CX77304-15

The CX77304-15 Power Amplifier Module(PAM) is designed in a compact form factor for dual-band cellular handsets comprising GSM850 and PCS1900 operation. It also supports Class 10 General Packet Radio Service (GPRS) multislot operation. The module consists of separate Heterojunction Bipolar Transistor (HBT) PA blocks for the GSM850 and PCS1900 bands, interface circuitry, and RF input and output ports internally matched for 50 Ω impedance to reduce the number of external components.

CX77304-15 PA blocks are fabricated on a single Gallium Arsenide (GaAs) die and share common power supply pins for current distribution. Extremely low leakage current (2 µA, typical) of the dual PA module maximizes handset standby time.

The CX77304-15 also contains band-select switching circuitry to select GSM (logic 0) and PCS (logic 1) as determined from the Band Select (BS) signal. In the block diagram shown below, the BS pin selects the PA output (PCS OUT or GSM OUT) while the Analog Power Control (APC) controls the level of output power. A custom CMOS IC provides the internal interface circuitry including a current amplifier that minimizes the required power control current (IAPC) to 10 µA, typical. The GaAs die, the Silicon (Si) die, and passive components are mounted on a multi-layer laminate substrate and the assembly encapsulated with plastic overmold.