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.

Tx Section
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.

Rx Section
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.