Available on Tape
and Reel For Pick and
Place Manufacturing.
USA/Canada:
Toll Free:
Europe:
(315) 432-8909
(800) 544-2414
+44 2392-232392
Model FB850
Rev. B
Femto Balun
50Ω to 100Ω Balanced
Description
The FB850 is a low profile sub-miniature balanced to unbalanced transformer
designed for differential inputs and output locations on next generation wireless
chipsets in an easy to use surface mount package covering 802.11a Uni-Band II and
Uni-Band III and the Japanese ISM band (4.9GHz). The FB850 is ideal for high
volume manufacturing and is higher performance than traditional ceramic baluns.
The FB850 has an unbalanced port impedance of 50Ω and a 100Ω balanced port
impedance*. This transformation enables single ended signals to be applied to
differential ports on modern integrated chipsets. The output ports have equal
amplitude (-3dB) with 180 degree phase differential. The FB850 is available on tape
and reel for pick and place high volume manufacturing.
ELECTRICAL SPECIFICATIONS**
Frequency
Unbalanced
Port
Impedance
Balanced
Port
Impedance*
Return
Loss
Insertion
Loss
GHz Ohms Ohms dB min dB max
5.15 – 5.35 17 0.5***
4.8 – 5.9 50 100 16 0.6***
Amplitude
Balance
Phase
Balance
Power
Handling
ΘJC
Operating
Temp.
dB Degrees max Watts ºC / Watt ºC
0 ± 0.5 180 ± 5.0
Features:
• 5.15 – 5.35 GHz Narrow Band
• 4.8 – 5.9 GHz Extended Band
• 180° Transformer
• 50 Ohm to 2 x 50 Ohm
• Low Insertion Loss
• Covers 802.11a Uni-Band II & III
• No DC Decoupling Capacitors
Required
• Input to Output DC Isolation
• Surface Mountable
• Tape & Reel
• Convenient Package 0 ± 0.6 180 ± 5.0 4 75 -55 to +85
**Specification based on performance of unit properly installed on microstrip printed circuit
boards with 50 Ω nominal impedance. Specifications subject to change without notice.
* 50Ω reference to ground
*** Insertion Loss stated at room temperature (0.55 dB Max at +85 ºC)
Outline Drawing
FB850 Rev B Mechanical Outline
Dimensions are in Inches [Millimeters]
Side ViewTop View (Near-side) Bottom View (Far-side)
.030±.003
[0.75±0.08]
.120±.005
[3.05±0.13]
.120±.005
[3.05±0.13]
456
3 1
2
6X .030±.004
[0.76±0.10]
Pin
3
6
1
2
4
5
Designation
Out 1
GND
Out 2
GND
In
GND Tolerances are Non-Cumulative
6X .010±.004
[0.24±0.10]
.095±.004
[2.41±0.10]
4X .010±.004
[0.25±0.10]
USA/Canada:
Toll Free:
Europe:
(315) 432-8909
(800) 544-2414
+44 2392-232392
Available on Tape and
Reel For Pick and Place
Manufacturing.
Model FB850
Rev. B
Typical Performance: 4.5 GHz. to 6.0 GHz.
Pin Configuration:
Balun Pin Configruation
Pin 3
Balanced Port
Terminals
Pin 1
λ4
Unbalanced Port
λ4
50 Ω
Pin 5
The internal configuration of the Xinger balun is diagramed to
the left; the unbalanced port is DC connected to ground and the
two balanced ports are DC connected and floating. For many
chipset applications there is an opportunity to eliminate two
decoupling capacitors and/or use a single bias point if
applicable. Differential drive is popular in integrated circuit since
it aids stability in the presence of bond wire and pin inductance,
provides some degree of immunity to power supply and ground
noise, and can provide higher output power in the case of some
device limits. The construction of the Xinger balun is bonded
multi-layered stripline made of low loss dielectric material with
plated through vias connecting the internal circuitry to the
external printed circuit board, similar to that of the Xinger
hybrids and directional couplers.
Available on Tape
and Reel For Pick and
Place Manufacturing.
USA/Canada:
Toll Free:
Europe:
(315) 432-8909
(800) 544-2414
+44 2392-232392
Model FB850
Rev. B
Typical Performance: 5.15 GHz. to 5.35 GHz.
Mounting Configuration:
4X .010
[0.25]
FB850 Rev B Mounting Footprint
Dimensions are in Inches [Millimeters]
6X .030
[0.76]
3X 50 Ω
Transmission
Line
.095
[2.41]
6X .022
[0.57]
3X .009
[0.22] Plated thru
holes to
ground
Solder Resist
Footprint Pad (s)
Circuit Pattern
In order for Xinger surface mount components to work
optimally, there must be a 50Ω transmission line to the
balanced port and 50Ω transmission lines from the
unbalanced ports. If this condition is not satisfied, amplitude
balance, insertion loss and VSWR may not meet published
specifications.
All of the Xinger components are constructed from ceramic
filled PTFE composites which possess excellent electrical
and mechanical stability having X and Y thermal coefficient
of expansion (CTE) of 17 ppm/oC
An example of the PCB footprint used in the testing of these
parts is shown to the left. in specific designs, the
transmission line widths need to be adjusted to the unique
dielectric coefficients and thicknesses as well as varying
pick and place equipment tolerances.
USA/Canada:
Toll Free:
Europe:
(315) 432-8909
(800) 544-2414
+44 2392-232392
Available on Tape and
Reel For Pick and Place
Manufacturing.
Model FB850
Rev. B
Packaging
Parts are oriented in tape as shown below.
.157
[4.00]
.079 [2.01] .157
[4.00]
Ø.059
[Ø1.50]
.069
[1.75]
.138
[3.50]
.063
[1.61]
Ø.039
[Ø0.99]
Dimensions are in inches [mm]
Direction of
Part Feed
(Unloading)
.315
[8.00]
.010
[0.25]
.031
[0.80]
.130
[3.30]
