MAX2385 Datasheet, PDF (1/18 Pages) Maxim Integrated Products – CDMA + GPS LNA/Mixers

19-2205; Rev 0; 10/01
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CDMA + GPS LNA/Mixers
General Description
The MAX2385/MAX2386 LNA/mixer ICs are designed
for CDMA/cdma2000 1x and GPS applications. The
MAX2385/MAX2386 are optimized for the Japanese
832MHz to 870MHz band, and can also be configured
for the Korean/Chinese/U.S. 869MHz to 894MHz band.
To optimize linearity and current consumption, the
CDMA LNA comprises four gain states. The high-gain
LNA has a reduced supply-current mode for use when
no transmit (Tx) signal is present, and a high linearity
mode, which minimizes Tx cross-modulation in the
presence of a large interfering signal during talk mode.
Two low-gain modes, provide higher cascade IIP3 at
lower current. The lowest gain setting provides an LNA
bypass and an ultra-low chip current of 4mA. This sig-
nificantly extends the phone’s standby time and lowers
the overall current consumption of the phone.
Gain-switching hysteresis can be adjusted by selection
of an off-chip resistor, which sets the current and linear-
ity in each mode to customize switchover points.
In GPS mode, the MAX2386 LNA offers high gain and
the MAX2385 features lower current consumption with
lower gain. The CDMA paths of the MAX2385/MAX2386
are identical.
The MAX2385/MAX2386 include an on-chip LO divider,
which enables the use of one VCO module for both cel-
lular and GPS modes. An on-chip LO buffer to drive the
Tx upconverter further reduces system complexity.
Features
o Low Average Current Consumption: 4.5mA
(CDMA)
o +2.7V to +3.6V Operation
o 2.0dB Cascade GPS Noise Figure
o 2.5 dB Cascade CDMA Noise Figure
o Adjustable IIP3
o LO Output Buffer to Drive Tx Upconverter
o 1µA Shutdown Current
o Tiny 2.1mm ✕ 2.7mm Chip-Scale Package
(UCSP™)
o Single VCO for GPS and CDMA Operation
o LO Divider Improves Phase Noise/Desensitization
Ordering Information
PART
TEMP. RANGE BUMP-PACKAGE
MAX2385EBP-T
-40°C to +85°C
5 ✕ 4 UCSP*
MAX2386EBP-T
-40°C to +85°C
5 ✕ 4 UCSP*
*Requires a special solder temperature profile described in the
Absolute Maximum Ratings section.
Applications
CDMA/cdma2000 1x Cellular Phones with GPS
Block Diagram
GPS PATH
MAX2385
MAX2386
Pin Configuration/Functional Diagram/Typical Operating
Circuit appears at end of data sheet.
CDMA PATH
÷2
LO BUFFER
OUTPUT
UCSP is a trademark of Maxim Products, Inc.
LO BUFFER
ENABLE
VCO
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