LA1787M Datasheet, PDF (4/54 Pages) Sanyo Semicon Device – Single-Chip Tuner IC for Car Radios

LA1787M
Function List
FM Front End (Equivalent to the Sanyo LA1193)
• Double input type double balanced mixer
• Pin diode drive AGC output
• MOSFET second gate drive AGC output
• Keyed AGC adjustment pin
• Differential IF amplifier
• Wide band AGC sensitivity setting pin, and narrow
band AGC sensitivity setting pin
• Local oscillator
FM IF
• IF limiter amplifier
• S-meter output (also used for AM) 6-stage pickup
• Multipath detection pin (shared FM signal meter)
• Quadrature detection
• AF preamplifier
• AGC output
• Band muting
• Weak input muting
• Soft muting adjustment pin
• Muting attenuation adjustment pin
• IF counter buffer output (also used for AM)
• SD (IF counter buffer on level) adjustment pin
• SD output (active high) (also used for AM)
Noise Canceller
• High-pass filter (first order)
• Delay circuit based low-pass filter (fourth order)
• Noise AGC
• Pilot signal compensation circuit
• Noise sensitivity setting pin
• Function for disabling the noise canceller in AM
mode
Multiplex Functions
• Adjustment-free VCO circuit
• Level follower type pilot canceller circuit
• HCC (high cut control)
• Automatic stereo/mono switching
• VCO oscillation stop function (AM mode)
• Forced monaural
• SNC (stereo noise controller)
• Stereo display pin
• Anti-birdie filter
AM
• Double balanced mixer (1st, 2nd)
• IF amplifier
• Detection
• RF AGC (narrow/wide)
• Pin diode drive pin
• IF AGC
• Signal meter output (also used for FM)
• Local oscillator circuits (first and second)
• Local oscillator buffer output
• IF counter buffer output (also used by the FM IF)
• SD (IF counter buffer on level) adjustment pin
• SD output (active high) (also used for AM)
• Wide AGC
• Detection output frequency characteristics
adjustment pin (low cut, high deemphasis)
• AM stereo buffer
MRC (multipath noise rejection circuit)
AM/FM switching output (linked to the FM V_CC)
No. 6655-4/54