HSMS-2850-TR1 Avago Technologies US Inc., HSMS-2850-TR1 Datasheet - Page 5

• Manufacturer Part Number: HSMS-2850-TR1
• Description: DETECTOR DIODE,1MHZ F(TEST),SOT-23
• Manufacturer: Avago Technologies US Inc.

Specifications of HSMS-2850-TR1

• Rohs Compliant: NO
• Diode Type: Schottky - Single
• Voltage - Peak Reverse (max): 2V
• Capacitance @ Vr, F: 0.3pF @ 1V, 1MHz
• Package / Case: SOT-23-3, TO-236-3, Micro3™, SSD3, SST3
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Current - Max: -
• Power Dissipation (max): -
• Resistance @ If, F: -
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

N-TYPE OR P-TYPE SILICON SUBSTRATE
PASSIVATION
N-TYPE OR P-TYPE EPI
CROSS-SECTION OF SCHOTTKY
Applications Information
Introduction
Agilent’s HSMS-285x family of
Schottky detector diodes has been
developed specifically for low
cost, high volume designs in small
signal (P
tions at frequencies below
1.5 GHz. At higher frequencies,
the DC biased HSMS-286x family
should be considered.
In large signal power or gain con-
trol applications (P
the HSMS-282x and HSMS-286x
products should be used. The
HSMS-285x zero bias diode is not
designed for large signal designs.
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 5, along
with its equivalent circuit.
Figure 5. Schottky Diode Chip.
R
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
heat — it does not contribute to
the rectified output of the diode.
C
S
J
is parasitic junction capaci-
is the parasitic series
BARRIER DIODE CHIP
METAL
SCHOTTKY JUNCTION
in
< -20 dBm) applica-
LAYER
PASSIVATION
in
> -20 dBm),
S
is lost as
EQUIVALENT
C
j
R
CIRCUIT
S
R
j
tance of the diode, controlled by
the thickness of the epitaxial layer
and the diameter of the Schottky
contact. R
resistance of the diode, a function
of the total current flowing
through it.
where
I
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:
On a semi-log plot (as shown in
the Agilent 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
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
S
S
n = ideality factor (see table of
T = temperature in °K
I
I
is a function of diode barrier
S
b
is seen in a curve that droops
R
= saturation current (see
= externally applied bias
I = I
j
SPICE parameters)
table of SPICE parameters)
current in amps
= –––––––––––– = R
= ––––– at 25°C
S
8.33 X 10
0.026
I
S
j
(exp
+ I
is the junction
I
S
b
+ I
(
––––––
V - IR
-5
b
0.026
n T
S
)
- 1)
V
– R
s
current, I
barrier height of the diode.
Through the choice of p-type or
n-type silicon, and the selection of
metal, one can tailor the charac-
teristics of a Schottky diode.
Barrier height will be altered, and
at the same time C
changed. In general, very low
barrier height diodes (with high
values of I
applications) are realized on
p-type silicon. Such diodes suffer
from higher values of R
the n-type. Thus, p-type diodes are
generally reserved for small signal
detector applications (where very
high values of R
R
mixer applications (where high
L.O. drive levels keep R
Measuring Diode Parameters
The measurement of the five
elements which make up the low
frequency equivalent circuit for a
packaged Schottky diode (see
Figure 6) is a complex task.
Various techniques are used for
each element. The task begins
with the elements of the diode
chip itself.
Figure 6. Equivalent Circuit of a
Schottky Diode.
FOR THE HSMS-285x SERIES
C
L
C
R
R
P
P
j
S
V
S
) and n-type diodes are used for
= 2 nH
= 0.18 pF
= 0.08 pF
= 25 Ω
= 9 KΩ
L
5
P
S
, and is related to the
S
, suitable for zero bias
R
S
V
swamp out high
J
C
and R
P
R
S
V
V
C
than do
low).
j
S
will be