Philips Semiconductors RF Communications Products

Product specification

SA608

Low voltage high performance mixer FM IF system

November 3, 1992

853-1679 08108

DESCRIPTION

The SA608 is a low voltage high performance
monolithic FM IF system incorporating a
mixer/oscillator, two limiting intermediate
frequency amplifiers, quadrature detector,
logarithmic received signal strength indicator
(RSSI), voltage regulator and audio and RSSI
op amps. The SA608 is available in 20-lead
dual-in-line plastic, 20-lead SOL
(surface-mounted miniature package) and
20-lead SSOP package.

The SA608 was designed for portable
communication applications and will function
down to 2.7V. The RF section is similar to
the famous NE605. The audio output is
buffered. The RSSI output has an internal
amplifier with the feedback pin accessible.
The SA608 also has an extra limiter output.
This signal is buffered from the output of the
limiter and can be used to perform frequency
check. This is accomplished by comparing a
reference frequency with the frequency check
signal using a comparator to a varactor or
PLL at the oscillator inputs.

FEATURES

Low power consumption: 3.5mA typical at
3V

Mixer input to >150MHz

Mixer conversion power gain of 17dB at
45MHz

XTAL oscillator effective to 150MHz (L.C.
oscillator or external oscillator can be used
at higher frequencies)

102dB of IF Amp/Limiter gain

2MHz limiter small signal bandwidth

Temperature compensated logarithmic
Received Signal Strength Indicator (RSSI)
with a 90dB dynamic range

Low external component count; suitable for
crystal/ceramic/LC filters

Excellent sensitivity: 0.31

V into 50

matching network for 12dB SINAD (Signal
to Noise and Distortion ratio) for 1kHz tone,
8kHz deviation with RF at 45MHz and IF at
455kHz

SA608 meets cellular radio specifications

Audio output internal op amp

RSSI output internal op amp

Buffered frequency check output

Internal op amps with rail-to-rail outputs

ESD protection: Human Body Model 2kV

Robot Model 200V

APPLICATIONS

Portable cellular radio FM IF

Cordless phones

Narrow band cellular applications
(NAMPS/NTACS)

RF level meter

Spectrum analyzer

Instrumentation

FSK and ASK data receivers

Log amps

Portable high performance communication
receivers

Single conversion VHF receivers

Wireless systems

PIN CONFIGURATION

RF IN+

RF IN

OSC-

OUT

OSCIN

RSSI

20 MIXER OUT

18 IF AMP IN

16 IF AMP OUT

15 GND

14 LIMITER IN

LIMITER

VCC

D, DK and N Packages

AUDIO

FREQ CHECK/

QUADRATURE 10

IF AMP

LIM OUT ()

DECOUPLING

IF AMP
DECOUPLING

LIMITER
DECOUPLING

DECOUPLING

OUT (+)

RSSI

FEEDBACK

ORDERING INFORMATION

DESCRIPTION

TEMPERATURE RANGE

ORDER CODE

DWG #

20-Pin Plastic Dual In-Line Package (DIP)

-40 to +85

SA608N

0408B

20-Pin Plastic Small Outline Large (SOL) package (Surface-mount)

-40 to +85

SA608D

0172D

20-Pin Plastic Shrink Small Outline Package (SSOP) (Surface-mount)

-40 to +85

SA608DK

1563

Philips Semiconductors RF Communications Products

Product specification

SA608

Low voltage high performance mixer FM IF system

November 3, 1992

BLOCK DIAGRAM

RSSI

IF
AMP

VREG

OSCILLATOR

LIMITER

MIXER

QUAD

+ 

AUDIO

ABSOLUTE MAXIMUM RATINGS

SYMBOL

PARAMETER

RATING

UNITS

Single supply voltage

STG

Storage temperature range

65 to +150

Operating ambient temperature range SA608

40 to +85

Thermal impedance

D package
DK package
N package

117

C/W

DC ELECTRICAL CHARACTERISTICS

= +3V, T

= 25

C; unless otherwise stated.

LIMITS

SYMBOL

PARAMETER

TEST CONDITIONS

SA608

UNITS

MIN

TYP

MAX

Power supply voltage range

2.7

7.0

DC current drain

3.5

4.2

Philips Semiconductors RF Communications Products

Product specification

SA608

Low voltage high performance mixer FM IF system

November 3, 1992

AC ELECTRICAL CHARACTERISTICS

= 25

C; V

= +3V, unless otherwise stated. RF frequency = 45MHz + 14.5dBV RF input step-up; IF frequency = 455kHz; R17 = 2.4k; R18

= 3.3k; RF level = 45dBm; FM modulation = 1kHz with

8kHz peak deviation. Audio output with de-emphasis filter and C-message weighted

filter. Test circuit 1. The parameters listed below are tested using automatic test equipment to assure consistent electrical characterristics. The
limits do not represent the ultimate performance limits of the device. Use of an optimized RF layout will improve many of the listed parameters.

LIMITS

SYMBOL

PARAMETER

TEST CONDITIONS

SA608

UNITS

MIN

TYP

MAX

Mixer/Osc section (ext LO = 220mV

RMS

)

Input signal frequency

150

MHz

OSC

Crystal oscillator frequency

150

MHz

Noise figure at 45MHz

6.2

Thirdorder input intercept point (50

source)

f1 = 45.0; f2 = 45.06MHz
Input RF Level = 52dBm

dBm

Conversion power gain

Matched 14.5dBV stepup

13.5

19.5

source

+2.5

RF input resistance

Singleended input

RF input capacitance

3.0

4.0

Mixer output resistance

(Pin 20)

1.25

1.5

IF section

IF amp gain

source

Limiter gain

source

Input limiting 3dB, R

= 2.4k

Test at Pin 18

109

dBm

AM rejection

80% AM 1kHz

Audio level

SINAD sensitivity

RF level 110dB

THD

Total harmonic distortion

S/N

Signaltonoise ratio

No modulation for noise

IF RSSI output, R

= 2k

IF level = 118dBm

0.3

0.8

IF level = 68dBm

.70

1.1

1.80

IF level = 23dBm

1.2

1.8

2.5

RSSI range

RSSI accuracy

+1.5

IF input impedance

1.3

1.5

IF output impedance

0.3

Limiter input impedance

1.30

1.5

Limiter output impedance

(Pin 11)

200

Limiter output level

(Pin 11) no load

load

130

115

RMS

Frequency check/lim () output impedance

(Pin 9)

200

Frequency check/lim () output level

(Pin 9)

no load
5k

load

130

115

RMS

RF/IF section (int LO)

Audio level

3V = V

, RF level = 27dBm

120

RMS

System RSSI output

3V = V

, RF level = 27dBm

2.2

System SINAD sensitivity

RF level = 117dBm

NOTE:

1. The generator source impedance is 50

, but the SA608 input impedance at Pin 18 is 1500

. As a result, IF level refers to the actual signal

that enters the SA608 input (Pin 18) which is about 21dB less than the "available power" at the generator.

2. By using 45k

load across the Quad detector coil, you will have Audio output at 115mV with 42dB distortion.

Philips Semiconductors RF Communications Products

Product specification

SA608

Low voltage high performance mixer FM IF system

November 3, 1992

CIRCUIT DESCRIPTION

The SA608 is an IF signal processing system
suitable for second IF systems with input fre-
quency as high as 150MHz. The bandwidth
of the IF amplifier and limiter is at least 2MHz
with 90dB of gain. The gain/bandwidth dis-
tribution is optimized for 455kHz, 1.5k

source applications. The overall system is
well-suited to battery operation as well as
high performance and high quality products
of all types.

The input stage is a Gilbert cell mixer with
oscillator. Typical mixer characteristics
include a noise figure of 6.2dB, conversion
gain of 17dB, and input third-order intercept
of 9dBm. The oscillator will operate in
excess of 200MHz in L/C tank configurations.
Hartley or Colpitts circuits can be used up to
100MHz for xtal configurations. Butler
oscillators are recommended for xtal
configurations up to 150MHz.

The output impedance of the mixer is a 1.5k

resistor permitting direct connection to a
455kHz ceramic filter. The input resistance
of the limiting IF amplifiers is also 1.5k

With most 455kHz ceramic filters and many
crystal filters, no impedance matching
network is necessary. The IF amplifier has
43dB of gain and 5.5MHz bandwidth. The IF
limiter has 60dB of gain and 4.5MHz
bandwidth. To achieve optimum linearity of
the log signal strength indicator, there must
be a 12dB(v) insertion loss between the first
and second IF stages. If the IF filter or
interstage network does not cause 12dB(v)
insertion loss, a fixed or variable resistor or
an L pad for simultaneous loss and
impedance matching can be added between
the first IF output (Pin 16) and the interstage
network. The overall gain will then be 90dB
with 2MHz bandwidth.

The signal from the second limiting amplifier
goes to a Gilbert cell quadrature detector.
One port of the Gilbert cell is internally driven
by the IF. The other output of the IF is
AC-coupled to a tuned quadrature network.

This signal, which now has a 90

phase

relationship to the internal signal, drives the
other port of the multiplier cell.

The demodulated output of the quadrature
drives an internal op amp. This op amp is
configured as a unity gain buffer.

A log signal strength completes the circuitry.
The output range is greater than 90dB and is
temperature compensated. This log signal
strength indicator exceeds the criteria for
AMPs or TACs cellular telephone. This
signal is buffered through an internal unity
gain op amp. The frequency check pin
provides a buffered limiter output. This is
useful for implementing an AFC (Automatic
Frequency Check) function. This same
output can also be used in conjunction with
limiter output (Pin 11) for demodulating FSK
(Frequency Shift Keying) data. Both pins are
of the same amplitude, but 180

out of phase.

NOTE: Limiter or Frequency Check output
has drive capability of a 5k

minimum or

higher in order to obtain 120mV

RMS

output

level.

NOTE: dB(v) = 20log V

OUT

Philips Semiconductors RF Communications Products

Product specification

SA608

Low voltage high performance mixer FM IF system

November 3, 1992

MINICIRCUIT ZSC21B

AUDIO

C14

IFT1

C10

30.5

SW3

SW4

SW1

VCC

EXT.
LOC
OSC

44.545

45MHZ

SW2

51.1

178

39.2

"C" WEIGHTED

AUDIO

MEASUREMENT

CIRCUIT

45.06

MHZ

50.5

2430

3880

96.5

32.6

71.5

C24

C22

C20

C19

C18

C15

C16

C17

FLT2

SW7

SW6

SW5

SW8

SW9

C23

C21

R17

2.4k

FLT1

25dB,

1500/50

PAD

10dB,

50/50

PAD

29dB,

929/50

PAD

10.6dB,

50/50

PAD

36dB,

156k/50

PAD

100pF NPO Ceramic
390pF NPO Ceramic

22pF NPO Ceramic
1nF Ceramic
10.0pF NPO Ceramic

10pF NPO Ceramic

100nF +10% Monolithic Ceramic

100nF +10% Monolithic Ceramic
100nF +10% Monolithic Ceramic

2.2

100nF +10% Monolithic Ceramic

F Tantalum (minimum) *

C21

C23

C26

Flt 1
Flt 2

IFT 1

L1
L2

R19

R10

R11

100nF +10% Monolithic Ceramic

10k

+1%

10k

+1%

16k

+5% 1/4W Carbon Composition

+1% 1/4W Metal Film

44.545MHz Crystal ICM4712701

0.8

H nominal

Toko 292CNST1038Z

455kHz (Ce = 180pF) Toko RMC2A6597H

Ceramic Filter Murata SFG455A3 or equiv

0.1

F +10% Monolithic Ceramic

147160nH Coilcraft UNI10/14204J08S

C1
C2
C5
C6
C7
C8
C9

C10
C12
C14
C15
C17
C18

Automatic Test Circuit Component List

1.3k

51.7

71.5

96.5

32.8

51.5

R14

+1%

DEEMPHASIS

FILTER

SW11

R10

R11

C12

C25

100nF +10% Monolithic Ceramic

R17

2.4k

+5% 1/4W Carbon Composition

Figure 1. SA607 45MHz Test Circuit (Relays as shown)

R19

16k

R18

3.3k

C26

R18

3.3k

+5% 1/4W Carbon Composition

C27

2.2

FREQ
CHECK

*NOTE: This value can be reduced when a battery is the power source.

RSSI

AMP

MIXER

QUAD

OSCILLATOR

VREG

LIMITER

Philips Semiconductors RF Communications Products

Product specification

SA608

Low voltage high performance mixer FM IF system

November 3, 1992

RSSI

AMP

MIXER

QUAD

AUDIO

C14

IFT1

C10

VCC

C18

C15

C17

FLT2

SW8

C23

C21

R17

2.4k

FLT1

51pF NPO Ceramic
220pF NPO Ceramic

5-30pF NPO Ceramic
1nF Ceramic
10.0pF NPO Ceramic

10pF NPO Ceramic

100nF +10% Monolithic Ceramic

100nF +10% Monolithic Ceramic
100nF +10% Monolithic Ceramic

2.2

100nF +10% Monolithic Ceramic

F Tantalum (minimum) *

C21

C23

C26

Flt 1
Flt 2

IFT 1

L1
L2

R19

R10

R11

100nF +10% Monolithic Ceramic

10k

+1%

8.2k

+1%

16k

+5% 1/4W Carbon Composition

+1% 1/4W Metal Film

44.545MHz Crystal Hy-Q

1.2

H Coilcraft 1008CS122

Ceramic Filter Murata SFG455A3 or equiv

0.1

F +10% Monolithic Ceramic

C1
C2
C5
C6
C7
C8
C9

C10
C12
C14
C15
C17
C18

Product Board SA608D/DK Component List

OSCILLATOR

R14

10k

+1%

VREG

LIMITER

C25

100nF +10% Monolithic Ceramic

R17

2.4k

+5% 1/4W Carbon Composition

Figure 2. SA608 45MHz Test Circuit (Relays as shown)

R19

11k

R18

3.3k

C26

R18

3.3k

+5% 1/4W Carbon Composition

C27

2.2

OUT

RSSI

OUTPUT

FREQ

CHECK

C12

*NOTE: This value can be reduced when a battery is the power source.

C19

390pF

C19 390pF +10% Monolithic Ceramic

0.33

H TOKO SCB1320Z

330

H TOKO 303LN1130

Philips Semiconductors RF Communications Products

Product specification

SA608

Low voltage high performance mixer FM IF system

November 3, 1992

RF GENERATOR

SA608 DEMO-BOARD

CMESSAGE

HP339A DISTORTION

ANALYZER

SCOPE

DC VOLTMETER

(+3)

45MHz

DE-EMPHASIS

FILTER

RSSI

AUDIO

Figure 3. SA608 Application Circuit Test Set Up

NOTES:
1. C-message: The C-message and de-emphasis filter combination has a peak gain of 10 for accurate measurements. Without the gain, the

measurements may be affected by the noise of the scope and HP339 analyzer. The de-emphasis filter has a fixed -6dB/Octave slope be-
tween 300Hz and 3kHz.

2. Ceramic filters: The ceramic filters can be 30kHz SFG455A3s made by Murata which have 30kHz IF bandwidth (they come in blue), or

16kHz CFU455Ds, also made by Murata (they come in black). All of our specifications and testing are done with the more wideband filter.

3. RF generator: Set your RF generator at 45.000MHz, use a 1kHz modulation frequency and a 6kHz deviation if you use 16kHz filters, or

8kHz if you use 30kHz filters.

4. Sensitivity: The measured typical sensitivity for 12dB SINAD should be 0.35

V or 116dBm at the RF input.

5. Layout: The layout is very critical in the performance of the receiver. We highly recommend our demo board layout.
6. RSSI: The smallest RSSI voltage (i.e., when no RF input is present and the input is terminated) is a measure of the quality of the layout and

design. If the lowest RSSI voltage is 500mV or higher, it means the receiver is in regenerative mode. In that case, the receiver sensitivity
will be worse than expected.

7. Supply bypass and shielding: All of the inductors, the quad tank, and their shield must be grounded. A 10-15

F or higher value tantalum

capacitor on the supply line is essential. A low frequency ESR screening test on this capacitor will ensure consistent good sensitivity in pro-
duction. A 0.1

F bypass capacitor on the supply pin, and grounded near the 44.545MHz oscillator improves sensitivity by 2-3dB.

8. R5 can be used to bias the oscillator transistor at a higher current for operation above 45MHz. Recommended value is 22k

, but should not

be below 10k

Philips Semiconductors RF Communications Products

Product specification

SA608

Low voltage high performance mixer FM IF system

November 3, 1992

Figure 6. Mixer Noise Figure vs Supply Voltage

TEMPERATURE (

NOISE FIGURE

8.00

7.75

7.50

7.25

7.00

6.75

6.50

6.25

6.00

5.75

5.50

5.25

5.00

2.7V

7.0V

Figure 7. Conversion Gain vs Supply Voltage

TEMPERATURE (

18.00

17.75

17.50

17.25

17.00

16.75

16.50

16.25

16.00

2.7V

7.0V

CONVERSION GAIN (dB)

Philips Semiconductors RF Communications Products

Product specification

SA608

Low voltage high performance mixer FM IF system

November 3, 1992

DECIBELS (dB)

125

115

105

95

85

75

65

55

45

35

25

RF LEVEL (dBm)

Figure 9. Sensitivity vs RF Level (40

10

15

20

25

30

35

40

45

50

55

60

65

VCC = 3V
RF = 45MHz

DEVIATION =

8kHz

AUDIO LEVEL = 52.5mVRMS

AUDIO

THD + NOISE

AM REJECTION

NOISE

DECIBELS (dB)

125

115

105

95

85

75

65

55

45

35

25

RF LEVEL (dBm)

Figure 10. Sensitivity vs RF Level (+25

10

20

25

30

35

40

45

50

55

60

65

VCC = 3V
RF = 45MHz

DEVIATION =

8kHz

AUDIO LEVEL = 58.5mVRMS

AUDIO

THD + NOISE

AM REJECTION

NOISE

Philips Semiconductors RF Communications Products

Product specification

SA608

Low voltage high performance mixer FM IF system

November 3, 1992

DECIBELS (dB)

125

115

105

95

85

75

65

55

45

35

25

RF LEVEL (dBm)

Figure 11. Sensitivity vs RF Level (Temperature 85

10

15

20

25

30

35

40

45

50

55

60

65

VCC = 3V
RF = 45MHz

DEVIATION =

8kHz

AUDIO LEVEL = 63.5mVRMS

AUDIO

THD + NOISE

AM REJECTION

NOISE

DECIBELS (dB)

10

15

20

25

30

35

40

45

50

55

60

65

55

35

15

105

125

TEMPERATURE (

VCC = 3V
RF = 45MHz

DEVIATION =

8kHz

AUDIO LEVEL = +58.6mVRMS

Figure 12. Relative Audio Level, Distortion, AM Rejection and Noise vs Temperature

AUDIO

DISTORTION

AM REJECTION

NOISE

RF LEVEL = 45dBm

Philips Semiconductors RF Communications Products

Product specification

SA608

Low voltage high performance mixer FM IF system

November 3, 1992

2.400

2.000

1.600

1.200

0.800

0.400

0.000

Figure 13. RSSI (455kHz IF @ 3V)

IF LEVEL (dBm)

+85

ROOM

VOL

AGE (V)

VOL

AGE (V)

2.1

2.0

1.9

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.1

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

125

115

105

95

85

75

65

55

45

35

25

RF LEVEL (dBm)

+85

+27

40

Figure 14. RSSI vs RF Level and Temperature - V

= 3V

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ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: SA608D