aiAlpha Silicon Schottky Diode Chips Service Manual

Alpha Industries, Inc. [781] 935-5150 • Fax [617] 824-4579 • Email [e-mail] • www.alphaind.com 1

Specifications subject to change without notice. 8/01A

Silicon Schottky Diode Chips

Features

■ For Detector and Mixer Applications

■ Low Capacitance for Usage Beyond 40 GHz

■ ZBD and Low Barrier Designs

■ P-Type and N-Type Junctions

■ 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 Ω to higher values. Maximum
sensitivity occurs when the source impedance equals the
video resistance.

Electrical Specifications at 25°C

Junction

C

J

1

R

T

2

VF@ 1 mA V

B

3

RV@ Zero Bias

Outline

Part Number Barrier

Type

(pF) (ΩΩ) (mV) (V) (kΩΩ)

Drawing

Max. Max. Min.–Max. Min. Typ.

CDC7630-000 ZBD P 0.25 30 135–240 1 5.5 526-006

CDC7631-000 ZBD P 0.15 80 150–300 2 7.2 526-006

CDB7619-000 Low P 0.10 40 275–375 2 735 526-006

CDB7620-000 Low P 0.15 30 250–350 2 537 526-006

CDF7621-000 Low N 0.10 20 270–350 2 680 526-011

CDF7623-000 Low N 0.30 10 240–300 2 245 526-011

1. CJfor low barrier diodes specified at 0 V. CJfor ZBDs specified at 0.15 V
reverse bias.

2. R

T

is the slope resistance at 10 mA. RSMax. may be calculated from:

R

S

= RT- 2.6 x N.

3. V

B

for low barrier diodes is specified at 10 µA. VBfor ZBDs is specified

at 100 µA.

In a detector circuit operating at zero bias, depending on
the video load impedance, a ZBD device with RVless than
10 kΩ may be more sensitive than a low barrier diode with
RVgreater than 100 kΩ. 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, RS, and will perform with lower conversion loss
in mixer circuits. The bond pad for the N-type Schottky
diode is the anode.

查询CDB7619-000供应商

Silicon Schottky Diode Chips

2 Alpha Industries, Inc. [781] 935-5150 • Fax [617] 824-4579 • Email [e-mail] • 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 Ω

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 Ω

50 Ω

100 Ω

200 Ω

500 Ω

Typical Performance Data

100

1000

10000

100000

1 10 100

Forward Bias (µA)

Video Resistance (Ω)

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 CurrentFigure 2. Video Resistance vs. Forward Bias Current