AD8305ACPZ-RL7 Analog Devices Inc, AD8305ACPZ-RL7 Datasheet - Page 20

• Manufacturer Part Number: AD8305ACPZ-RL7
• Description: IC, LOGARITHMIC AMP, 20mV, LFCSP-16
• Manufacturer: Analog Devices Inc
• Type: Logarithmic Converterr

Specifications of AD8305ACPZ-RL7

• No. Of Amplifiers: 1
• Dynamic Range, Decades: 5
• Scale Factor V / Decade: 0.2
• Supply Voltage Range: 3V To 12V
• Amplifier Case Style: LFCSP
• Supply Current: 5.4mA
• Input Offset Voltage: 20mV
• Design Resources: Interfacing ADL5315 to Translinear Logarithmic Amplifier (CN0056) Interfacing ADL5317 High Side Current Mirror to a Translinear Logarithmic Amplifier in an Avalanche Photodiode Power Detector
• Applications: Fiber Optics
• Mounting Type: Surface Mount
• Package / Case: 16-LFCSP
• Rohs Compliant: Yes
• Number Of Channels: 1
• Number Of Elements: 3
• Power Supply Requirement: Single/Dual
• Single Supply Voltage (typ): 5V
• Dual Supply Voltage (typ): ±3/±5V
• Power Dissipation: 500mW
• Rail/rail I/o Type: Rail to Rail Output
• Single Supply Voltage (min): 3V
• Single Supply Voltage (max): 12V
• Dual Supply Voltage (min): ±1.5V
• Dual Supply Voltage (max): ±6V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 16
• Package Type: LFCSP EP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: AD8305ACPZ-RL7

AD8305
The setup shown in Figure 44 was used for frequency response
measurements of the logarithmic amplifier section. The
AD8138 output is offset to 1.5 V dc and modulated to a depth
of 5% at frequency. R1 is chosen (over a wide range of values up
to 1.0 GΩ) to provide I
from the measurement system.
ALKALINE
The configuration in Figure 45 is used to measure the noise
performance. Batteries provide both the supply voltage and the
input current to minimize the introduction of spurious noise
and ground loop effects. The entire evaluation system,
including the current setting resistors, is mounted in a closed
aluminum enclosure to provide additional shielding to external
noise sources.
“D” CELL
Figure 45. Configuration for Noise Spectral Density Measurement
+
–
SOURCE
1nF
1nF
1kΩ
R1
200kΩ
1kΩ
TRIGGER
HP 89410A
1
2
3
4
PD
. The buffer was used to deload VLOG
VRDZ
IREF
INPT
CHANNEL 1
VREF
COMM COMM COMM COMM
VSUM
16
5
VNEG VNEG VPOS
AD8305
15
6
CHANNEL 2
14
7
13
8
VOUT
SCAL
VLOG
BFIN
0.1µF
12
11
10
9
ALKALINE
“D” CELL
+ –
+
–
+
–
Rev. B | Page 20 of 24
Figure 46 shows the setup used to make the pulse response
measurements. As with the bandwidth measurement, the
VLOG is connected directly to BFIN and the buffer amplifier is
configured for unity gain. The output of the buffer is connected
through a short cable to the TDS5104 scope with input
impedance set to 1 MΩ. The LeCroy’s output is offset to create
the initial pedestal current for a given value of R1, the pulse
then creates one-decade current step.
LECROY 9210
Figure 46. Configuration for Logarithmic Amplifier Pulse Response
CH A
9213
1nF 1kΩ
1nF
1kΩ
200kΩ
R1
1
2
3
4
IREF
INPT
VRDZ
VREF
Measurement
COMM COMM COMM COMM
VSUM
16
5
VNEG VNEG VPOS
AD8305
15
6
14
7
TDS5104
13
8
VOUT
SCAL
VLOG
BFIN
0.1µF
12
11
10
9
+V
CH1
S