3
3–39
Alpha Industries
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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
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.
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
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
Sampling Phase Detectors
SPD Series
3–40 Alpha Industries
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Electrical Specifications at 25
°
C
Microwave
Monolithic Schottky
Diode Pair Beam
Lead
Coupling
Beam Lead Step Recovery Diode
Part
Number
Microwave
Signal
Level
dBm
Operating
Frequency
GHz
VF
@ 1 mA
mV RS
CJ @ 0V
pf
Coupling
Capacitors
CL
pf CJ @ 6V
pf TL
nS TT
pS VB
V
Typ. Max. Typ. Typ. Typ. Typ. Typ. Typ. Typ. Min.
SPD2835–211 4 240 3 0.40 1.0 0.35 25 50 14
SPD2826–211 –3 to 0 12 275 6 0.25 0.6 0.35 25 50 14
SPD2827–211 18 300 10 0.12 0.5 0.35 25 50 14
SPD2828–211 20 325 15 0.08 0.5 0.35 25 50 14
SPD2050–211 4 350 3 0.40 1.0 0.35 25 50 14
SPD2829–211 0 to +3 12 375 6 0.25 0.6 0.35 25 50 14
SPD2830–211 18 400 10 0.12 0.5 0.35 25 50 14
SPD2831–211 20 450 15 0.08 0.5 0.35 25 50 14
SPD2092–211 4 550 3 0.40 1.0 0.35 25 50 14
SPD2093–211 0 to +13 12 575 6 0.25 0.6 0.35 25 50 14
SPD2832–211 18 625 10 0.12 0.5 0.35 25 50 14
SPD2833–211 20 675 15 0.08 0.5 0.35 25 50 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
800
600
400
200
0 2 4 6 8 10 12 14 16 18 20
Ref. Frequency: 100 MHz
Ref. Input Power: +17 dBm
DRO/VCOI Power: 0 dBm
VCO/DRO (Microwave) Frequency (GHz)
Beat Note ( ) Output Voltage (mV)
f
Suggested Circuit Configuration
Reference
Frequency
Input
10–500 MHz
100Ω
100Ω
Microwave
Input
IF
Output
47 pF
10K
RFC
1. Input transformer 10:1 turns ratio low impedance at SRD; MCL617 or
equivalent.
47 pF 22 pF
Input
Trans-
formation
SRD
100Ω
39 pF
CL
CL
10KΩ
Sampling Phase Detectors
SPD Series
3–41
Alpha Industries
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150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
300
–40–30–20–10 0 10 20 30 40 50 60 70 80 90 100
Degrees C
Output Voltage (mV ppk)
Beat Note Voltage vs Temperature
(Frequency 100 MHz, Ref Power +10 dBm)
150
175
200
225
250
275
300
15 16 17 18 19 20 21 22 23 24
Power (dBm) of Reference
Beat Note Output (mV ppk)
Beat Note Voltage vs Power
(100 MHz Reference)
Outline Drawing
211 (Epoxy)
0.035 (0.89 mm)
MAX.
0.103 (2.62 mm)
0.097 (2.46 mm)
0.078 (1.98)
0.072 (1.83)
0.022 (0.56 mm)
0.018 (0.46 mm)
(5 PLCS.)
0.050
(1.27
mm)
0.012 (0.30 mm)
(2 PLCS. MIN.)
0.062 (1.57
mm) (4 PLCS.)
1
23
4
5
0.012 (0.30 mm)
0.008 (0.20 mm)
0.005 (0.13 mm)
0.003 (0.08 mm)
(5 PLCS.)
EPOXY
ENCAPSULATION
SCHEMATIC
METAL PARTS GOLD PLATED
1
23
4
5
0.028 (0.58 mm)
0.017 (0.43 mm)
(4 PLCS.)
217 (Hermetic)
SCHEMATIC
23
4
15
0.220 (5.59mm)
0.210 (5.33mm)
.063 (1.60mm)
TYP
0.130 (3.30mm)
TYP
3
2
NC
NC
1
0.045 (1.14mm)
TYP 5
4
0.013 (0.33mm)
0.007 (0.18mm)
7 PLCS
0.130
(3.30 mm)
TYP 0.268 (6.81mm)
0.252 (6.40mm)
0.065
(1.65mm)
MAX
0.007 (0.18mm)
0.003 (0.08mm)
7 PLCS
0.160 (4.06mm)
0.120 (3.05 mm)
7 PLCS
0.031 (0.79mm)
MAX 7 PLCS
Sampling Phase Detectors
SPD Series
