19-3469; Rev 2; 4/08
KIT
ATION
EVALU
BLE
AVAILA
Single-Chip Global Positioning System
Receiver Front-End
General Description
Features
♦
Complete Single-Chip GPS Front-End Receiver
♦
Single-Ended or Differential Outputs at 1.023MHz
♦
Low 4.5dB Typical Noise Figure
♦
No External IF SAW or Discrete Filters Required
♦
Very Low 32mW Power Consumption at +2.4V
♦
Wide +2.4V to +3.6V Operational Supply Voltage
Range
♦
Extended -40°C to +85°C Temperature Range
MAX2742
The MAX2742 complete single-chip global positioning
system (GPS) RF front-end utilizes many innovative and
leading-edge RF CMOS design techniques. This high-
performance, state-of-the-art device consumes extreme-
ly low power and eliminates the need for costly SAW
and bulky discrete IF filters. The MAX2742 incorporates
a fully integrated low-noise amplifier (LNA) and mixer, IF
section, digital sampler, and local oscillator synthesizer.
The intended input signal for the MAX2742 is the L1
GPS signal 1.57542GHz. This device supports high-
accuracy output quantization, which delivers the best
performance obtainable for the GPS receiver. The
power consumption of the MAX2742 is as low as 32mW
at a +2.4V supply.
The MAX2742 is available in a space-saving 48-pin
TQFP package and is specified for the extended (-40°C
to +85°C) temperature range.
Applications
In-Vehicle Navigation Systems (IVNS)
Location-Based Services (PDAs and
Accessories)
Recreational Handheld/Walkie Talkies
Geographical Information Systems (GISs)
Telematics (Vehicle, Asset Tracking, and
Inventory Management)
Emergency Roadside Assistance
XTALIN2
XTALIN1
Ordering Information
PART
MAX2742ECM
MAX2742ECM+
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
48 TQFP-EP*
48 TQFP-EP*
*EP
= Exposed paddle.
+Denotes
lead-free package.
Block Diagram/
Pin Configuration
CPOUT
VTUNE
48
RBIAS
CBIAS
V
DD
V
DD
GND
GND
RFIN
GND
GND
1
2
3
4
5
6
7
8
9
VGA
AGC
COMP
LNA
BIAS
CP
CONTROL
BLOCK
47
46
45
44
43
42
41
40
39
38
37
36 I.C.
35 I.C.
34 I.C.
PFD
DIV
33 I.C.
32 V
DD
31 DIN
30 GND
29 CLKOUT2
28 DOUT
27 I.C.
26 CLKOUT1
25 V
DD
13
GND
14
DCLK
15
CLKENB2
16
CLKENB1
17
V
DD
18
AGCFLT
19
OUT-
20
OUT+
21
I.C.
22
I.C.
23
V
DD
24
GND
SHDN
GND
GND
GND
V
DD
V
DD
V
DD
I.C.
Emergency Response Systems
Digital Cameras/Camcorders
Consumer Electronics
TCXO
BUFFER
MAX2742
IFSEL 10
I.C. 11
V
DD
12
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Single-Chip Global Positioning System
Receiver Front-End
MAX2742
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND ...........................................................-0.3V to +3.7V
All Other Pins to GND.................................-0.3V to (V
DD
+ 0.3V)
RF LNA Input Power .......................................................+10dBm
Continuous Power Dissipation (T
A
= +70°C)
48-Pin TQFP-EP (derate 12.5mW/°C above +70°C) ....100mW
CAUTION!
ESD SENSITIVE DEVICE
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Soldering Temperature (10s) ...........................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS
(MAX2742 EV kit, V
DD
= +2.4V to +3.6V, V
SHDN
= V
DD
, T
A
= -40°C to +85°C. Typical values are at V
DD
= +3V and T
A
= +25°C,
unless otherwise noted.)
PARAMETER
Supply Voltage
Supply Current
Logic-Input High Voltage
Logic-Input Low Voltage
Logic-Input Bias Current
-40
CONDITIONS
V
DD
= +3.0V, T
A
= +25°C (Note 1)
Shutdown mode, V
SHDN
= 0V
V
DD
- 0.5
0.5
+40
MIN
2.4
TYP
14
10
MAX
3.6
20
UNITS
V
mA
µA
V
V
µA
AC ELECTRICAL CHARACTERISTICS
(MAX2742 EV kit, V
DD
= +2.4V to +3.6V, V
SHDN
= V
DD
, T
A
= -40°C to +85°C. Typical values are at V
DD
= +3V and T
A
= +25°C,
unless otherwise noted.)
PARAMETER
GENERAL PERFORMANCE
Maximum Conversion Gain
Input Frequency
Noise Figure
Return Loss (S11)
LNA/Mixer Input IP3
Output IF Frequency
OUTPUT STAGE
Output Rise/Fall Time
Output-Voltage-Level Low
Output-Voltage-Level High
Differential (VOUT+, VOUT-), C
L
< 20pF
Single ended (DOUT), C
L
< 20pF
Differential
Single ended
Differential
Single ended
25
5
V
DD
- 0.9
0
V
DD
ns
V
V
f
1
= 1.5MHz and f
2
= 2.0MHz above carrier frequency
Measured at quantizer input
(Notes 2, 3)
91
102
1575.42
4.5
-15
-32
1.023
117
dB
MHz
dB
dB
dBm
MHz
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
Single-Chip Global Positioning System
Receiver Front-End
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX2742 EV kit, V
DD
= +2.4V to +3.6V, V
SHDN
= V
DD
, T
A
= -40°C to +85°C. Typical values are at V
DD
= +3V and T
A
= +25°C,
unless otherwise noted.)
PARAMETER
SYNTHESIZER
TCXO Input Frequency
Charge-Pump Current
Phase Noise
Comparison Frequency Spur
VCO Turning Range
VCO Tuning Gain
IF STAGE
IF Stage Gain
Dynamic Range IF Stage Gain
Bandpass Filter 1dB Corner
Frequency
Bandpass Filter 60dB High-Side
Rejection
Image Rejection
In-Band Ripple
AGC Loop Lock Time
Low-frequency corner
High-frequency corner
VGA set at maximum gain
77
50
0.1
3.2
5.0
18
1
1
dB
dB
MHz
MHz
dB
dB
ms
f
OFFSET
= 10kHz offset, BW
LOOP
= 70kHz
f
OFFSET
= 1MHz offset, BW
LOOP
= 70kHz
BW
LOOP
= 70kHz
(Notes 2, 3)
(Notes 2, 3)
148
139
Fundamental frequency crystal
18.414
0.4
-71
-106
-66
210
200
277
305
MHz
mA
dBc/Hz
dBc
MHz
MHz/V
CONDITIONS
MIN
TYP
MAX
UNITS
MAX2742
Note 1:
At T
A
= +25°C, min/max limits are guaranteed by production test.
Note 2:
At T
A
= -40°C, min/max limits are guaranteed by design and characterization.
Note 3:
At T
A
= +25°C and +85°C, min/max limits are guaranteed by production test.
_______________________________________________________________________________________
3
Single-Chip Global Positioning System
Receiver Front-End
MAX2742
Typical Operating Characteristics
(MAX2742 EV kit, V
DD
= +3V, and T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. TEMPERATURE
MAX2742 toc01
LNA/MIXER GAIN
vs. TEMPERATURE
29
28
LNA-MIXER GAIN (dB)
27
26
25
24
23
22
21
V
CC
= +3.0V
V
CC
= +2.7V
MAX2742 toc02
16
15
SUPPLY CURRENT (mA)
V
CC
= +3.0V
14
13
12
11
10
-40
-20
0
20
40
60
V
CC
= +2.7V
V
CC
= +2.4V
30
V
CC
= +2.4V
20
80
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
MAXIMUM IF STAGE GAIN
vs. TEMPERATURE
MAX2742 toc03
TOTAL CONVERSION GAIN
vs. TEMPERATURE
MAX2742 toc04
80
105
79
V
CC
= +3.0V
VGA GAIN (dB)
78
V
CC
= +2.7V
104
SYSTEM GAIN (dB)
V
CC
= +3.0V
103
77
102
V
CC
= +2.7V
76
75
-40
-20
0
20
V
CC
= +2.4V
101
V
CC
= +2.4V
100
40
60
80
-40
-20
TEMPERATURE (°C)
0
20
40
TEMPERATURE (°C)
60
80
4
_______________________________________________________________________________________
Single-Chip Global Positioning System
Receiver Front-End
Pin Description
PIN
1
2
3, 4, 12, 17, 23,
25, 32, 39, 44, 46
5, 6, 8, 9, 13, 24,
30, 38, 42, 45
7
10
11, 21, 22,
27, 33–36, 40
14
15
16
18
19, 20
26
28
29
31
37
41
43
47, 48
—
NAME
RBIAS
CBIAS
V
DD
GND
RFIN
IFSEL
I.C.
DCLK
CLKENB2
CLKENB1
AGCFLT
OUT-, OUT+
CLKOUT1
DOUT
CLKOUT2
DIN
SHDN
VTUNE
CPOUT
XTALIN1,
XTALIN2
EP
FUNCTION
External Bias Resistor. Connect a 100kΩ
±1%
resistor in parallel with a 0.1µF capacitor in
series with a 71kΩ resistor to GND.
External Bias Capacitor. Connect a 0.1µF capacitor to GND.
Supply Voltage. Bypass to GND with 100pF and 100nF capacitors as close to the pin as
possible with the smaller value capacitor closer to the pin.
Ground. Connect to PC board ground plane.
LNA Input. Requires external matching network.
IF Output Select. Selects output type. Drive high for single-ended output, drive low for
differential output.
Internally Connected. Leave unconnected.
Digital Control Clock
Clock Output Enable 2. Drive high to enable limited-swing clock output.
Clock Output Enable 1. Drive high to enable full-swing clock output.
AGC External Filter
Differential Comparator Outputs
Full-Swing Clock Output
Digital Output
Limited-Swing Clock Output
Digital-Control Data Input
Shutdown. Drive SHDN low to disable all device functions. Drive SHDN high for normal
operation.
VCO Tuning Input. Connect directly to the loop filter output.
Charge-Pump Output. Connect directly to the loop filter input.
Crystal Oscillator Input. Connect XTALIN1 and XTALIN2 together and to the TCXO output
through a coupling capacitor.
Exposed Paddle. Internally connected to GND. Connect to PC board ground plane for
optimal performance.
MAX2742
_______________________________________________________________________________________
5
51单片机
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