AD8307ARZ Analog Devices Inc, AD8307ARZ Datasheet - Page 16

• Manufacturer Part Number: AD8307ARZ
• Description: IC LOGARITHMIC AMP 92DB 8-SOIC
• Manufacturer: Analog Devices Inc
• Type: Logarithmic Amplifierr

Specifications of AD8307ARZ

• Applications: Receiver Signal Strength Indication (RSSI)
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• No. Of Amplifiers: 1
• Dynamic Range, Decades: 4.6
• Scale Factor V / Decade: 0.5
• Response Time: 500ns
• Supply Voltage Range: 2.7V To 5.5V
• Supply Current: 8mA
• Input Offset Voltage: 500µV
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD8307
It can be desirable to increase the speed of the output response,
with the penalty of increased ripple. One way to do this is by
connecting a shunt load resistor from Pin OUT to ground,
which raises the low-pass corner frequency. This also alters the
logarithmic slope, for example, to 7.5 mV/dB using a 5.36 kΩ
resistor, while reducing the 10% to 90% rise time to 25 ns. The
ripple amplitude for the 50 MHz input remains at 0.5 mV, but
this is now equivalent to ±0.07 dB. If a negative supply is available,
the output pin can be connected directly to the summing node
of an external op amp connected as an inverting mode transresis-
tance stage.
Note that while the AD8307 can operate down to supply voltages
of 2.7 V, the output voltage limit is reduced when the supply
drops below 4 V. This characteristic is the result of necessary
headroom requirements, approximately two V
design of the output stage.
BE
drops, in the
Rev. D | Page 16 of 24
OUT
LGM
LGP
25mV/dB
C
4
FLT
0µA TO 220µA
DETECTORS
FROM ALL
2µA/dB
C1
2.5pF
Figure 31. Simplified Output Interface
3pF
R1
12.5kΩ
1pF
1.25kΩ
1.25kΩ
C2
1.25kΩ
1.25kΩ
~400mV
8.25kΩ
60kΩ
60µA
BIAS
7
5
2
VPS
INT
COM