BCM43907 Preliminary Data Sheet
WLAN Radio Subsystem
Section 8: WLAN Radio Subsystem
The BCM43907 includes an integrated dual-band WLAN RF transceiver that has been optimized for use in
2.4 GHz and 5 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 or 5 GHz U-NII
bands. 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. In addition, these control signals can be used
to support optional external 5 GHz band power and low-noise amplifiers. See the reference board schematics
for more information.
A block diagram of the radio subsystem is shown in Figure 14 on page 52. Note that integrated on-chip baluns
(not shown) convert the fully differential transmit and receive paths to single-ended signal pins.
Receiver Path
The BCM43907 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 or the entire 5 GHz U-NII band. The 2.4 GHz
and 5 GHz paths each have a dedicated on-chip low-noise amplifier (LNA).
Transmit Path
Baseband data is modulated and upconverted to the 2.4 GHz ISM or 5 GHz U-NII bands, respectively. Linear
on-chip power amplifiers deliver high output powers while meeting IEEE 802.11a/b/g/n specifications without the
need for external PAs. When using the internal PA, which is required in the 2.4 GHz band and optional in the
5 GHz band, closed-loop output power control is completely integrated.
Calibration
The BCM43907 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 • 43907-DS104-R
Page 51
BROADCOM CONFIDENTIAL
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