Ordering number : EN873G
Monolithic Linear IC
LA1235
FM IF System Applications
Overview
The LA1235 is a high integrated IC developed for use in high S/N, low distortion FM IF system applications. This IC
features S/N = 88dB, distortion factor = 0.015% and has almost all functions required for FM tuner IF stage.
The IF amplifier and limiter stage consist of 6 stages of double ended differential amplifier having an excellent AMR, and
this stage is followd by the signal meter driver which consists of 4 stages of level detector, thereby creating extended
linearity up to strong input. The FM detector stage consists of a double balanced quadrature detector to which a low
frequency preamplifire and a muting controller are attached. The muting drive stage consists of an OR circuit for weak
signal muting drive output which detects signal intensity and detuning muting drive output which detects S curve DC
output and enables the prevention of noise at the time of weak signal and detuning. Further, the weak signal muting drive
output circuit contains a Schmitt circuit having hysteresis and enables the prevention of muting malfunction due to
amplitude component at the time of weak signal. The AFC output and tuning meter drive stage is of current drive type
which makes it possible to adjust AFC sensitivity and muting band width by means of an external resistor, and the built-in
tuning meter null (short) circuit foreces the tuning meter to be [0] when th IF amplifier stops working.
The IF amplifier stop circuit, being a circuit to stop the FM IF amlifier at the time of AM reception, makes it possible to
decrease shock noise due to FM-AM receiving mode switchover.
Features
Functions
• High S/N (88dB typ.).
• Low distortion (0.015% typ.).
• Weak signal muting dirve output having hysteresis.
• Tuning mete null (short) circuit.
• Signal meter dirve output having wide dynamic range.
• High limiting sensitivity.
• Built-in constant-voltage regulated circuit
(Operating voltage : 10 to 14V).
• IF amplifier, Limiter.
• Quadrature detection.
• AF preamplifier.
• Signal intesity muting drive output.
• Detuning muting drive output.
• AF signal muting circuit.
• Signal meter drive output.
• AFC, tuning meter drive output.
• IF amplifier stop circuit.
• Tunig meter null circuit.
Any and all SANYO Semiconductor Co.,Ltd. products described or contained herein are, with regard to
"standard application", intended for the use as general electronics equipment (home appliances, AV equipment,
communication device, office equipment, industrial equipment etc.). The products mentioned herein shall not be
intended for use for any "special application" (medical equipment whose purpose is to sustain life, aerospace
instrument, nuclear control device, burning appliances, transportation machine, traffic signal system, safety
equipment etc.) that shall require extremely high level of reliability and can directly threaten human lives in case
of failure or malfunction of the product or may cause harm to human bodies, nor shall they grant any guarantee
thereof. If you should intend to use our products for applications outside the standard applications of our
customer who is considering such use and/or outside the scope of our intended standard applications, please
consult with us prior to the intended use. If there is no consultation or inquiry before the intended use, our
customer shall be solely responsible for the use.
Specifications of any and all SANYO Semiconductor Co.,Ltd. products described or contained herein stipulate
the performance, characteristics, and functions of the described products in the independent state, and are not
guarantees of the performance, characteristics, and functions of the described products as mounted in the
customer' s products or equipment. To verify symptoms and states that cannot be evaluated in an independent
device, the customer should always evaluate and test devices mounted in the customer' s products or
equipment.
52808 MS JK/O2097HA (KT)/63095HA (KOTO)/O076AT/8044KI, TS/4241KI/3091KI NO.873-1/13
