50 Q nominal input / conjugate matched balun to ST S2-LP, 433 MHz with integrated harmonic filter Features • 50 Q nominal input / conjugate matched to ST S2-LP for 433 MHz frequency operation • Low insertion loss • Low amplitude imbalance • Low phase imbalance Flip-Chip (6 bumps) package • Small footprint • Very low profile < 620 pm after reflow • High RF performance • 433 MHz impedance matched balun filter Pinout diagram - Top view Product status Description This device is an ultra-miniature balun. The BALF-SPI2-02D3 integrates matching network and harmonics filter. Matching impedance has been customized for the ST S2-LP transceiver. The BALF-SPI2-02D3 uses STMicroelectronics IPD technology on non-conductive glass substrate which optimize RF performance. DS12508 - Rev 1 - May 2018 For further information contact your local STMicroelectronics sales office.

1 Characteristics Table 1. Absolute maximum ratings (Tamb = 25 °C)

Figure 3. Amplitude imbalance

1.2 RF measurements (Tx filter) Figure 5. Transmission 0 (dB)

BALF-SPI2-02D3 ST S2-LP application diagram example ST S2-LP application diagram example Figure 8. ST S2-LP application diagram example

2 Package information In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: www.st.com. ECOPACK® is an ST trademark. Table 4. Flip-Chip 6 bumps dimensions (in mm)

BALF-SPI2-02D3 Flip-chip 6 bumps packing information Flip-chip 6 bumps packing information Figure 10. Marking Dot, ST logo ECOPACK grade xx = marking z = manufacturing location yww = datecode Figure 11. Flip Chip tape and reel specifications Dot identifying Pin All dimensions are typical values in mm User direction of unreeling

3.1 Land pattern Figure 12. Recommended balun land pattern (*)Clearance 250ym is needed to ensure good sensitivity. (**)1000 ym length between S2-LP & balun (between center QFN pads to center IPD pads). Figure 13. PCB stack-up recommendations Bottom plane 35um + 31 um GND plane

BALF-SPI2-02D3 Stencil opening design Stencil opening design Figure 14. Footprint - 3 mils stencil -non solder mask defined Copper pad diameter: 220 µm recommended 180 µm minimum 260 µm maximum Solder mask opening: 320 µm recommended 300 µm minimum 340 µm maximum Solder stencil opening: 220 µm recommended Figure 16. Footprint - 5 mils stencil -non solder mask defined Copper pad diameter: 220 µm recommended 180 µm minimum 260 µm maximum Solder mask opening: 320 µm recommended 300 µm minimum 340 µm maximum Solder stencil opening: 330 µm recommended* *depending on paste, it can go down to 270 µm...

Manual positioning is not recommended. It is recommended to use the lead recognition capabilities of the placement system, not the outline centering Standard tolerance of ±0.05 mm is recommended. 1.0 N placement force is recommended. Too much placement force can lead to squeezed out solder paste and cause solder joints to short. Too low placement force can lead to insufficient contact between package and solder paste that could cause open solder joints or badly centered packages. To improve the package placement accuracy, a bottom side optical control should be performed with a high resolution...

4 Ordering information Table 5. Ordering information

BALF-SPI2-02D3 Revision history Table 6. Document revision history

IMPORTANT NOTICE – PLEASE READ CAREFULLY STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, enhancements, modifications, and improvements to ST products and/or to this document at any time without notice. Purchasers should obtain the latest relevant information on ST products before placing orders. ST products are sold pursuant to ST’s terms and conditions of sale in place at the time of order acknowledgement. Purchasers are solely responsible for the choice, selection, and use of ST products and ST assumes no liability for application assistance...