User's Manual

10
¾ UART x2
¾ GPIO x24 (shared)
¾ SPI/PCM
¾ I2C
¾ JTAG
¾ MDC/MDIO
• Packaging
¾ 17mm x 17mm BGA-292 Package
¾ I/O : 3.3V/2.5V(RGMII), 3.3/5V PCI I/O
11b/g/n Transceiver
RT2820 is a monolithic SiGe RF IC that integrates multiple half-duplex
direct-conversion radio transceivers designed for IEEE802.11b/g/n WLAN
systems or other wireless LAN applications operating in 2.4GHz ISM bands.
The IC has two concurrent transmit channels and three concurrent receive
channels. The multiple channels are designed to improve robustness and
throughput during wireless operation. Each receive channel achieves low
noise figure, high input sensitivity, high linearity, and high output
power while consuming low DC power. Each receive path features a gain
selectable, low-noise amplifiers (LNA), followed by RF-to-baseband I/Q
demodulators, discrete-step variable-gain amplifiers and integrated
channel-selection filters. The transmit chain includes integrated
reconstruction filters, a baseband-to-RF I/Q modulator, discrete-step
variable-gain amplifiers for power-level control, and pre-drivers for
external power amplifiers. The modulator and demodulator are driven by
internal VCO. The VCO is phase-locked by an internal 3-wire-interface
PLL. The bandwidth of the integrated channel-selection filters and the
reconstruction filters can be programmed to narrow-band (10MHz) and
wide- band (20MHz). Their bandwidth is calibrated by an internal
autonomous calibration circuit. To help IQ mismatch calibration, a
baseband transmit-to-receive loopback feature is provided. A crystal
oscillator using external crystal and three low dropout regulators (LDO)
are also integrated. The RT2820 is housed in a 76-pin 9x9mm2 leadless
QFN package and is well suited for PCMCIA, MiniPCI, PCI, USB boards or
embedded applications. It is designed to work seamlessly with RT2860B
and RT2880 baseband/Mac IC.
RT2820 Transceiver Features