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参数资料
| 型号： | LA1776M |
| 元件分类： | 调谐器 |
| 英文描述： | 2-BAND, AUDIO TUNER, PQFP64 |
| 封装： | 14 X 14 MM, QFP-64 |
| 文件页数： | 17/41页 |
| 文件大小： | 547K |
| 代理商： | LA1776M |
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No.8085-24/41
LA1776M
3-2. Two-Signal Sensitivity Suppression
Like the earlier Sanyo products, the LA1776M's 3D AGC determines the amount of wide-band AGC applied
using the information acquired from three frequency characteristics.
RF and antenna circuit information: Mixer input AGC
Mixer circuit information: Mixer output AGC
<- Three dimensions
CF selectivity: S-meter output
3-3. FE Block AGC
Like the earlier Sanyo products, the LA1776M uses the follow two functions
(1) PIN diode antenna input control
(2) FET second gate control
The AGC input pins are pin 58 (narrow AGC) and pin 55 (wide AGC).
Applying AGC
The PIN diode drive circuit is turned on when (roughly) (VCC – V2) is 1 V or higher.
In application circuits, there will be about 30 to 40 dB of attenuation. When an adequate current flows in the
antenna attenuator PIN diode and the impedance falls, the FET second gate voltage falls, the FET gm falls, and
the AGC operates. The recommended FET is the Sanyo 3SK263, which is an enhanced type MOSFET, and
thus the full AGC will be applied when the voltage between the second gate and the source (G2-S) is 0. Note
that if a depletion type MOSFET were used, AGC would not be applied unless VG2-S were lower than 0 V.
3-4. Mixer
The LA1776M's mixer circuit is a double balanced mixer that used balanced signals for both the input and
output.
Input type: base input
Input impedance: 2 k
7
6
5
4
3
2
1
0
9
8
–20 –10
0
20
30
10
40
50
60
70
80
90
100
110 120 130
Pin 2 voltage
Region where the AGC
does not operate
AGC amount due
to the PIN diode
PIN diode voltage
AGC amount due
to the MOSFET's
second gate.
A
G
C
v
o
lt
a
g
e
–
V
Field strength - dB
OSC
63
64
59
60
2 k
2 k
相关PDF资料 |
PDF描述 |
|---|---|
| LA1776M | 2-BAND, AUDIO TUNER, PQFP64 |
| LA1780M | 2-BAND, AUDIO TUNER, PQFP64 |
| LA1781M | AM/FM, AUDIO SINGLE CHIP RECEIVER, PQFP64 |
| LA1784M | AM/FM, AUDIO SINGLE CHIP RECEIVER, PQFP64 |
| LA1787NM | AM/FM, AUDIO SINGLE CHIP RECEIVER, PQFP64 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LA1776M_09 | 制造商:SANYO 制造商全称:Sanyo Semicon Device 功能描述:Single-Chip Tuner IC for Car Radios |
| LA1776M-MPB-E | 功能描述:调谐器 RoHS:否 制造商:NXP Semiconductors 功能: 噪声系数: 工作电源电压: 最小工作温度: 最大工作温度: |
| LA177B/HG-2 | 制造商:LIGITEK 制造商全称:LIGITEK electronics co., ltd. 功能描述:LED ARRAY |
| LA177B-1-SRG | 制造商:LIGITEK 制造商全称:LIGITEK electronics co., ltd. 功能描述:LED ARRAY |
| LA177B-HG-2 | 制造商:LIGITEK 制造商全称:LIGITEK electronics co., ltd. 功能描述:LED ARRAY |
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