Philips Semiconductors
SA612A
Double-balanced mixer and oscillator
Product specification
Replaces data of September 17, 1990
1997 Nov 07
RF COMMUNICATIONS PRODUCTS
IC17 Data Handbook
Philips Semiconductors
Product specification
SA612A
Double-balanced mixer and oscillator
2
1997 Nov 07
853-0391 18662
DESCRIPTION
The SA612A is a low-power VHF monolithic double-balanced mixer
with on-board oscillator and voltage regulator. It is intended for low
cost, low power communication systems with signal frequencies to
500MHz and local oscillator frequencies as high as 200MHz. The
mixer is a "Gilbert cell" multiplier configuration which provides gain
of 14dB or more at 45MHz.
The oscillator can be configured for a crystal, a tuned tank
operation, or as a buffer for an external L.O. Noise figure at 45MHz
is typically below 6dB and makes the device well suited for high
performance cordless phone/cellular radio. The low power
consumption makes the SA612A excellent for battery operated
equipment. Networking and other communications products can
benefit from very low radiated energy levels within systems. The
SA612A is available in an 8-lead dual in-line plastic package and an
8-lead SO (surface mounted miniature package).
FEATURES
Low current consumption
Low cost
Operation to 500MHz
Low radiated energy
Low external parts count; suitable for crystal/ceramic filter
Excellent sensitivity, gain, and noise figure
PIN CONFIGURATION
D, N Packages
8
7
6
5
1
2
3
4
INPUT A
INPUT B
GND
OUTPUT A
OSCILLATOR
OSCILLATOR
OUTPUT B
VCC
SR00098
Figure 1. Pin Configuration
APPLICATIONS
Cordless telephone
Portable radio
VHF transceivers
RF data links
Sonabuoys
Communications receivers
Broadband LANs
HF and VHF frequency conversion
Cellular radio mixer/oscillator
ORDERING INFORMATION
DESCRIPTION
TEMPERATURE RANGE
ORDER CODE
DWG #
8-Pin Plastic Dual In-Line Plastic (DIP)
-40 to +85
C
SA612AN
SOT97-1
8-Pin Plastic Small Outline (SO) package (Surface-Mount)
-40 to +85
C
SA612AD
SOT96-1
BLOCK DIAGRAM
8
7
6
5
4
3
2
1
OSCILLATOR
VOLTAGE
REGULATOR
GROUND
V
CC
SR00099
Figure 2. Block Diagram
Philips Semiconductors
Product specification
SA612A
Double-balanced mixer and oscillator
1997 Nov 07
3
ABSOLUTE MAXIMUM RATINGS
SYMBOL
PARAMETER
RATING
UNIT
V
CC
Maximum operating voltage
9
V
T
STG
Storage temperature
-65 to +150
C
T
A
Operating ambient temperature range SA612A
-40 to +85
C
AC/DC ELECTRICAL CHARACTERISTICS
T
A
=25
C, V
CC
= 6V, Figure 3
SYMBOL
PARAMETER
TEST CONDITION
LIMITS
UNIT
SYMBOL
PARAMETER
TEST CONDITION
Min
Typ
Max
UNIT
V
CC
Power supply voltage range
4.5
8.0
V
DC current drain
2.4
3.0
mA
f
IN
Input signal frequency
500
MHz
f
OSC
Oscillator frequency
200
MHz
Noise figured at 45MHz
5.0
dB
Third-order intercept point at 45MHz
RF
IN
=-45dBm
-13
dBm
Conversion gain at 45MHz
14
17
dB
R
IN
RF input resistance
1.5
k
C
IN
RF input capacitance
3
pF
Mixer output resistance
(Pin 4 or 5)
1.5
k
DESCRIPTION OF OPERATION
The SA612A is a Gilbert cell, an oscillator/buffer, and a temperature
compensated bias network as shown in the equivalent circuit. The
Gilbert cell is a differential amplifier (Pins 1 and 2) which drives a
balanced switching cell. The differential input stage provides gain
and determines the noise figure and signal handling performance of
the system.
The SA612A is designed for optimum low power performance.
When used with the SA614A as a 45MHz cordless phone/cellular
radio 2nd IF and demodulator, the SA612A is capable of receiving
-119dBm signals with a 12dB S/N ratio. Third-order intercept is
typically -15dBm (that's approximately +5dBm output intercept
because of the RF gain). The system designer must be cognizant of
this large signal limitation. When designing LANs or other closed
systems where transmission levels are high, and small-signal or
signal-to-noise issues not critical, the input to the SA612A should be
appropriately scaled.
Philips Semiconductors
Product specification
SA612A
Double-balanced mixer and oscillator
1997 Nov 07
4
TEST CONFIGURATION
8
7
6
5
4
3
2
1
OUTPUT
150pF
330pF
120pF
1.5 to
100nF
220pF
INPUT
47pF
22pF
1nF
100nF
10nF
VCC
6.8
F
5.5
H
0.209 to
0.283
H
44.2
H
10pF
34.545MHz THIRD OVERTONE CRYSTAL
612A
0.5 to 1.3
H
SR00101
Figure 3. Test Configuration
1
2
3
4
5
6
7
8
GND
BUFFER
1.5k
BIAS
BIAS
BIAS
1.5k
1.5k
1.5k
VCC
18k
25k
SR00102
Figure 4. Equivalent Circuit
Philips Semiconductors
Product specification
SA612A
Double-balanced mixer and oscillator
1997 Nov 07
5
Besides excellent low power performance well into VHF, the
SA612A is designed to be flexible. The input, output, and oscillator
ports can support a variety of configurations provided the designer
understands certain constraints, which will be explained here.
The RF inputs (Pins 1 and 2) are biased internally. They are
symmetrical. The equivalent AC input impedance is approximately
1.5k || 3pF through 50MHz. Pins 1 and 2 can be used
interchangeably, but they should not be DC biased externally. Figure
5 shows three typical input configurations.
The mixer outputs (Pins 4 and 5) are also internally biased. Each
output is connected to the internal positive supply by a 1.5k
resistor. This permits direct output termination yet allows for
balanced output as well. Figure 6 shows three single-ended output
configurations and a balanced output.
The oscillator is capable of sustaining oscillation beyond 200MHz in
crystal or tuned tank configurations. The upper limit of operation is
determined by tank "Q" and required drive levels. The higher the Q
of the tank or the smaller the required drive, the higher the
permissible oscillation frequency. If the required L.O. is beyond
oscillation limits, or the system calls for an external L.O., the
external signal can be injected at Pin 6 through a DC blocking
capacitor. External L.O. should be 200mV
P-P
minimum to 300mV
P-P
maximum.
Figure 7 shows several proven oscillator circuits. Figure 7a is
appropriate for cordless phones/cellular radio. In this circuit a third
overtone parallel-mode crystal with approximately 5pF load
capacitance should be specified. Capacitor C3 and inductor L1 act
as a fundamental trap. In fundamental mode oscillation the trap is
omitted.
Figure 8 shows a Colpitts varacter tuned tank oscillator suitable for
synthesizer-controlled applications. It is important to buffer the
output of this circuit to assure that switching spikes from the first
counter or prescaler do not end up in the oscillator spectrum. The
dual-gate MOSFET provides optimum isolation with low current.
The FET offers good isolation, simplicity, and low current, while the
bipolar circuits provide the simple solution for non-critical
applications. The resistive divider in the emitter-follower circuit
should be chosen to provide the minimum input signal which will
assume correct system operation.
INPUT
612A
1
2
612A
1
2
612A
1
2
a. Single-Ended Tuned Input
b. Balanced Input (For Attenuation
of Second-Order Products)
c. Single-Ended Untuned Input
SR00103
Figure 5. Input Configuration
Philips Semiconductors
Product specification
SA612A
Double-balanced mixer and oscillator
1997 Nov 07
6
612A
4
5
612A
4
5
612A
4
5
612A
4
5
a. Single-Ended Ceramic Filter
b. Single-Ended Crystal Filter
c. Single-Ended IFT
d.. Balanced Output
CFU455
or Equivalent
12pF
CT*
*CT matches 3.5k
to next stage
Filter K&L 38780 or Equivalent
SR00104
Figure 6. Output Configuration
612A
4
5
a. Colpitts Crystal Oscillator
(Overtone Mode)
b. Colpitts L/C Tank Oscillator
c. Hartley L/C Tank Oscillator
3
6
2
7
1
8
612A
4
5
3
6
2
7
1
8
612A
4
5
3
6
2
7
1
8
TC02101S
TC02111S
TC02121S
XTAL
L1
C1
C2
C3
SR00105
Figure 7. Oscillator Circuits
Philips Semiconductors
Product specification
SA612A
Double-balanced mixer and oscillator
1997 Nov 07
7
612A
4
5
3
6
2
7
1
8
+6V
7pF
10pF
TO
BUFFER
DC CONTROL VOLTAGE
FROM SYNTHESIZER
MV2105
OR EQUIVALENT
1000pF
1000pF
5.5
H
0.10pF
10
F
0.06
H
0.1
F
3SK126
100k
2pF
TO SYNTHESIZER
100k
100k
330
2k
TO SYNTHESIZER
2N5484
2N918
0.01
F
0.01
F
1.0nF
0.01pF
SR00106
Figure 8. Colpitts Oscillator Suitable for Synthesizer Applications and Typical Buffers
Philips Semiconductors
Product specification
SA612A
Double-balanced mixer and oscillator
1997 Nov 07
8
TEST CONFIGURATION
8
7
6
5
4
3
2
1
SFG455A3
100nF
220pF
INPUT
47pF
22pF
1nF
100nF
10nF
VCC
6.8
F
0.5 to 1.3
H
0.209 to 0.283
H
5.6pF
44.545MHz THIRD OVERTONE CRYSTAL
612A
OR EQUIVALENT
455kHZ
45MHz IN
5.5
H
SR00107
Figure 9. Typical Application for Cordless/Cellular Radio
Philips Semiconductors
Product specification
SA612A
Double-balanced mixer and oscillator
1997 Nov 07
9
3.50
3.25
3.00
2.75
2.50
2.25
2.00
1.75
1.50
40 30 20 10
0
10
20
30
40
50
60
70
80 90
SUPPL
Y
CURRENT 9mA)
TEMPERATURE
O
C
4.5V
6.0V
8.5V
SR00108
Figure 10. I
CC
vs Supply Voltage
40 30 20 10
0
10
20
30
40
50
60
70
80
90
20.0
19.5
19.0
18.5
18.0
17.5
17.0
16.5
16.0
15.5
15.0
14.5
14.0
CONVERSION GAIN (dB)
TEMPERATURE
O
C
4.5V
6.0V
8.5V
SR00109
Figure 11. Conversion Gain vs Supply Voltage
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
INPUT INTERCEPT POINT (dBm)
14.5
15.0
15.5
16.0
16.5
17.0
TEMPERATURE
O
C
40 30 20 10
0
10
20
30
40
50
60 70
80
90
SR00110
Figure 12. Third-Order Intercept Point
6.00
5.75
5.50
5.25
5.00
4.75
4.50
4.25
4.00
40 30 20 10
0
10
20
30
40
50
60 70
80 90
NOISE FIGURE (dB)
TEMPERATURE
O
C
4.5V
6.0V
8.5V
SR00111
Figure 13. Noise Figure
80
60
40
20
0
20
20
0
20
40
60
3rd ORDER PRODUCT
FUND. PRODUCT
IF OUTPUT POWER (dBm)
RF INPUT LEVEL (dBm)
RF1 = 45MHz, IF = 455kHz, RF2 = 45.06MHz
SR00112
Figure 14. Third-Order Intercept and Compression
10
11
12
13
14
15
16
17
18
4
5
6
7
8
9
10
VCC (VOLTS)
INTERCEPT (dBm)
SR00113
Figure 15. Input Third-Order Intermod Point vs V
CC
Double-balanced mixer oscillator
Philips Semiconductors
Product specification
SA612
1997 Nov 07
10
SO8:
plastic small outline package; 8 leads; body width 3.9mm
SOT96-1
Double-balanced mixer oscillator
Philips Semiconductors
Product specification
SA612
1997 Nov 07
11
DIP8:
plastic dual in-line package; 8 leads (300 mil)
SOT97-1
Double-balanced mixer oscillator
Philips Semiconductors
Product specification
SA612
1997 Nov 07
12
Philips Semiconductors and Philips Electronics North America Corporation reserve the right to make changes, without notice, in the products,
including circuits, standard cells, and/or software, described or contained herein in order to improve design and/or performance. Philips
Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright,
or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask
work right infringement, unless otherwise specified. Applications that are described herein for any of these products are for illustrative purposes
only. Philips Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testing
or modification.
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Philips Semiconductors and Philips Electronics North America Corporation Products are not designed for use in life support appliances, devices,
or systems where malfunction of a Philips Semiconductors and Philips Electronics North America Corporation Product can reasonably be expected
to result in a personal injury. Philips Semiconductors and Philips Electronics North America Corporation customers using or selling Philips
Semiconductors and Philips Electronics North America Corporation Products for use in such applications do so at their own risk and agree to fully
indemnify Philips Semiconductors and Philips Electronics North America Corporation for any damages resulting from such improper use or sale.
This data sheet contains preliminary data, and supplementary data will be published at a later date. Philips
Semiconductors reserves the right to make changes at any time without notice in order to improve design
and supply the best possible product.
Philips Semiconductors
811 East Arques Avenue
P.O. Box 3409
Sunnyvale, California 940883409
Telephone 800-234-7381
DEFINITIONS
Data Sheet Identification
Product Status
Definition
Objective Specification
Preliminary Specification
Product Specification
Formative or in Design
Preproduction Product
Full Production
This data sheet contains the design target or goal specifications for product development. Specifications
may change in any manner without notice.
This data sheet contains Final Specifications. Philips Semiconductors reserves the right to make changes
at any time without notice, in order to improve design and supply the best possible product.
Copyright Philips Electronics North America Corporation 1997
All rights reserved. Printed in U.S.A.
Philips
Semiconductors
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