Sampling Phase Detectors
SPD Series
Features
Low Cost Design
Rugged, Modular, Hybrid Construction
Phase Locks VCO and DROs up to 20 GHz
Wide Frequency Range
Available for Oscillator Signal Levels from
–3 dBm to +13 dBm
Hermetic Package Available
3
Description
Alpha’s series of Sampling Phase Detectors (SPD’s)
consist of a hybrid assembly of an SRD comb
generator, coupling capacitors and microwave mixer
diodes. This module makes an inexpensive way of
phase locking a commercial VCO source to a low
frequency stable reference. Each part in the series is
optimized to operate in standard narrow band
commercial systems. All units handle reference
frequencies in the 50 to 500 MHz band. Component
selection within Alpha allows us to minimize beat note
output.
It is easiest to think of the SPD in its two constituent
forms; a comb generator and subharmonic mixer.
circuit with shunt capacitors will result in larger
amplitude beat note signals.
The subharmonic mixer portion is the Schottky series
pair. Various drive levels can be used to tailor
intermodulation and beat note performance.
The basic operation of a SPD is when the reference
signal is fed into the SRD. This sets up a strong pulse,
rich in harmonics that is used to strobe the mixer
diodes on. The balanced mixer design converts the
sampled oscillator signal and matching harmonics into
an IF beat note. This signal can then be used in
feedback loop to correct tuning voltage on the VCO.
Typical applications include phase locking of
oscillators
in
TVRO,
VSAT,
DBS
and
telecommunications markets.
Leadless chip carriers and surface mount versions
are also available
The comb generator portion consists of the external
reference, amplifier and impedance transformer. The
external circuit matches into the low impedance of the
SRD portion of the SPD. Careful attention to matching
by setting the right transformer ratio, detuning the
Alpha Industries
•
[617] 935 5150
•
Fax
[617] 824 4579
•
E-mail
sales@alphaind.com
•
Visit our web site:
www.alphaind.com
3–39
Sampling Phase Detectors
SPD Series
Electrical Specifications at 25°C
Monolithic Schottky
Diode Pair
Part
Number
Microwave
Signal
Level
dBm
Typ.
SPD2835–211
SPD2826–211
SPD2827–211
SPD2828–211
SPD2050–211
SPD2829–211
SPD2830–211
SPD2831–211
SPD2092–211
SPD2093–211
SPD2832–211
SPD2833–211
0 to +13
0 to +3
–3 to 0
Operating
Frequency
GHz
Max.
4
12
18
20
4
12
18
20
4
12
18
20
V
F
@ 1 mA
mV
Typ.
240
275
300
325
350
375
400
450
550
575
625
675
R
S
W
Typ.
3
6
10
15
3
6
10
15
3
6
10
15
C
J
@ 0V
pf
Typ.
0.40
0.25
0.12
0.08
0.40
0.25
0.12
0.08
0.40
0.25
0.12
0.08
Beam
Lead
Coupling
Capacitors
C
L
pf
Typ.
1.0
0.6
0.5
0.5
1.0
0.6
0.5
0.5
1.0
0.6
0.5
0.5
Beam Lead Step Recovery Diode
C
J
@ 6V
pf
Typ.
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
T
L
nS
Typ.
25
25
25
25
25
25
25
25
25
25
25
25
T
T
pS
Typ.
50
50
50
50
50
50
50
50
50
50
50
50
V
B
V
Min.
14
14
14
14
14
14
14
14
14
14
14
14
Any of the above can be made in hermetic packages. The part number series is SPDXXXX–217.
Typical Performance Data
SPD 3465–18 Low Drive
1000
Beat Note (
f
) Output Voltage (mV)
Suggested Circuit Configuration
10KW
100Ω
47 pF
22 pF
Microwave
Input
800
600
Reference
Frequency
Input
10–500 MHz
C
L
SRD
RFC
I
F
Output
400
Input
Trans-
formation
C
L
100Ω
39 pF
200
Ref. Frequency: 100 MHz
Ref. Input Power: +17 dBm
DRO/VCOI Power: 0 dBm
100Ω
47 pF
10KΩ
1.
0
2
4
6
8
10
12
14
16
18
20
Input transformer 10:1 turns ratio low impedance at SRD; MCL617 or
equivalent.
VCO/DRO (Microwave) Frequency (GHz)
3–40
Alpha Industries
•
[617] 935 5150
•
Fax
[617] 824 4579
•
E-mail
sales@alphaind.com
•
Visit our web site:
www.alphaind.com
Sampling Phase Detectors
SPD Series
300
290
280
270
260
250
240
230
220
210
200
190
180
170
160
150
–40 –30 –20 –10 0 10 20 30 40 50 60 70 80 90 100
300
Beat Note Output (mV ppk)
Output Voltage (mV ppk)
275
250
225
200
175
150
15
16
17
18
19
20
21
22
23
24
Degrees C
Power (dBm) of Reference
Beat Note Voltage vs Temperature
(Frequency 100 MHz, Ref Power +10 dBm)
Beat Note Voltage vs Power
(100 MHz Reference)
Outline Drawing
211 (Epoxy)
0.103 (2.62 mm)
0.097 (2.46 mm)
2
0.028 (0.58 mm)
0.017 (0.43 mm)
(4 PLCS.)
SCHEMATIC
3
4
217 (Hermetic)
SCHEMATIC
2 3
4
0.220 (5.59mm)
0.210 (5.33mm)
.063 (1.60mm)
TYP
2
0.062 (1.57
mm) (4 PLCS.)
2
3
0.050
(1.27
mm)
1
5
1
5
0.065
(1.65mm)
MAX
4
0.078 (1.98)
0.072 (1.83)
0.022 (0.56 mm)
0.018 (0.46 mm)
(5 PLCS.)
3
0.130 (3.30mm) 0.007 (0.18mm)
0.003 (0.08mm)
TYP
7 PLCS
0.130
(3.30 mm)
TYP 0.268 (6.81mm)
0.252 (6.40mm)
4
0.160 (4.06mm)
0.120 (3.05 mm)
7 PLCS
0.013 (0.33mm)
0.007 (0.18mm)
7 PLCS
0.031 (0.79mm)
MAX 7 PLCS
NC
NC
1
0.012 (0.30 mm)
(2 PLCS. MIN.)
5
EPOXY
ENCAPSULATION
0.035 (0.89 mm)
MAX.
0.012 (0.30 mm)
0.008 (0.20 mm)
0.005 (0.13 mm)
0.003 (0.08 mm)
(5 PLCS.)
1
0.045 (1.14mm)
TYP
5
METAL PARTS GOLD PLATED
Alpha Industries
•
[617] 935 5150
•
Fax
[617] 824 4579
•
E-mail
sales@alphaind.com
•
Visit our web site:
www.alphaind.com
3–41
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