Additional Information:
The MAX2681 is a miniature, low-cost, low-noise downconverter mixer designed for low-voltage, low-current operation, and is ideal for portable communications equipment. The MAX2681 can be used with input radio frequencies (RFs) between 400MHz and 2500MHz, to downconvert to intermediate frequencies (IF) between 10MHz to 500MHz. The input RF for a global positioning system (GPS) receiver is 1575MHz. Assuming a 70MHz IF, and high-side local oscillator (LO) injection (f
LO = 1645MHz), the MAX2681 achieves +10.5dB of gain, has a noise figure of 9.6dB, an input third-order intercept point (IIP3) of -0.8dBm and draws 8.8mA of supply current from a +3.0V supply. See
Figure 1 for component values and the schematic.
For application of the MAX2681 at 900MHz, 1950MHz of 2450MHz, or for further device information, consult the MAX2680/MAX2681/MAX2682 data sheet. For higher input IP3 performance, refer to the application note 890, "
Silicon Germanium (SiGe) Downconverter Tuned for GPS Receivers."
Figure 1. The MAX2681 EV kit schematic.
Table 1. The MAX2681 GPS Performance
V
CC = +3.0V, f
RF1 = 1575MHz, f
RF2 = 1576MHz, f
LO = 1645MHz, P
LO = -5dBm, f
IF = 70MHz
Parameter
|
Measure
Performance
|
Conversion Gain |
+10.5dB
|
Noise Figure |
9.6dB
|
Input Third-Order Intercept Point |
-0.8dBm
|
RF Input Return Loss |
-19.3dB
|
Supply Current |
8.8mA
|
NOTE: PCB losses are not taken into account.
© , Maxim Integrated Products, Inc.
|
The content on this webpage is protected by copyright laws of the United States and of foreign countries. For requests to copy this content, contact us.
APP 957:
APPLICATION NOTE
957,
AN957,
AN 957,
APP957,
Appnote957,
Appnote 957
|
maxim_web:en/products/power/display-power-control/display-drivers,maxim_web:en/products/comms/wireless-rf
maxim_web:en/products/power/display-power-control/display-drivers,maxim_web:en/products/comms/wireless-rf