ADL5565-EVALZ(Rev0) View Datasheet(PDF) - Analog Devices
Part Name
Description
Manufacturer
ADL5565-EVALZ Datasheet PDF : 28 Pages
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ADL5565
CIRCUIT DESCRIPTION
BASIC STRUCTURE
The ADL5565 is a low noise, fully differential amplifier/ADC
driver that can operate from 2.8 V to 5.2 V. It provides three
gain options, 6 dB, 12 dB, and 15.5 dB, without the need for
external resistors and has wide bandwidths of greater than 6
GHz for all gains. Differential input impedance is 200 Ω for 6
dB, 100 Ω for 12 dB, and 67 Ω for 15.5 dB. It has a differential
output impedance of 10 Ω.
0.1µF
200Ω
1/2 RS
AC
VIP2 50Ω
VIP1 100Ω
VIN1 100Ω
5Ω
RL
1/2 RS
VIN2 50Ω
5Ω
200Ω
0.1µF
Figure 30. Basic Structure
The ADL5565 is composed of a fully differential amplifier with
on-chip feedback and feed forward resistors. The two feedforward
resistors on each input set this pin-strappable amplifier in three
different gain configurations of 6 dB, 12 dB, and 15.5 dB, and by
using two external resistors, any gain from 0 dB to 15.5 dB can be
realized. The amplifier is designed to provide high differential
open-loop gain and an output common-mode circuit that enables
the user to change the common-mode voltage from the VCOM
pin. The amplifier is designed to provide superior low distortion at
frequencies up to and beyond 300 MHz with low noise and low
power consumption from a 3.3 V power supply at 70 mA.
The ADL5565 is very flexible in terms of I/O coupling. It can be
ac-coupled or dc-coupled at the inputs and/or the outputs within
the specified input and output common-mode levels. The input
of the device can be configured as single-ended or differential
with similar third-order distortion performance. Due to the
internal connections between the inputs and outputs, an output
common-mode voltage between 1.4 V and 1.8 V at 3.3 V and
1.4 V to 3 V at 5 V must be maintained for the best distortion.
For a dc-coupled input, the input common mode should be
between 1.2 V and 2 V at the 3.3 V supply, and 1.2 V to 3.8 V at
the 5 V supply. The device has been characterized using 2 V p-p
into a 200 Ω ac-coupled output. If the inputs are ac-coupled, the
input and output common-mode voltages are set by VCC/2 when
no external circuitry is used. The ADL5565 provides an output
common-mode voltage set by VCOM, which allows driving an
ADC directly without external components. Although distortion is
similar over the specified frequency range at both 3.3 V and 5 V,
lower distortion results on the 5 V supply for signal swings larger
than 2 V p-p.
Rev. 0 | Page 16 of 28
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