Rainbow Electronics MAX2130 - Manual (Page 6)

MAX2130
Broadband, Two-Output, Low-Noise
Amplifier for TV Tuner Applications
6 _______________________________________________________________________________________
Detailed Description
The MAX2130 is a broadband, high-gain, low-distortion
low-noise amplifier (LNA) with two outputs intended for
operation over the 44MHz to 878MHz frequency range.
The device operates from a +5V supply and features
externally adjustable bias control circuitry that allows
minimum linearity requirements to be met while reduc-
ing current consumption.
Input
The IN port is a broadband 75 Ω input that provides a
guaranteed minimum input return loss of 7.4dB (allow-
ing for 2:1 VSWR at output) across the 44MHz to
878MHz frequency range. AC-couple the IN port with a
0.1µF DC-blocking capacitor.
Outputs
The OUT1 port is a broadband, 75 Ω, open-collector
output for the LNA. It requires a pullup inductor to V CC
for proper biasing, as well as a 0.1µF DC-blocking
capacitor. See the Applications Information section for
proper inductor selection.
The OUT2 port is a broadband, 75 Ω output for the loop-
out amplifier. The loop-out amplifier is internally biased
and does not require a pullup inductor. AC-couple the
OUT2 port with a 0.1µF DC-blocking capacitor.
Bias Circuitry
The linearity and supply current for both amplifiers are
externally programmable with a single resistor, R
BIAS
,
from BIAS to GND. A nominal resistor value of 15k Ω
sets an input IP3 of +17.5dBm, an input IP2 of
+27dBm, and a supply current of 93mA. Decrease the
resistor value to improve linearity at the cost of
increased supply current. Increase the resistor value to
decrease supply current and degrade linearity. Use
resistor values greater than 10k
Ω. Gain is not signifi-
cantly affected by the R BIAS value.
Applications Information
Inductor Selection
The OUT1 port of the LNA requires a pull-up inductor to
V
CC for proper biasing. The exact value of the inductor
is not important as long as it has broadband imped-
ance >150
Ω (<500Ω) at 10MHz across the 44MHz to
878MHz frequency band. Table 1 is a list of recom-
mended inductors.
Pin Description
PIN NAME FUNCTION
1 V CC
Supply Voltage Input. Bypass with a 1000pF capacitor in parallel with a 47pF capacitor as close to
the pin as possible. (See Typical Application Circuit.)
2 IN
Broadband Input to Low-Noise Amplifier and Loop-Out Amplifier. Internally matched to 75 Ω.
Requires 0.1 µF DC-blocking capacitor. (See Typical Application Circuit.)
3 BIAS
Bias-Setting Resistor Connection. Connect a resistor, R BIAS , from BIAS to GND to set the linearity
and supply current of the LNA and the loop-out amplifier.
4, 6, 7, EP GND
Ground. Connect to ground plane with a low-inductance connection. Solder exposed paddle evenly
to the board groundplane.
5 OUT2
Output of Loop-Out Amplifier. Requires a 0.1 µF DC-blocking capacitor. (See Typical Application
Circuit.)
8 OUT1
Open-Collector Output of Low-Noise Amplifier. Requires a pullup inductor to V CC , as well as a 0.1 µF
DC-blocking capacitor. (See Typical Application Circuit.)
PART NUMBER MANUFACTURER
BLM11A221S Murata
BLM11A471SG Murata
BLM10A221SG Murata
BLM21A331SG Murata
Table 1. OUT1 Pullup Inductor
Recommended Components