AD8375 Datasheet, PDF (1/6 Pages) Analog Devices – 24dB Range, 1dB Step Size Programmable VGA

Preliminary Technical Data
24dB Range, 1dB Step Size Programmable
VGA
AD8375
FEATURES
-4 to 20dB Gain Range
1 dB Step Size ± 0.2 dB
Differential input and output
150 Ω Differential Input
Open Collector Differential Output
8dB noise figure @ maximum gain
OIP3 of ~50dBm at 140MHz
−3 dB bandwidth of 690 MHz
Parallel 5-bit Control Interface
Wide input dynamic range
Power-down feature
Single 5V Supply Operation
24 Lead LFCSP 4 x 4 mm Package
APPLICATIONS
Differential ADC drivers
High IF Sampling Receivers
High Output Power IF Amplification
Instrumentation
GENERAL DESCRIPTION
The AD8375 is a digitally controlled, variable gain wide
bandwidth amplifier that provides precise gain control, high IP3
and low noise figure. The excellent distortion performance and
high signal bandwidth makes the AD8375 an excellent gain
control device for a variety of receiver applications.
For wide input dynamic range applications, the AD8375 pro-
vides a broad 24dB gain range with 1 dB resolution. The gain is
adjusted through a 5-pin control interface and can be driven
using standard TTL levels. The open-collector outputs provide a
flexible interface, allowing the overall signal gain to be set by
the loading resistance. The AD8375 offers a maximum trans-
conductance gain of 67 mΩ^-1’s, resulting in a signal gain of 20dB
when driving a 150-Ohm load. The maximum signal gain
increases to ~24dB when driving a 250-Ohm differential load.
FUNCTIONAL BLOCK DIAGRAM
Figure 1.
Using a high speed SiGe process and incorporating proprietary
distortion cancellation techniques, the AD8375 achieves
50 dBm output IP3 at 140 MHz.
The AD8375 is powered on by applying the appropriate logic
level to the PWUP pin. The quiescent current of the AD8375 is
typically 130mA. When powered down, the AD8375 consumes
less than 5mA and offers excellent input to output isolation. The
gain setting is preserved when powered down.
Fabricated on an ADI’s high speed SiGe process, the AD8375
provides precise gain adjustment capabilities with good distortion
performance. The AD8375 amplifier comes in a compact,
thermally enhanced 4 x 4mm 24-lead LFCSP package and
operates over the temperature range of −40°C to +85°C.
Rev. PrB
March 13, 2007
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