MAX2745 Datasheet, PDF (1/9 Pages) Maxim Integrated Products – Single-Chip Global Positioning System Receiver Front-End

19-3425; Rev 0; 10/04
EVAALVUAAILTAIOBNLEKIT _{Single-Chip Global Positioning System}
Receiver Front-End
General Description
The MAX2745 complete single-chip global positioning
system (GPS) RF front-end downconverter utilizes many
innovative and leading-edge RF CMOS design tech-
niques. This high-performance, state-of-the-art device
consumes extremely low power and eliminates the
need for costly SAW and bulky discrete IF filters. The
MAX2745 incorporates a fully integrated low-noise
amplifier (LNA) and mixer, IF section, digital sampler,
and local oscillator synthesizer. The MAX2745 also pro-
vides a voltage supply for an external LNA. In addition,
the MAX2745 features a voltage booster, which can
extend the power-supply voltage to as low as 1.6V.
The MAX2745 supports both 3rd overtone crystal
designs in 32MHz and fundamental frequency crystal
designs in 16MHz, as well as a TCXO implementation.
In addition, the MAX2745 incorporates an on-chip tem-
perature sensor and crystal oscillator with trimmed
capacitors, resulting in a very accurate frequency and
additional system cost savings.
The MAX2745 is available in a space-saving 48-pin
TQFP package and is specified for the extended (-40°C
to +85°C) temperature range. The power consumption
of this device is as low as 41mW at 2.4V.
Applications
In-Vehicle Navigation Systems (IVNSs)
Location-Based Services (PDAs and
Accessories)
Telematics (Vehicle/Asset Tracking and
Inventory Management)
Recreational Handheld/Walkie Talkies
Geographical Information Systems (GISs)
Emergency Roadside Assistance
Emergency Response Systems
Digital Cameras/Camcorders
Consumer Electronics
Features
o Complete Single-Chip GPS Radio for 16.368MHz
and 32.736MHz Floorplans
o Single-Ended or Differential Outputs at 4.092MHz
o Low 3.5dB Typical Noise Figure
o No External IF SAW or Discrete Filters Required
o On-Chip Temperature Sensor
o 2.4V to 3.6V Operational Supply Voltage Range
o Power Consumption as Low as 41mW at 2.4V
o Wide -40°C to +85°C Operational Temperature
Range
Ordering Information
PART
MAX2745ECM
TEMP RANGE
-40°C to +85°C
*EP = Exposed paddle.
PIN-PACKAGE
48 TQFP-EP*
Typical Operating Circuit appears at end of data sheet
Block Diagram/
Pin Configuration
48 47 46 45 44 43 42 41 40 39 38 37
RBIAS 1
36 BPF_CTRL
CBIAS 2
VCXO
MAX2745
TEMPERATURE
SENSOR
35 ODS
VDD 3
VDD 4
GND 5
BIAS
PFD _CHG
DIVIDER ^PUMP
34 CFS
33 COE
32 VDD
GND 6
RFIN 7
LNA/MIXER
VSPORT
31 SCLK
VCO
30 GND
GND 8
29 VOUT+
VDD 9
IEXT_LNA 10
VDD 11
BANDPASS FILTER
AGC
QUANTIZER
FILTER AUTOMATIC TUNING
VOLTAGE
BOOSTER
28 VOUT-
27 VDD
26 GND
AGC_FIL 12
25 VDD
13 14 15 16 17 18 19 20 21 22 23 24
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