GaAs Dual-Band Power Amp Simplifies Cell Phone Designs

Both 900 and 1800 MHz amplifiers plus a negative voltage generator have been integrated onto a GaAs chip, allowing new GSM/DCS dual-band cell phone designs to be implemented with a single chip rather than the three chips previously required. The IC meets all 3.6V GSM performance specs. And its voltage generator eliminates the spurious outputs often seen in designs using a separate negative supply voltage. In addition, the chip includes a gate-drain switching function that connects the negative voltage to the gate before the positive supply is connected to the drain, protecting the device from over-current situations.
The MRFIC1859 dual-band integrated power amplifier also exhibits excellent crosstalk performance, with isolation between the two channels pegged at -30 dBm. In 2.0W GSM900 cell phones, the chip can provide peak output power of 3.0W and in 1.0W DCS1800 phones, it can deliver 2.0W. The device is General Packet Radio Service (GPRS) compatible and can also be used in PCS1900 phones. MRFIC1859 comes housed in a new, high-power, low-profile 32-pin TQFP package with a backside metal contact.