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RF COMMUNICATIONS PRODUCTS
SA612A
Double-balanced mixer and oscillator
Product specification
Replaces data of September 17, 1990
IC17 Data Handbook
Philips Semiconductors
1997 Nov 07
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Philips Semiconductors Product specification
SA612ADouble-balanced mixer and oscillator
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).
FEA TURES
•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
1
INPUT A
2
INPUT B
3
GND
OUTPUT A
4
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
8
V
CC
7
OSCILLATOR
6
OSCILLATOR
5
OUTPUT B
SR00098
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
8765
V
CC
VOLTAGE
REGULATOR
OSCILLATOR
GROUND
4321
SR00099
Figure 2. Block Diagram
1997 Nov 07 853-0391 18662
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Philips Semiconductors Product specification
SA612ADouble-balanced mixer and oscillator
ABSOLUTE MAXIMUM RATINGS
SYMBOL PARAMETER RATING UNIT
V
CC
T
STG
T
A
AC/DC ELECTRICAL CHARACTERISTICS
TA=25°C, V
V
CC
f
IN
f
OSC
R
IN
C
IN
= 6V , Figure 3
CC
Maximum operating voltage 9 V
Storage temperature -65 to +150 °C
Operating ambient temperature range SA612A -40 to +85 °C
LIMITS
Min Typ Max
Power supply voltage range 4.5 8.0 V
DC current drain 2.4 3.0 mA
Input signal frequency 500 MHz
Oscillator frequency 200 MHz
Noise figured at 45MHz 5.0 dB
Third-order intercept point at 45MHz RFIN=-45dBm -13 dBm
Conversion gain at 45MHz 14 17 dB
RF input resistance 1.5 kΩ
RF input capacitance 3 pF
Mixer output resistance (Pin 4 or 5) 1.5 kΩ
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.
1997 Nov 07
3
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Philips Semiconductors Product specification
SA612ADouble-balanced mixer and oscillator
TEST CONFIGURA TION
0.5 to 1.3µH
22pF
34.545MHz THIRD OVERTONE CRYSTAL
10pF
150pF
6.8µF
V
CC
5.5µH
100nF
1nF
10nF
8765
47pF
INPUT
220pF
18k
6
7
25k
BUFFER
BIAS
44.2µH
4321
0.209 to
0.283µH
100nF
612A
Figure 3. Test Configuration
8
V
CC
1.5k
45
1.5k
1.5 to
OUTPUT
330pF
120pF
SR00101
BIAS
1997 Nov 07
1
1.5k
3
GND
1.5k
2
BIAS
SR00102
Figure 4. Equivalent Circuit
4