The SKY78191-21 SkyOne® Multimode Multiband Tx-Rx Front-
End Module (FEM) supports 2G / 3G / 4G mobile devices and
operates efficiently in 3G/4G modes. The FEM consists of a lowband
3G/4G PA block, low- and high-band 2G PA blocks, a silicon
controller containing the MIPI RFFE interface, RF band switches,
antenna switches, a bi-directional coupler, and integrated filters
for Bands 8, 12, 20 and 26. Extremely low leakage current
maximizes device standby time.
The IC die and passive components are mounted on a multi-layer
laminate substrate. The assembly encapsulated in a 7.6 mm x 6.0
mm x 0.75 mm, 56-pad MCM, SMT plastic package allows a
highly manufacturable, low cost solution.
The SKY78191-21 FEM is optimized for LTE Advanced which
utilizes Carrier Aggregation for higher data rates. The combined
filtering, RF matching, and TRx switching internal to the FEM
optimizes performance for popular Downlink (DL) CA band
combinations, all in a compact and low cost solution. The FEM
contains necessary components between the antenna and RFIC
transceiver and is optimized to provide superior Rx sensitivity and
Selecting the linear-GMSK operation standard disables VRAMP
input, so all PA biasing depends only on MIPI mode selection. The
transmitted envelope is then a linear function of RF input.
Selecting VRAMP-enabled operation, the PA controller provides
VRAMP control of the GMSK envelope and reduces sensitivity to
input drive, temperature, power supply, and process variations.
Skyworks’ Finger-Based Integrated Power Amplifier Control
(FB-iPAC) minimizes output power variation into mismatch.
In EDGE linear mode, VRAMP voltage and MIPI-based bias
settings jointly optimize PA linearity and efficiency.
Exceptional RF coexistence planning and system techniques are
employed to minimize Rx de-sensitizing ("de-sense").