Alpha Industries, Inc. [781] 935-5150
Fax [617] 824-4579 Email sales@alphaind.com www.alphaind.com
1
Specifications subject to change without notice. 8/01A
Silicon Schottky Diode Chips
Features
I For Detector and Mixer Applications
I Low Capacitance for Usage Beyond 40 GHz
I ZBD and Low Barrier Designs
I P-Type and N-Type Junctions
I Large Bond Pad Chip Design
Description
Alpha's product line of silicon Schottky diode chips are
intended for use as detector and mixer devices in hybrid
integrated circuits at frequencies from below 100 MHz to
higher than 40 GHz. Alpha's "Universal Chip" design
features a 4 mil diameter bond pad that is offset from the
semiconductor junction preventing damage to the active
junction as a result of wire bonding.
As power-sensing detectors, these Schottky diode chips
all have the same voltage sensitivity so long as the output
video impedance is much higher than the video
resistance of the diode. Figure 1 shows the expected
detected voltage sensitivity as a function of RF source
impedance in an untuned circuit. Note that sensitivity is
substantially increased by transforming the source
impedance from 50
to higher values. Maximum
sensitivity occurs when the source impedance equals the
video resistance.
Electrical Specifications at 25C
Junction
C
J
1
R
T
2
V
F
@ 1 mA
V
B
3
R
V
@ Zero Bias
Outline
Part Number
Barrier
Type
(pF)
(
)
(mV)
(V)
(k
)
Drawing
Max.
Max.
Min.Max.
Min.
Typ.
CDC7630-000
ZBD
P
0.25
30
135240
1
5.5
526-006
CDC7631-000
ZBD
P
0.15
80
150300
2
7.2
526-006
CDB7619-000
Low
P
0.10
40
275375
2
735
526-006
CDB7620-000
Low
P
0.15
30
250350
2
537
526-006
CDF7621-000
Low
N
0.10
20
270350
2
680
526-011
CDF7623-000
Low
N
0.30
10
240300
2
245
526-011
1. C
J
for low barrier diodes specified at 0 V. C
J
for ZBDs specified at 0.15 V
reverse bias.
2. R
T
is the slope resistance at 10 mA. R
S
Max. may be calculated from:
R
S
= R
T
- 2.6 x N.
3. V
B
for low barrier diodes is specified at 10
A. V
B
for ZBDs is specified
at 100
A.
In a detector circuit operating at zero bias, depending on
the video load impedance, a ZBD device with R
V
less than
10 k
may be more sensitive than a low barrier diode with
R
V
greater than 100 k
. Applying forward bias reduces
the diode video resistance as shown in Figure 2. Lower
video resistance also increases the video bandwidth but
does not increase voltage sensitivity, as shown in
Figure 3. Biased Schottky diodes have better temperature
stability and also may be used in temperature
compensated detector circuits.
P-type Schottky diodes generate lower 1/F noise and are
preferred for Doppler mixers and biased detector
applications. The bond pad for the P-type Schottky diode
is the cathode. N-type Schottky diodes have lower parasitic
resistance, R
S
, and will perform with lower conversion loss
in mixer circuits. The bond pad for the N-type Schottky
diode is the anode.
Silicon Schottky Diode Chips
2
Alpha Industries, Inc. [781] 935-5150
Fax [617] 824-4579 Email sales@alphaind.com www.alphaind.com
Specifications subject to change without notice. 8/01A
SPICE Model Parameters
Parameter
CDB7619
CDB7620
CDF7621
CDF7623
CDC7630
CDC7631
Units
IS
3.70E-08
5.40E-08
4.0E-08
1.1E-07
5.0E-06
3.8E-06
A
R
S
9
14
12
6
20
51
N
1.05
1.12
1.05
1.04
1.05
1.05
TT
1E-11
1E-11
1E-11
1E-11
1E-11
1E-11
S
C
J0
0.08
0.15
0.10
0.22
0.14
0.08
pF
M
0.35
0.35
0.35
0.32
0.40
0.4
E
G
0.69
0.69
0.69
0.69
0.69
0.69
eV
XTI
2.0
2.0
2.0
2.0
2.0
2.0
F
C
0.5
0.5
0.5
0.5
0.5
0.5
B
V
2.0
4.0
3.0
2.0
2.0
2.0
V
I
BV
1.00E-05
1.00E-05
1.0E-05
1.0E-05
1.0E-04
1.0E-04
A
V
J
0.495
0.495
0.495
0.495
0.340
0.340
V
0.1
1
10
100
1000
10000
-40
-30
-20
-10
0
10
Input Power (dBm)
Detected Voltage (mV)
25
50
100
200
500
Typical Performance Data
100
1000
10000
100000
1
10
100
Forward Bias (
A)
Video Resistance (
)
ZBD
Low Barrier
RF SOURCE
IMPEDANCE
DETECTOR
VOLTAGE
VIDEO LOAD
IMPEDANCE
RFC
P
Input
Zero Biased Detector
RF SOURCE
IMPEDANCE
DETECTOR
VOLTAGE
VIDEO LOAD
IMPEDANCE
RFC
P
Input
Biased Detector
0.001
0.01
0.1
1
10
100
1000
10000
0.001
0.01
0.1
1
10
Forward Current (mA)
Detected Voltage (mV)
-30 dBm
-20 dBm
-10dBm
0 dBm
+10 dBm
Figure 1. Detected Voltage vs. Input
Power and RF Source Impedance
Figure 3. Detected Voltage vs. Forward Current
Figure 2. Video Resistance vs. Forward Bias Current
Silicon Schottky Diode Chips
Alpha Industries, Inc. [781] 935-5150
Fax [617] 824-4579 Email sales@alphaind.com www.alphaind.com
3
Specifications subject to change without notice. 8/01A
Characteristic
Value
Reverse Voltage (V
R
)
Voltage Rating
Forward Current (I
F
)
50 mA
Power Dissipation (P
D
)
75 mW
Storage Temperature (T
ST
)
-65C to +150C
Operating Temperature (T
OP
)
-65C to +150C
Absolute Maximum Ratings
0.015 (0.38 mm)
0.013 (0.33 mm)
0.015 (0.38 mm)
0.013 (0.33 mm)
BONDING PAD
DIAMETER
0.0035 (0.089 mm)
0.0045 (0.114 mm)
0.0085 (0.216 mm)
0.0065 (0.165 mm)
526-006 = Cathode bond pad.
526-011 = Anode bond pad.
Outline Drawing
526-006, 526-011
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