AD8313ARM Analog Devices Inc, AD8313ARM Datasheet - Page 19

IC LOGARTIHMIC AMP 70DB 8-MSOP

AD8313ARM

Manufacturer Part Number
AD8313ARM
Description
IC LOGARTIHMIC AMP 70DB 8-MSOP
Manufacturer
Analog Devices Inc
Type
Logarithmic Ampr
Datasheet

Specifications of AD8313ARM

Rohs Status
RoHS non-compliant
Frequency
100MHz ~ 2.5GHz
Rf Type
RADAR, 802.11/Wi-Fi, 8.2.16/WiMax, Wireless LAN
Input Range
-65dBm ~ 0dBm
Accuracy
±1dB
Voltage - Supply
2.7 V ~ 5.5 V
Current - Supply
13.7mA
Package / Case
8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
Number Of Channels
1
Number Of Elements
8
Power Supply Requirement
Single
Voltage Gain Db
84dB
Input Resistance
0.0009@5VMohm
Input Bias Current
10@5VnA
Single Supply Voltage (typ)
3/5V
Dual Supply Voltage (typ)
Not RequiredV
Power Dissipation
200mW
Rail/rail I/o Type
Rail to Rail Output
Single Supply Voltage (min)
2.7V
Single Supply Voltage (max)
5.5V
Dual Supply Voltage (min)
Not RequiredV
Dual Supply Voltage (max)
Not RequiredV
Operating Temp Range
-40C to 85C
Operating Temperature Classification
Industrial
Mounting
Surface Mount
Pin Count
8
Package Type
MSOP
Lead Free Status / RoHS Status
Not Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
AD8313ARM
Manufacturer:
AD
Quantity:
5 510
Part Number:
AD8313ARM
Manufacturer:
NAIS
Quantity:
5 510
Part Number:
AD8313ARM
Manufacturer:
AD
Quantity:
4 130
Part Number:
AD8313ARM
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Part Number:
AD8313ARM-REEL
Manufacturer:
AD
Quantity:
5 510
Part Number:
AD8313ARM-REEL
Manufacturer:
LT
Quantity:
5 510
Part Number:
AD8313ARM-REEL
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Part Number:
AD8313ARM-REEL7
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Part Number:
AD8313ARM-REEL7
Manufacturer:
ADI
Quantity:
19 062
Part Number:
AD8313ARMZ
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Part Number:
AD8313ARMZ-REEL
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Part Number:
AD8313ARMZ-REEL7
Manufacturer:
ADI
Quantity:
12 608
INCREASING OUTPUT CURRENT
To drive a more substantial load, either a pull-up resistor or an
emitter-follower can be used.
In Figure 40, a 1 kΩ pull-up resistor is added at the output,
which provides the load current necessary to drive a 1 kΩ load
to 1.7 V for V
intercept and the slope. As a result, the transfer function of the
AD8313 is shifted upward (intercept shifts downward).
In Figure 41, an emitter-follower provides the current gain,
when a 100 Ω load can readily be driven to full-scale output.
While a high ß transistor such as the BC848BLT1 (min ß = 200)
is recommended, a 2 kΩ pull-up resistor between VOUT and
+V
In addition to providing current gain, the resistor/potentiometer
combination between VSET and the emitter of the transistor
increases the log slope to as much as 45 mV/dB, at maximum
resistance. This gives an output voltage of 4 V for a 0 dBm input.
If no increase in the log slope is required, VSET can be connected
directly to the emitter of the transistor.
+V
+V
S
S
S
can provide additional base current to the transistor.
+V
+V
10Ω
10Ω
R1
R3
S
S
Figure 40. Increasing AD8313 Output Current Capability
Figure 41. Output Current Drive Boost Connection
10Ω
10Ω
R1
R3
S
0.1µF
0.1µF
= 2.7 V. The pull-up resistor slightly lowers the
0.1µF
0.1µF
1
2
3
4
INHI
INLO
VPOS VOUT
VPOS PWDN
AD8313
1
2
3
4
COMM
INHI
INLO
VPOS VOUT
VPOS PWDN
VSET
AD8313
COMM
8
7
6
5
VSET
13kΩ
+V
+V
S
8
7
6
5
10kΩ
S
1kΩ
20mV/dB
BC848BLT1
β
MIN
R
= 200
R
100Ω
L
L
= 1kΩ
OUTPUT
Rev. D | Page 19 of 24
EFFECT OF WAVEFORM TYPE ON INTERCEPT
Although specified for input levels in dBm (dB relative to
1 mW), the AD8313 responds to voltage and not to power. A
direct consequence of this characteristic is that input signals of
equal rms power but differing crest factors produce different
results at the log amp’s output.
Different signal waveforms vary the effective value of the log
amp’s intercept upward or downward. Graphically, this looks
like a vertical shift in the log amp’s transfer function. The
device’s logarithmic slope, however, is in principle not affected.
For example, if the AD8313 is being fed alternately from a
continuous wave and from a single CDMA channel of the same
rms power, the AD8313 output voltage differs by the equivalent
of 3.55 dB (64 mV) over the complete dynamic range of the
device (the output for a CDMA input being lower).
Table 6 shows the correction factors that should be applied to
measure the rms signal strength of a various signal types. A
continuous wave input is used as a reference. To measure the
rms power of a square wave, for example, the mV equivalent of
the dB value given in the table (18 mV/dB × 3.01 dB) should be
subtracted from the output voltage of the AD8313.
Table 6. Shift in AD8313 Output for Signals with
Differing Crest Factors
Signal Type
CW Sine Wave
Square Wave or DC
Triangular Wave
GSM Channel (All Time Slots On)
CDMA Channel
PDC Channel (All Time Slots On)
Gaussian Noise
Correction Factor
(Add to Output Reading)
0 dB
−3.01 dB
+0.9 dB
+0.55 dB
+3.55 dB
+0.58 dB
+2.51 dB
AD8313

Related parts for AD8313ARM