SKY77354 Power Amplifier Module (PAM) is designed in a compact form factor for quad-band cellular handsets comprising GSM850/900, DCS1800 and PCS1900, supporting fixed gain Gaussian Minimum-Shift Keying (GMSK) and linear Enhanced Data for GSM Evolution (EDGE) modulation. Class 12 General Packet Radio Service (GPRS) multi-slot operation is also supported.
The module consists of GSM850/900 PA and DCS1800/PCS1900 PA blocks, impedance matching circuitry for 50 fi input and output impedances, and a Multi-function Power Amplifier Control (MFC) block. A custom BiCMOS 1C provides the internal MFC function and interface circuitry.
Two separate Heterojunction Bipolar Transistor (HBT) PA blocks are fabricated onto a single InGaP die; one supports the GSM850/900 bands, the other the DCS1800/PCS1900 bands. Both PA blocks share common power supply pads to distribute current. The InGaP and silicon dies and the passive components are mounted on a multi-layer laminate substrate. The entire assembly is encapsulated with plastic overmold.
RF input and output ports of the SKY77354 are internally matched to a 50 Q load to reduce the number of external components. Extremely low leakage current (15 uA, typical) of the PAM module maximizes handset standby time.
The SKY77354 also contains switching circuitry to select GSM or DCS/PCS bands and select high or low power modes.