Description
The CXG1047FN dual band GaAs PA is a 3-stage power amplifier that may be used for both GSM900 and DCS1800 applications. To achieve minimum die-size and package dimensions, it contains one amplifier chain with a single input and output.
The PA has a single RF input for both the GSM900 and DCS1800 transmit signals. The amplifier can be configured for 2 separate inputs. Power control is best achieved by variation of VDD1/VDD2 and VDD3 drain voltages with an external transistor. A proposed power control circuit configuration is described. External PMOS drain switch should be used to achieve low leakage.

Features
• Single positive rail only
• Typical output power of 35.5dBm at 900MHz and 33dBm at 1800MHz
• Typical efficiency of 37% at 900MHz and 37% at 1800MHz
• Small package size with integral heat-sink: 16-pin HSOF (5.6 × 4.4 × 0.9mm)
• 3-stage amplifier chain
•Simple pin diode circuitry is used to switch between 1800 and 900MHz matching circuits
• Off mode insertion loss typically 27dB at 900MHz (Pin = +6dBm at VDD = 0V)
• Typical transmit noise @20MHz offset –79dBm/100kHz

Applications
    Dual-band handsets transmitting on the GSM900 or DCS1800 frequencies