Philips Semiconductors RF Communications Products
Product specification
Low voltage high performance mixer FM IF system
SA608
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.
•
Low external component count; suitable for
crystal/ceramic/LC filters
PIN CONFIGURATION
D, DK and N Packages
•
Excellent sensitivity:
0.31µV into 50Ω
matching network for 12dB SINAD (Signal
to Noise and Distortion ratio) for 1kHz tone,
8kHz deviation with RF at 45MHz and IF at
455kHz
RF IN+
1
20 MIXER OUT
19 IF AMP
DECOUPLING
18 IF AMP IN
17 IF AMP
DECOUPLING
16 IF AMP OUT
15 GND
14 LIMITER IN
13 LIMITER
DECOUPLING
12 LIMITER
DECOUPLING
11
LIMITER
OUT (+)
RF IN– 2
DECOUPLING
OSC-
3
4
5
6
7
•
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
OUT
OSC
IN
RSSI
V
CC
AUDIO
RSSI 8
FEEDBACK
FREQ CHECK/ 9
LIM OUT (–)
QUADRATURE 10
IN
APPLICATIONS
•
Portable cellular radio FM IF
•
Cordless phones
•
Narrow band cellular applications
(NAMPS/NTACS)
FEATURES
3V
•
Low power consumption:
3.5mA typical at
•
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)
•
RF level meter
•
Spectrum analyzer
•
Instrumentation
•
FSK and ASK data receivers
•
Log amps
•
Portable high performance communication
receivers
•
102dB of IF Amp/Limiter gain
•
2MHz limiter small signal bandwidth
•
Temperature compensated logarithmic
Received Signal Strength Indicator (RSSI)
with a 90dB dynamic range
•
Single conversion VHF receivers
•
Wireless systems
ORDERING INFORMATION
DESCRIPTION
20-Pin Plastic Dual In-Line Package (DIP)
20-Pin Plastic Small Outline Large (SOL) package (Surface-mount)
20-Pin Plastic Shrink Small Outline Package (SSOP) (Surface-mount)
TEMPERATURE RANGE
-40 to +85°C
-40 to +85°C
-40 to +85°C
ORDER CODE
SA608N
SA608D
SA608DK
DWG #
0408B
0172D
1563
November 3, 1992
2
853-1679 08108
Philips Semiconductors RF Communications Products
Product specification
Low voltage high performance mixer FM IF system
SA608
BLOCK DIAGRAM
20
19
18
17
16
15
14
13
12
11
IF
AMP
MIXER
RSSI
LIMITER
QUAD
OSCILLATOR
–
+
V
REG
+ –
E
B
AUDIO
1
2
3
4
5
6
7
8
9
10
ABSOLUTE MAXIMUM RATINGS
SYMBOL
V
CC
T
STG
T
A
θ
JA
PARAMETER
Single supply voltage
Storage temperature range
Operating ambient temperature range SA608
Thermal impedance
D package
DK package
N package
RATING
7
–65 to +150
–40 to +85
90
117
75
UNITS
V
°
C
°
C
°
C/W
DC ELECTRICAL CHARACTERISTICS
V
CC
= +3V, T
A
= 25
°
C; unless otherwise stated.
LIMITS
SYMBOL
PARAMETER
TEST CONDITIONS
MIN
V
CC
I
CC
Power supply voltage range
DC current drain
2.7
3.5
SA608
TYP
MAX
7.0
4.2
V
mA
UNITS
November 3, 1992
3
Philips Semiconductors RF Communications Products
Product specification
Low voltage high performance mixer FM IF system
SA608
= 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
MIN
Mixer/Osc section (ext LO = 220mV
RMS
)
f
IN
f
OSC
Input signal frequency
Crystal oscillator frequency
Noise figure at 45MHz
Third–order input intercept point (50Ω
source)
Conversion power gain
RF input resistance
RF input capacitance
Mixer output resistance
IF section
IF amp gain
Limiter gain
Input limiting –3dB, R
17
= 2.4k
AM rejection
Audio
THD
S/N
level
2
RF level –110dB
–35
No modulation for noise
IF level = –118dBm
IF level = –68dBm
IF level = –23dBm
RSSI range
RSSI accuracy
IF input impedance
IF output impedance
Limiter input impedance
Limiter output impedance
Limiter output level
Frequency check/lim (–) output impedance
Frequency check/lim (–) output level
RF/IF section (int LO)
Audio level
System RSSI output
System SINAD sensitivity
3V = V
CC
, RF level = –27dBm
3V = V
CC
, RF level = –27dBm
RF level = –117dBm
120
2.2
12
mV
RMS
V
dB
(Pin 11)
(Pin 11)
(Pin 9)
(Pin 9)
no load
5kΩ load
no load
5kΩ load
1.30
1.3
.70
1.2
SINAD sensitivity
Total harmonic distortion
Signal–to–noise ratio
IF RSSI output, R
9
= 2kΩ
1
50Ω source
50Ω source
Test at Pin 18
80% AM 1kHz
35
44
58
–109
45
60
17
–50
62
0.3
1.1
1.8
90
+1.5
1.5
0.3
1.5
200
130
115
200
130
115
0.8
1.80
2.5
80
dB
dB
dBm
dB
mV
dB
dB
dB
V
V
V
dB
dB
kΩ
kΩ
kΩ
Ω
mV
RMS
Ω
mV
RMS
(Pin 20)
1.25
f1 = 45.0; f2 = 45.06MHz
Input RF Level = –52dBm
Matched 14.5dBV step–up
50Ω source
Single–ended input
13.5
150
150
6.2
–9
17
+2.5
8
3.0
1.5
4.0
19.5
MHz
MHz
dB
dBm
dB
dB
kΩ
pF
kΩ
SA608
TYP
MAX
UNITS
AC ELECTRICAL CHARACTERISTICS
T
A
= 25
°
C; V
CC
= +3V, unless otherwise stated. RF frequency = 45MHz + 14.5dBV RF input step-up; IF frequency = 455kHz; R17 = 2.4k; R18
NOTE:
1. The generator source impedance is 50Ω, but the SA608 input impedance at Pin 18 is 1500Ω. 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 45kΩ load across the Quad detector coil, you will have Audio output at 115mV with –42dB distortion.
November 3, 1992
4
Philips Semiconductors RF Communications Products
Product specification
Low voltage high performance mixer FM IF system
SA608
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, 1.5kΩ
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 1.5kΩ
resistor permitting direct connection to a
455kHz ceramic filter. The input resistance
of the limiting IF amplifiers is also 1.5kΩ.
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 5kΩ minimum or
higher in order to obtain 120mV
RMS
output
level.
NOTE: dB(v) = 20log V
OUT
/V
IN
November 3, 1992
5
Philips Semiconductors RF Communications Products
Product specification
Low voltage high performance mixer FM IF system
SA608
–
25dB,
–
10dB,
1500/50
Ω
PAD 50/50
Ω
PAD
–
29dB,
929/50
Ω
PAD
–
10.6dB,
50/50
Ω
PAD
–
36dB,
156k/50
Ω
PAD
50.5
3880
2430
C24
SW9
96.5
71.5
51.5
C26
R18
3.3k
96.5
32.8
71.5
C19
SW6
C18
C17
51.7
32.6
1.3k
C16
SW5
C15
C20
C22
FLT1
C23
SW8
C21
SW7
R17
2.4k
FLT2
20
19
18
17
16
15
14
13
12
11
IF
AMP
MIXER
LIMITER
RSSI
QUAD
OSCILLATOR
– +
V
REG
– +
1
2
3
4
5
6
R10
7
8
9
10
C1
SW1
SW3
SW4
C8
R9
C9
SW11
R11
C2
L1
C7
R4
51.1
C5
L2
C6
C4 EXT.
LOC
OSC
44.545
45.06
MHZ
MINI–CIRCUIT ZSC2–1B
X1
R7
30.5
R6
178
R8
39.2
V
CC
C10
C12
R19
16k
SW2
R1
DEEMPHASIS
FILTER
IFT1
C3
R3
R2
”C” WEIGHTED
AUDIO
MEASUREMENT
CIRCUIT
C14
45MHZ
AUDIO
FREQ
CHECK
Automatic Test Circuit Component List
C1
C2
C5
C6
C7
C8
C9
C10
C12
C14
C15
C17
C18
C21
C23
C25
100pF NPO Ceramic
390pF NPO Ceramic
100nF +10% Monolithic Ceramic
22pF NPO Ceramic
1nF Ceramic
10.0pF NPO Ceramic
100nF +10% Monolithic Ceramic
10
µ
F Tantalum (minimum) *
2.2µF
100nF +10% Monolithic Ceramic
10pF NPO Ceramic
100nF +10% Monolithic Ceramic
100nF +10% Monolithic Ceramic
100nF +10% Monolithic Ceramic
100nF +10% Monolithic Ceramic
100nF +10% Monolithic Ceramic
C26
C27
Flt 1
Flt 2
IFT 1
L1
L2
X1
R9
R10
R11
R14
R17
R18
R19
0.1µF +10% Monolithic Ceramic
2.2µF
Ceramic Filter Murata SFG455A3 or equiv
Ceramic Filter Murata SFG455A3 or equiv
455kHz (Ce = 180pF) Toko RMC–2A6597H
147–160nH Coilcraft UNI–10/142–04J08S
0.8
µ
H nominal
Toko 292CNS–T1038Z
44.545MHz Crystal ICM4712701
2kΩ +1% 1/4W Metal Film
10kΩ +1%
10kΩ +1%
5kΩ +1%
2.4kΩ +5% 1/4W Carbon Composition
3.3kΩ +5% 1/4W Carbon Composition
16kΩ +5% 1/4W Carbon Composition
*NOTE: This value can be reduced when a battery is the power source.
Figure 1. SA607 45MHz Test Circuit (Relays as shown)
November 3, 1992
6
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