sa612

Philips Semiconductors

SA612ADouble-balanced mixer and oscillator

Product specificationReplaces data of September 17, 1990 1997 Nov 07

RF COMMUNICATIONS PRODUCTS

IC17 Data Handbook

Philips Semiconductors Product specification


21997 Nov 07 853-0391 18662

DESCRIPTIONThe SA612A is a low-power VHF monolithic double-balanced mixerwith on-board oscillator and voltage regulator. It is intended for lowcost, low power communication systems with signal frequencies to500MHz and local oscillator frequencies as high as 200MHz. Themixer is a “Gilbert cell” multiplier configuration which provides gainof 14dB or more at 45MHz.

The oscillator can be configured for a crystal, a tuned tankoperation, or as a buffer for an external L.O. Noise figure at 45MHzis typically below 6dB and makes the device well suited for highperformance cordless phone/cellular radio. The low powerconsumption makes the SA612A excellent for battery operatedequipment. Networking and other communications products canbenefit from very low radiated energy levels within systems. TheSA612A is available in an 8-lead dual in-line plastic package and an8-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 CONFIGURATIOND, 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 INFORMATIONDESCRIPTION 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

4321

OSCILLATORVOLTAGEREGULATOR

GROUND

VCC

SR00099

Figure 2. Block Diagram



1997 Nov 07 3

ABSOLUTE MAXIMUM RATINGSSYMBOL PARAMETER RATING UNIT

VCC Maximum operating voltage 9 V

TSTG Storage temperature -65 to +150 °C

TA Operating ambient temperature range SA612A -40 to +85 °C

AC/DC ELECTRICAL CHARACTERISTICS TA=25°C, VCC = 6V, Figure 3

SYMBOL PARAMETER TEST CONDITIONLIMITS

UNITSYMBOL PARAMETER TEST CONDITIONMin Typ Max

UNIT

VCC Power supply voltage range 4.5 8.0 V

DC current drain 2.4 3.0 mA

fIN Input signal frequency 500 MHz

fOSC 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

RIN RF input resistance 1.5 kΩ

CIN RF input capacitance 3 pF

Mixer output resistance (Pin 4 or 5) 1.5 kΩ

DESCRIPTION OF OPERATIONThe SA612A is a Gilbert cell, an oscillator/buffer, and a temperaturecompensated bias network as shown in the equivalent circuit. TheGilbert cell is a differential amplifier (Pins 1 and 2) which drives abalanced switching cell. The differential input stage provides gainand determines the noise figure and signal handling performance ofthe 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 istypically -15dBm (that’s approximately +5dBm output interceptbecause of the RF gain). The system designer must be cognizant ofthis large signal limitation. When designing LANs or other closedsystems where transmission levels are high, and small-signal orsignal-to-noise issues not critical, the input to the SA612A should beappropriately scaled.



1997 Nov 07 4

TEST CONFIGURATION

8 7 6 5

4321

OUTPUT

150pF

330pF

120pF

1.5 to

100nF

220pF

INPUT

47pF

22pF1nF

100nF10nF

VCC

6.8µF

5.5µH

0.209 to0.283µH

44.2µH

10pF34.545MHz THIRD OVERTONE CRYSTAL

612A

0.5 to 1.3µH

SR00101

Figure 3. Test Configuration

12

3

4 5

6

7

8

GND

BUFFER1.5k

BIAS BIAS

BIAS

1.5k

1.5k 1.5k

VCC

18k

25k

SR00102

Figure 4. Equivalent Circuit



1997 Nov 07 5

Besides excellent low power performance well into VHF, theSA612A is designed to be flexible. The input, output, and oscillatorports can support a variety of configurations provided the designerunderstands certain constraints, which will be explained here.

The RF inputs (Pins 1 and 2) are biased internally. They aresymmetrical. The equivalent AC input impedance is approximately1.5k || 3pF through 50MHz. Pins 1 and 2 can be usedinterchangeably, but they should not be DC biased externally. Figure5 shows three typical input configurations.

The mixer outputs (Pins 4 and 5) are also internally biased. Eachoutput is connected to the internal positive supply by a 1.5kΩresistor. This permits direct output termination yet allows forbalanced output as well. Figure 6 shows three single-ended outputconfigurations and a balanced output.

The oscillator is capable of sustaining oscillation beyond 200MHz incrystal or tuned tank configurations. The upper limit of operation isdetermined by tank “Q” and required drive levels. The higher the Qof the tank or the smaller the required drive, the higher the

permissible oscillation frequency. If the required L.O. is beyondoscillation limits, or the system calls for an external L.O., the

external signal can be injected at Pin 6 through a DC blockingcapacitor. External L.O. should be 200mVP-P minimum to 300mVP-Pmaximum.

Figure 7 shows several proven oscillator circuits. Figure 7a isappropriate for cordless phones/cellular radio. In this circuit a thirdovertone parallel-mode crystal with approximately 5pF loadcapacitance should be specified. Capacitor C3 and inductor L1 actas a fundamental trap. In fundamental mode oscillation the trap isomitted.

Figure 8 shows a Colpitts varacter tuned tank oscillator suitable forsynthesizer-controlled applications. It is important to buffer theoutput of this circuit to assure that switching spikes from the firstcounter or prescaler do not end up in the oscillator spectrum. Thedual-gate MOSFET provides optimum isolation with low current.The FET offers good isolation, simplicity, and low current, while thebipolar circuits provide the simple solution for non-criticalapplications. The resistive divider in the emitter-follower circuitshould be chosen to provide the minimum input signal which willassume correct system operation.

INPUT

612A

1 2

612A

1 2

612A

1 2

a. Single-Ended Tuned Input b. Balanced Input (For Attenuationof Second-Order Products)

c. Single-Ended Untuned Input

SR00103

Figure 5. Input Configuration



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

CFU455or Equivalent

12pF CT*

*CT matches 3.5k Ω 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

C2C3

SR00105

Figure 7. Oscillator Circuits



1997 Nov 07 7

612A

4 5

3 6

2 7

1 8

+6V

7pF 10pF

TOBUFFER

DC CONTROL VOLTAGEFROM SYNTHESIZER

MV2105OR EQUIVALENT

1000pF

1000pF

5.5µH

0.10pF10µF

0.06µH

0.1µF

3SK126100k

2pF TO SYNTHESIZER

100k

100k

330

2k

TO SYNTHESIZER

2N5484

2N918

0.01µF

0.01µF

1.0nF

0.01pF

SR00106

Figure 8. Colpitts Oscillator Suitable for Synthesizer Applications and Typical Buffers



1997 Nov 07 8

TEST CONFIGURATION

8 7 6 5

4321SFG455A3

100nF

220pF

INPUT

47pF

22pF

1nF

100nF 10nF

VCC

6.8µF

0.5 to 1.3µH

0.209 to 0.283µH

5.6pF44.545MHz THIRD OVERTONE CRYSTAL

612A

OR EQUIVALENT455kHZ

45MHz IN

5.5µH

SR00107

Figure 9. Typical Application for Cordless/Cellular Radio



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

SU

PP

LY C

UR

RE

NT

9m

A)

TEMPERATURE OC

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

CO

NV

ER

SIO

N G

AIN

(dB

)

TEMPERATURE OC

4.5V

6.0V8.5V

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

INP

UT

INT

ER

CE

PT

PO

INT

(dB

m)

–14.5

–15.0

–15.5

–16.0

–16.5

–17.0

TEMPERATURE OC

–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

NO

ISE

FIG

UR

E (

dB)

TEMPERATURE OC

4.5V6.0V8.5V

SR00111

Figure 13. Noise Figure

–80 –60 –40 –20 0 20

20

0

–20

–40

–60

3rd ORDER PRODUCT

FUND. PRODUCT

IF O

UT

PU

T P

OW

ER

(dB

m)

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)

INT

ER

CE

PT

(dB

m)

SR00113

Figure 15. Input Third-Order Intermod Point vs V CC

Double-balanced mixer oscillator


SA612

1997 Nov 07 10

SO8: plastic small outline package; 8 leads; body width 3.9mm SOT96-1



SA612

1997 Nov 07 11

DIP8: plastic dual in-line package; 8 leads (300 mil) SOT97-1



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. PhilipsSemiconductors 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 maskwork right infringement, unless otherwise specified. Applications that are described herein for any of these products are for illustrative purposesonly. Philips Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testingor modification.

LIFE SUPPORT APPLICATIONSPhilips 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 expectedto result in a personal injury. Philips Semiconductors and Philips Electronics North America Corporation customers using or selling PhilipsSemiconductors and Philips Electronics North America Corporation Products for use in such applications do so at their own risk and agree to fullyindemnify 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. PhilipsSemiconductors reserves the right to make changes at any time without notice in order to improve designand supply the best possible product.

Philips Semiconductors811 East Arques AvenueP.O. Box 3409Sunnyvale, California 94088–3409Telephone 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. Specificationsmay change in any manner without notice.

This data sheet contains Final Specifications. Philips Semiconductors reserves the right to make changesat any time without notice, in order to improve design and supply the best possible product.

Copyright Philips Electronics North America Corporation 1997All rights reserved. Printed in U.S.A.

This datasheet has been download from:

www.datasheetcatalog.com

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