BCM43903 Datasheet, PDF (39/87 Pages) Cypress Semiconductor – WICED™ IEEE 802.11 b/g/n SoC with an Embedded Applications Processor

BCM43903 Preliminary Data Sheet
WLAN Radio Subsystem
Section 8: WLAN Radio Subsystem
The BCM43903 includes an integrated WLAN RF transceiver that has been optimized for use in 2.4 GHz
Wireless LAN systems. It has been designed to provide low-power, low-cost, and robust communications for
applications operating in the globally available 2.4 GHz unlicensed ISM band. The transmit and receive sections
include all on-chip filtering, mixing, and gain control functions.
Ten RF control signals are available to drive external RF switches. See the reference board schematics for more
information.
A block diagram of the radio subsystem is shown in Figure 10 on page 39. Note that integrated on-chip baluns
(not shown) convert the fully differential transmit and receive paths to single-ended signal pins.
Receiver Path
The BCM43903 has a wide dynamic range, direct conversion receiver that employs high-order on-chip channel
filtering to ensure reliable operation in the noisy 2.4 GHz ISM band. The 2.4 GHz path has a dedicated on-chip
low-noise amplifier (LNA).
Transmit Path
Baseband data is modulated and upconverted to the 2.4 GHz ISM band. Linear on-chip power amplifiers deliver
high output powers while meeting IEEE 802.11b/g/n specifications without the need for external PAs. When
using the internal PA, which is required in the 2.4 GHz band, closed-loop output power control is completely
integrated.
Calibration
The BCM43903 features dynamic and automatic on-chip calibration to continually compensate for temperature
and process variations across components. These calibration routines are performed periodically during the
course of normal radio operation. Examples of some of the automatic calibration algorithms are baseband filter
calibration for optimum transmit and receive performance and LOFT calibration for carrier leakage reduction. In
addition, I/Q calibration and VCO calibration are performed on-chip. No per-board calibration is required during
manufacturing testing. This helps to minimize the test time and cost in large-volume production environments.
Broadcom^®
March 12, 2016 • 43903-DS102-R
BROADCOM CONFIDENTIAL
Page 38