FM Communications Receivers

The MC13135/MC13136 are the second generation of single chip, dual conversion FM communications receivers developed by Motorola. Major improvements in signal handling, RSSI and first oscillator operation have been made. In addition, recovered audio distortion and audio drive have improved. Using Motorola’s MOSAIC 1.5 process, these receivers offer low noise, high gain and stability over a wide operating voltage range.
Both the MC13135 and MC13136 include a Colpitts oscillator, VCO tuning diode, low noise first and second mixer and LO, high gain limiting IF, and RSSI. The MC13135 is designed for use with an LC quadrature detector and has an uncommitted op amp that can be used either for an RSSI buffer or as a data comparator. The MC13136 can be used with either a ceramic discriminator or an LC quad coil and the op amp is internally connected for a voltage buffered RSSI output.
These devices can be used as stand–alone VHF receivers or as the lower IF of a triple conversion system. Applications include cordless telephones, short range data links, walkie–talkies, low cost land mobile, amateur radio receivers, baby monitors and scanners.

• Complete Dual Conversion FM Receiver – Antenna to Audio Output
• Input Frequency Range – 200 MHz
• Voltage Buffered RSSI with 70 dB of Usable Range
• Low Voltage Operation – 2.0 to 6.0 Vdc (2 Cell NiCad Supply)
• Low Current Drain – 3.5 mA Typ
• Low Impedance Audio Output < 25 Ω
• VHF Colpitts First LO for Crystal or VCO Operation
• Isolated Tuning Diode
• Buffered First LO Output to Drive CMOS PLL Synthesizer