Abstract: The WiBro reference design is a complete RF front-end solution designed to meet requirements for the WiBro 2.3GHz to 2.4GHz mobile WMAN (Wireless Metropolitan Area Network) standard. This reference design uses the MAX2837 direct-conversion transceiver and demonstrates a complete WiBro single-band RF-to-baseband solution. It serves as a platform for designs in multiple form factors such as CardBus, miniPCI, and custom CPE modules. The design can be easily adapted for WiBro-only 3.3V laptop applications, or WiBro-only 5.0V CPE applications.
Complete RF-to-Baseband WiBro Solution
+23dBm Transmit Power at 5% EVM and Meets Spectral Mask Requirements
VBATT = +3.6V, VCC = +2.85V, fRF = 2347MHz, VIN = 90mVRMS, WiBro signal, RF specs are antenna referred, TA = +25°CFigure 3. Output EVM for the reference design. The WiBro reference design delivers more than 23dBm of output power at the antenna, while meeting the required EVM specification of 5.5% over the entire 2.3GHz to 2.4GHz band.Figure 4. Transmit capture for the reference design. This capture shows the transmit spectrum, EVM constellation, and spectrum of the reference design at 23dBm of output power at the antenna. Measured EVM = 3.9% at 23dBm at 2.347GHz.Figure 5. 2.35GHz, 10MHz spectral mask using ETSI EN 301 021 F mask. This capture shows that the WiBro reference design meets the ETSI-EN-301-021F spectral mask at 23dBm of output power at the antenna.Figure 6. Receive gain characteristic across the 2.3GHz to 2.4GHz band. Gain variation over frequency is less than 0.2dB. Gain-control range, not including LNA gain steps, is 62dB, approximately 2dB per gain step.Figure 7. Gain characteristic across three LNA gain attenuations and temperatures. Gain variation over temperature for LNA attenuations 0dB and -16dB is approximately 5dB, and roughly 3dB for -32dB gain attenuation. The WiBro reference design includes the following components: MAX2837 direct-conversion transceiver, Micro Mobio MMPA372X PA, MAX8510 regulators, Murata balanced-to-unbalanced SAW bandpass filters, Hexawave HWS466 SPDT Tx/Rx switch, and Vishay Si1563DH load switch.The MAX2837 is a single-chip, wideband, direct-conversion transceiver designed for 2.3GHz to 2.7GHz WiBro and WiMax radios. The transceiver is fully equipped with an on-chip broadband VCO, fast settling sigma delta RF synthesizer, crystal oscillator, programmable lowpass filters, proprietary DC offset cancellation, I/Q error and carrier leakage detection circuits. The MAX2837 offers less than 1.4% of transmit EVM at -3dBm driver output power, and receive sensitivity better than -79dBm. When integrated with the MMPA372X PA and Murata BPF, the reference design can deliver at least 23dBm of output power at the antenna, while meeting WiBro EVM and spectral-mask requirements with margin.
IEEE is a registered service mark of the Institute of Electrical and Electronics Engineers. SPI is a trademark of Motorola, Inc. WiBro is a trademark of the Telecommunications Technology Association, Republic of Korea. WiMAX is a trademark of the WiMAX Forum.
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