HSMP-381C Datasheet, PDF (5/9 Pages) Broadcom Corporation. – Surface Mount RF PIN Low Distortion Attenuator Diodes

Typical Applications for HSMP-481x Low Inductance Series (continued)
Co-Planar Waveguide Shunt Connection for HSMP-481x
Series
Co-Planar waveguide, with ground on the top side of the
printed circuit board, is shown in Figure 10. Since it elimi-
nates the need for via holes to ground, it offers lower shunt
parasitic inductance and higher maximum attenuation
when compared to microstrip circuit.
Co-Planar Waveguide
Groundplane
Center Conductor
Groundplane
Equivalent Circuit Model
HSMP-381x Chip*
R_s
R_j
2.5 Ω
C_j
R_T = 2.5 + R_j
C_T = C_P + C_j
R_j =
80
I^0.9
Ω
0.18 pF*
* Measured at -20 V
I = Forward Bias Current in mA
*See AN1124 for package models.
Figure 10. Circuit Layout.
R_j
0.3 pF
0.75 nH
Figure 11. Equivalent Circuit.
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