AD8362ARU-REEL7 Analog Devices Inc, AD8362ARU-REEL7 Datasheet - Page 17

• Manufacturer Part Number: AD8362ARU-REEL7
• Description: IC,Threshold Detector,TSSOP,16PIN,PLASTIC
• Manufacturer: Analog Devices Inc

Specifications of AD8362ARU-REEL7

• Rohs Status: RoHS non-compliant
• Frequency: 50Hz ~ 3.8GHz
• Rf Type: Cellular, GSM, CDMA, TDMA, TETRA
• Input Range: -52dBm ~ 8dBm
• Accuracy: 0.5dB
• Voltage - Supply: 4.5 V ~ 5.5 V
• Current - Supply: 20mA
• Package / Case: 16-TSSOP (0.173", 4.40mm Width)
• Pin Count: 16
• Screening Level: Industrial
• Package Type: TSSOP
• Lead Free Status / Rohs Status: Not Compliant

loop to settle. Because the scaling parameters of the two
squarers are accurately matched, it follows that Equation 4
is satisfied only when
In a formal solution, extract the square root of both sides to
provide an explicit value for the root-mean-square (rms) value.
However, it is apparent that by forcing this identity through
varying the VGA gain and extracting the mean value by the
filter provided by the capacitor(s), the system inherently
establishes the relationship
Substituting the value of V
As a measurement device, V
other parameters can be fixed by design. To solve Equation 7,
therefore,
The quantity V
because VSET must be 0 when rms (V
When connected as a measurement device, the output of the
buffer is tied directly to VSET, which closes the AGC loop.
Making the substitution VOUT = VSET and changing the
log base to 10, as needed in a decibel conversion,
where V
voltage for each decade of change in the input amplitude.
Note that V
In the AD8362, V
test signal. Because a decade corresponds to 20 dB, this slope
can also be stated as 50 mV/dB. The Altering the Slope section
explains how the effective value of V
user. The intercept, V
relative to 50 Ω). In an ideal system, VOUT would cross zero
for an rms input of that value. In a single-supply realization of
the function, VOUT cannot run fully down to ground; here, V
is the extrapolated value.
VOLTAGE VS. POWER CALIBRATION
The AD8362 can be used as an accurate rms voltmeter from
arbitrarily low frequencies to microwave frequencies. For low
frequency operation, the input is usually specified either in
volts rms or in dBV (decibels relative to 1 V rms).
MEAN(V
rms(V
rms[G
rms[G
VSET = V
VOUT = V
SLP
SIG
O
O
is the slope voltage, that is, the change in output
SLP
V
V
) = V
IN
IN
= V
SIG
GNS
Z
/V
SLP
exp(−VSET/V
= V
2
) = V
SLP
ATG
log[rms(V
GNS
ATG
log
ATG
is laser-trimmed to 1 V using a 100 MHz
] = exp(VSET/V
Z
log (10) = 2.303 V
10
, is also laser-trimmed to 224 μV (−60 dBm
ATG
/G
[rms(V
2
O
SIG
is defined as the intercept voltage
IN
IN
from Equation 3,
)/V
GNS
is the unknown quantity and all
IN
)/V
)] = V
Z
]
Z
]
SLP
GNS
IN
ATG
can be altered by the
GNS
)
) = V
.
Z
.
(10)
Rev. D | Page 17 of 32
(5)
(6)
(7)
(8)
(9)
Z
At high frequencies, signal levels are commonly specified in
power terms. In these circumstances, the source and termina-
tion impedances are an essential part of the overall scaling. For
this condition, the output voltage can be expressed as
where P
In practice, the response deviates slightly from the ideal straight
line suggested by Equation 11. This deviation is called the law
conformance error. In defining the performance of high accuracy
measurement devices, it is customary to provide plots of this
error. In general terms, it is computed by extracting the best
straight line to the measured data using linear regression over
a substantial region of the dynamic range and under clearly
specified conditions.
Figure 45 shows the output of the circuit of Figure 47 over the
full input range. The agreement with the ideal function (law
conformance) is also shown. This was determined by linear
regression on the data points over the central portion of the
transfer function for the +25°C data.
The error at −40°C, +25°C, and +85°C was then calculated by
subtracting the ideal output voltage at each input signal level
from the actual output and dividing this quantity by the mean
slope of the regression equation to provide a measurement of
the error in decibels (scaled on the right-hand axis of Figure 45).
The error curves generated in this way reveal not only the devia-
tions from the ideal transfer function at a nominal temperature,
but also the additional errors caused by temperature changes.
Notice that there is a small temperature dependence in the
intercept (the vertical position of the error plots).
Figure 45 further reveals a periodic ripple in the conformance
curves. This is due to the interpolation technique used to select
the signals from the attenuator, not only at discrete tap points,
but anywhere in between, thus providing continuous attenua-
tion values. The selected signal is then applied to the 3.5 GHz,
40 dB fixed gain amplifier in the remaining stages of the VGA
of the AD8362.
3.8
3.5
3.2
2.9
2.6
2.3
2.0
1.7
1.4
1.1
0.8
0.5
0.2
VOUT = SLOPE × (P
–60 –55 –50 –45 –40 –35 –30 –25 –20 –15
IN
Figure 45. Output Voltage and Law Conformance Error
and the intercept P
@ T
INPUT AMPLITUDE (dBm)
A
= −40°C, +25°C, and +85°C
IN
− P
Z
are expressed in dBm.
Z
)
–10
–5
0
5
10 15
AD8362
3.0
2.5
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
(11)