LA1136N Datasheet, PDF (16/28 Pages) Sanyo Semicon Device – AM Tuners for Car Radios and Home Stereos

LA1136N, 1136NM, 1137N, 1137NM
6. Wideband AGC Sensitivity
The wideband AGC circuit two-signal sensitivity and shortwave interference suppression characteristics have been achieved by
reducing the sensitivity by approximately 10 dB from that of previous devices. If a FET with low gm and high I_DSS is used, the
sensitivity can be increased by increasing the external sensitivity adjustment resistor (30 Ω). However, the voltage drop across this
resistor can cause the cascade AGC transistor to saturate. Therefore, if the sensitivity is to be increased by a large amount, a choke
coil should be added as shown in the figure below.
Unit (resistance: Ω, capacitance: F)
7. The local oscillation level increased during LW (approx. 50°C or greater)
27 kΩ should be added between pins 19 and 23 for LA1136N, and between pins 15 and 19 for LA1137N. Not necessary for MW.
8. Image Interference Reduction
Image interference in the alignment circuit can be reduced by up to 70 dB at fr = 1.4 MHz by injecting a 2.3 MHz trap signal into
the primary coil. Note that this technique reduces the sensitivities at frequencies above 1.4 MHz.
9. Upgraded Features of LA1136 and LA1137 to LA1136N and LA1137N
Upgraded features
IF count buffer output voltage
74 dBµ, zero modulation,
fr = 1 MHz when STOP RQ = 0 V
LA1136, LA1137 LA1136N, LA1137N
Test circuit LA1137N
80 mVp-p
1.5 mVp-p
Signal detector output voltage
when V_CC OFF
Test circuit LA1137N
0.7 V
5V
Unit (resistance: Ω, capacitance: F)
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