The SKY68001-31 is a hybrid, multi-band multi-chip RF front-end (RFFE) module supporting cellular LTE CatM1/CATNB1 (half-duplex system) transceiver platforms. The module integrates the entire RF front end necessary for an LTE multi-band radio operating in low-band B5/B8/B12/B13/B17/B18/B19/B20/B26 and mid-band B1/B2/B3/B4/B25/B39/B66 frequencies, including Rx low-pass filters, broadband 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 12 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 3GPP-compliant for B5/B8/B12/B13/B17/B18/B19/B20/B26 and mid-band B1/B2/B3/B4/B25/B39/B66.

Rx Section

Receive low-pass filters are integrated into the module along with the necessary matching to yield a 50Ω single-ended impedance for the antenna and Rx ports. The 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 low-pass filters are cascaded with the  low throw count switch to establish a lower insertion loss and noise figure than conventional LTE receivers.


  • Cellular IoT modem devices targeting low-power wide area network (LPWAN):
  • 4G LTE technology capability
  • Dedicated LTE half-duplex operation (HD-FDD) for Cat-M1/Cat-NB1
  • Designed to meet 3GPP Rel-12 and Rel-13 specifications (with compatible cellular transceiver)
  • LTE universal modem products (low-band and mid-band):
  • Low-band B5/B8/B12/B13/B17/B18/B19/B20/B26
  • Mid-band B1/B2/B3/B4/B25/B39/B66
  • PAE optimized for Class 3 LTE output power (+23 dBm)


  • Cost-optimized front end for low-data-rate applications
  • Low-loss post-PA transmit front end for enhanced transmitter efficiency (compared to LTE-FDD radio front ends)
  • Broadband PA supporting APT mode of operation or Vcc fixed supply (≥ 2.85 V)
  • Integrated low-pass filters for harmonic rejection to comply with spurious emission requirements
  • Integrated SP6T antenna Tx/Rx switch
  • Integrated Rx low-pass filters for out-of-band rejection
  • Optimized to support LTE for 1 to 12 RB
  • MIPI RFFE control interface, 2.0 compliant
  • Pin-to-pin compatible with the SKY68000-31 and SKY68011-31
  • Two additional Aux ports offer greater flexibility for more bands on the Tx or Rx path
  • Adaptive biasing scheme for maximum PA efficiencies
  • Small, low-profile package (4 mm x 5 mm x 0.9 mm) (MSL3 @ 260 °C per JEDEC J-STD-020)
  • Lead (Pb)-free and RoHS-compliant