AD8375_1 Datasheet, PDF (1/24 Pages) Analog Devices – Ultralow Distortion IF VGA

FEATURES
Bandwidth of 630 MHz (−3 dB)
Gain range: −4 dB to +20 dB
Step size: 1 dB ± 0.2 dB
Differential input and output
Noise figure: 8 dB @ maximum gain
Output IP3 of ~50 dBm at 200 MHz
Output P1dB of 19 dBm at 200 MHz
Provides constant SFDR vs. gain
Parallel 5-bit control interface
Power-down feature
Single 5 V supply operation
24-lead, 4 mm × 4 mm LFCSP
APPLICATIONS
Differential ADC drivers
High IF sampling receivers
Wideband multichannel receivers
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 make the AD8375 an excellent gain
control device for a variety of receiver applications.
Using an advanced high speed SiGe process and incorporating
proprietary distortion cancellation techniques, the AD8375
achieves 50 dBm output IP3 at 200 MHz.
The AD8375 provides a broad 24 dB 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 impedance. Thus, the signal
voltage gain is directly proportional to the load.
The AD8375 is powered on by applying the appropriate logic
level to the PWUP pin. The quiescent current of the AD8375 is
typically 130 mA. When powered down, the AD8375 consumes
less than 5 mA and offers excellent input-to-output isolation.
Ultralow Distortion IF VGA
AD8375
FUNCTIONAL BLOCK DIAGRAM
VPOS
COMM
VCOM
VIN+
VIN–
AD8375
α
POST-AMP
REGISTERS
AND
GAIN DECODER
PWUP
OUT+
OUT+
OUT–
OUT–
A4 A3 A2 A1 A0
Figure 1.
Fabricated on an Analog Devices, Inc., high speed SiGe process,
the AD8375 is supplied in a compact, thermally enhanced,
4 mm × 4 mm, 24-lead LFCSP package and operates over the
temperature range of −40°C to +85°C.
–40
65
–50
60
–60
55
OIP3
–70
50
–80
–90
–100
45
HD2
40
HD3
35
–110
40 60
30
80 100 120 140 160 180 200
FREQUENCY (MHz)
Figure 2. Harmonic Distortion and Output IP3 vs. Frequency
Rev. 0
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