INTEGRATED CIRCUITS
SA615
High performance low power mixer FM IF
system
Product specification
Replaces data of 1992 Nov 03
IC17 Data Handbook
1997 Nov 07
Philips
Semiconductors
Philips Semiconductors
Product specification
High performance low power mixer FM IF system
SA615
DESCRIPTION
The SA615 is a high performance monolithic low-power FM IF
system incorporating a mixer/oscillator, two limiting intermediate
frequency amplifiers, quadrature detector, muting, logarithmic
received signal strength indicator (RSSI), and voltage regulator. The
SA615 combines the functions of Signetics’ SA602 and SA604A, but
features a higher mixer input intercept point, higher IF bandwidth
(25MHz) and temperature compensated RSSI and limiters
permitting higher performance application. The SA615 is available in
20-lead dual-in-line plastic, 20-lead SOL (surface-mounted miniature
package) and 20-lead SSOP (shrink small outline package).
The SA605 and SA615 are functionally the same device types. The
difference between the two devices lies in the guaranteed
specifications. The SA615 has a higher I
CC
, lower input third order
intercept point, lower conversion mixer gain, lower limiter gain, lower
AM rejection, lower SINAD, higher THD, and higher RSSI error than
the SA615. Both the SA605 and SA615 devices will meet the EIA
specifications for AMPS and TACS cellular radio applications.
For additional technical information please refer to application notes
AN1994, 1995 and 1996, which include example application
diagrams, a complete overview of the product, and artwork for
reference.
PIN CONFIGURATION
N, D and DK Packages
RF
IN
RF BYPASS
XTAL OSC
XTAL OSC
MUTE
IN
V
CC
RSSI
OUT
MUTED AUDIO OUT
UNMUTED AUDIO OUT
QUADRATURE IN
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
MIXER OUT
IF AMP DECOUPLING
IF AMP IN
IF AMP DECOUPLING
IF AMP OUT
GND
LIMITER IN
LIMITER DECOUPLING
LIMITER DECOUPLING
LIMITER OUT
NOTE:
See back page for package dimensions
SR00341
Figure 1. Pin Configuration
FEATURES
•
Low power consumption: 5.7mA typical at 6V
•
Mixer input to >500MHz
•
Mixer conversion power gain of 13dB at 45MHz
•
Mixer noise figure of 4.6dB at 45MHz
•
XTAL oscillator effective to 150MHz (L.C. oscillator to 1GHz local
oscillator can be injected)
APPLICATIONS
•
102dB of IF Amp/Limiter gain
•
25MHz limiter small signal bandwidth
•
Temperature compensated logarithmic Received Signal Strength
Indicator (RSSI) with a dynamic range in excess of 90dB
•
Two audio outputs – muted and unmuted
•
Low external component count; suitable for crystal/ceramic/LC
filters
•
Cellular radio FM IF
•
High performance communications receivers
•
Single conversion VHF/UHF receivers
•
SCA receivers
•
RF level meter
•
Spectrum analyzer
•
Instrumentation
•
FSK and ASK data receivers
•
Log amps
•
Wideband low current amplification
•
Excellent sensitivity:
0.22µV into 50Ω matching network for 12dB
SINAD (Signal to Noise and Distortion ratio) for 1kHz tone with RF
at 45MHz and IF at 455kHz
•
SA615 meets cellular radio specifications
•
ESD hardened
ORDERING INFORMATION
DESCRIPTION
20-Pin Plastic Dual In-Line Package (DIP)
20-Pin Plastic Small Outline Large (SOL) package
20-Pin Plastic Shrink Small Outline Package (SSOP)
TEMPERATURE RANGE
–40 to +85°C
–40 to +85°C
–40 to +85°C
ORDER CODE
SA615N
SA615D
SA615DK
DWG #
SOT146-1
SOT108-1
SOT266-1
1997 Nov 07
2
853-1402 18665
Philips Semiconductors
Product specification
High performance low power mixer FM IF system
SA615
BLOCK DIAGRAM
20
19
18
17
16
15
14
13
12
11
IF
AMP
LIMITER
RSSI
OSCILLATOR
E
B
1
2
3
4
5
6
7
8
9
10
SR00342
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 SA615
Thermal impedance
D package
N package
SSOP package
PARAMETER
RATING
9
–65 to +150
–40 to +85
90
75
117
UNITS
V
°C
°C
°C/W
DC ELECTRICAL CHARACTERISTICS
V
CC
= +6V, T
A
= 25
°
C; unless otherwise stated.
LIMITS
SYMBOL
PARAMETER
TEST CONDITIONS
MIN
V
CC
I
CC
Power supply voltage range
DC current drain
Mute switch input threshold
(ON)
(OFF)
1.7
1.0
4.5
5.7
SA615
TYP
MAX
8.0
7.4
V
mA
V
V
UNITS
1997 Nov 07
3
Philips Semiconductors
Product specification
High performance low power mixer FM IF system
SA615
AC ELECTRICAL CHARACTERISTICS
T
A
= 25
°
C; V
CC
= +6V, unless otherwise stated. RF frequency = 45MHz + 14.5dBV RF input step–up; IF frequency = 455kHz; R17 = 5.1k; RF
level = –45dBm; FM modulation = 1kHz with +8kHz peak deviation. Audio output with C-message weighted filter and de-emphasis capacitor.
Test circuit Figure 3. 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 = 300mV)
f
IN
f
OSC
Input signal frequency
Crystal oscillator frequency
Noise figure at 45MHz
Third-order input intercept point
Conversion power gain
RF input resistance
RF input capacitance
Mixer output resistance
IF section
IF amp gain
Limiter gain
Input limiting -3dB, R
17
= 5.1k
AM rejection
Audio level, R
10
= 100k
Unmuted audio level, R
11
= 100k
SINAD sensitivity
THD
S/N
Total harmonic distortion
Signal-to-noise ratio
IF RSSI output, R
9
= 100kΩ
1
No modulation for noise
IF level = -118dBm
IF level = -68dBm
IF level = -18dBm
RSSI range
RSSI accuracy
IF input impedance
IF output impedance
Limiter intput impedance
Unmuted audio output resistance
Muted audio output resistance
RF/IF section (int LO)
Unmuted audio level
System RSSI output
4.5V = V
CC
, RF level = -27dBm
4.5V = V
CC
, RF level = -27dBm
450
4.3
mV
RM
S
SA615
TYP
500
150
5.0
MAX
UNITS
MHz
MHz
dB
dBm
dB
dB
kΩ
4.0
pF
kΩ
dB
dB
dBm
43
260
dB
mV
RM
S
f1 = 45.00; f2 = 45.06MHz
Matched 14.5dBV step-up
50Ω source
Single-ended input
(Pin 20)
50Ω source
50Ω source
Test at Pin 18
80% AM 1kHz
15nF de-emphasis
150pF de-emphasis
RF level -118dB
-30
0
1.7
3.6
25
60
3.0
1.25
8.0
-12
13
-1.7
4.7
3.5
1.50
39.7
62.5
-109
33
150
530
12
-42
68
160
2.5
4.8
80
+2
1.40
0.85
1.40
1.6
1.0
1.6
58
58
800
3.3
5.8
mV
dB
dB
dB
mV
V
V
dB
dB
kΩ
kΩ
kΩ
kΩ
kΩ
R
9
= 100kΩ Pin 16
R
9
= 100kΩ Pin 16
V
NOTE:
1. The generator source impedance is 50Ω, but the SA615 input impedance at Pin 18 is 1500Ω. As a result, IF level refers to the actual signal
that enters the SA615 input (Pin 8) which is about 21dB less than the ”available power” at the generator.
1997 Nov 07
4
Philips Semiconductors
Product specification
High performance low power mixer FM IF system
SA615
CIRCUIT DESCRIPTION
The SA615 is an IF signal processing system suitable for second IF
or single conversion systems with input frequency as high as 1GHz.
The bandwidth of the IF amplifier is about 40MHz, with 39.7dB(v) of
gain from a 50Ω source. The bandwidth of the limiter is about
28MHz with about 62.5dB(v) of gain from a 50Ω source. However,
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 5dB, conversion gain of
13dB, and input third-order intercept of –10dBm. The oscillator will
operate in excess of 1GHz 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 of the mixer is internally loaded with 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. 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 can be added between the first IF output (Pin 16) and the
interstage network.
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.
Overall, the IF section has a gain of 90dB. For operation at
intermediate frequencies greater than 455kHz, special care must be
given to layout, termination, and interstage loss to avoid instability.
The demodulated output of the quadrature detector is available at
two pins, one continuous and one with a mute switch. Signal
attenuation with the mute activated is greater than 60dB. The mute
input is very high impedance and is compatible with CMOS or TTL
levels.
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.
NOTE: dB(v) = 20log V
OUT
/V
IN
1997 Nov 07
5
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