Flip-Chip (6 bumps) package
TX
GND
RXP RXN
GND
ANT
Pinout diagram - Top view
Features
• 50 Ω nominal input / conjugate matched to ST S2-LP for 433 MHz frequency
operation
• Low insertion loss
• Low amplitude imbalance
• Low phase imbalance
• Small footprint
• Very low profile < 620 μm after reflow
• High RF performance
• RF BOM and area reduction
•ECOPACK®2 compliant component
Applications
• 433 MHz impedance matched balun filter
• Optimized for ST S2-LP sub GHz RFIC
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.
Product status
BALF-SPI2-02D3
50 Ω nominal input / conjugate matched balun to ST S2-LP, 433 MHz with
integrated harmonic filter
BALF-SPI2-02D3
Datasheet
DS12508 - Rev 1 - May 2018
For further information contact your local STMicroelectronics sales office.
www.st.com
1Characteristics
Table 1. Absolute maximum ratings (Tamb = 25 °C)
Symbol Parameter Value Unit
PIN Input power RFIN 20 dBm
VESD
ESD ratings human body model (JESD22-A114), all I/O one at a time while others connected to
GND 2000
V
ESD ratings machine model (JESD22-A115), all I/O 200
TOP Operating temperature -40 to +105 °C
Table 2. Impedances (Tamb = 25 °C)
Symbol Parameter
Value
Unit
Min. Typ. Max.
ZRX Nominal differential RX balun impedance
- matched ST S2-LP - Ω
ZTX Nominal TX filter impedance
ZANT Antenna impedance - 50 - Ω
Table 3. Electrical characteristics and RF performances (Tamb = 25 °C)
Symbol Parameter Test condition
Value
Unit
Min. Typ. Max.
f Frequency range 433 MHz
ILRX-ANT Insertion loss in bandwidth without mismatch loss (RX balun) 1.95 2.20 dB
ILTX-ANT Insertion loss in bandwidth without mismatch loss (TX filter) 3.15 3.60 dB
RLRX-ANT Input return loss in bandwidth (RX balun) 11 12 dB
RLTX-ANT Input return loss in bandwidth (TX filter) 6.5 8.0 dB
ɸimb Output phase imbalance (RX balun) -2.1 2.1 °
Aimb Output amplitude imbalance (RX balun) -1.1 1.1 dB
Att Harmonic levels (TX filter)
Attenuation at 2fo 52 58
dB
Attenuation at 3fo 53 63
Attenuation at 4fo 54 55
Attenuation at 5fo 54 55
Attenuation at 6fo 55 56
Attenuation at 7fo 56 57
BALF-SPI2-02D3
Characteristics
DS12508 - Rev 1 page 2/13
1.1 RF measurements (Rx balun)
Figure 1. Insertion loss
(dB)
f(MHz)
-1.5
-2.0
-1.0
-0.5
0.0
-2.5
430 435 440 445 450 455 460 465 470
-3.0
Figure 2. Return loss on antenna
0
(dB)
f(MHz)
-15
-20
-10
-5
-25
430 435 440 445 450 455 460 465 470
Figure 3. Amplitude imbalance
(dB)
f(MHz)
0.0
-0.5
0.5
1.0
1.5
-1.5
-1.0
430 435 440 445 450 455 460 465 470
Figure 4. Phase imbalance
3
(deg)
f(MHz)
0
-1
1
2
-2
-4
430 435 440 445 450 455 460 465 470
-2
4
BALF-SPI2-02D3
RF measurements (Rx balun)
DS12508 - Rev 1 page 3/13
1.2 RF measurements (Tx filter)
Figure 5. Transmission
0(dB)
f(GHz)
0.0 0.5 1.0 1.5 2.0 2.5 3.0
-30
-40
-20
-10
-70
3.5
-50
-60
Figure 6. Insertion loss
(dB)
f(MHz)
-3.0
-3.5
-2.5
-2.0
0.0
-4.0
-1.5
-1.0
-0.5
430 435 440 445 450 455 460 465 470
Figure 7. Return loss on antenna
0(dB)
f(MHz)
-15
-20
-10
-5
-25
430 435 440 445 450 455 460 465 470
BALF-SPI2-02D3
RF measurements (Tx filter)
DS12508 - Rev 1 page 4/13
1.3 ST S2-LP application diagram example
Figure 8. ST S2-LP application diagram example
BALF-SPI2-02D3
ST S2-LP application diagram example
DS12508 - Rev 1 page 5/13
2Package 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.
2.1 Flip-Chip 6 bumps package information
Figure 9. Flip-Chip 6 bumps package outline (bottom and side view)
D2
E1 fE2
fE1
D1
fD2 fD1
D
E
Diam : b
A1A2
A
Table 4. Flip-Chip 6 bumps dimensions (in mm)
Parameter Min. Typ. Max.
A 0.580 0.630 0.680
A1 0.180 0.205 0.230
A2 0.380 0.400 0.420
b 0.230 0.255 0.280
D 2.050 2.100 2.150
D1 1.210
D2 0.500
E 1.500 1.550 1.600
E1 1.060
fD1 0.195
fD2 0.195
fE1 0.195
fE2 0.295
BALF-SPI2-02D3
Package information
DS12508 - Rev 1 page 6/13
2.2 Flip-chip 6 bumps packing information
Figure 10. Marking
x
y
x
w
z
w
Dot, ST logo
ECOPACK grade
xx = marking
z = manufacturing
location
yww = datecode
Figure 11. Flip Chip tape and reel specifications
Dot identifying Pin A1 location
User direction of unreeling
All dimensions are typical values in mm
4.0
4.0
2.0
8.0
1.75
3.5
Ø 1.50
0.72
1.64
0.22
2.19
xxxxxx
xx x
yyyyyyy y y
xxxxxx
xx x
wwwwwww w w
z
w wwwww w
z
z
BALF-SPI2-02D3
Flip-chip 6 bumps packing information
DS12508 - Rev 1 page 7/13
3PCB assembly recommendations
3.1 Land pattern
Figure 12. Recommended balun land pattern
Note: (*)Clearance 250 µm is needed to ensure good sensitivity.
(**)1000 µm length between S2-LP & balun (between center QFN pads to center IPD pads).
Figure 13. PCB stack-up recommendations
BALF-SPI2-02D3
PCB assembly recommendations
DS12508 - Rev 1 page 8/13
3.2 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 15. Footprint - 3 mils stencil - solder mask defined
Copper pad diameter:
220 µm recommended
180 µm minimum
260 µm maximum
Solder mask opening:
320 µm recommended
300 µm minimum
Solder stencil opening:
220 µm recommended
Figure 16. Footprint - 5 mils stencil -non solder mask
defined
*depending on paste, it can go down to 270 µm
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*
Figure 17. Footprint - 5 mils stencil - solder mask defined
*depending on paste, it can go down to 270 µm
Copper pad diameter:
220 µm recommended
180 µm minimum
260 µm maximum
Solder mask opening:
320 µm recommended
300 µm minimum
Solder stencil opening:
330 µm recommended*
3.3 Solder paste
1. Halide-free flux qualification ROL0 according to ANSI/J-STD-004.
2. “No clean” solder paste is recommended.
3. Offers a high tack force to resist component movement during high speed.
4. Use solder paste with fine particles: powder particle size 20-38 µm.
BALF-SPI2-02D3
Stencil opening design
DS12508 - Rev 1 page 9/13
3.4 Placement
1. Manual positioning is not recommended.
2. It is recommended to use the lead recognition capabilities of the placement system, not the outline centering
3. Standard tolerance of ±0.05 mm is recommended.
4. 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.
5. To improve the package placement accuracy, a bottom side optical control should be performed with a high
resolution tool.
6. For assembly, a perfect supporting of the PCB (all the more on flexible PCB) is recommended during solder
paste printing, pick and place and reflow soldering by using optimized tools.
3.5 PCB design preference
1. To control the solder paste amount, the closed via is recommended instead of open vias.
2. The position of tracks and open vias in the solder area should be well balanced. A symmetrical layout is
recommended, to avoid any tilt phenomena caused by asymmetrical solder paste due to solder flow away.
3.6 Reflow profile
Figure 18. ST ECOPACK® recommended soldering reflow profile for PCB mounting
250
0
50
100
150
200
240210180150120906030 300270
-6 °C/s
240-245 °C
2 - 3 °C/s
Temperature (°C) -2 °C/s
-3 °C/s
Time (s)
0.9 °C/s
60 sec
(90 max)
Note: Minimize air convection currents in the reflow oven to avoid component movement.
Note: More information is available in the application note:
• AN2348 Flip-Chip: “Package description and recommendations for use”
BALF-SPI2-02D3
Placement
DS12508 - Rev 1 page 10/13
4Ordering information
Table 5. Ordering information
Order code Marking Package Weight Base qty. Delivery mode
BALF-SPI2-02D3 TN Flip-Chip 6 bumps 3.4 mg 5000 Tape and reel
BALF-SPI2-02D3
Ordering information
DS12508 - Rev 1 page 11/13
Revision history
Table 6. Document revision history
Date Revision Changes
02-May-2018 1 Initial release.
BALF-SPI2-02D3
DS12508 - Rev 1 page 12/13
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 or the design of
Purchasers’ products.
No license, express or implied, to any intellectual property right is granted by ST herein.
Resale of ST products with provisions different from the information set forth herein shall void any warranty granted by ST for such product.
ST and the ST logo are trademarks of ST. All other product or service names are the property of their respective owners.
Information in this document supersedes and replaces information previously supplied in any prior versions of this document.
© 2018 STMicroelectronics – All rights reserved
BALF-SPI2-02D3
DS12508 - Rev 1 page 13/13
