Surface Mount RF Schottky
Detector Diodes in SOT-363
(SC-70, 6 Lead)
Technical Data
HSMS-285L/P
HSMS-286K/L/P/R
Features
• Unique configurations in
surface mount SOT-363
package
– increase flexibility
– save board space
– reduce cost
• Excellent sensitivity for
better detection
– HSMS-286a for higher
frequencies
– HSMS-285a zero bias for less
power consumption
• HSMS-286K grounded
center leads provide up to
10 dB higher isolation
• Matched diodes for
consistent performance
• Better thermal conductivity
for higher power dissipation
Package Lead Code
Identification
(Top View)
HIGH ISOLATION
UNCONNECTED PAIR
6
5
4
Description
Hewlett-Packard’s HSMS-285L/P
and HSMS-286K/L/P/R families have
been optimized for use as detectors
in the 915 MHz to 5.8 GHz range.
The HSMS-285a, with a bandwidth
of 0.01 - 7 GHz, requires no battery
or power supply, and is well suited
as a very simple and inexpensive
detector. The HSMS-286a operates
in the 0.3 - 8 GHz range and is a high
performance detector for upper
frequencies.
Available in various package
configurations, these two families
of detector diodes provide low cost
solutions to a wide variety of design
problems. Hewlett-Packard’s
manufacturing techniques assure
that when multiple diodes are
mounted into a single SOT-363
package, they are taken from
adjacent sites on the wafer, assuring
the highest possible degree of
match.
UNCONNECTED
TRIO
6
5
4
1
2
3
K
BRIDGE
QUAD
6
5
4
1
2
L
3
6
RING
QUAD
5
4
1
2
P
3
1
2
R
3
Pin Connections and
Package Marking
1
2
3
6
5
4
PL
Applications
Both are ideal for RF/ID and RF
Tag; cellular and other consumer
applications requiring small and
large signal detection; modulation;
RF to DC conversion; or voltage
doubling.
Notes:
1. Package marking provides
orientation and identification.
2. See “Electrical Specifications” for
appropriate package marking.
4
Typical Parameters, Single Diode
FORWARD VOLTAGE DIFFERENCE (mV)
100
I
F
– FORWARD CURRENT (mA)
100
FORWARD CURRENT (mA)
FORWARD CURRENT (µA)
100
I
F
(left scale)
10
10
10
T
A
= +85°C
T
A
= +25°C
T
A
= –55°C
1
1
10
0.1
.1
∆V
F
(right scale)
0.01
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8
V
F
– FORWARD VOLTAGE (V)
.01
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
FORWARD VOLTAGE (V)
1
0.05
0.10
0.15
0.20
1
0.25
FORWARD VOLTAGE (V)
Figure 1. +25°C Forward Current vs.
Forward Voltage, HSMS-285a Series.
Figure 2. Forward Current vs. Forward
Voltage at Temperature, HSMS-286a
Series.
30
Figure 3. Forward Voltage Match,
HSMS-286a Series.
10000
R
L
= 100 KΩ
1000
VOLTAGE OUT (mV)
VOLTAGE OUT (mV)
2.45 GHz
100
915 MHz
10,000
R
L
= 100 KΩ
915 MHz
20
µA
VOLTAGE OUT (mV)
10
µA
1000
5
µA
100
Frequency = 2.45 GHz
Fixed-tuned FR4 circuit
10
R
L
= 100 KΩ
10
2.45 GHz
10
5.8 GHz
DIODES TESTED IN FIXED-TUNED
FR4 MICROSTRIP CIRCUITS.
5.8 GHz
1
DIODES TESTED IN FIXED-TUNED
FR4 MICROSTRIP CIRCUITS.
1
0.3
-50
-40
-30
-20
-10
0
0.3
-50
-40
POWER IN (dBm)
-30
1
–40
–30
–20
–10
0
10
POWER IN (dBm)
POWER IN (dBm)
Figure 4. +25°C Output Voltage vs.
Input Power, HSMS-285a Series at Zero
Bias, HSMS-286a Series at 3
µA
Bias.
Figure 5. +25°C Expanded Output
Voltage vs. Input Power. See Figure 4.
Figure 6. Dynamic Transfer
Characteristic as a Function of DC Bias,
HSMS-286a.
40
35
OUTPUT VOLTAGE (mV)
OUTPUT VOLTAGE (mV)
3.1
2.9
2.7
2.5
2.3
2.1
1.9
1.7
1.5
1.3
1.1
FR4 MICROSTRIP CIRCUIT.
0.9
0 10 20 30 40 50 60 70 80 90 100
TEMPERATURE (°C)
MEASUREMENTS MADE USING A
FREQUENCY = 2.45 GHz
P
IN
= -40 dBm
R
L
= 100 KΩ
30
25
20
15
10
5
.1
Input Power =
–30 dBm @ 2.45 GHz
Data taken in fixed-tuned
FR4 circuit
R
L
= 100 KΩ
1
10
100
BIAS CURRENT (µA)
Figure 7. Voltage Sensitivity as a
Function of DC Bias Current,
HSMS-286a.
Figure 8. Output Voltage vs.
Temperature, HSMS-285a Series.
5
Applications Information
Introduction
Hewlett-Packard’s HSMS-285L and
HSMS-285P zero bias Schottky
diodes have been developed
specifically for low cost, high
volume detector applications
where bias current is not available.
The HSMS-286L, HSMS-286P and
HSMS-286R DC biased Schottky
diodes have been developed for
low cost, high volume detector
applications where stability over
temperature is an important
design consideration.
Schottky Barrier Diode
Characteristics
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 9, along with its
equivalent circuit.
METAL
R
S
of the total current flowing
through it.
R
j
=
=
8.33 x 10
-5
n T
I
S
+ I
b
0.026
I
S
+ I
b
where
n = ideality factor (see table of
SPICE parameters)
T = temperature in
°K
I
S
= saturation current (see
table of SPICE parameters)
I
b
= externally applied bias
current in amps
I
S
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.
The Height of the Schottky
Barrier
The current-voltage characteristic
of a Schottky barrier diode at
room temperature is described by
the following equation:
at 25°C
= R
V
– R
s
altered, and at the same time C
J
and R
S
will be changed. In general,
very low barrier height diodes
(with high values of I
S
, suitable for
zero bias applications) are realized
on p-type silicon. Such diodes
suffer from higher values of R
S
than do the n-type. Thus, p-type
diodes are generally reserved for
detector applications (where very
high values of R
V
swamp out high
R
S
) and n-type diodes are used for
mixer applications (where high
L.O. drive levels keep R
V
low).
Measuring Diode Linear
Parameters
The measurement of the five
elements which make up the
equivalent circuit for a packaged
Schottky diode (see Figure 10) is a
complex task. Various techniques
are used for each element. The
task begins with the elements of
the diode chip itself.
C
P
N-TYPE OR P-TYPE SILICON SUBSTRATE
PASSIVATION
N-TYPE OR P-TYPE EPI
PASSIVATION
LAYER
SCHOTTKY JUNCTION
C
j
R
j
I = I
S
(e
(
V – IR
S
0.026
– 1)
L
P
R
S
R
V
)
C
J
CROSS-SECTION OF SCHOTTKY
BARRIER DIODE CHIP
EQUIVALENT
CIRCUIT
Figure 9. Schottky Diode Chip.
R
S
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 R
S
is lost as
heat — it does not contribute to
the rectified output of the diode.
C
J
is parasitic junction capacitance
of the diode, controlled by the
thickness of the epitaxial layer and
the diameter of the Schottky
contact. R
j
is the junction
resistance of the diode, a function
On a semi-log plot (as shown in
the HP 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 R
S
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, I
S
, 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
FOR THE HSMS-285A or HSMS-286A SERIES
C
P
= 0.08 pF
L
P
= 2 nH
Figure 10. Equivalent Circuit of a
Schottky Diode.
R
S
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
high value of current (such as
5 mA). This slope is converted into
a resistance R
d
.
R
S
= R
d
–
0.026
I
f
京公网安备 11010802033920号
EEWORLD
