CX77304-16

The CX77304-16 Power Amplifier Module (PAM) is designed in a compact form factor for tri-band cellular handsets comprising EGSM900, DCS1800, and PCS1900 operation. It also supports Class 10 General Packet Radio Service (GPRS) multislot operation.

CX77304-16 PAM consists of separate Heterojunction Bipolar Transistor (HBT) PA blocks for EGSM900 and DCS1800/PCS1900 PA bands, interface circuitry, and RF input and output ports internally matched to 50 W to reduce the number of external components. The PA blocks are fabricated on a single Gallium Arsenide (GaAs) die. Optimized for lithium ion battery operation, both PA blocks share common power supply pins to distribute current. Extremely low leakage current (2 µA, typical) of the dual PAM maximizes handset standby time.

The CX77304-16 also contains band-select switching circuitry to select EGSM (logic 0) and DCS/PCS (logic 1) as determined from the Band Select (BS) signal. In the block diagram shown below, the BS pin selects the PA output (DCS/PCS OUT or EGSM OUT) while the Analog Power Control (APC) controls the level of output power. A custom CMOS integrated circuit 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.