The ML13150 is a narrowband FM IF subsystem targeted at cellular and other analog applications. The ML13150 has an onboard Colpitts VCO that can be crystal controlled or phased lock for second LO in dual conversion receivers. The mixer is a double balanced configuration with excellent third order intercept. It is useful to beyond 200 MHz. The IF amplifier is split to accommodate two low cost cascaded filters. RSSI output is derived by summing the output of both IF sections., The quadrature detector is a unique design eliminating the conventional tunable quadrature coil.