LTE Dual-Band Front-End Module for IoT

The SKY68000-21 is a hybrid, dual-band multi-chip RF front-end (RFFE) module supporting cellular LTE for CAT0/CATM1/CATNB1 (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 36 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 into the module along with the necessary matching to yield 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 guaranteeing 3GPP LTE blocking test conformance. The Rx SAW filters are cascaded with the low throw count switch to establish a lower insertion loss and noise figure than conventional LTE receivers.

MIPI RFFE Controller Interface

The SKY68000-21 functional operation is fully controllable by a single MIPI interface that is used to drive the PA in various optimized bias modes, to provide band selection, and to control the antenna switch Tx, Rx, and band selection.


  • 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)
  • Dual-band 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 SP4T antenna Tx/Rx switch
  • Integrated Rx SAW filters for out of band rejection for both Band 13 and Band 4
  • Optimized to support LTE for 1 to 36 RB
  • MIPI RFFE control interface, 2.0 compliant
  • Lead (Pb)-free and RoHS-compliant
  • Pin-to-pin compatible with the SKY68001-11 and SKY68011-11
  • 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)
Product Summary SKY68000-21: LTE Dual-Band Front-End Module for IoT SKY68000_21_204391C_PS.pdf (139 KB)
ProductName : SKY68000-21
Frequency (MHz) : 777-787
Description : LTE B4/B13 FEM for IoT
Typical Linear LTE Power
(dBm) :
Supply Voltage (V) : 2.85-3.3
Package (mm) : 24-pad MCM, 4 x 5 x 0.9
Product Information: New
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