LA7780M [SANYO]
QPSK Downconverter for CATV Systems; QPSK下变频器的CATV系统
| 型号： | LA7780M |
| 厂家： | 
SANYO SEMICON DEVICE |
| 描述： | QPSK Downconverter for CATV Systems |
| 文件： | 总9页 (文件大小：192K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Ordering number : EN5268A
Monolithic Linear IC
LA7780M
QPSK Downconverter for CATV Systems
Overview
Functions
• Preamplifier
The LA7780M is a downconverter for QPSK data
demodulation for digital CATV transmission. This IC
integrates a preamplifier, an AGC amplifier, a mixer, an
oscillator, a post-amplifier, and other circuits in a single
chip, and provides all the functions required from cable
signal input through output to the A/D converter.
• AGC amplifier
• Mixer
• Oscillator
• Post amplifier
• IF AGC (internal/external)
• AGC detector
Features
Package Dimensions
unit: mm
• Since a preamplifier is built in, the LA7780M has
adequate sensitivity to handle the input signal from the
cable directly.
3108-MFP24D
(Input signal level:–30 to +30 dBm)
[LA7780M]
• Both internal and external AGC are supported as the
AGC amplifier drive technique.
24
13
• The output amplitude of the post amplifier used to drive
the A/D converter is 2 Vp-p (typical).
• Applications can be designed to use either a crystal or an
inductor oscillator.
1
12
15.3
0.25
0.4
1.27
0.67
Specifications
Maximum Ratings at Ta = 25°C
SANYO: MFP24D
Parameter
Maximum supply voltage
Symbol
Conditions
Ratings
Unit
V
V
CC max
V max
I4
Pins 5, 6, and 17
Pins 4, 12, and 24
7.0
VCC
30
Circuit voltage
V
The pin 4 output current
The pin 13 sink current
The pin 16 sink current
Ta ≤ 70°C
mA
mA
mA
mW
°C
Circuit current
I13
2
I16
2
Allowable power dissipation
Operating temperature
Storage temperature
Pd max
Topr
Tstg
540
–20 to +70
–55 to +150
°C
Any and all SANYO products described or contained herein do not have specifications that can handle
applications that require extremely high levels of reliability, such as life-support systems, aircraft’s
control systems, or other applications whose failure can be reasonably expected to result in serious
physical and/or material damage. Consult with your SANYO representative nearest you before using
any SANYO products described or contained herein in such applications.
SANYO assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other
parameters) listed in products specifications of any and all SANYO products described or contained
herein.
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN
D1698RM (OT) No. 5268-1/9
LA7780M
Operating Conditions at Ta = 25°C
Parameter
Recommended supply voltage
Operating supply voltage range
Symbol
VCC
Conditions
Ratings
5.0
4.5 to 5.5
Unit
V
Pins 5, 6, and 17
Pins 5, 6, and 17
V
CC op
V
AC Characteristics at Ta = 25°C, V = 5.0 V, internal AGC mode, Pin 24 is left open.
CC
Ratings
typ
80
Parameter
Symbol
Conditions
Unit
min
64
max
95
Circuit current
Itotal
f(in)
Pins 4, 5, 6, and 17: no signal
Pins 1, 8, and 9
mA
MHz
Vp-p
dB
RF input frequency range
IF output level
30
1.6
40
150
2.5
VO(IF)
Pin 13: *1
2.0
IF output IM3
VO(IM3) Pin 13: *2
IF output frequency bandwidth
Local oscillator frequency range
AGC amplifier input sensitivity
AGC range
BW
Pin 13: *3
15
MHz
MHz
dBmV
dB
f(LO)
Pins 18, 19, 20, and 21
30
200
–17
Vin(RF2) Pins 8 and 9: *4
–25
60
–21
80
GR
Pin 13: IF output level < ±1 dB
Pin 13: Compare with the state when
Vin (RF2) = 30 dBmV
AGC flatness
∆VO(IF)
–1
0
+1
21
dB
Preamplifier gain
G(RF1)
VOmax
Pin 4: *5
Pin 4: *6
17
50
19
dB
Maximum preamplifier output level
dBmV
Pin 23: The pin 23 frequency is 1/2 that of
the local oscillator
Oscillator output level
VO(OSC)
500
800
1000
mVp-p
Operating Modes
Mode
Pin 10
GND
Pin 11
Pin 12
Connected to pin 11
With a capacitor between
pin 11 and ground
Internal AGC
External AGC
(Narrow control range: 3 to 5 V)
GND
With a capacitor between
pin 11 and ground
External AGC voltage supply
Pin 12 = high impedance
(AGC divider inactive)
External AGC
(Wide control range: 0 to 5 V)
Open
(AGC divider active)
With a capacitor between
pin 11 and ground
External AGC voltage supply
Pin 12 = low impedance (14 kΩ)
Internal AGC
GC
Note: In internal AGC mode, the IF output level can be adjusted by varying the pin 24 DC voltage.
Caution:
Note 1.
Other conditions:
Input: SG = 69.55 MHz, 20 dBm V
Internal AGC mode
Pin 24 left open.
Output: The post amplifier output (pin 13) at 5 MHz
Transfer ratio = 1 : 1
No. 5268-2/9
LA7780M
Note 2.
Input: SG1 = 69.55 MHz, SG2 = 70.55 MHz
Other conditions:
Internal AGC mode
Pin 24 left open.
Output: The post amplifier output (pin 13)
Point
= 20 dBmV (69.55 MHz) + 20 dBmV (70.55 MHz)
Note 3.
Post amplifier output level = –3 dB
Remove the low-pass filter between pins 14 and 16.
Short the coil of 27 µH and remove the capacitors of 27 pF and 15 pF.)
(
Note 4.
Input: SG1 = 69.55 MHz
Other conditions:
Internal AGC mode
Pin 24 left open.
Output: The signal level such that the post
amplifier output (pin 13) falls by –3 dB.
Note 5.
SG = 75 MHz, 20 dBm V
Note 6.
SG1 = 75 MHz, SG2 = 76 MHz,
Adjust the pin 1 level until the IM3 in the pin 4 output is 40 dB.
Output:RF1-OUT (pin 4)
VO(IM3) = 40 dB
No. 5268-3/9
LA7780M
Pin Assignment
Top view
Usage Notes
• The oscillator may stop if the power supply rise time is extremely short. To prevent this problem, insert a 500 kΩ
resistor between pin 18 and ground or between pin 21 and ground. (This applies when a crystal oscillator is used.)
• This IC should be used with the pin 13 output level between 1 Vp-p and 2 Vp-p.
• Use a low-pass filter with a 6-dB attenuation between pins 14 and 16.
• Since the high-frequency process is adopted, care must be taken to prevent the influence of static electricity.
Block Diagram
No. 5268-4/9
LA7780M
Pin Descriptions
Pin No.
Function
Pin voltage (V)
Note
Equivalent circuit
1
RF1 input
2.8
2
3
RF gain
1.3
Impedance connected to pin 2 must be > 45 Ω
GND
0
4
RF1 output
Open collector
VCC
VCC
5
6
7
5.0
5.0
0
GND
8
9
RF2 input (1)
RF2 input (2)
2.5
2.5
V = 2.5 V
R = 1 kΩ
Pin 10 → GND : Internal or external AGC
Internal/external
AGC switch
0 (GND)
(narrow control range)
10
1.0 (open)
Pin 10 → open : External AGC (wide control range)
I1 = 20 µA
11
12
AGC filter 2
AGC filter 1
Open collector
I2 = 100 µA
Open base
(Pin 10 → GND)
4.0 (Pin 10 open)
I3, I4 & Q1 are switched on and off by pin 10.
Continued on next page.
No. 5268-5/9
LA7780M
Continued from preceding page.
Pin No.
Function
Pin voltage (V)
2, 3
Note
Equivalent circuit
R = 30 Ω
13
Post-amp output
I = 7 mA
V = 2.1 V
14
Post-amp input
2.0
R = 300 Ω
15
16
17
GND
IF output
VCC
0
R = 100 Ω
1.7
I = 3.5 mA
5.0
3.0
18
19
20
21
Oscillator input 4
Oscillator input 3
Oscillator input 2
Oscillator input 1
V = 3.0 V
R = 5 kΩ
I = 1 mA
3.0
0
22
23
GND
R = 100 Ω
Divider output
3.3
I = 1 mA
Output level
adjustment
24
2.5
R = 25 kΩ
No. 5268-6/9
LA7780M
Test Circuit
No. 5268-7/9
LA7780M
Sample Application Circuit
No. 5268-8/9
LA7780M
Specifications of any and all SANYO 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.
SANYO Electric Co., Ltd. strives to supply high-quality high-reliability products. However, any and all
semiconductor products fail with some probability. It is possible that these probabilistic failures could
give rise to accidents or events that could endanger human lives, that could give rise to smoke or fire,
or that could cause damage to other property. When designing equipment, adopt safety measures so
that these kinds of accidents or events cannot occur. Such measures include but are not limited to protective
circuits and error prevention circuits for safe design, redundant design, and structural design.
In the event that any or all SANYO products (including technical data, services) described or contained
herein are controlled under any of applicable local export control laws and regulations, such products must
not be exported without obtaining the export license from the authorities concerned in accordance with the
above law.
No part of this publication may be reproduced or transmitted in any form or by any means, electronic or
mechanical, including photocopying and recording, or any information storage or retrieval system,
or otherwise, without the prior written permission of SANYO Electric Co., Ltd.
Any and all information described or contained herein are subject to change without notice due to
product/technology improvement, etc. When designing equipment, refer to the “Delivery Specification”
for the SANYO product that you intend to use.
Information (including circuit diagrams and circuit parameters) herein is for example only; it is not
guaranteed for volume production. SANYO believes information herein is accurate and reliable, but
no guarantees are made or implied regarding its use or any infringements of intellectual property rights
or other rights of third parties.
This catalog provides information as of October, 1998. Specifications and information herein are subject
to change without notice.
PS No. 5268-9/9
相关型号：
©2020 ICPDF网 联系我们和版权申明