ADI 公司的調(diào)制器ADL5375和解調(diào)器ADL5382是寬帶無線" title="寬帶無線">寬帶無線基站解決方案，ADL5375工作在400 MHz - 6 GHz，而ADL5382工作在700 -2700MHz。它們具有極好的相位精確度和放大平衡功能，廣泛用于通信系統(tǒng)如GSM/EDGE, CDMA2000, WCDMA, TDSCDMA和WiMAX的高性能" title="高性能">高性能中頻或直接射頻調(diào)制。本文介紹了ADL5375和ADL5382的主要性能，方框圖以及評估板" title="評估板">評估板電路圖。
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1．400 MHz to 6 GHz Broadband Quadrature Modulator ADL5375
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The ADL5375 is a broadband quadrature modulator designed for operation from 400 MHz to 6 GHz. Its excellent phase accuracy and amplitude balance enable high performance intermediate frequency or direct radio frequency modulation for communications systems.
The ADL5375 provides a greater than 500 MHz, 3 dB baseband bandwidth, making it ideally suited for use in broadband zero IF or low IF-to-RF applications and in broadband digital predistortion transmitters. In addition, the ADL5375 offers output gain flatness of ±0.5 dB from 450 MHz to 3 GHz and a broadband output return loss of less than ?15 dB.
The ADL5375 accepts two differential baseband inputs and a single-ended LO and generates a single-ended 50 Ω output. Two versions offer input baseband bias levels of 500 mV (ADL5375-05) and 1.5 V (ADL5375-15).
The ADL5375 is fabricated using an advanced silicongermanium bipolar process. It is available in a 24-lead, exposedpaddle, Pb-free, LFCSP_VQ package. Performance is specified over a ?40°C to +85°C temperature range. A Pb-free evaluation board is ADL5375主要特性" title="主要特性">主要特性：
Output frequency range: 400 MHz to 6 GHz
Modulation bandwidth: 500 MHz (3 dB)
1 dB output compression: ≥ 9.4 dBm from 500 MHz to 4 GHz
Output return loss: ≤ 15 dB from 500 MHz to 5 GHz
Noise floor: ?161 dBm/Hz @ 900 MHz
SB suppression: ≤ ?40 dBc, 450 MHz to 4 GHz and vs. temp
LO leakage: ≤ ?40 dBm, 450 MHz to 2 GHz and vs. temp
Baseband bias levels of 500 mV and 1.5 V
Single supply: 4.75 V to 5.25 V
24-lead LFCSP_VQ package
ADL5375應(yīng)用：
Cellular communications systems
GSM/EDGE, CDMA2000, WCDMA, TDSCDMA
WiMAX/broadband wireless access systems
Multi-band, Multi-standard radios
Satellite modems
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圖1。ADL5375功能方框圖
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圖2。ADL5375評估板電路圖
2．700 to 2700MHz Quadrature Demodulator ADL5382
The ADL5382 is a high performance quadrature I-Q demodulator that covers an RF input frequency range from 700 MHz to 2.7 GHz. With a NF = 14dB, IP1dB = 13dBm and IIP3 = 30dBm, the demodulator offers outstanding dynamic range suitable for the demanding infrastructure direct-conversion requirements. The differential RF inputs provide a well-behaved broad-band input impedance of 50Ω and should be driven from a 1:1 balun for best performance.
Excellent quadrature accuracy is achieved using on-chip poly-phase filters for LO quadrature generation. Over a wide range of local oscillator (LO) levels, excellent demodulation accuracy is achieved with phase and amplitude balances < 0.25 dB and < 0.5o, respectively. The demodulated in-phase (I) and quadrature (Q) differential outputs are fully buffered. The ADL5382 provides voltage conversion gain of 5dB independent of differential load impedances that can be as low as 100 Ω with a drive capability exceeding 2Vpp in to 200 Ω.
The fully balanced design minimizes effects from 2nd order distortion. The leakage from the LO port to the RF port is <-60dBc. Differential DC-offsets at the I and Q outputs are <10mV. Both of these factors contribute to the excellent IIP2 of >60dBm.
The ADL5382 operates off a 4.75V to 5.25V supply. The supply current is programmable with an external resistor from the BIAS pin to ground. The ADL5382 is fabricated using Analog Devices’ advanced Silicon-Germanium bipolar process and is available in a 24-lead exposed paddle LFCSP package. Performance is specified over a -40oC to +85oC temperature range.
ADL5382主要特性：
I/Q Demodulator
Operating RF frequency
700 MHz to 2700MHz
IIP3 +30 dBm
IIP2 +60dBm
Input P1dB +13dBm
NF 14 dB @ 900MHz
Voltage Conversion Gain of 5dB
Quadrature demodulation accuracy
Phase accuracy <0.5°
Amplitude balance <0.25 dB
LO Input –10 to +5 dBm
Demodulation Bandwidth ~500 MHz
I/Q Drive 2Vpk into 200Ω
Programmable Power Consumption
ADL5382主要應(yīng)用：
QAM/QPSK demodulator
W-CDMA/CDMA/CDMA2000/GSM
Point-to-(Multi)Point Radio
WiMax
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圖3。ADL5382方框圖
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圖4。ADL5382評估板電路圖