Document
Philips Semiconductors
Product specification
Low-voltage mixer FM IF system
SA676
DESCRIPTION
The SA676 is a low-voltage 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 SA676 is available in a 20-pin SSOP (shrink small outline package). The SA676 was designed for cordless telephone applications in which efficient and economic integrated solutions are required and yet high performance is desirable. Although the product is not targeted to meet the stringent specifications of high performance cellular equipment, it will exceed the needs for analog cordless phones. The minimal amount of external components and absence of any external adjustments makes for a very economical solution.
PIN CONFIGURATION
DK Package
RF IN+ 1 RF IN– DECOUPLING 2 OSCOUT 3 OSCIN 4 RSSI OUT 5 VCC 6 AUDIO FEEDBACK 7 AUDIO OUT 8 RSSI FEEDBACK 9 QUADRATURE IN 10 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
FEATURES
• Low power consumption: 3.5mA typical at 3V • Mixer input to >100MHz • Mixer conversion power gain of 17dB at 45MHz • XTAL oscillator effective to 100MHz (L.C. oscillator or external
oscillator can be used at higher frequencies)
SR00514
Figure 1. Pin Configuration
• 102dB of IF Amp/Limiter gain • 2MHz IF amp/limiter small signal bandwidth • Temperature compensated logarithmic Received Signal Strength
Indicator (RSSI) with a 70dB dynamic range
• Audio output internal op amp • RSSI output internal op amp • Internal op amps with rail-to-rail outputs • ESD protection: Human Body Model 2kV
Robot Model 200V
• Low external component count; suitable for crystal/ceramic/LC
filters
APPLICATION
• Cordless phones
ORDERING INFORMATION
DESCRIPTION 20-Pin Plastic Shrink Small Outline Package (Surface-mount) TEMPERATURE RANGE -40 to +85°C ORDER CODE SA676DK DWG # SOT266-1
BLOCK DIAGRAM
20 19 18 17 16 15 14 13 12 11
IF AMP MIXER RSSI
LIMITER
QUAD OSCILLATOR
+ – VREG E B
– +
AUDIO
1
2
3
4
5
6
7
8
9
10
SR00515
Figure 2. Block Diagram
1993 Dec 15
6–129
853-1726 11659
Philips Semiconductors
Product specification
Low-voltage mixer FM IF system
SA676
ABSOLUTE MAXIMUM RATINGS
SYMBOL VCC TSTG TA θJA Single supply voltage Storage temperature range Operating ambient temperature range Thermal impedance DK package PARAMETER RATING 7 –65 to +150 –40 to +85 117 UNITS V °C °C °C/W
DC ELECTRICAL CHARACTERISTICS VCC = +3V, TA = 25°C; unless otherwise stated.
LIMITS SYMBOL VCC ICC PARAMETER Power supply voltage range DC current drain TEST CONDITIONS MIN 2.7 3.5 SA676 TYP MAX 7.0 5.0 V mA UNITS
AC ELECTRICAL CHARACTERISTICS
TA = 25°C; VCC = +3V, unless otherwise stated. RF frequency = 45MHz; +14.5dBV RF input step-up; IF frequency = 455kHz; R17 = 2.4kΩ and R18 = 3.3kΩ; RF level = –45dBm; FM modulation = 1kHz with ±5kHz peak deviation. Audio output with de-emphasis filter and C-message weighted filter. Test circuit Figure 3. 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. SYMBOL PARAMETER TEST CONDITIONS LIMITS MIN TYP 100 100 7.0 f1 = 45.0; f2 = 45.06MHz Input RF level = –52dBm Matched 14.5dBV step–up 50Ω source RF input resistance RF input capacitance Mixer output resistance IF section IF amp gain Limiter gain AM rejection Audio level SINAD sensitivity THD S/N Total harmonic distortion Signal–to–noise ratio IF RSSI output, R9 = 2kΩ1 RSSI range IF input impedance IF output impedance Limiter input impedance Limiter output impedance Limiter output voltage Pin 18 Pin 16 Pin 14 Pin 11 Pin 11 1.3 1.3 No modulation for noise IF level = –110dBm IF level = –50dBm 50Ω source 50Ω source 30% AM 1kHz Gain of two IF level –110dBm 60 44 58 50 120 17 –55 60 0.5 1.7 70 1.5 0.3 1.5 0.3 130 .90 2.2 dB dB dB mV dB dB dB V V dB kΩ kΩ kΩ kΩ mVRMS (Pin 20) 1.25 Single–ended input 10 –10 17 +2.5 8 3.0 1.5 4.0 MAX UNITS
Mixer/Osc section (ext LO = 220mVRMS) fIN fOSC Input signal frequency Crystal oscillator frequency Noise figure at 45MHz Third–order input intercept point (50Ω source) Conversion power gain MHz MHz dB dBm dB dB kΩ pF kΩ
1993 Dec 15
6–130
Philips Semiconductors
Product specification
Low-voltage mixer FM IF system
SA676
AC ELECTRICAL CHARACTERISTICS
SYMBOL RF/IF section (int LO) System SINAD sensitivity PARAMETER
(Continued) TEST CONDITIONS MIN RF level = –114dBm LIMITS TYP 12 MAX dB UNITS
NOTE: 1. The generator source impedance is 50Ω, but the SA676 input impedance at Pin 18 is 1500Ω. As a result, IF level refers to the actual signal that enters the SA676 input (Pin 18) which is about 21dB less than the “ava.