Datasheet HSMS-280x (Avago Technologies) - 3

Quad Capacitance A C
Capacitance of Schottky diode quads is measured using
1 C3
an HP4271 LCR meter. This instrument effectively isolates
C
individual diode branches from the others, allowing accurate capacitance measurement of each branch or
C2 C4
each diode. The conditions are: 20 mV R.M.S. voltage at 1
B
MHz. Avago defines this measurement as “CM”, and it is The equivalent adjacent capacitance is the capacitance equivalent to the capaci tance of the diode by itself. The between points A and C in the figure below. This capaci- equivalent diagonal and adja cent capacitances can then tance is calculated using the following formula be calculated by the formulas given below. 1 CADJACENT = C1 + ____________ In a quad, the diagonal capaci tance is the capacitance 1 1 1 –– + –– + –– between points A and B as shown in the figure below. C The diagonal capacitance is calculated using the follow- 2 C3 C4 ing formula This information does not apply to cross-over quad C C 1 x C2 C3 x C4 diodes. DIAGONAL = _______ + _______ C1 + C2 C3 + C4
Linear Equivalent Circuit, Diode Chip SPICE Parameters Parameter Units HSMS-280x
Rj BV V 75 CJ0 pF 1.6 RS EG eV 0.69 IBV A E-5 IS A 3.00E-08 C N 1.08 j RS Ω 30 RS = series resistance (see Table of SPICE parameters) PB V 0.65 C j = junction capacitance (see Table of SPICE parameters) PT 2 8.33 X 10-5 nT Rj = M 0.5 I b + Is where Ib = externally applied bias current in amps Is = saturation current (see table of SPICE parameters) T = temperature, K n = ideality factor (see table of SPICE parameters) Note: To effectively model the packaged HSMS-280x product, please refer to Application Note AN1124. 3