MAX2066
50MHz to 1000MHz High-Linearity,
Serial/Parallel-Controlled Digital VGA
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Detailed Description
The MAX2066 high-linearity digital variable-gain amplifi-
er is a general-purpose, high-performance amplifier
designed to interface with 50Ω systems operating in the
50MHz to 1000MHz frequency range.
The MAX2066 integrates a digital attenuator to provide
31dB of gain control, as well as a driver amplifier opti-
mized to provide high gain, high IP3, low noise figure,
and low power consumption. For applications that do
not require high linearity, the bias current of the amplifi-
er can be adjusted by an external resistor to further
reduce power consumption.
The attenuator is controlled as a slave peripheral using
either the SPI-compatible interface or a parallel bus
with 31dB total adjustment range in 1dB steps. An
added feature allows “rapid-fire” gain selection
between each of the four unique steps (prepro-
grammed by the user through the SPI-compatible inter-
face). The 2-pin control allows the user to quickly
access any one of four customized attenuation states
without reprogramming the SPI bus. Because each
stage has its own external RF input and RF output, this
component can be configured to either optimize NF
(amplifier configured first), or OIP3 (amplifier last). The
device’s performance features include 22dB stand-
alone amplifier gain (amplifier only), 5.2dB NF at maxi-
mum gain (includes attenuator insertion loss), and a
high OIP3 level of +42.4dBm. Each of these features
makes the MAX2066 an ideal VGA for numerous receiv-
er and transmitter applications.
In addition, the MAX2066 operates from a single +5V
supply, or a single +3.3V supply with slightly reduced
performance, and has adjustable bias to trade current
consumption for linearity performance.
5-Bit Digital Attenuator Control
The MAX2066 integrates a 5-bit digital attenuator to
achieve a high level of dynamic range. The digital
attenuator has a 31dB control range, a 1dB step size,
and is programmed either through a dedicated 5-bit
parallel bus or through the 3-wire SPI. See the
Applications Information
section and Table 1 for attenu-
ator programming details. The attenuator can be used
for both static and dynamic power control.
Driver Amplifier
The MAX2066 includes a high-performance driver with
a fixed gain of 22dB. The driver amplifier circuit is opti-
mized for high linearity for the 50MHz to 1000MHz fre-
quency range.
Applications Information
SPI Interface and Attenuator Settings
The attenuator can be programmed through the 3-wire
SPI/MICROWIRE™-compatible serial interface using
5-bit words. Twenty-eight bits of data are shifted in MSB
first and framed by CS. When CS is low, the clock is
active and data is shifted on the rising edge of the
clock. When CS transitions high, the data is latched
and the attenuator setting changes (Figure 1). See
Table 2 for details on the SPI data format.
Table 1. Control Logic
