HMC714LP5 Datasheet, PDF (32/40 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
RF Input Interface (Continued)
Tuning, Single Ended Interface:
fc ± 300 MHz
10
10
9
9
8
8
7
7
6
6
5
5
4
4
3
3
2
2
1
1
0
0
900
1400 1900 2400 2900 3400 3900
FREQUENCY (MHz)
RMS Output Interface and Transient Response
Output transient response is determined by the integration capacitances C_INTA & C_INTB and output load conditions.
Using larger values of C_INT will narrow the operating bandwidth of the integrator, resulting in a longer averaging
time-interval and a more filtered output signal; however it will also slow the power detector’s transient response. A
larger C_INT value favors output accuracy over speed. For the fastest possible transient settling times, leave the C_INT
pins free of any external capacitance. This configuration will operate the integrator at its widest possible bandwidth,
resulting in short averaging time-interval and an output signal with little filtering. Most applications will choose to
have some external integration capacitance, maintaining a balance between speed and accuracy. Furthermore, error
performance over crest factor is degraded when C_INT is very small (for C_INT < 100 pF).
Modulation and deviation results in Electrical Specification Table 2 are provided with CINT = 0.1 uF.
Start by selecting C_INT using the following expression, and then adjust the value as needed, based on the application’s
preference for faster transient settling or output accuracy.
C_INT
=
1500
uF/(2*π
*ƒ ),
lam
in
Farads,
where
ƒ
lam
=
lowest
amplitude-modulation
component
frequency
in
Hertz
Example:
when
ƒ
lam
=
10
kHz,
C_INT
=
1500
μF/(2*π*1000)
=
24E-9
Farads
~
22
nF
CINT
0
100 pF
1 nF
10 nF
Table: Transient response vs. C_INT capacitance: with C_OFS = 0
RMS Rise - Time
over Dynamic Range
Pin = 0 dBm
Pin = -30 dBm
RMS Fall - Time
Pin = -10 dBm
Pin = 0 dBm
35 nsec
120 nsec
200 nsec
1.18 usec
80 nsec
410 nsec
720 nsec
1.26 usec
780 nsec
3.3 usec
5.6 usec
7 usec
7.8 usec
32.4 usec
54 usec
66.4 usec
Input signal is 1900 MHz CW-tone switched on and off
RMS is loaded with 1kΩ, 4 pF, and V_TGT = 2V,
12
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