Overview

The LA1136N/NM and LA1137N/NM are high-performance AM electronic tuner ICs offering sophisticated functions. They are especially suited for use in car radio and home stereo

(antenna: loop) applications.

Features

.Excellent cross modulation characteristic: Meets the requirements for preventing not only adjacent-channel interference but also interference caused by all channels within broadcast band.

.Narrow-band signal meter output: Usable as auto search stop signal. Has linearity up to 100 dBµ.

.Local oscillation buffer output: Facilitates designing of electronic tuner system, frequency display, etc.

.OSC (with ALC): Improves tracking error because oscillation output is stabilized at a low level (350 mVrms: LA1137N) for varactor diode.

.MIX: Double-balanced differential MIX meeting the requirements for preventing spurious interference, IF interference.

.Good characteristic at high input: 130 dBµ input fm = 400 Hz 80%mod THD = 0.5% typ.

.High S/N: Good S/N at medium input (55 dB typ).

.Usable sensitivity: (S/N = 20 dB input): 25 dBµ(when using 2SK715 )

.VCC variation compensation: Less variation in gain, distortion: 8 to 12 V

Functions

.MIX

.OSC (with ALC)

.IF amplifier

.Detector

.AGC (normal)

.RF wide-band AGC

.Auto search stop signal (Signal meter output)

.Local oscillation buffer output

.IF band switching circuit (for LA1136N only)

.IF count buffer

.Stop detector output (can be set independently)

.Tweet prevention circuit

.AGC (RF, IF) time constant switching circuit

.IF AGC circuit

.Pin-diode driver

.AM stereo decoder IF output (for LA1136N only)

.Circuit preventing incorrect seek operation