RF142

RF142 Heterojunction Bipolar Transistor Power Amplifier Dual-Band Controller for GSM and PCS Applications The RF142 Power Amplifier (PA) controller is a highly integrated, monolithic device optimized for use in 900 MHz, 1800 MHz, and 1900 MHz Global System For Mobile communications® (GSM®) and other Time Division Multiple Access (TDMA) applications. The control current output from the RF142 can be used to control the transmit power of a dual or multi-band Heterojunction Bipolar Transistor (HBT) PA. The device consists of two sections: an RF detector, and a gain controller. The RF142, when combined with a PA and a coupler, forms a closed PA control loop, where the PA output power is controlled by a single analog reference voltage, typically supplied by the baseband. The RF142 device package and pin configuration are shown in Figure 1. The signal pin assignments and functional pin descriptions are specified in Table 1. An RF142 block diagram is shown in Figure 2. Features RF PA controller for use with HBT PAs 50 dB detector dynamic range Broadband, logarithmic power detector (800 MHz to 2000 MHz) Logarithmic RF power detector requires no external diodes Integrator and gain shaping block enhance loop stability and linearity Three-cell battery operation (2.7 V to 5.0 V) Standby mode with 20 µA of current consumption 20-pin Thin Shrink Small Outline Package (TSSOP) Applications Transmit power control for dual or multi-band GSM digital cellular handsets G ND1 V...