General Description
The MAX1479 crystal-referenced phase-locked-loop
(PLL) VHF/UHF transmitter is designed to transmit ASK,
OOK, and FSK data in the 300MHz to 450MHz frequency
range. The MAX1479 supports data rates up to 100kbps
in ASK mode and 20kbps in FSK mode (both
Manchester coded). The device provides an adjustable
output power of more than +10dBm into a 50
load. The
crystal-based architecture of the MAX1479 eliminates
many of the common problems of SAW-based transmit-
ters by providing greater modulation depth, faster fre-
quency settling, higher tolerance of the transmit
frequency, and reduced temperature dependence.
These improvements enable better overall receiver per-
formance when using the MAX1479 together with a
superheterodyne receiver such as the MAX1470,
MAX1471, MAX1473, or MAX7033.
The MAX1479 is available in a 16-pin thin QFN pack-
age (3mm x 3mm) and is specified for the automotive
temperature range from -40°C to +125°C.
Applications
Remote Keyless Entry
Tire Pressure Monitoring
Security Systems
Radio-Controlled Toys
Wireless Game Consoles
Wireless Computer Peripherals
Wireless Sensors
RF Remote Controls
Garage Door Openers
Features
ETSI-Compliant EN300 220
+2.1V to +3.6V Single-Supply Operation
Supports ASK, OOK, and FSK Modulations
Adjustable FSK Shift
+10dBm Output Power into 50 Load
Low Supply Current (6.7mA in ASK Mode,
and 10.5mA in FSK Mode)
Uses Small Low-Cost Crystal
Small 16-Pin Thin QFN Package
Fast-On Oscillator--200µs Startup Time
Programmable Clock Output
MAX1479
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
________________________________________________________________ Maxim Integrated Products
1
16
15
14
13
9
10
11
12
CLK0
CLK1
DEV0
DEV1
TOP VIEW
4
3
2
1
ENABLE
EP
DIN
MODE
V
DD
5
6
7
8
V
DD_
PA
CLKOUT
PAOUT
ROUT
MAX1479
GND
XTAL2
XTAL1
DEV2
THIN QFN
(3mm x 3mm)
Pin Configuration
Ordering Information
MAX1479
ENABLE
DIN
MODE
V
DD
CLKOUT
V
DD_
PA
ROUT
P
AOUT
CLK0
CLK1
DEV0
DEV1
DEV2
XT
AL1
XT
AL2
GND
CRYSTAL
DRIVER
4
3
2
1
5
6
7
8
9
10
11
12
13
14
15
16
CLOCK
DIVIDER
DIVIDE
BY 32
LOOP
FILTER
ASK
FSK
PA
ENVELOPE
SHAPING
DEVIATION
PD/CP
VCO
Functional Diagram
19-3353; Rev 0; 8/04
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
*EP = Exposed paddle.
PART
TEMP RANGE
PIN-PACKAGE
MAX1479ATE
-40°C to +125°C
16 Thin QFN-EP*
Typical Application Circuit appears at end of data sheet.
MAX1479
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS
(Typical Application Circuit, all RF inputs and outputs are referenced to 50
, V
DD
= +2.1V to +3.6V, V
ENABLE
= V
DD
, T
A
= -40°C to
+125°C, unless otherwise noted. Typical values are at V
DD
= +2.7V, T
A
= +25°C, unless otherwise noted.) (Note 1)
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.
V
DD
to GND .............................................................-0.3V to +4V
All Other Pins to GND ................................-0.3V to (V
DD
+ 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
16-Pin Thin QFN (derate 14.7mW/°C above +70°C)...1176.5mW
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage
V
DD
2.1
3.6
V
f
RF
= 315MHz
2.9
4.3
PA off, V
DIN
at
0% duty cycle
(ASK or FSK)
(Note 2)
f
RF
= 433MHz
3.3
4.8
f
RF
= 315MHz
6.7
10.7
V
DIN
at 50% duty
cycle (ASK)
(Notes 3, 4)
f
RF
= 433MHz
7.3
11.4
f
RF
= 315MHz (Note 2)
10.5
17.1
Supply Current
I
DD
V
DIN
at 100%
duty cycle (FSK)
f
RF
= 433MHz (Note 4)
11.4
18.1
mA
T
A
= +25°C
0.2
T
A
< +85
°C (Note 4)
120
300
Standby Current
I
STDBY
V
ENABLE
< V
IL
T
A
< +125
°C (Note 2)
700
1600
nA
DIGITAL INPUTS AND OUTPUTS
Data Input High
V
IH
(Note 2)
V
DD
-
0.25
V
Data Input Low
V
IL
(Note 2)
0.25
V
Maximum Input Current
I
IN
20
µA
Output Voltage High
V
OH
CLKOUT, load = 10k
|| 10pF (Note 4)
V
DD
-
0.25
V
Output Voltage Low
V
OL
CLKOUT, load = 10k
|| 10pF (Note 4)
0.25
V
MAX1479
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
_______________________________________________________________________________________
3
Note 1: Supply current, output power, and efficiency are greatly dependent on board layout and PAOUT match.
Note 2: 100% tested at T
A
= +125°C. Guaranteed by design and characterization over temperature.
Note 3: 50% duty cycle at 10kHz ASK data (Manchester coded).
Note 4: Guaranteed by design and characterization, not production tested.
Note 5: V
ENABLE
= V
IL
to V
ENABLE
= V
IH
. f
OFFSET
is defined as the frequency deviation from the desired carrier frequency.
Note 6: Dependent on crystal and PC board trace capacitance.
Note 7: V
ENABLE
> V
IH
, V
DATA
> V
IH
, Efficiency = P
OUT
/ (V
DD
x I
DD
).
Note 8: Dependent on PC board trace capacitance.
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
SYSTEM PERFORMANCE
Frequency Range
f
RF
(Note 2)
300
450
MHz
Settle to within 50kHz
200
Turn-On Time (Note 5)
t
ON
Settle to within 5kHz
350
µs
ASK mode (Manchester coded)
100
Maximum Data Rate (Note 4)
FSK mode (Manchester coded)
20
kbps
f
RF
= 315MHz
55
Maximum FSK Frequency
Deviation
DEV[2:0] = 111
(Note 6)
f
RF
= 433MHz
80
kHz
T
A
= +25°C, V
DD
= +2.7V
6.8
10
12.0
T
A
= +125°C, V
DD
= +2.1V
2.7
5.3
Output Power (Note 2)
P
OUT
T
A
= -40°C, V
DD
= +3.6V
12.2
16.1
dBm
f
RF
= 315MHz
35
Transmit Efficiency with CW Tone
(Note 7)
f
RF
= 433MHz
34
%
f
RF
= 315MHz
27
Transmit Efficiency at 50% Duty
Cycle
f
RF
= 433MHz
25
%
PHASE-LOCKED-LOOP PERFORMANCE
VCO Gain
K
VCO
280
MHz/V
f
OFFSET
= 100kHz
-75
f
RF
= 315MHz
f
OFFSET
= 1MHz
-98
f
OFFSET
= 100kHz
-74
Phase Noise
f
RF
= 433MHz
f
OFFSET
= 1MHz
-98
dBc/Hz
f
RF
= 315MHz
-50
Maximum Carrier Harmonics
f
RF
= 433MHz
-45
dBc
Reference Spur
-40
dBc
Loop Bandwidth
BW
300
kHz
Crystal Frequency Range
f
XTAL
f
RF
/32
MHz
Crystal Tolerance
50
ppm
Crystal Load Capacitance
C
LOAD
(Note 8)
4.5
pF
Clock Output Frequency
D eter m i ned b y C LK0 and C LK1; see Tab l e 1
F
XTAL
/ N
MHz
AC ELECTRICAL CHARACTERISTICS
(Typical Application Circuit, all RF inputs and outputs are referenced to 50
, V
DD
= +2.1V to +3.6V, V
ENABLE
= V
DD
, T
A
= -40°C to
+125°C, unless otherwise noted. Typical values are at V
DD
= +2.7V, T
A
= +25°C, unless otherwise noted.) (Note 1)
MAX1479
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
4
_______________________________________________________________________________________
Typical Operating Characteristics
(Typical Application Circuit, V
DD
= +2.7V, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX1479 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
3.3
3.0
2.4
2.7
8
9
10
11
13
12
14
15
7
2.1
3.6
f
RF
= 315MHz
PA ON
T
A
= -40
°C
T
A
= +25
°C
T
A
= +125
°C
T
A
= +85
°C
3.3
3.0
2.7
2.4
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
5.0
2.1
3.6
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX1479 toc02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
f
RF
= 315MHz
PA 50% DUTY CYCLE AT 10kHz
T
A
= -40
°C
T
A
= +25
°C
T
A
= +125
°C
T
A
= +85
°C
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX1479 toc03
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
3.3
3.0
2.4
2.7
8
9
10
11
13
12
14
15
7
2.1
3.6
f
RF
= 433MHz
PA ON
T
A
= -40
°C
T
A
= +25
°C
T
A
= +125
°C
T
A
= +85
°C
3.3
3.0
2.7
2.4
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
5.0
2.1
3.6
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX1479 toc04
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
f
RF
= 433MHz
PA 50% DUTY CYCLE AT 10kHz
T
A
= -40
°C
T
A
= +25
°C
T
A
= +125
°C
T
A
= +85
°C
SUPPLY CURRENT vs. OUTPUT POWER
MAX1479 toc05
AVERAGE OUTPUT POWER (dBm)
SUPPLY CURRENT (mA)
6
2
-2
-6
-10
3
4
5
6
7
8
9
10
11
12
2
-14
10
f
RF
= 315MHz
PA ON
50% DUTY CYCLE
SUPPLY CURRENT vs. OUTPUT POWER
MAX1479 toc06
AVERAGE OUTPUT POWER (dBm)
SUPPLY CURRENT (mA)
6
2
-2
-6
-10
3
4
5
6
7
8
9
10
11
12
2
-14
10
f
RF
= 433MHz
PA ON
50% DUTY CYCLE
SUPPLY CURRENT AND OUTPUT POWER
vs. EXTERNAL RESISTOR
MAX1479 toc07
EXTERNAL RESISTOR (
)
SUPPLY CURRENT (mA)
OUTPUT POWER (dBm)
1k
100
1
10
4
6
8
10
14
12
16
18
2
-12
-8
-4
0
8
4
12
16
-16
0.1
10k
f
RF
= 315MHz
PA ON
POWER
CURRENT
SUPPLY CURRENT AND OUTPUT POWER
vs. EXTERNAL RESISTOR
MAX1479 toc08
EXTERNAL RESISTOR (
)
SUPPLY CURRENT (mA)
OUTPUT POWER (dBm)
1k
100
1
10
4
6
8
10
14
12
16
18
2
0.1
10k
f
RF
= 433MHz
PA ON
POWER
CURRENT
-12
-8
-4
0
8
4
12
16
-16
MAX1479
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
_______________________________________________________________________________________
5
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX1479 toc10
SUPPLY VOLTAGE (V)
OUTPUT POWER (dBm)
3.3
3.0
2.7
2.4
6
8
10
12
14
16
4
2.1
3.6
f
RF
= 433MHz
PA ON
T
A
= +25
°C
T
A
= +125
°C
T
A
= +85
°C
T
A
= -40
°C
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX1479 toc11
SUPPLY VOLTAGE (V)
OUTPUT POWER (dBm)
3.3
3.0
2.7
2.4
6
8
10
12
14
16
4
2.1
3.6
f
RF
= 315MHz
PA ON
ENVELOPE SHAPING
DISABLED
T
A
= +25
°C
T
A
= +125
°C
T
A
= +85
°C
T
A
= -40
°C
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX1479 toc12
SUPPLY VOLTAGE (V)
OUTPUT POWER (dBm)
3.3
3.0
2.7
2.4
6
8
10
12
14
16
4
2.1
3.6
f
RF
= 433MHz
PA ON
ENVELOPE SHAPING
DISABLED
T
A
= +25
°C
T
A
= +125
°C
T
A
= +85
°C
T
A
= -40
°C
PHASE NOISE vs. OFFSET FREQUENCY
MAX1479 toc13
OFFSET FREQUENCY (Hz)
PHASE NOISE (dBc/Hz)
1M
100k
10k
1k
-130
-120
-110
-100
-90
-80
-70
-60
-50
-40
-140
100
10M
f
RF
= 315MHz
f
RF
= 433MHz
CLOCK SPUR MAGNITUDE
vs. SUPPLY VOLTAGE
MAX1479 toc14
SUPPLY VOLTAGE (V)
CLKOUT SPUR MAGNITUDE (dBc)
3.3
3.0
2.7
2.4
-65
-60
-55
-50
-45
-40
-70
2.1
3.6
f
RF
= 315MHz
CLKOUT SPUR = f
RF
± f
CLKOUT
10pF LOAD CAPACITANCE
f
CLKOUT
= f
XTAL
/16
f
CLKOUT
= f
XTAL
/4
f
CLKOUT
= f
XTAL
/8
FREQUENCY STABILITY
vs. SUPPLY VOLTAGE
MAX1479 toc15
SUPPLY VOLTAGE (V)
FREQUENCY STABILITY (ppm)
3.3
3.0
2.7
2.4
-8
-6
-4
-2
0
2
4
6
8
10
-10
2.1
3.6
f
RF
= 315MHz
f
RF
= 433MHz
Typical Operating Characteristics (continued)
(Typical Application Circuit, V
DD
= +2.7V, T
A
= +25°C, unless otherwise noted.)
OUTPUT POWER vs. SUPPLY VOLTAGE
MAX1479 toc09
SUPPLY VOLTAGE (V)
OUTPUT POWER (dBm)
3.3
3.0
2.7
2.4
6
8
10
12
14
16
4
2.1
3.6
f
RF
= 315MHz
PA ON
T
A
= +25
°C
T
A
= +125
°C
T
A
= +85
°C
T
A
= -40
°C
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