DESCRIPTION

The SA58641 is a 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 SA58641 is available in 20-lead SSOP (shrink small outline package).

The SA58641 was designed for high bandwidth portable communication applications and will function down to 2.7 V. The RF section is similar to the famous SA605. The data output has a minimum bandwidth of 600 kHz. 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.

SA58641 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.

FEATURES

• Wideband data output (600 kHz min.)

• Fast RSSI rise and fall times

• Low power consumption: 7.5 mA typ. at 5 V

• Mixer input to >500 MHz

• Mixer noise figure of 12 dB at 240 MHz

• XTAL oscillator effective to 150 MHz (L.C. oscillator to 1 GHz local

oscillator can be injected)

• 92 dB of IF Amp/Limiter gain

• 25 MHz limiter small signal bandwidth

• Temperature compensated logarithmic Received Signal Strength

Indicator (RSSI) with a dynamic range in excess of 90 dB

• RSSI output internal op amp

• Internal op amps with rail-to-rail outputs

• Low external component count; suitable for crystal/ceramic/LC

filters

• Excellent sensitivity: 0.54 µV into 50 Ω matching network for

12 dB SINAD (Signal to Noise and Distortion ratio) for 1 kHz tone

with RF at 240 MHz and IF at 10.7 MHz

• ESD hardened

• 10.7 MHz filter matching (330 Ω)

• Power-down mode (ICC = 200 µA)

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