MAX2642EXT+T Maxim Integrated Products, MAX2642EXT+T Datasheet - Page 6

• Manufacturer Part Number: MAX2642EXT+T
• Description: RF Amplifier IC AMP LOW NOISE with Gain-Step, Adju
• Manufacturer: Maxim Integrated Products
• Type: General Purpose Amplifierr

Specifications of MAX2642EXT+T

• Operating Frequency: 1000 MHz
• Noise Figure: 4.3 dB at 900 MHz
• Operating Supply Voltage: 3 V, 5 V
• Supply Current: 6.7 mA
• Maximum Power Dissipation: 245 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Number Of Channels: 1 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

900MHz SiGe, High IP3,
Low-Noise Amplifiers
Input matching is required for optimum performance.
The MAX2642/MAX2643 require a simple LC matching
network, as shown in the Typical Operating Circuit. To
further reduce cost and external component count,
replace the external inductor with a microstrip transmis-
sion line. The Typical Operating Circuit shows the rec-
ommended input-matching networks for the MAX2642/
MAX2643 at 900MHz. These values are optimized for
best simultaneous gain, noise figure, and return-loss
performance. To aid in the design of the matching net-
work for other frequencies, Tables 1–6 list typical
device S-parameters for various biases, and Tables 7,
8, and 9 list typical device noise parameters.
The MAX2642’s DC bias voltage at RFOUT serves as
an attenuation step input. When the DC voltage at
RFOUT through a 33kΩ resistor is less than +0.6V, the
device is in high-gain mode; if the DC voltage is greater
than +2.0V, the device is in low-gain mode. A standard
logic output can be applied as shown in the Typical
Operation Circuit. If no bias is applied, the device is in
high-gain mode.
6
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PIN
2, 5
1
3
4
6
Applications Information
RFOUT
NAME
BIAS
GND
RFIN
V
Attenuation Step (MAX2642)
CC
Resistor Bias Control. Connect a resistor, R
current (see Applications Information). The current through this pin is approximately 50mV divided
by R
Ground. For optimum performance, provide a low-inductance connection to the ground plane.
Amplifier Input. AC-couple to this pin with a DC-blocking capacitor. External matching network is
required for optimum performance.
Supply Voltage. Bypass with a 47pF capacitor directly to ground at the supply pin. Additional
bypassing may be necessary for long V
Amplifier Output. Internally matched to 50Ω. DC bias on this pin selects gain mode (MAX2642) or
shutdown mode (MAX2643) (see Applications Information).
BIAS
.
Input Matching
For the MAX2643, the recommended shutdown method
is to set the DC voltage at the RFOUT pin in a manner
similar to the MAX2642’s attenuation step. That is, when
the DC voltage at RFOUT is below +0.6V, the device is
shut down; if the DC voltage is greater than +2.0V, the
device is enabled.
For the MAX2642, shutdown is achieved by leaving
BIAS unconnected. Figure 1 shows the suggested
shutdown methods. Avoid capacitance at the BIAS pin
by connecting the bias resistor from BIAS to the switch.
Table 10 summarizes the operational modes.
A properly designed PC board is essential to any
RF/microwave circuit. Use controlled impedance lines
on all high-frequency inputs and outputs. Bypass with
decoupling capacitors located close to the device V
pin. For long V
additional decoupling capacitors. These additional
capacitors can be located farther away from the device
package. Proper grounding of the GND pins is essen-
tial. If the PC board uses a topside RF ground, connect
it directly to all GND pins. For a board where the
ground plane is not on the component layer, the best
technique is to connect the GND pins to the board with
a plated through-hole located close to the package.
CC
lines.
BIAS
FUNCTION
, from BIAS to ground. R
CC
lines, it may be necessary to add
BIAS
Pin Description
sets IP3 and supply
Layout Issues
Shutdown
CC