RF COMMUNICATIONS PRODUCTS
SA617
Low-voltage high performance mixer
FM IF system
Product specification
Replaces data of November 3, 1992
IC17 Data Handbook
1997 Nov 07
Philips Semiconductors
Philips Semiconductors
Product specification
Low-voltage high performance mixer FM IF system
SA617
DESCRIPTION
The SA617 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 SA617 is available in 20-lead SSOP package.
The SA617 was designed for portable communication applications
and will function down to 2.7V. The RF section is similar to the
famous SA605. The audio output has an internal amplifier with the
feedback pin accessible. The RSSI output is buffered. The SA617
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.
PIN CONFIGURATION
DK Package
RF IN+
RF IN– DECOUPLING
OSC
OUT
OSC
IN
RSSI OUT
V
CC
AUDIO FEEDBACK
1
2
3
4
5
6
7
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
LIM OUT (+)
AUDIO OUT 8
FREQ CHECK/LIM OUT (–) 9
QUADRATURE IN 10
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)
SR00405
Figure 1. Pin Configuration
•
Internal op amps with rail-to-rail outputs
•
ESD protection: Human Body Model 2kV
Robot Model 200V
•
102dB of IF Amp/Limiter gain
•
2MHz IF amp/limiter small signal bandwidth
•
Temperature compensated logarithmic Received Signal Strength
Indicator (RSSI) with a 80dB dynamic range
APPLICATIONS
•
Low external component count; suitable for crystal/ceramic/LC
filters
•
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
•
SA617 meets cellular radio specifications
•
Audio output internal op amp
•
RSSI output internal op amp
•
Buffered frequency check output
•
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
ORDERING INFORMATION
DESCRIPTION
20-Pin Plastic Shrink Small Outline Package (SSOP) (Surface-mount)
TEMPERATURE RANGE
-40 to +85°C
ORDER CODE
SA617DK
DWG #
SOT266-1
1997 Nov 07
2
853-1678 18665
Philips Semiconductors
Product specification
Low-voltage high performance mixer FM IF system
SA617
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
SR00406
Figure 2. Block Diagram
ABSOLUTE MAXIMUM RATINGS
SYMBOL
V
CC
T
STG
T
A
θ
JA
Single supply voltage
Storage temperature range
Operating ambient temperature range SA617
Thermal impedance
DK package
PARAMETER
RATING
7
–65 to +150
–40 to +85
117
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
SA617
TYP
MAX
7.0
5.0
V
mA
UNITS
1997 Nov 07
3
Philips Semiconductors
Product specification
Low-voltage high performance mixer FM IF system
SA617
= 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 NO TAG. 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 level
SINAD sensitivity
THD
S/N
Total harmonic distortion
Signal–to–noise ratio
IF RSSI output, R
9
= 2kΩ
1
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/limiter output impedance
Frequency Check/limiter 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
240
2.2
12
(Pin 11)
(Pin 11)
(Pin 9)
(Pin 9)
No load
2.4kΩ load
No load
2.4kΩ load
1.30
1.3
.70
1.0
50Ω source
50Ω source
Test at Pin 18
80% AM 1kHz
Gain of two (2kΩ AC load)
RF level –110dB
–30
60
44
58
–105
40
114
13
–45
62
0.3
1.1
1.8
80
+2.0
1.5
0.3
1.5
200
130
115
200
130
115
0.8
2.0
2.5
dB
dB
dBm
dB
mV
dB
dB
dB
V
V
V
dB
dB
kΩ
kΩ
kΩ
Ω
(Pin 20)
1.25
f1 = 45.0; f2 = 45.06MHz
Input RF Level = –52dBm
Matched 14.5dBV step–up
50Ω source
Single–ended input
11.0
150
150
6.8
–9
17
+2.5
8
3.0
1.5
4.0
MHz
MHz
dB
dBm
dB
dB
kΩ
pF
kΩ
SA617
TYP
MAX
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
UNITS
mV
RMS
Ω
mV
RMS
mV
RMS
V
dB
NOTE:
1. The generator source impedance is 50Ω, but the SA617 input impedance at Pin 18 is 1500Ω. As a result, IF level refers to the actual signal
that enters the SA617 input (Pin 18) which is about 21dB less than the “available power” at the generator.
1997 Nov 07
4
Philips Semiconductors
Product specification
Low-voltage high performance mixer FM IF system
SA617
CIRCUIT DESCRIPTION
The SA617 is an IF signal processing system suitable for second IF
systems with input frequency as high as 150MHz. The bandwidth of
the IF amplifier and limiter is at least 2MHz with 90dB of gain. The
gain/bandwidth distribution 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 can be configured as a unity gain buffer, or for
simultaneous gain, filtering, and 2nd-order temperature
compensation if needed. It can drive an AC load as low as 2kΩ with
a rail-to-rail output.
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 output or Frequency Check output has drive
capability of a load minimum of 2kΩ or higher to obtain 115mV
output level.
NOTE: dB(v) = 20log V
OUT
/V
IN
1997 Nov 07
5
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