AD8347 Down conversion wideband quadrature demodulator 800MHz～2.7GHz IQ Demodula

Description

AD8347 Down conversion wideband quadrature demodulator 800MHz～2.7GHz IQ Demodula
1、 Product application
AD8347 is a single-chip down conversion wideband quadrature demodulator produced by ad company. The chip can receive RF input in the range of 800mhz-2.7ghz, and downconvert the input signal into mutually orthogonal baseband (if) I / Q components.
The chip has the following characteristics:
(1) The chip has high integration, simple peripheral circuit, small circuit size and low power consumption. Ad 8347 integrates RF controlled gain amplifier (AGC), quadrature down converter, local oscillation driver, DC offset zero adjustment circuit, and dual channel differential output amplifier with adjustable DC common mode level. The chip even integrates a basic live level detector. The chip can provide the maximum gain of 70dB. Therefore, only a single chip ad 8347, a small amount of peripheral components, a LNA and a lo circuit are needed to form a complete receiver system. The volume of the whole receiver can be minimized. When the AD8347 is supplied with 5V voltage, the typical working current is 64ma and the power consumption is only 320MW.
(2) The RF signal input port and LO signal input port of ad 8347 have two modes of differential input and single ended input, which can be driven by different LNA and VC o; similarly, the baseband output port of the chip also has two modes of differential output and single end output, which can drive a variety of ADC.
(3) It can be applied to various signal output modes of RF circuit. Ad 8347 is not only suitable for analog single channel signal output mode, but also suitable for analog dual channel signal output mode. As we all know, the analog dual channel signal output mode requires that the I / Q two-way output signals have excellent phase and amplitude balance. The chip can control the quadrature phase accuracy within 1 ° and the I / Q amplitude imbalance below 0.3d B, which meets this requirement well.
(4) Ad 8347 provides a variable gain range of 70dB. In most of the operating ranges of the chip, there is a good linear relationship between the gain and the control voltage. Therefore, the chip can easily realize complex wide dynamic range receiver design.
Ad 8347 has the following four characteristics:
① It has the advantages of high integration, simple peripheral circuit, small circuit size and low power consumption; ② the input / output ports have two modes of differential and single ended; ③ it can be applied to various signal output modes of RF front-end circuit; ④ it has a variable gain range of 70dB. It is a very easy to use AGC device.
Application range:
1. Cellular base station
2. Wireless link
3. Wireless local loop
4. If broadband demodulator
5. Radio frequency instrument
6. Satellite modem
2、 Product picture:
3、 Technical index
1. Supply voltage + 5V DC (typical current 64ma)
2. Working frequency: 800mhz-2.7ghz, input: 50 ohm;
3. Maximum input power: 10dBm;
4. Variable gain range: 69.5db
5. Control voltage range (0-1.2vdc), negative gain mode, internal potentiometer or external Da for program control
6. Provide PDF file schematic diagram
7. It can be configured into AGC mode and VCA mode
4、 Mode configuration
1. AGC mode: connect J3, J5, J8, J9 on the front and J10 and J2 on the back, and disconnect the front J7 to configure AGC mode.
2. VGA mode: connect front J3, J7 and back J10 and J2, disconnect front J5, J8 and J9, and configure AGC mode.
3. Due to the flexible application of AD8347, you can refer to PDF for specific settings
5、 AD8347 test record
Test environment:
(1)RF:800MHz  -30dBm  LO:801MHz  -8dBm
(2)RF:1000MHz -30dBm  LO:1001MHz -8dBm
(3)RF:1000MHz -30dBm  LO:1000.1MHz -8dBm
(4)RF:2700MHz  -30dBm  LO:2701MHz  -8dBm
RF:2700MHz -30dBm LO:2700.1MHz -8dBm
）
It can be seen from the figure that the phase difference between the two IQ signals is 90 degrees, and the orthogonal demodulation is realized. After testing, it is proved that the input is from - 60dbm to 10dBm,
When the frequency changes from 800MHz to 2700mhz, it can be demodulated well, and there is no obvious distortion in the frequency range of 20MHz.
（
RF:1000MHz  -30dBm   LO:1020MHz  -8dBm
）
（
RF:1000MHz  -30dBm   LO:1005MHz  -8dBm
）
It can be seen from the above figure that the effect of the filter on the I-channel signal (blue) is obviously better. Of course, adding the filter is at the cost of the loss of signal amplitude.
(7) Voltage control gain test
RF:1000MHz  -30dBm   LO:1005MHz  -8dBm
When J5, J8, J9 are disconnected and J6 is connected, the amplitude of output signal can be adjusted by adjusting potentiometer R6.