ADL5562-EVALZ AD [Analog Devices], ADL5562-EVALZ Datasheet - Page 13

• Manufacturer Part Number: ADL5562-EVALZ
• Description: 3.3 GHz Ultralow Distortion RF/IF Differential Amplifier
• Manufacturer: AD [Analog Devices]

CIRCUIT DESCRIPTION
BASIC STRUCTURE
The ADL5562 is a low noise, fully differential amplifier/ADC
driver that uses a 3.3 V supply. It provides three gain options
(6 dB, 12 dB, and 15.5 dB) without the need for external resistors
and has wide bandwidths of 2.6 GHz for 6 dB, 2.3 GHz for 12 dB,
and 2.1 GHz for 15.5 dB. Differential input impedance is 400 Ω
for 6 dB, 200 Ω for 12 dB, and 133 Ω for 15.5 dB. It has a
differential output impedance of 10 Ω and a common-mode
adjust voltage of 1.25 V to 1.85 V.
1
1
/
/
2
2
AC
R
R
S
S
0.1µF
0.1µF
Figure 30. Basic Structure
VIP2
VIP1
VIN1
VIN2
100Ω
200Ω
200Ω
100Ω
400Ω
400Ω
5Ω
5Ω
R
L
Rev. A | Page 13 of 24
The ADL5562 is composed of a fully differential amplifier with
on-chip feedback and feed-forward resistors. The two feed-forward
resistors on each input set this pin-strappable amplifier in three
different gain configurations of 6 dB, 12 dB, and 15.5 dB. 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 a 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. The low distortion and noise are
realized with a 3.3 V power supply at 80 mA.
The ADL5562 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 distortion performance. Due to the
internal connections between the inputs and outputs, keep the
output common-mode voltage between 1.25 V and 1.85 V for
the best distortion. For a dc-coupled input, the input common
mode should be between 1 V and 2.3 V for the best distortion.
The device has been characterized using 2 V p-p into 200 Ω. 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 ADL5562 provides an output common-mode voltage set by
VCOM, which allows driving an ADC directly without external
components, such as a transformer or ac coupling capacitors,
provided the VCOM of the amplifier is within the VCOM of the
ADC. For dc-coupled requirements, the input VCM must be set
by the VCOM pin in all three gain settings.
ADL5562