESS
C
5.4 0.10
0.062 0.001
0.205 0.004
0.0025 0.00004
T
t
CAVITY TO PERFORATION
(WIDTH DIRECTION)
F
3.50 0.05
0.138 0.002
CAVITY TO PERFORATION
(LENGTH DIRECTION)
P
2.00 0.05
0.079 0.002
2
ANGLE
FOR SOT-323 (SC70-3 LEAD)
FOR SOT-363 (SC70-6 LEAD)
An
8°C MAX
Part Number Ordering Information
10°C MAX
No. of
Part Number
HSMS-286x-TR2*
HSMS-286x-TR1*
HSMS-286x-BLK *
Devices
10000
3000
Container
13" Reel
7" Reel
100
antistatic bag
where x = 0, 2, 3, 4, 5, B, C, E, F, K, L, P or R for
HSMS-286x.
* For lead-free option, the part number will have the
character “G” at the end, eg. HSMS-286x-TR2G for a
10,000 lead-free reel.
For product information and a complete list of distributors, please go to our web site:
www.avagotech.com
Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies, Limited
in the United States and other countries.
Data subject to change. Copyright © 2006 Avago Technologies, Limited. All rights reserved.
Obsoletes 5989-2495EN
5989-4023EN August 22, 2006
相关型号:
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