CC26xx HW Training RF Front End options and Antennas Fredrik Kervel, Bluetooth Smart Applications 1 Reference Schematic VDD_EB VDDS Decoupling Capacitors VDDS Pin 11 Pin 28 C2 C3 C4 C6 C7 DNM 100nF 100nF 10uF 100nF BLM18HE152SN1 2 1 FL1 Pin 18 DCDC_SW2 VDDS VDDS R1 100k 6 DIO_0 7 DIO_1 8 DIO_2 9 DIO_3 10 DIO_4 15 DIO_5/JTAG_TDO DIO_6/JTAG_TDI16 20 DIO_7 21 DIO_8 22 DIO_9 23 DIO_10 24 DIO_11 25 DIO_12 26 DIO_13 27 DIO_14 nRESET JTAG_TCK JTAG_TMS C20 100nF 19 14 13 12 C19 1uF 33 U1 DIO_0 DIO_1 DIO_2 DIO_3 DIO_4 DIO_5 DIO_6 DIO_7 DIO_8 DIO_9 DIO_10 DIO_11 DIO_12 DIO_13 DIO_14 RESET_N JTAG_TCKC JTAG_TMSC VDDR VDDS VDDS2 VDDS_DCDC VDDR VDDR DCDC_SW RX_TX RF_N RF_P X24M_P X24M_N X32K_Q2 X32K_Q1 L1 10uH Place L1 and C8 close to pin 17 10uF 100nF C10 C16 100nF DNM C31 17 DCDC_SW L21 2.4nH 3 2 1 RFN 6.8pF A1 C21 1 2 1 1pF 1 L10 6.8nH X24M_P X24M_N RFP 5 4 2 C11 VSS CC2650F128RHB 1 L11 2.4nH 2 L12 2 1 C12 2nH C13 DNM 1pF L13 2nH 2 C14 R12 12pF 0 3 1 C15 2.4GHz DNM R12 and C15 for antenna matching Y2 24MHz Y1 1 32.768kHz Pin 32 2 DCOUPL 12pF C9 RX_TX 1pF C17 C8 VDDR 28 11 18 29 32 31 30 VDDR Decoupling Capacitors Pin 29 1 3 C18 12pF 2 4 2 RF pins RF_P: RF positive output / input RF_N: RF negative output / input RX_TX: Optional RF bias pin Several options on output configuration: 6 7 8 9 10 15 16 20 21 22 23 24 25 26 27 19 14 13 12 33 U1 DIO_0 DIO_1 DIO_2 DIO_3 DIO_4 DIO_5 DIO_6 DIO_7 DIO_8 DIO_9 DIO_10 DIO_11 DIO_12 DIO_13 DIO_14 RESET_N JTAG_TCKC JTAG_TMSC DCOUPL VSS VDDS VDDS2 VDDS_DCDC VDDR VDDR DCDC_SW RX_TX RF_N RF_P X24M_P X24M_N X32K_Q2 X32K_Q1 28 11 18 29 32 17 3 2 1 31 30 - Differential output: Both RF pins are used and a balun + a pi-filter is required between the CC26xx and the antenna - Single ended output: Only one of the RF pins is used for RF output. Only a pi-filter is required between the CC26xx and the antenna. Output power is reduced and sensitivity is degraded - External biasing of the RF pins can be applied through the RX_TX pin. This will improve sensitivity, but requires an additional inductor. - For single ended configuration, the unused RF pin may alternatively be used as bias pin - RX_TX can be used for external control of for example an RF switch RX_TX RFN RFP 5 4 CC26xx-5x5 Note: - The CC26xx 7x7 package does not have RX_TX-pin, while the CC13xx 7x7 package does. 3 RF Frontend options External bias - BLE: 1 6.8pF L21 2.4nH RX_TX RFN RFP Sensitivity: Sensitivity: C31 1 1 1pF L10 6.2nH 2 1 L11 1 L12 2 2nH 2 2 C13 2nH C14 ANT RF_N RF_P 12pF 1pF 2.7nH C11 1 L13 -96 dBm - Zigbee: -97 dBm - Zigbee: -100 dBm C21 2 - BLE: -97 dBm L21 15nH 2 1 L12 C14 2 ANT C12 2nH C13 1.2pF 1.2pF 12pF 1pF Sensitivity: Sensitivity: Internal bias C31 - BLE: 1 6.8pF L21 2.4nH RFN RFP 1pF 1 C11 L11 1 2 L12 2 2nH 2.7nH 1 L13 C13 2nH 1pF 2 C14 ANT 12pF -94 dBm - Zigbee: -95 dBm - Zigbee: -99 dBm C21 2 - BLE: -96 dBm RF_P 1 L12 C14 2 ANT C12 2nH C13 1.2pF 1.2pF 12pF 1pF Pout_max = 5 dBm Differential output Pout_max = 2 dBm Single-ended output 4 RF Frontend options Differential Single Ended Ext. Bias Int. Bias Ext. Bias Int. Bias Output Power 5 5 2 2 [dBm] BLE Sensitivity -97 -96 -96 -94 [dBm] Zigbee Sensitivity -100 -99 -97 -95 [dBm] Inductors 5 4 2 1 Capacitors 5 5 3 3 10 9 5 4 5 Antennas for 2.4 GHz • PCB antennas – – – – DN007 Low (no) cost Simple to integrate (follow the reference design ) Good performance TI reference design for two different sizes which typically fits within customer requirements (board space), DN007 and AN043 – Application Notes: • DN007: http://www.ti.com/litv/pdf/swru120b • AN043: http://www.ti.com/litv/pdf/swra117d • Antenna selection guide: http://www.ti.com/litv/pdf/swra161b • Chip antennas – – – – AN043 Can be used in applications where size is critical Performance is comparable to PCB antennas (depending on size) Cost is (obviously) higher Contact antenna manufacturer for recommendations • Johanson, TDK, etc. • Antenna tuning – Required for both PCB- and chip antennas – Can be don with matching network..... – ..... or Antenna length (PCB antennas) 6 Available reference designs • CC2650EM-7ID (7x7, Internal bias, Differential output) • CC2650EM-5XD (5x5, External bias, Differential output) • CC2650EM-4XS (4x4, External bias, Single ended output) • CC2650EM-Murbal (5x5, Internal bias, Integrated balun) 7