HMC714LP5 Datasheet, PDF (31/40 Pages) Hittite Microwave Corporation – DUAL RMS POWER DETECTOR 0.1 - 3.9 GHz

v05.0309
HMC714LP5 / 714LP5E
DUAL RMS POWER DETECTOR
0.1 - 3.9 GHz
12
RF Input Interface
The INP_A and INN_A pins are differential inputs on one of two power detectors, which we will refer to as channel A.
INP_B and INN_B pins are differential inputs on the other power detector, channel B. The inputs for both channels can
be externally configured with differential or single-ended input. Power match components are placed on these input
terminals, along with DC blocking capacitors. The coupling capacitor values also set the lower spectral boundary of
the input signal bandwidth. The inputs can be reactively matched (refer to input return loss graphs), but a resistor
network should be sufficient for good wideband performance.
Differential Input Interface:
The value of RD (=RDA=RDB) depends on the balun used; if the balun is
50Ω on both sides of the SE-Diff conversion,
then R
D
where
R = the desired power match impedance in ohms.
M
For R = 50Ω, RD = 67Ω ≈ 68Ω
M
12 - 144
Single-Ended Input Interface:
Tuned SE-interface: for signal frequencies > 900MHz
Choose L and C elements from the following graph for narrowband tuning of
the SE-interface:
R31/34 = 30Ω, R32/35 = 50Ω, C1/6 =1 nF
R30/33 = 270Ω,
Wideband SE-interface: for signal frequencies < 900 MHz
R31/34 = 0Ω, R32/35 = OPEN, R1/R3 = 68Ω,
R30/33 = Open
C2, C5 is 1 nF decoupling caps.
For wideband (un-tuned) input interfaces, choose the input decoupling capacitor values by first determining the
lowest spectral component the power detector is required to sense, ƒ .
L
Input d_≈ecouplin₁g capacitor value
p × f_L × 3.2
farads, where ƒ is in Hertz.
L
Ex. If the power detector needs to sense down to 10 MHz, the decoupling capacitor value should be
1/(π*10E6*3.2) = 10 nF
A DC bias (Vcc-1.5V) is present on the INP[A,B] and IN[A,B] pins, and should not be overridden.
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