Page 1
RF COMMUNICATIONS PRODUCTS
SA636
Low voltage high performance mixer FM
IF system with high-speed RSSI
Product specification
Replaces data of 1994 Jun 16
IC17 Data Handbook
Philips Semiconductors
1997 Nov 07
Page 2
Philips Semiconductors Product specification
Low voltage high performance mixer FM IF
system with high-speed RSSI
DESCRIPTION
The SA636 is a low-voltage high performance monolithic FM IF
system with high-speed RSSI incorporating a mixer/oscillator, two
limiting intermediate frequency amplifiers, quadrature detector,
logarithmic received signal strength indicator (RSSI), voltage
regulator, wideband data output and fast RSSI op amps. The
SA636 is available in 20-lead SSOP (shrink small outline package).
The SA636 was designed for high bandwidth portable
communication applications and will function down to 2.7V . The RF
section is similar to the famous SA605. The data output has a
minimum bandwidth of 600kHz. This is designed to demodulate
wideband data. The RSSI output is amplified. The RSSI output has
access to the feedback pin. This enables the designer to adjust the
level of the outputs or add filtering.
SA636 incorporates a power down mode which powers down the
device when Pin 8 is low. Power down logic levels are CMOS and
TTL compatible with high input impedance.
APPLICATIONS
•DECT (Digital European Cordless Telephone)
•Digital cordless telephones
•Digital cellular telephones
•Portable high performance communications receivers
•Single conversion VHF/UHF receivers
•FSK and ASK data receivers
•Wireless LANs
FEATURES
•Wideband data output (600kHz min.)
•Fast RSSI rise and fall times
•Low power consumption: 6.5mA typ at 3V
•Mixer input to >500MHz
•Mixer conversion power gain of 11dB at 240MHz
•Mixer noise figure of 12dB at 240MHz
PIN CONFIGURATION
•XTAL oscillator effective to 150MHz (L.C. oscillator to 1GHz local
•92dB of IF Amp/Limiter gain
•25MHz limiter small signal bandwidth
•Temperature compensated logarithmic Received Signal Strength
•RSSI output internal op amp
•Internal op amps with rail-to-rail outputs
•Low external component count; suitable for crystal/ceramic/LC
•Excellent sensitivity: 0.54µV into 50Ω matching network for 12dB
•ESD hardened
•10.7MHz filter matching (330Ω)
•Power down mode (I
SA636
DK Package
1
RF
IN
RF BYPASS
XTAL OSC (EMITTER)
XTAL OSC (BASE)
RSSI FEEDBACK
RSSI
POWER DOWN CONTROL
DATA OUT
QUADRATURE IN
oscillator can be injected)
Indicator (RSSI) with a dynamic range in excess of 90dB
filters
SINAD (Signal to Noise and Distortion ratio) for 1kHz tone with RF
at 240MHz and IF at 10.7MHz
2
3
4
5
V
CC
6
7
OUT
8
9
10
Figure 1. Pin Configuration
= 200µA)
CC
20
MIXER OUT
19
IF AMP DECOUPLING
18
IF AMP IN
17
IF AMP DECOUPLING
16
IF AMP OUT
15
GND
LIMITER IN
14
13
LIMITER DECOUPLING
12
LIMITER DECOUPLING
LIMITER OUT
11
SR00491
ORDERING INFORMATION
DESCRIPTION TEMPERATURE RANGE ORDER CODE DWG #
20-Pin Plastic Shrink Small Outline Package (Surface-mount) -40 to +85°C SA636DK
1997 Nov 07 853-1757 18664
2
SOT266-1
Page 3
Philips Semiconductors Product specification
Input current
A
Input level
V
Low voltage high performance mixer FM IF system
with high-speed RSSI
BLOCK DIAGRAM
20 19 18 17 16 15 14 13 12 11
IF
AMP
MIXER
OSCILLATOR
EB
Figure 2. Block Diagram
ABSOLUTE MAXIMUM RATINGS
SYMBOL PARAMETER RATING UNITS
V
CC
V
IN
T
STG
T
A
NOTE: θJA, Thermal impedance DK package 117°C/W
Single supply voltage 0.3 to 7 V
Voltage applied to any other pin –0.3 to (VCC+0.3) V
Storage temperature range -65 to +150
Operating ambient temperature range SA636 –40 to +85
GND
V
CC
RSSI
FAST
RSSI
LIMITER
QUAD
+–
PWR
DWN
+–
AUDIO
10987654321
SA636
SR00492
°C
°C
DC ELECTRICAL CHARACTERISTICS
VCC = +3V, TA = 25°C; unless otherwise stated.
LIMITS
SYMBOL PARAMETER TEST CONDITIONS SA636 UNITS
MIN TYP MAX
V
I
I
t
t
OFF
Power supply voltage range 2.7 3.0 5.5 V
CC
DC current drain Pin 8 = HIGH 5.5 6.5 7.5 mA
CC
p
p
Standby Pin 8 = LOW 0.2 0.5 mA
CC
Power up time RSSI valid (10% to 90%) 10 µs
ON
Pin 8 LOW –10 10
Pin 8 HIGH –10 10
Pin 8 LOW 0 0.3V
Pin 8 HIGH 0.7V
CC
Power down time RSSI invalid (90% to 10%) 5 µs
CC
V
CC
µ
1997 Nov 07
3
Page 4
Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
with high-speed RSSI
AC ELECTRICAL CHARACTERISTICS
TA = 25°C; VCC = +3V, unless otherwise stated. RF frequency = 240.05MHz + 14.5dBV RF input step-up; IF frequency = 10.7MHz; RF level =
-45dBm; FM modulation = 1kHz with ±125kHz peak deviation. Audio output with C-message weighted filter and de-emphasis capacitor. Test
circuit Figure 1. The parameters listed below are tested using automatic test equipment to assure consistent electrical characteristics. 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 SA636 UNITS
MIN TYP MAX
Mixer/Osc section (ext LO = 160mV
f
Input signal frequency 500 MHz
IN
f
OSC
IF section
THD Total harmonic distortion -43 -38 dB
S/N Signal-to-noise ratio No modulation for noise 60 dB
RF/IF section (int LO)
External oscillator (buffer) 500 MHz
Noise figure at 240MHz 12 dB
Third-order input intercept point Matched f1=240.05; f2=240.35MHz -16 dBm
Conversion power gain Matched 14.5dBV step-up 8 11 14 dB
RF input resistance Single-ended input 700 Ω
RF input capacitance 3.5 pF
Mixer output resistance (Pin 20) 330 Ω
IF amp gain 330Ω load 38 dB
Limiter gain 330Ω load 54 dB
Input limiting -3dB Test at Pin 18 –105 dBm
AM rejection 80% AM 1kHz 50 dB
Data level R
3dB data bandwidth 600 700 kHz
SINAD sensitivity RF level = -111dBm 16 dB
IF RSSI output with buffer IF level = -68dBm 0.3 0.6 1.0 V
IF RSSI output rise time IF frequency = 10.7MHz
(10kHz pulse, no 10.7MHz filter) RF level = -56dBm 1.2 µs
(no RSSI bypass capacitor) RF level = -28dBm 1.1 µs
IF RSSI output fall time IF frequency = 10.7MHz
(10kHz pulse, no 10.7MHz filter) RF level = -56dBm 2.0 µs
(no RSSI bypass capacitor) RF level = -28dBm 7.3 µs
RSSI range 90 dB
RSSI accuracy +1.5 dB
IF input impedance 330 Ω
IF output impedance 330 Ω
Limiter input impedance 330 Ω
Limiter output impedance 300 Ω
Limiter output level with no load 130 mV
System RSSI output RF level = -10dBm 1.4 V
System SINAD RF level = -106dBm 12 dB
RMS
)
= 100kΩ 120 130 mV
LOAD
IF level = -118dBm 0.2 0.5 V
IF level = -10dBm 0.9 1.3 1.8 V
SA636
RMS
RMS
1997 Nov 07
4
Page 5
Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
with high-speed RSSI
PERFORMANCE CHARACTERISTICS
9.0
8.5
V
8.0
7.5
7.0
6.5
SUPPLY CURRENT (mA)
6.0
5.5
5.0
–50 –40 –30 –20 –10 0 10 20 30 40 50 60 70 80 90
TEMPERATURE (°C)
= 5V
CC
VCC = 3V
= 2.7V
V
CC
Supply Current vs Temperature and Supply Voltage
20
19
18
17
16
15
14
(dB)
13
12
MIXER GAIN
11
10
9
8
7
6
5
–40 0 25 70 85
Temperature (°C)
RF level = -45 dBm
5.5V
3.0V
2.7V
Mixer Power Gain vs Temperature and Supply Voltage
300
250
5.5V
200
3.0V
150
2.7V
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
POWER DOWN SUPPLY CURRENT (mA)
0.05
0.00
–50 –40 –30 –20 –10 0 10 20 30 40 50 60 70 80 90
Power Down Supply Current vs Temperature and Supply Voltage
–5
–7
–9
–11
–13
–15
MIXER IIP3 (deB)
–17
–19
–21
–23
–25
Mixer IIP3 at 240MHz vs Temperature and Supply Voltage
20
0
–20
–40
AUDIO (dB)
–60
VCC = 5V
= 3V
V
CC
V
= 2.7V
CC
TEMPERATURE (°C)
RF level = -45 dBm
5.5V
3.0V
–40 0 25 70 85
AUDIO
AM REJECTION
Temperature (°C)
DISTORTION
2.7V
SA636
100
100
AUDIO REFERENCE (mVrms)
50
0
–40 0257085
Temperature (°C)
Audio Reference Level vs Temperature and Supply Voltage
Figure 3. Performance Characteristics
1997 Nov 07
–80
–100
–120
NOISE
12dB SINAD
–50–40 –30 –20 –10 0 10 20 30 40 50 60 70 80 90
TEMPERATURE (°C)
12dB SINAD and Relative Audio, THD, Noise
and AM Rejection for VCC = 3V vs Temperature
RF = 240MHz, Level = –68dBm, Deviation = 125kHz
5
SR00493
Page 6
Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
with high-speed RSSI
PERFORMANCE CHARACTERISTICS (continued)
RSSI (V)
RSSI (V)
10
0
–10
–20
–30
–40
–50
–60
–70
RELATIVE TO AUDIO OUTPUT (dB)
–80
–90
–110
0
–10
–20
–30
–40
–50
–60
–70
–80
IF OUTPUT POWER (dBm)
–90
–100
–110
–65
2
1.8
1.6
1.4
1.2
1
0.8
RSSI (V)
0.6
0.4
0.2
0
–110
10
RELATIVE TO AUDIO OUTPUT (dB)
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–110
NOISE
–100
AUDIO
AM REJECTION
THD+N
–90
–80
RF INPUT LEVEL (dBm)
–70
–60
–50
–40
–30
–20
RSSI
–10
Receiver RF Performance — T = 25°C,
Audio Level = 129mV
10
0
–10
–20
–30
–40
–50
–60
RELATIVE TO AUDIO OUTPUT (dB)
–70
–80
–90
–110
Receiver RF Performance – T = 85°C, Audio Level = 131mV
85
–5
–7
–9
–11
–13
–15
MIXER IIP3 (dB)
–17
–19
–21
–23
–25
AUDIO
AM REJECTION
THD+N
NOISE
–90
–80
–70
–100
–40 0 25 70
–60
5.5V
Temperature (°C)
RMS
–50
–40
RF level = -45 dBm
3.0V
–30
RSSI
–20
2.7V
–10
Mixer IIP3 at 240MHz vs Temperature and Supply Voltage
Figure 4. Performance Characteristics
2
1.8
1.6
1.4
1.3
1.0
0.8
0.6
0.4
0.2
0
0
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0
RMS
SA636
AUDIO
AM REJECTION
THD+N
NOISE
RSSI
–90
–80
–70
–60
–50
–40
–30
–20
–25
–30
–10
–20
–40°C
25°C
85°C
–20
–100
RF INPUT LEVEL (dBm)
Receiver RF Performance — T = –40°C,
–60
Audio Level = 118mV
–55
–50
–45
RF INPUT POWER (dBm)
–40
–35
RMS
–30
Mixer Third Order Intercept and Compression
–90
–80
–70
–60
–50
–100
RF INPUT LEVEL (dBm)
–40
RSSI vs RF Input Level and Temperature
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
0
–15
–10
SR00494
RSSI (V)
–10
0
1997 Nov 07
6
Page 7
Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
with high-speed RSSI
PERFORMANCE CHARACTERISTICS (continued)
50.00
48.00
46.00
44.00
V
= 5V
30.00
CC
VCC = 3V
= 2.7V
V
CC
50.00
70.00
90.00
42.00
40.00
38.00
POWER GAIN (dB)
36.00
34.00
32.00
30.00
–50.00
–30.00
10.00
–10.00
TEMPERATURE (°C)
SA626 IF Amplifier Gain vs Temperature vs Supply Voltage
0.8
5.5V
3.0V
600kHz Data Rate,
IF = 9.85MHz,
Dev = 288kHz,
RF = -40dBm
2.7V
0.7
0.6
0.5
0.4
0.3
DATA LEVEL (Vp-p)
0.2
0.1
0
–40 0 25 70 85
Temperature (°C)
Data Level vs Temperature and Supply Voltage
65.00
63.00
61.00
59.00
57.00
55.00
53.00
POWER GAIN (dB)
51.00
49.00
47.00
45.00
SA626 Limiting Amplifier Gain vs Temperature vs Supply Voltage
0.8
0.7
0.6
0.5
0.4
0.3
DATA LEVEL (Vp-p)
0.2
0.1
0
Data Level vs Temperature and Supply Voltage
SA636
= 5V
V
CC
VCC = 3V
V
= 2.7V
CC
10.00
30.00
50.00
–50.00
–30.00
–10.00
TEMPERATURE (°C)
5.5V
3.0V
2.7V
1kHz Data Rate,
IF = 9.85MHz,
Dev = 288kHz,
RF = -40dBm
–40 0257085
Temperature (°C)
70.00
90.00
1997 Nov 07
SR00495
Figure 5. Performance Characteristics
7
Page 8
Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
with high-speed RSSI
PERFORMANCE CHARACTERISTICS (continued)
300
250
5.5V
200
3.0V
150
100
AUDIO REFERENCE (mVrms)
50
0
–40 0 257085
Temperature (°C)
2.7V
Audio Reference Level vs Temperature and Supply Voltage
0.8
0.7
0.6
5.5V
1kHz Data Rate,
IF = 9.85MHz,
Dev = 288kHz,
RF = -40dBm
0.8
0.7
0.6
0.5
0.4
0.3
DATA LEVEL (Vp-p)
0.2
0.1
0
–40 0 257085
Data Level vs Temperature and Supply Voltage
600kHz Data Rate,
IF = 9.85MHz,
Dev = 288kHz,
RF = -40dBm
5.5V
3.0V
Temperature (°C)
SA636
2.7V
0.5
0.4
0.3
DATA LEVEL (Vp-p)
0.2
0.1
0
–40 0257085
3.0V
2.7V
Temperature (°C)
Data Level vs Temperature and Supply Voltage
Figure 6. Performance Characteristics
SR00496
1997 Nov 07
8
Page 9
Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
with high-speed RSSI
PIN FUNCTIONS
PIN
No.
1 RF IN +1.07 6
2
PIN
MNEMONIC
RF
DC V EQUIVALENT CIRCUIT
0.8k
1
0.8k
No.
2
+1.07 7
PIN
PIN
MNEMONIC
RSSI
FEEDBACK
RSSI
OUTBYPASS
DC V EQUIVALENT CIRCUIT
V
CC
+0.20
+0.20
—
6
+
—
+
SA636
V
CC
7
XTAL
3
XTAL
4
5V
CC
+1.57 8
4
3
18k
MIX
150µA
+2.32 9
V
5
REF
+3.00 10
BANDGAP
POWER
DOWNOSC
DATA
OUTOSC
QUAD.
IN
+2.75
+1.09
+3.00
R
8
R
V
CC
+
—
80k
10
9
20µA
1997 Nov 07
SR00497
Figure 7. Pin Functions
9
Page 10
Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
with high-speed RSSI
PIN FUNCTIONS (continued)
PIN
No.
11
12
PIN
MNEMONIC
LIMITER
OUT
LIMITER
DC V EQUIVALENT CIRCUIT
PIN
No.
+1.35 16
11
8.8k
+1.23 17
PIN
MNEMONIC
IF
AMP OUT
IF AMP
DECOUPDECOUP
DC V EQUIVALENT CIRCUIT
+1.22
140Ω
8.8k
+1.22
SA636
16
14
+1.23 18
330Ω
50µA
12
13
+1.23 19
13
14
LIMITER
LIMITER
15 GND 0 20
IF
AMP INCOUPLING
IF AMP
DECOUPIN
MIXER
OUT
+1.22
+1.22
+1.03
18
330Ω
50µA
17
19
110Ω
20
400µA
1997 Nov 07
SR00498
Figure 8. Pin Functions (cont.)
10
Page 11
Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
with high-speed RSSI
IF/LIM OUT
L5
MIXER
C12
C11
FLT1
21
21
C13
20 19 18 17 16 15 14
R2
C14
IF
AMP
R4
R3
IF/LIM IN
C16
R5
21 21
C15
R6
FLT2
R7
C17
R9
R8
C19
C18
13 12 11
LIMITER
SA636
R11
C20
R10
SW5
MIXER
OSCILLATOR
C3C1
*L1
RF IN LO IN
C2
*L2
L3
C4
C5
Automatic Test Circuit Component List
R1
8.2kΩ select
R2
6.42kΩ
R3
347.8Ω
R4
49.9Ω
R5
1kΩ
R6
49.9Ω
R7
6.42kΩ
R8
347.8Ω
R9
49.9Ω
R10
1kΩ
R11
49.9Ω
*NOTE: This value can be reduced when a battery is the power source.
C1
0.1µF
C2
1–5pF select for input match
C3
0.1µF
C4
0.1µF
C5
1–5pF select for input match
C6
100pF
*C7
6.8µF 10V
C8
1µF
C9
39pF select
C10
0.1µF
C11
0.1µF
Figure 9. SA636 240.05MHz (RF) / 10.7MHz (IF) Test Circuit
C21
PWR
DWN
QUAD
–
+
DATA
RSSI
+
V
CC
–
10987654321
C6
C7
PWR
RSSI
V
CC
OUT
C12
C13
C14
C15
C16
C17
C18
C19
C20
C21
DWN
CTRL
160pF select
1000pF
0.1µF
1000pF
0.1µF
0.1µF
1000pF
1000pF
0.1µF
1pF
FLT
FLT
L1
L2
L3
L4
L5
FLT1
FLT2
FLT3
FLT4
C8
R1
3
4
DATA
OUT
C9
C10
L4
150nH select for input match
22nH select for input match
47nH select for input match
5.6µH select for input match
1.27–2.25µH select for mixer
output match
10.7MHz (Murata SFE10.7MA5-A)
10.7MHz (Murata SFE10.7MA5-A)
“C” message weighted
Active de-emphasis
SR00501
1997 Nov 07
11
Page 12
Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
with high-speed RSSI
SMA
RF IN
J1
110.592MHz
+/–288kHz
SMA
120.392MHz
LO IN
J2
@–10dBm
C4
1nF
R1
51
C1
5–30pF
C3
1nF
R4
33k
R3
22k
L1
180nH
C2
10nF
U1
1
RF IN
2
RF BYPASS
XTAL
3
OSC (EMITTER)
XTAL
4
OSC (BASE)
5
V
CC
6
RSSI FEEDBACK
7
RSSI OUT
8
PD CTRL
MIXER OUT
IF AMP
DECOUPLING 1
IF IN
IF AMP
DECOUPLING 2
IF OUT
GROUND
LIMITER IN
LIMITER DEC1
C20
68pF
20
19
18
17
16
15
14
13
C19
1nF
C18
68pF
SA636
L4
680nH
C21
330pF
C17
1nF
C16
100pF
C13
100pF
+3V
V
GND
J3
RSSI
PWR DWN
DATA OUT
1997 Nov 07
CC
R2
10
+
C5
15µF
C6
100nF
9
10
DATA OUT
QUAD IN
LIMITER DEC2
LIMITER OUT
12
11
C11 C12
1nF 1nF
SA636
C14
C7
470pF
1.2k
C10
15pF
C8
5-30pF
+
C9
82pF
R5
L2
2.2µH
47pF
C15
330pF
L3
680nH
R6
560
SR00500
Figure 10. SA636 110.592MHz (RF) / 9.8MHz (IF) DECT Application Circuit
12
Page 13
Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
with high-speed RSSI
Table 1. DECT Application Circuit Electrical Characteristics
RF frequency = 110.592MHz; IF frequency = 9.8MHz; RF level = -45dBm; FM modulation = 100kHz with ±288kHz peak deviation.
SYMBOL
Mixer/Osc section (ext LO = 160mV
PG Conversion power gain 13 dB
NF Noise Figure at 110MHz 12 dB
IIP3 Third order input intercept Matched f1 = 110.592; f2 = 110.892MHz -15 dBm
R
C
IF section
RF/IF section (internal LO)
NOTE:
1. 10dB S/N corresponds to BER = 10
RF input resistance 690 Ω
IN
RF input capacitance 3.6 pF
IN
IF amp gain 330Ω load 38 dB
Limiter amp gain 330Ω load 54 dB
Data level R
3dB data bandwidth 700 kHz
System RSSI output RF level = -10dBm 1.4 V
System S/N
PARAMETER TEST CONDITIONS TYPICAL UNITS
)
RMS
= 3kΩ 130 mV
LOAD
1
-3
.
RF level = -83dBm 10 dB
SA636
RMS
RF GENERATOR
110.592MHz
LO / GENERATOR
120.392MHz
DC VOLTMETER
SCOPE
Figure 11. SA636 Application Circuit Test Set Up
NOTES:
1. RF generator: Set your RF generator at 110.592MHz, use a 100kHz modulation frequency and a ±288kHz deviation.
2. Layout: The layout is very critical in the performance of the receiver. We highly recommend our demo board layout.
3. 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.
4. Supply bypass and shielding: All of the inductors, the quad tank, and their shield must be grounded. A 0.1µF bypass capacitor on the
supply pin improves sensitivity.
SA636 DEMO BOARD
RSSI DATA
SPECTRUM
ANALYZER
VCC = 3V
SR00502
1997 Nov 07
13
Page 14
Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
with high-speed RSSI
TOP SILK SCREEN (SSOP)
SA636
1997 Nov 07
SR00503
Figure 12. SA636 Demoboard Layout (Not Actual Size)
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Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
with high-speed RSSI
CIRCUIT DESCRIPTION
The SA636 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 38dB of gain
from a 50Ω source. The bandwidth of the limiter is about 28MHz
with about 54dB of gain from a 50Ω source. However, the
gain/bandwidth distribution is optimized for 10.7MHz, 330Ω source
applications. The overall system is well-suited to battery operation
as well as high performance and high quality products of all types,
such as cordless and cellular hand-held phones.
The input stage is a Gilbert cell mixer with oscillator. Typical mixer
characteristics include a noise figure of 14dB, conversion gain of
11dB, and input third-order intercept of -16dBm. 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 330Ω resistor
permitting direct connection to a 10.7MHz ceramic filter for
narrowband applications. The input resistance of the limiting IF
amplifiers is also 330Ω. With most 10.7MHz ceramic filters and
many crystal filters, no impedance matching network is necessary.
For applications requiring wideband IF filtering, such as DECT,
external LC filters are used (see Figure 10). To achieve optimum
linearity of the log signal strength indicator, there must be a 6dB(v)
insertion loss between the first and second IF stages. If the IF filter
or interstage network does not cause 6dB(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
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 frequency at 10.7MHz. Special care must be given to
layout, termination, and interstage loss to avoid instability.
The demodulated output (DATA) of the quadrature is a voltage
output. This output is designed to handle a minimum bandwidth of
600kHz. This is designed to demodulate wideband data, such as in
DECT applications.
A Receive Signal Strength Indicator (RSSI) 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, DECT and RCR-28 cordless
telephone. This signal drives an internal op amp. The op amp is
capable of rail-to-rail output. It can be used for gain, filtering, or
2nd-order temperature compensation of the RSSI, if needed.
NOTE: dB(v) = 20log V
SA636
° phase
OUT/VIN
1997 Nov 07
15
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Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
SA636
with high-speed RSSI
SO20: plastic small outline package; 20 leads; body width 7.5 mm SOT163-1
1997 Nov 07
16
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Philips Semiconductors Product specification
Low voltage high performance mixer FM IF system
with high-speed RSSI
SA636
DEFINITIONS
Data Sheet Identification Product Status Definition
Objective Specification
Preliminary Specification
Product Specification
Formative or in Design
Preproduction Product
Full Production
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. Philips
Semiconductors 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 mask
work right infringement, unless otherwise specified. Applications that are described herein for any of these products are for illustrative purposes
only. Philips Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testing
or modification.
LIFE SUPPORT APPLICA TIONS
Philips 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 expected
to result in a personal injury. Philips Semiconductors and Philips Electronics North America Corporation customers using or selling Philips
Semiconductors and Philips Electronics North America Corporation Products for use in such applications do so at their own risk and agree to fully
indemnify Philips Semiconductors and Philips Electronics North America Corporation for any damages resulting from such improper use or sale.
Philips Semiconductors
811 East Arques Avenue
P.O. Box 3409
Sunnyvale, California 94088–3409
Telephone 800-234-7381
This data sheet contains the design target or goal specifications for product development. Specifications
may change in any manner without notice.
This data sheet contains preliminary data, and supplementary data will be published at a later date. Philips
Semiconductors reserves the right to make changes at any time without notice in order to improve design
and supply the best possible product.
This data sheet contains Final Specifications. Philips Semiconductors reserves the right to make changes
at any time without notice, in order to improve design and supply the best possible product.
Philips Semiconductors and Philips Electronics North America Corporation
register eligible circuits under the Semiconductor Chip Protection Act.
Copyright Philips Electronics North America Corporation 1994
All rights reserved. Printed in U.S.A.
1997 Nov 07
17
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