Isl3985, a large power amplifier with integrated detector, is introduced by INTERSIL company. This new power amplifier is used with prism wireless local area network (WLAN) chipset and works in 2.4GHz frequency band. Its high output power can increase the distance by 15% and double the data throughput in the maximum range.
The main features are: 2.7-3.6v single power supply, 21dBm output power for DSSS signal, ACPR of the first / second sidelobe is less than – 30dbc / – 50dbc, two-stage power gain is 28dB, linear input power of detector is 15dB, CMOS level is compatible. Its package is a 5x5mm lead-free QFN package with 16 pads, which occupies small space and has high heat dissipation efficiency. Therefore, it can be used in IEEE 802.11b, 11Mbps and 54Mbps standard access point and WLAN card, 2.4GHz ISM band and TDMA packet protocol radio transmission.
Isl3985rfpa optimizes its performance by setting the bias current by adjusting the external low temperature coefficient resistor. The on-chip bias network provides optimal bias current and temperature compensation.
The power detection of isl3985 provides a DC output voltage proportional to the logarithm of the output power. When the output power is 21dBm, the detection accuracy of the detector is within 0.5dB. The slope of the detector output voltage is 100 mV / DB in the whole 15 dB dynamic range. The purpose of the detector is to optimize the output power compensation caused by manufacturing deviation.
In the application of prism WLAN, HFA3861B or hfa3863 baseband processor dynamically monitors the output power of isl3985 by using the output of detector. When the AGC voltage of hfa3783if quadrature modem needs to be adjusted, the output voltage will change. This will provide the most possible error free data transmission rate in a certain working environment, and compensate for channel to channel and temperature related changes in the transmission chain.
Editor in charge: GT