The SKY68000-31 is a hybrid, dual-band multi-chip RF front-end
(RFFE) module supporting cellular LTE-M/NB-IoT
(half-duplex system) transceiver platforms. The module integrates
the entire RF front end necessary for an LTE dual-band radio
operating in Band 13 and Band 4 including Rx SAW filters,
dual-band PA with bias controller, Tx low-pass harmonic filter,
antenna switch, and MIPI RFFE controller.
The PA load-line
is optimized for high efficiency while
simultaneously meeting 3GPP ACLR and emissions mask
specifications with LTE up to 6 RB. An integrated LPF is
implemented to reject the PA and transceiver harmonics while at
the same time minimizing any post PA loss for an optimized
transmit current consumption. Out-of-band emissions
performance is emphasized by the design to be compliant for
Band 13 and Band 4.
Receive SAW filters are integrated in to the module along with the
necessary matching, yielding a 50 Ω single-ended impedance for
the antenna and Rx ports. The SAW filters provide a high level of
rejection to out-of-band interferers protecting the transceiver from
high blocking signal levels and to support 3GPP LTE blocking test
conformance. The Rx SAW filters cascaded with the low throw
count switch establishes a lower insertion loss and noise figure
than conventional LTE receivers.
MIPI RFFE Controller Interface
The SKY68000-31 functional operation is fully controllable by a
single MIPI interface which is used to drive the PA in various
optimized bias modes as well as providing band selection and
controlling the antenna switch Tx, Rx, and band selection.