AD8361ART-EVAL(2000) View Datasheet(PDF) - Analog Devices
Part Name
Description
Manufacturer
AD8361ART-EVAL Datasheet PDF : 16 Pages
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AD8361
With the 100 pF capacitor shown in Figures 32–34, the high-
pass corner frequency is about 8 MHz.
+VS 2.7 – 5.5V
0.01F
RFIN
R1
75⍀
CC
100pF
100pF
AD8361
1 VPOS SREF 8
2 IREF VRMS 7
3 RFIN
FLTR 6
4 PWDN COMM 5
V rms
CFLTR
Figure 32. Basic Connections for Ground Referenced Mode
+VS 2.7 – 5.5V
0.01F
RFIN
R1
75⍀
CC
100pF
100pF
AD8361
1 VPOS SREF 8
2 IREF VRMS 7
V rms
3 RFIN
4 PWDN
FLTR 6
COMM 5
CFLTR
Figure 33. Basic Connections for Internal Reference Mode
+VS 2.7 – 5.5V
0.01F
RFIN
R1
75⍀
CC
100pF
100pF
AD8361
1 VPOS SREF 8
2 IREF VRMS 7
V rms
3 RFIN
4 PWDN
FLTR 6
COMM 5
CFLTR
Figure 34. Basic Connections for Supply Referenced Mode
The output voltage is nominally 7.5 times the input rms voltage
(a conversion gain of 7.5 V/V rms). Three different modes of
operation are set by the pins SREF and IREF. In addition to the
ground referenced mode shown in Figure 32, where the output
voltage swings from around near ground to 4.9 V on a 5.0 V
supply, two additional modes allow an offset voltage to be added to
the output. In the internal reference mode, (Figure 33), the
output voltage swing is shifted upward by an internal reference
voltage of 350 mV. In supply referenced mode (Figure 34), an
offset voltage of VS/7.5 is added to the output voltage. Table I
summarizes the connections, output transfer function and mini-
mum output voltage (i.e., zero signal) for each mode.
Output Swing
Figure 35 shows the output swing of the AD8361 for a 5 V supply
voltage for each of the three modes. It is clear from Figure 35,
that operating the device in either internal reference mode or
supply referenced mode, will reduce the effective dynamic range as
the output headroom decreases. The response for lower supply
voltages is similar (in the supply referenced mode, the offset is
smaller), but the dynamic range will be reduced further, as head-
room decreases. Figure 36 shows the response of the AD8361 to
a CW input for various supply voltages.
5.0
SUPPLY REF
4.5
4.0
INTERNAL REF
3.5
3.0
GROUND REF
2.5
2.0
1.5
1.0
0.5
0.0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
INPUT – V rms
Figure 35. Output Swing for Ground, Internal and Supply
Referenced Mode. VPOS = 5 V (micro_SOIC Only)
5.5
5.5V
5.0
4.5
5.0V
4.0
3.0V
3.5
3.0
2.5
2.0
2.7V
1.5
1.0
0.5
0.0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
INPUT – V rms
Figure 36. Output Swing for Supply Voltages of 2.7 V,
3.0 V, 5.0 V and 5.5 V (micro_SOIC Only)
Dynamic Range
Because the AD8361 is a linear responding device with a nomi-
nal transfer function of 7.5 V/V rms, the dynamic range in dB is
not clear from plots such as Figure 35. As the input level is
increased in constant dB steps, the output step size (per dB)
will also increase. Figure 37 shows the relationship between the
output step size (i.e., mV/dB) and input voltage for a nominal
transfer function of 7.5 V/V rms.
Table I. Connections and Nominal Transfer Function for
Ground, Internal, and Supply Reference Modes
Reference
Mode
Ground
Internal
Supply
IREF
VPOS
OPEN
VPOS
SREF
COMM
COMM
VPOS
Output
Intercept
(No Signal)
Zero
0.350 V
VS/7.5
Output
7.5 VIN
7.5 VIN + 0.350 V
7.5 VIN + VS/7.5
–10–
REV. A
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