AVAGO HSMS-2822 Surface mount rf schottky barrier Datasheet

HSMS-282x
Surface Mount RF Schottky ­Barrier Diodes
Data Sheet
Description/Applications
Features
These Schottky diodes are specifically designed for both
analog and digital applications. This series offers a wide
range of specifica­tions and package con­figura­tions to give
the ­designer wide flexi­bility. Typical applications of these
Schottky diodes are mixing, detecting, switching, sam‑
pling, clamping, and wave shaping. The HSMS‑282x series
of diodes is the best all-around choice for most applica‑
tions, featuring low series resistance, low forward voltage
at all current levels and good RF characteristics.
• Low Turn-On Voltage (As Low as 0.34 V at 1 mA)
Note that Avago’s manufacturing techniques assure that
dice found in pairs and quads are taken from adjacent
sites on the wafer, assuring the highest degree of match.
Package Lead Code Identification,
SOT-23/SOT-143 (Top View)
SINGLE
3
SERIES
3
1
1
#0
2
UNCONNECTED
PAIR
3
4
1
#5
2
2
#2
RING
QUAD
3
4
1
#7
2
#3
2
#8
2
Package Lead Code Identification, SOT-323
(Top View)
• Single, Dual and Quad Versions
• Unique Configurations in Surface Mount SOT-363
Package
– increase flexibility
– save board space
– reduce cost
• HSMS-282K Grounded Center Leads Provide up to 10
dB Higher Isolation
• Better Thermal Conductivity for Higher Power Dissipation
BRIDGE
QUAD
3
4
1
• Six-sigma Quality Level
• Matched Diodes for Consistent Performance
COMMON
ANODE
3
1
• Low FIT (Failure in Time) Rate*
COMMON
CATHODE
3
1
#4
#9
• For more information see the Surface Mount Schottky
Reliability Data Sheet.
2
CROSS-OVER
QUAD
3
4
1
• Lead-free Option Available
2
Package Lead Code Identification, SOT-363
(Top View)
HIGH ISOLATION
UNCONNECTED PAIR
6
5
1
2
4
K
3
COMMON
CATHODE QUAD
SINGLE
SERIES
B
COMMON
ANODE
C
COMMON
CATHODE
E
F
6
5
1
2
6
1
4
M
3
BRIDGE
QUAD
5
2
P
UNCONNECTED
TRIO
6
5
1
2
4
L
3
COMMON
ANODE QUAD
6
5
1
2
4
6
3
1
4
N
3
RING
QUAD
5
2
4
R
3
Pin Connections and Package Marking
2
6
GUx
1
5
3
4
Notes:
1. Package marking provides orientation and identification.
2. See “Electrical Specifications” for appropriate package marking.
Absolute Maximum Ratings[1] TC = 25°C
Symbol
Parameter
Unit
SOT-23/SOT-143
SOT-323/SOT-363
If
Forward Current (1 μs Pulse)
Amp
1
1
PIV
Peak Inverse Voltage
V
15
15
Tj
Junction Temperature
°C
150
150
Tstg
Storage Temperature
°C
-65 to 150
-65 to 150
θjc
Thermal Resistance
°C/W
500
150
[2]
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.
Electrical Specifications TC = 25°C, Single Diode[3]
Maximum Maximum
Minimum
Maximum Forward
Reverse
Part
Package
Breakdown
Forward Voltage
Leakage
Maximum
Number Marking Lead
Voltage
Voltage
VF (V) @
IR (nA) @
Capacitance
HSMS[4]
Code
Code Configuration
VBR (V)
VF (mV)
IF (mA)
VR (V)
CT (pF)
2820
C0
0
2822
C2
2
2823
C3
3
2824
C4
4
2825
C5
5
2827
C7
7
2828
C8
8
2829
C9
9
282B
C0
B
282C
C2
C
282E
C3
E
282F
C4
F
282K
CK
K
282L
CL
L
282M
HH
M
282N
NN
N
282P
CP
P
282R
OO
R
Single
Series
Common Anode
Common Cathode
Unconnected Pair
Ring Quad[4]
Bridge Quad[4]
Cross-over Quad
Single
Series
Common Anode
Common Cathode
High Isolation
Unconnected Pair
Unconnected Trio
Common Cathode Quad
Common Anode Quad
Bridge Quad
Ring Quad
15
340
0.5
10
100
Test Conditions
IR = 100 mA IF = 1 mA[1]
Notes:
1. ∆VF for diodes in pairs and quads in 15 mV maximum at 1 mA.
2. ∆CTO for diodes in pairs and quads is 0.2 pF maximum.
3. Effective Carrier Lifetime (τ) for all these diodes is 100 ps maximum measured with Krakauer method at 5 mA.
4. See section titled “Quad Capacitance.”
5. RD = RS + 5.2Ω at 25°C and If = 5 mA.
1
Typical
Dynamic
Resistance
RD (Ω)[5]
1.0
12
VR = 0V[2]
f = 1 MHz
IF = 5 mA
Quad Capacitance
Linear Equivalent Circuit Model Diode Chip
Capacitance of Schottky diode quads is measured using
an HP4271 LCR meter. This instrument effectively isolates
individual diode branches from the others, allowing ac‑
curate capacitance measurement of each branch or each
diode. The conditions are: 20 mV R.M.S. voltage at 1 MHz.
Avago defines this measurement as “CM”, and it is equiva‑
lent to the capaci­tance of the diode by itself. The equiva‑
lent diagonal and adja­cent capaci-tances can then be cal‑
culated by the formulas given below.
In a quad, the diagonal capaci­tance is the capacitance be‑
tween points A and B as shown in the figure below. The
diagonal capacitance is calculated using the following
formula
C3 x C 4
C1 x C 2
C DIAGONAL = _______
+ _______
C1 + C 2
C3 + C4
The equivalent
is the capacitance
C2
Ccapacitance
C 1 xadjacent
3xC 4
C DIAGONAL = _______
+ _______
between
A____________
and C in1 the figure below. This capaci‑
=C
+
C ADJACENT points
C 11 + C 2
C3 + C4
tance is calculated
using
formula
1 the
1 following
1
–– + –– + ––
1 3 C4
C2 C
C ADJACENT = C 1 + ____________
1 1
1
–– -5+ nT
–– + ––
8.33 X 10
Rj=
I +C
I 2 C 3 C4
b
s
This information
8.33 does
X 10 -5not
nT apply to cross-over quad di‑
Rj=
odes.
I b+ Is
C1
C3
A
C
C2
C4
B
Rj
RS
Cj
RS = series resistance (see Table of SPICE parameters)
C j = junction capacitance (see Table of SPICE parameters)
Rj =
8.33 X 10-5 nT
Ib + Is
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-282x product,
please refer to Application Note AN1124.
ESD WARNING:
Handling Precautions Should Be Taken To Avoid Static Discharge.
SPICE Parameters
Parameter
Units
HSMS-282x
BV
V
15
CJ0
pF
0.7
EG
eV
0.69
IBV
A
1E-4
IS
A
2.2E-8
N
1.08
RS
Ω
6.0
PB
V
0.65
PT
2
M
0.5
Typical Performance, TC = 25°C (unless otherwise noted), Single Diode
0.1
0.8
0.20
0.30
0.40
100
TA = +125C
TA = +75C
TA = +25C
10
1
0.50
0
5
IF - FORWARD CURRENT (mA)
RD – DYNAMIC RESISTANCE ()
100
10
10
IF (Left Scale)
10
10
VF (Right Scale)
1
0.3
100
2
0.2
0.4
0.6
0.8
1.0
1.2
1
6
8
1.0
IF (Left Scale)
10
VF (Right Scale)
1
0.10
0.3
1.4
0.15
0.1
0.25
0.20
VF - FORWARD VOLTAGE (V)
Figure 5. Typical Vf Match, Series Pairs and Quads
at Mixer Bias Levels.
1
4
100
VF - FORWARD VOLTAGE (V)
Figure 4. Dynamic Resistance vs. Forward
Current.
Figure 6. Typical Vf Match, Series Pairs at Detector
Bias Levels.
10
-25C
+25C
+75C
0.1
RF in
0.01
18 nH
3.3 nH
-30
10
1
DC bias = 3 A
-20
HSMS-282B
100 pF
-10
Vo
100 K
0
Pin – INPUT POWER (dBm)
Figure 7. Typical Output Voltage vs. Input Power,
Small Signal Detector Operating at 850 MHz.
VO – OUTPUT VOLTAGE (V)
VO – OUTPUT VOLTAGE (V)
0
Figure 3. Total Capacitance vs. Reverse Voltage.
30
IF – FORWARD CURRENT (mA)
0
VR – REVERSE VOLTAGE (V)
30
1000
1
0.2
15
Figure 2. Reverse Current vs. Reverse Voltage at
Temperatures.
Figure 1. Forward Current vs. Forward Voltage at
Temperatures.
1
0.1
0.4
VR – REVERSE VOLTAGE (V)
VF – FORWARD VOLTAGE (V)
0.001
-40
10
0.6
IF - FORWARD CURRENT (µA)
0.10
1000
0.1
0.01
0.001
+25C
68
0.0001
1E-005
-20
HSMS-282B
RF in
-10
Vo
100 pF
0
10
CONVERSION LOSS (dB)
0
10,000
VF - FORWARD VOLTAGE DIFFERENCE (mV)
1
0.01
1
VF - FORWARD VOLTAGE DIFFERENCE (mV)
10
100,000
CT – CAPACITANCE (pF)
TA = +125C
TA = +75C
TA = +25C
TA = –25C
IR – REVERSE CURRENT (nA)
IF – FORWARD CURRENT (mA)
100
9
8
7
4.7 K
20
30
Pin – INPUT POWER (dBm)
Figure 8. Typical Output Voltage vs. Input Power,
Large Signal Detector Operating at 915 MHz.
6
0
2
4
6
8
10
12
LOCAL OSCILLATOR POWER (dBm)
Figure 9. Typical Conversion Loss vs. L.O. Drive,
2.0 GHz (Ref AN997).
Applications Information
Product Selection
Avago’s family of surface mount Schottky diodes provide
unique solutions to many design problems. Each is opti‑
mized for certain applications.
The first step in choosing the right product is to select
the diode type. All of the products in the HSMS‑282x fam‑
ily use the same diode chip–they differ only in package
configuration. The same is true of the HSMS-280x, -281x,
285x, -286x and -270x families. Each family has a different
set of characteristics, which can be compared most easily
by consulting the SPICE parameters given on each data
sheet.
The HSMS‑282x family has been optimized for use in RF
applications, such as
• DC biased small signal detectors to 1.5 GHz.
• Biased or unbiased large signal detectors (AGC or
power monitors) to 4 GHz.
• Mixers and frequencymultipliers to 6 GHz.
The other feature of the HSMS‑282x family is its unit‑to‑unit
and lot‑to‑lot consistency. The silicon chip used in this
series has been designed to use the fewest possible pro‑
cessing steps to minimize variations in diode characteris‑
tics. Statistical data on the consistency of this product, in
terms of SPICE parameters, is available from Avago.
For those applications requiring very high breakdown
voltage, use the HSMS‑280x family of diodes. Turn to the
HSMS‑281x when you need very low flicker noise. The
HSMS‑285x is a family of zero bias detector diodes for small
signal applications. For high frequency detector or mixer
applications, use the HSMS‑286x family. The HSMS‑270x
is a series of specialty diodes for ultra high speed clipping
and clamping in digital circuits.
Schottky Barrier Diode Characteristics
Stripped of its package, a Schottky barrier diode chip
consists of a metal-semiconductor barrier formed by de‑
position of a metal layer on a semiconductor. The most
common of several different types, the passivated diode,
is shown in Figure 10, along with its equivalent circuit.
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 the rectified out‑
put of the diode. CJ is parasitic junction capaci­tance of the
diode, controlled by the thick-ness of the epitaxial layer
and the diameter of the Schottky contact. Rj is the junc‑
tion resistance of the diode, a function of the total current
flowing through it.
8.33 X 10 -5 nT
R j = –––––––––––– = R V – R
I S+Ib
0.026
≈ ––––– at 25 °C
I S+Ib
V - IR
where
–––––S
I = I S (e 0.026 – 1)
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
Rv = sum of junction and series resistance, the slope of the
V-I curve
IS is a function of diode barrier height, and can range from
picoamps for high barrier diodes to as much as 5 µA for
-5 nT
very low8.33
barrier
diodes.
X 10
R j = –––––––––––– = R V – R s
+Ib
The Height ofI theS Schottky
Barrier
The current-voltage character­istic of a Schottky barrier
0.026 temperature is described by the following
diode at
≈ room
––––– at 25 °C
equation:I S + I b
I = I S (e
V - IR
0.026
–––––S
– 1)
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 is deter­mined
by the saturation current, IS, and is related to the barrier
height of the diode.
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 applica­tions) are realized on p-type silicon. Such
diodes suffer from higher values of RS than do the n‑type.
RS
METAL
PASSIVATION
N-TYPE OR P-TYPE EPI
PASSIVATION
LAYER
SCHOTTKY JUNCTION
Cj
Rj
N-TYPE OR P-TYPE SILICON SUBSTRATE
CROSS-SECTION OF SCHOTTKY
BARRIER DIODE CHIP
Figure 10. Schottky Diode Chip.
s
HSMS-285A/6A fig 9
EQUIVALENT
CIRCUIT
Thus, p-type diodes are generally reserved for detector
applications (where very high values of RV swamp out
high RS) and n-type diodes such as the HSMS-282x are
used for mixer applications (where high L.O. drive levels
keep RV low). DC biased detectors and self-biased detec‑
tors used in gain or power control circuits.
Detector Applications
Detector circuits can be divided into two types, large signal
(Pin > ‑20 dBm) and small signal (Pin < ‑20 dBm). In general,
the former use resistive impedance matching at the in‑
put to improve flatness over frequency — this is possible
since the input signal levels are high enough to produce
adequate output voltages without the need for a high Q
reactive input matching network. These circuits are selfbiased (no external DC bias) and are used for gain and
power control of amplifiers.
Small signal detectors are used as very low cost receivers,
and require a reactive input impedance matching net‑
work to achieve adequate sensitivity and output voltage.
Those operating with zero bias utilize the HSMS‑ 285x
family of detector diodes. However, superior performance
over temperature can be achieved with the use of 3 to 30
µA of DC bias. Such circuits will use the HSMS‑282x family
of diodes if the operating frequency is 1.5 GHz or lower.
Typical performance of single diode detectors (using
HSMS‑2820 or HSMS‑282B) can be seen in the transfer
curves given in Figures 7 and 8. Such detectors can be re‑
alized either as series or shunt circuits, as shown in Figure
11.
DC Bias
• The two diodes are in parallel in the RF circuit, lowering
the input impedance and making the design of the RF
matching network easier.
• The two diodes are in series in the output (video) circuit,
doubling the output voltage.
• Some cancellation of even‑order harmonics takes place
at the input.
DC Bias
Zero Biased Diodes
DC Biased Diodes
Figure 12. Voltage Doubler.
The most compact and lowest cost form of the doubler is
achieved when the HSMS‑2822 or HSMS-282C series pair
is used.
Both the detection sensitivity and the DC forward voltage
of a biased Schottky detector are temperature sensitive.
Where both must be compensated over a wide range of
temperatures, the differential detector[2] is often used.
Such a circuit requires that the detector diode and the
reference diode exhibit identical characteristics at all DC
bias levels and at all temperatures. This is accomplished
through the use of two diodes in one package, for exam‑
ple the HSMS‑2825 in Figure 13. In the Avago assembly
facility, the two dice in a surface mount package are taken
from adjacent sites on the wafer (as illustrated in Figure
14). This assures that the characteristics of the two diodes
are more highly matched than would be possible through
individual testing and hand matching.
bias
Shunt inductor provides
video signal return
Shunt diode provides
video signal return
Zero Biased Diodes
DC Bias
DC Biased Diodes
differential
amplifier
matching
network
HSMS-2825
Figure 11. Single Diode Detectors.
The series and shunt circuits can be combined into a volt‑
age doubler[1], as shown in Figure 12. The doubler offers
three advantages over the single diode circuit.
Figure 13. Differential Detector.
[1] Avago Application Note 956‑4, “Schottky Diode Voltage Doubler.”
[2] Raymond W. Waugh, “Designing Large‑Signal Detectors for Handsets
and Base Stations,” Wireless Systems Design, Vol. 2, No. 7, July 1997,
pp 42 – 48.
bias
differential
amplifier
matching
network
HSMS-282P
Figure 14. Fabrication of Avago Diode Pairs.
Figure 17. Voltage Doubler ­Differential Detector.
In high power applications, coupling of RF energy from
the detector diode to the reference diode can introduce
error in the differential detector. The HSMS‑282K diode
pair, in the six lead SOT‑363 package, has a copper bar
between the diodes that adds 10 dB of additional isola‑
tion between them. As this part is manufactured in the
SOT‑363 package it also provides the benefit of being
40% smaller than larger SOT‑143 devices. The HSMS‑282K
is illustrated in Figure 15 — note that the ground connec‑
tions must be made as close to the package as possible to
minimize stray inductance to ground.
However, care must be taken to assure that the two refer‑
ence diodes closely match the two detector diodes. One
possible configuration is given in Figure 16, using two
HSMS‑2825. Board space can be saved through the use of
the HSMS‑282P open bridge quad, as shown in Figure 17.
PA
detector diode
Vbias
While the differential detector works well over tempera‑
ture, another design approach[3] works well for large signal
detectors. See Figure 18 for the schematic and a physical
layout of the circuit. In this design, the two 4.7 KΩ resis‑
tors and diode D2 act as a variable power divider, assuring
constant output voltage over temperature and improving
output linearity.
RF in
D1
68 Ω
4.7 KΩ
33 pF
Vo
4.7 KΩ
D2
68 Ω
HSMS-282K
reference diode
to differential amplifier
Figure 15. High Power Differential Detector.
The concept of the voltage doubler can be applied to the
differential detector, permitting twice the output voltage
for a given input power (as well as improving input im‑
pedance and suppressing second harmonics).
bias
differential
amplifier
HSMS-2825
matching
network
HSMS-2825
Figure 16. Voltage Doubler ­Differential Detector.
HSMS-2825
or
HSMS-282K
33 pF
RFin
HSMS-282K
Vo
4.7 KΩ
Figure 18. Temperature Compensated Detector.
In certain applications, such as a dual‑band cellphone
handset operating at both 900 and 1800 MHz, the second
harmonics generated in the power control output detec‑
tor when the handset is working at 900 MHz can cause
problems. A filter at the output can reduce unwanted
emissions at 1800 MHz in this case, but a lower cost so‑
lution is available[4]. Illustrated schematically in Figure
19, this circuit uses diode D2 and its associated passive
components to cancel all even order harmonics at the
detector’s RF input. Diodes D3 and D4 provide tempera‑
ture compensation as described above. All four diodes are
contained in a single HSMS‑ 282R package, as illustrated
in the layout shown in Figure 20.
[3] Hans Eriksson and Raymond W. Waugh, “A Temperature Compensated
Linear Diode Detector,” to be published.
D1
RF in
68 Ω
D2
R1
V+
HSMS-2829
R3
V–
R2
C1
R4
C2
D3
RF in
LO in
D4
C1 = C2 ≈ 100 pF
R1 = R2 = R3 = R4 = 4.7 KΩ
D1 & D2 & D3 & D4 = HSMS-282R
IF out
Figure 19. Schematic of Suppressed Harmonic Detector.
HSMS-282R
4.7 KΩ
4.7 KΩ
V+
V–
100 pF
100 pF
RF in
68 Ω
Figure 20. Layout of Suppressed Harmonic Detector.
Note that the forgoing discussion refers to the output volt‑
age being extracted at point V+ with respect to ground. If
a differential output is taken at V+ with respect to V‑, the
circuit acts as a voltage doubler.
Figure 22. Planar Double Balanced Mixer.
A review of Figure 21 may lead to the question as to why
the HSMS‑282R ring quad is open on the ends. Distor‑
tion in double balanced mixers can be reduced if LO drive
is increased, up to the point where the Schottky diodes
are driven into saturation. Above this point, increased LO
drive will not result in improvements in distortion. The use
of expensive high barrier diodes (such as those fabricated
on GaAs) can take advantage of higher LO drive power,
but a lower cost solution is to use a eight (or twelve) diode
ring quad. The open design of the HSMS-282R permits this
to easily be done, as shown in Figure 23.
LO in
RF in
Mixer applications
The HSMS‑282x family, with its wide variety of packaging,
can be used to make excellent mixers at frequencies up
to 6 GHz.
The HSMS‑2827 ring quad of matched diodes (in the SOT‑143
package) has been designed for double balanced mixers.
The smaller (SOT‑363) HSMS-282R ring quad can similarly
be used, if the quad is closed with external connections as
shown in Figure 21.
LO in
HSMS-282R
HSMS-282R
IF out
Figure 23. Low Distortion Double Balanced Mixer.
This same technique can be used in the single-balanced
mixer. Figure 24 shows such a mixer, with two diodes in
each spot normally occupied by one. This mixer, with a
sufficiently high LO drive level, will display low distortion.
HSMS-282R
RF in
RF in
180°
hybrid
Low pass
filter
IF out
LO in
Figure 24. Low Distortion Balanced Mixer.
IF out
Figure 21. Double Balanced Mixer.
Both of these networks require a crossover or a three di‑
mensional circuit. A planar mixer can be made using the
SOT‑143 crossover quad, HSMS‑2829, as shown in Figure
22. In this product, a special lead frame permits the cross‑
over to be placed inside the plastic package itself, elimi‑
nating the need for via holes (or other measures) in the RF
portion of the circuit itself.
[4] Alan Rixon and Raymond W. Waugh, “A Suppressed Harmonic Power
Detector for Dual Band ‘Phones,” to be published.
Sampling Applications
The six lead HSMS‑282P can be used in a sampling circuit,
as shown in Figure 25. As was the case with the six lead
HSMS‑282R in the mixer, the open bridge quad is closed
with traces on the circuit board. The quad was not closed
internally so that it could be used in other applications,
such as illustrated in Figure 17.
sample
point
HSMS-282P
sampling
pulse
Note that θjc, the thermal resistance from diode junction
to the foot of the leads, is the sum of two component re‑
sistances,
θ jc = θ pkg + θchip
Package thermal resistance for the SOT‑3x3 package is ap‑
proximately 100°C/W, and the chip thermal resistance for
the HSMS‑282x family 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.
Equation (1) would be straightforward to solve but for the
fact that diode forward voltage is a function of tempera‑
ture as well as forward current. The equation for Vf is:
sampling circuit
Figure 25. Sampling Circuit.
Thermal Considerations
The obvious advantage of the SOT‑323 and SOT‑363 over
the SOT‑23 and SOT‑142 is combination of smaller size
and extra leads. However, the copper leadframe in the
SOT‑3x3 has a thermal conductivity four times higher than
the Alloy 42 leadframe of the SOT‑23 and SOT‑143, which
enables the smaller packages to dissipate more power.
The maximum junction temperature for these three fami‑
lies of Schottky diodes is 150°C under all operating con‑
ditions. The following equation applies to the thermal
analysis of diodes:
Tj = (Vf If + PRF) θjc + Ta
where
Tj = junction temperature
Ta = diode case temperature
θjc = thermal resistance
V f I f = DC power dissipated
PRF = RF power dissipated
(2)
11600 (V f – I f R s )
nTf – I f R s ) – 1
e 11600 (V
nT
e
–1
If = I S
If = I S
(3)
where
n = ideality factor
T = temperature in °K
Rs = diode series resistance
and IS (diode saturation current) is given by
(1)
Is = I0
Is = I0
2
n – 4060
T 2e
n – 4060
298
T
( )
( 298 )
e
( 11T
(T
1
298
1
–
298
–
)
)
(4)
Equation (4) is substituted into equation (3), and equa‑
tions (1) and (3) are solved simultaneously to obtain the
value of junction temperature for given values of diode
case temperature, DC power dissipation and RF power
dissipation.
Diode Burnout
Assembly Instructions
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 con‑
trolled 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.[5] Formerly available only
in radar warning receivers and other high cost electronic
warfare applications, these diodes have been adapted to
commercial and consumer circuits.
SOT-3x3 PCB Footprint
Avago offers a com­plete line of surface mountable PIN
limiter diodes. Most notably, our HSMP-4820 (SOT-23) can
act as a very fast (nanosecond) power-sensitive switch
when placed between the antenna and the Schottky di‑
ode, shorting out the RF circuit temporarily and reflecting
the excessive RF energy back out the antenna.
[5] Avago Application Note 1050, “Low Cost, Surface Mount Power
Limiters.”
Recommended PCB pad layouts for the miniature SOT3x3 (SC-70) packages are shown in Figures 26 and 27 (di‑
mensions are in inches). These layouts provide ample al‑
lowance for package placement by automated assembly
equipment without adding parasitics that could impair
the performance.
0.026
0.079
0.039
0.022
Dimensions in inches
Figure 26. Recommended PCB Pad Layout for Avago’s SC70 3L/SOT‑323 Products.
0.026
0.079
0.039
0.018
Dimensions in inches
Figure 27. Recommended PCB Pad Layout for Avago's SC70 6L/SOT‑363 Products.
10
SMT Assembly
Reliable assembly of surface mount components is a com‑
plex process that involves many 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 packages, will reach solder reflow temperatures fast‑
er than those with a greater mass.
Avago’s diodes have been qualified to the time-tempera‑
ture profile shown in Figure 28. This profile is representa‑
tive of an IR reflow type of surface mount assembly pro‑
cess.
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 preheat zones.
The preheat zones increase the temperature of the board
and components to prevent thermal shock and begin
evaporating solvents from the solder paste. The reflow
zone briefly elevates the temperature sufficiently to pro‑
duce a reflow of the solder.
The rates of change of temperature 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 reflow zone (TMAX) should not exceed 260°C.
These parameters are typical for a surface mount assem‑
bly 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.
tp
Tp
Critical Zone
T L to Tp
Ramp-up
Temperature
TL
Ts
Ts
tL
max
min
Ramp-down
ts
Preheat
25
t 25° C to Peak
Time
Figure 28. Surface Mount Assembly Profile.
Lead-Free Reflow Profile Recommendation (IPC/JEDEC J-STD-020C)
Reflow Parameter
Lead-Free Assembly
Average ramp-up rate (Liquidus Temperature (TS(max) to Peak)
3°C/ second max
Preheat
Temperature Min (TS(min))
150°C
Temperature Max (TS(max))
200°C
Time (min to max) (tS)
60-180 seconds
Ts(max) to TL Ramp-up Rate
Time maintained above:
3°C/second max
Temperature (TL)
217°C
Time (tL)
60-150 seconds
Peak Temperature (TP)
260 +0/-5°C
Time within 5 °C of actual
Peak temperature (tP)
20-40 seconds
Ramp-down Rate
6°C/second max
Time 25 °C to Peak Temperature
8 minutes max
Note 1: All temperatures refer to topside of the package, measured on the package body surface
11
Package Dimensions
Outline SOT-323 (SC-70 3 Lead)
Outline 23 (SOT-23)
e2
e1
e1
XXX
E
XXX
E
E1
E1
e
e
L
B
L
B
C
D
C
DIMENSIONS (mm)
DIMENSIONS (mm)
D
A
A1
Notes:
XXX-package marking
Drawings are not to scale
SYMBOL
A
A1
B
C
D
E1
e
e1
e2
E
L
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
Outline 143 (SOT-143)
A
A1
Notes:
XXX-package marking
Drawings are not to scale
SYMBOL
A
A1
B
C
D
E1
e
e1
E
L
Outline SOT-363 (SC-70 6 Lead)
e2
DIMENSIONS (mm)
e1
HE
B1
E
XXX
E1
e
B
e
D
DIMENSIONS (mm)
A
Notes:
XXX-package marking
Drawings are not to scale
MIN.
MAX.
1.15
1.35
1.80
2.25
1.80
2.40
0.80
1.10
0.80
1.00
0.00
0.10
0.10
0.40
0.650 BCS
0.15
0.30
0.10
0.20
0.10
0.30
C
D
A1
SYMBOL
E
D
HE
A
A2
A1
Q1
e
b
c
L
E
L
12
MIN.
MAX.
0.80
1.00
0.00
0.10
0.15
0.40
0.10
0.20
1.80
2.25
1.10
1.40
0.65 typical
1.30 typical
1.80
2.40
0.425 typical
SYMBOL
A
A1
B
B1
C
D
E1
e
e1
e2
E
L
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
Q1
A1
A2
b
c
A
L
Device Orientation
For Outlines SOT-23, -323
REEL
TOP VIEW
END VIEW
4 mm
CARRIER
TAPE
8 mm
USER
FEED
DIRECTION
ABC
For Outline SOT-143
ABC
For Outline SOT-363
TOP VIEW
END VIEW
TOP VIEW
4 mm
END VIEW
4 mm
ABC
ABC
ABC
ABC
Note: "AB" represents package marking code.
"C" re presents date code.
13
ABC
Note: "AB" represents package marking code.
"C" represents date code.
COVER TAPE
8 mm
ABC
8 mm
ABC
ABC
ABC
ABC
Note: "AB" represents package marking code.
"C" represents date code.
Tape Dimensions and Product Orientation For Outline SOT-23
P
P2
D
E
P0
F
W
D1
t1
Ko
9° MAX
13.5° MAX
8° MAX
B0
A0
DESCRIPTION
SYMBOL
SIZE (mm)
SIZE (INCHES)
CAVITY
LENGTH
WIDTH
DEPTH
PITCH
BOTTOM HOLE DIAMETER
A0
B0
K0
P
D1
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
PERFORATION
DIAMETER
PITCH
POSITION
D
P0
E
1.50 + 0.10
4.00 ± 0.10
1.75 ± 0.10
0.059 + 0.004
0.157 ± 0.004
0.069 ± 0.004
CARRIER TAPE
WIDTH
THICKNESS
W
t1
8.00 + 0.30 – 0.10
0.229 ± 0.013
0.315 +0.012 – 0.004
0.009 ± 0.0005
DISTANCE
BETWEEN
CENTERLINE
CAVITY TO PERFORATION
(WIDTH DIRECTION)
F
3.50 ± 0.05
0.138 ± 0.002
CAVITY TO PERFORATION
(LENGTH DIRECTION)
P2
2.00 ± 0.05
0.079 ± 0.002
For Outline SOT-143
P
D
P2
P0
E
F
W
D1
t1
9° M A X
9° MAX
K0
A0
B0
DESCRIPTION
SYMBOL
SIZE (mm)
SIZE (INCHES)
CAVITY
LENGTH
WIDTH
DEPTH
PITCH
BOTTOM HOLE DIAMETER
A0
B0
K0
P
D1
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
PERFORATION
DIAMETER
PITCH
POSITION
D
P0
E
1.50 + 0.10
4.00 ± 0.10
1.75 ± 0.10
0.059 + 0.004
0.157 ± 0.004
0.069 ± 0.004
CARRIER TAPE
WIDTH
THICKNESS
W
t1
8.00 +0.30 – 0.10
0.254 ± 0.013
0.315+0.012 – 0.004
0.0100 ± 0.0005
DISTANCE
CAVITY TO PERFORATION
(WIDTH DIRECTION)
F
3.50 ± 0.05
0.138 ± 0.002
CAVITY TO PERFORATION
(LENGTH DIRECTION)
P2
2.00 ± 0.05
0.079 ± 0.002
14
Tape Dimensions and Product Orientation For Outlines SOT-323, -363
P
P2
D
P0
E
F
W
C
D1
t 1 (CARRIER TAPE THICKNESS)
K0
An
A0
An
B0
SYMBOL
SIZE (mm)
SIZE (INCHES)
CAVITY
DESCRIPTION
LENGTH
WIDTH
DEPTH
PITCH
BOTTOM HOLE DIAMETER
A0
B0
K0
P
D1
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
PERFORATION
DIAMETER
PITCH
POSITION
D
P0
E
1.55 ± 0.05
4.00 ± 0.10
1.75 ± 0.10
0.061 ± 0.002
0.157 ± 0.004
0.069 ± 0.004
CARRIER TAPE
WIDTH
THICKNESS
W
t1
8.00 ± 0.30
0.254 ± 0.02
0.315 ± 0.012
0.0100 ± 0.0008
COVER TAPE
WIDTH
TAPE THICKNESS
C
Tt
5.4 ± 0.10
0.062 ± 0.001
0.205 ± 0.004
0.0025 ± 0.00004
DISTANCE
CAVITY TO PERFORATION
(WIDTH DIRECTION)
F
3.50 ± 0.05
0.138 ± 0.002
CAVITY TO PERFORATION
(LENGTH DIRECTION)
P2
2.00 ± 0.05
0.079 ± 0.002
FOR SOT-323 (SC70-3 LEAD)
An
ANGLE
Tt (COVER TAPE THICKNESS)
FOR SOT-363 (SC70-6 LEAD)
8 °C MAX
10 °C MAX
Part Number Ordering Information
Part Number
No. of
Devices
Container
HSMS-282x-TR2G
10000
13" Reel
HSMS-282x-TR1G
3000
7" Reel
HSMS-282x-BLKG
100
antistatic bag
x = 0, 2, 3, 4, 5, 7, 8, 9, B, C, E, F, K, L, M, N, P or R
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 in the United States and other countries.
Data subject to change. Copyright © 2005-2008 Avago Technologies. All rights reserved. Obsoletes 5989-4030EN
AV02-1320EN - June 26, 2008