19-4093; Rev 1; 4/11
KIT
ATION
EVALU
BLE
AVAILA
300MHz to 450MHz Frequency-Programmable
ASK/FSK Transmitter
General Description
The MAX7057 frequency-programmable UHF transmit-
ter is designed to transmit ASK/FSK data at a wide
range of frequencies from 300MHz to 450MHz. The
MAX7057 has internal tuning capacitors at the output of
the power amplifier that are programmable for match-
ing to an antenna or load. This allows the user to
change to a new frequency and match the antenna at
the new frequency simultaneously. The MAX7057 trans-
mits at a data rate up to 100kbps nonreturn-to-zero
(NRZ) (50kbps Manchester coded). Typical transmitted
power into a 50Ω load is +9.2dBm with a +2.7V supply.
The device operates from +2.1V to +3.6V and typically
draws under 12.5mA of current in FSK mode (8.5mA in
ASK mode) when the antenna-matching network is
designed to operate over the 315MHz to 433.92MHz
frequency range. For narrower operating frequency
ranges, the matching network can be redesigned to
improve efficiency. The standby current is less than
1µA at room temperature.
The MAX7057 reference frequency from the crystal
oscillator is multiplied by a fully integrated fractional-N
phase-locked loop (PLL). The multiplying factor of the
PLL is set by a 16-bit number, with 4 bits for integer
and 12 bits for fraction; the multiplying factor can be
anywhere between 19 and 28. The 12-bit fraction in the
synthesizer sets a tuning resolution equal to the refer-
ence frequency divided by 4096; frequency deviation
can be set as low as ±2kHz and as high as ±100kHz.
The fractional-N synthesizer eliminates the problems
associated with oscillator-pulling FSK signal generation.
The MAX7057 has a serial peripheral interface (SPI™)
for selecting all the necessary settings.
The MAX7057 is available in a 16-pin SO package and
is specified to operate in the -40°C to +125°C automo-
tive temperature range.
Features
o
Programmable Frequency Operation with Single
Crystal
o
Internal Variable Capacitor for Antenna Tuning
with Single-Matching Network
o
100kbps Data Rate (NRZ)
o
+2.1V to +3.6V Single-Supply Operation
o
< 12.5mA (FSK), < 8.5mA (ASK) DC Current Drain
o
< 1µA Standby Current
o
ASK/FSK Modulation
o
47% Carrier Tuning Range Using One Crystal
MAX7057
Ordering Information
PART
MAX7057ASE+
TEMP RANGE
-40°C to +125°C
PIN-PACKAGE
16 SO
+Denotes
a lead(Pb)-free package/RoHs-compliant package.
Pin Configuration
TOP VIEW
+
16 DVDD
15 GPO
CS 1
SDI 2
MAX7057
SCLK 3
PAGND 4
PAOUT 5
ROUT 6
PAVDD 7
AVDD 8
14 DGND
13 DIN
12 ENABLE
11 AGND
10 XTAL1
9 XTAL2
Applications
RF Remote Controls
Garage Door Openers
Home Automation
Automotive
Wireless Sensors
Wireless Game Consoles
Wireless Computer Peripherals
Security Systems
Typical Application Circuit and Functional Diagram appear
at end of data sheet.
SPI is a trademark of Motorola, Inc.
________________________________________________________________
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.
300MHz to 450MHz Frequency-Programmable
ASK/FSK Transmitter
MAX7057
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, PAVDD, AVDD, DVDD to AGND,
DGND, PAGND ...................................................-0.3V to +4.0V
All Other Pins..................................._GND - 0.3V to _V
DD
+ 0.3V
Continuous Power Dissipation (T
A
= +70°C)
16-Pin SO (derate 8.7mW/°C above +70°C)...............695.7mW
Operating Temperature .....................................-40°C to +125°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°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
(Typical
Application Circuit,
50Ω system impedance, tuned for 315MHz to 433.92MHz operation, V
AVDD
= V
DVDD
= V
PAVDD
= +2.1V
to +3.6V, f
RF
= 300MHz to 450MHz, f
CRYSTAL
= 16MHz, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at V
AVDD
= V
DVDD
= V
PAVDD
= +2.7V, T
A
= +25°C, unless otherwise noted. All min and max values are 100% tested at T
A
= +125°C, and
guaranteed by design and characterization over temperature, unless otherwise noted.)
PARAMETER
Supply Voltage
SYMBOL
V
DD
CONDITIONS
PAVDD, AVDD, and DVDD connected to
power supply, V
DD
PA off, V
DIN
at 0%
duty cycle (ASK)
Supply Current
I
DD
f
RF
= 315MHz
f
RF
= 433.92MHz
MIN
2.1
TYP
2.7
3.9
4.5
8.1
8.5
12.2
12.4
0.8
1
6.2
0.9 x
V
DVDD
0.1 x
DV
DD
13
9
V
OH
V
OL
I
SINK
= 500µA (GPO)
I
SOURCE
= 500µA (GPO)
V
DD
-
0.37
0.36
6.4
20.1
µA
MAX
3.6
6.5
7.5
15.1
15.0
23.7
22.4
mA
UNITS
V
V
DIN
at 50% duty cycle f
RF
= 315MHz
(ASK) (Notes 1, 2, 3)
f
RF
= 433.92MHz
V
DIN
at 100% duty
cycle (FSK) (Note 1)
f
RF
= 315MHz
f
RF
= 433.92MHz
T
A
= +25°C (Note 3)
T
A
< +85°C (Note 3)
T
A
< +125°C
Standby Current
DIGITAL I/O
Input High Threshold
Input Low Threshold
Input Pulldown Sink Current
Input Pullup Source Current
Output-Voltage High
Output-Voltage Low
I
STDBY
V
ENABLE
< V
IL
V
IH
V
IL
V
V
µA
µA
V
V
2
_______________________________________________________________________________________
300MHz to 450MHz Frequency-Programmable
ASK/FSK Transmitter
AC ELECTRICAL CHARACTERISTICS
(Typical
Application Circuit,
50Ω system impedance, tuned for 315MHz to 433.92MHz operation, V
AVDD
= V
DVDD
= V
PAVDD
= +2.1V
to +3.6V, f
RF
= 300MHz to 450MHz, f
CRYSTAL
= 16MHz, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at V
AVDD
= V
DVDD
= V
PAVDD
= +2.7V, T
A
= +25°C, unless otherwise noted. All min and max values are 100% tested at T
A
= +125°C, and
guaranteed by design and characterization over temperature, unless otherwise noted.)
PARAMETER
GENERAL CHARACTERISTICS
Frequency Range
ENABLE transition low-to-high, frequency
settled to within 50kHz of the desired carrier
Power-On Time
t
ON
ENABLE transition low-to-high, frequency
settled to within 5kHz of the desired carrier
ASK mode
Maximum Data Rate
FSK mode
Frequency Switching Time
PHASE-LOCKED LOOP (PLL)
VCO Gain
K
VCO
f
RF
= 315MHz
PLL Phase Noise
f
RF
= 433.92MHz
Loop Bandwidth
Reference Frequency Input Level
Frequency-Divider Range
Frequency Deviation (FSK)
CRYSTAL OSCILLATOR
Crystal Frequency
Frequency Pulling by V
DD
Crystal Load Capacitance
POWER AMPLIFIER (PA)
(Note 4)
T
A
= +25°C (Note 3)
Output Power (Note 1)
P
OUT
T
A
= +125°C, V
AVDD
= V
DVDD
= V
PAVDD
=
+2.1V
T
A
= -40°C, V
AVDD
= V
DVDD
= V
PAVDD
=
+3.6V (Note 3)
Modulation Depth
Maximum Carrier Harmonics
Reference Spur
With output matching
network
f
RF
= 315MHz
f
RF
= 433.92MHz
3.8
2.4
f
XTAL
10.71
16
4
10
9.2
5.2
12.6
71
-29
-44
-45
17.0
dB
dBc
dBc
16.4
dBm
23.68
MHz
ppm/V
pF
19
±2
10kHz offset
1MHz offset
10kHz offset
1MHz offset
320
-78
-98
-73
-98
300
500
28
±100
kHz
kHz
mV
P-P
dBc/Hz
MHz/V
Manchester encoded
Nonreturn-to-Zero
Manchester encoded
Nonreturn-to-Zero
300
120
µs
260
50
100
50
100
70
µs
kbps
450
MHz
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX7057
Time from end of SPI write to frequency
settled to within 5kHz of desired carrier
_______________________________________________________________________________________
3
300MHz to 450MHz Frequency-Programmable
ASK/FSK Transmitter
MAX7057
AC ELECTRICAL CHARACTERISTICS (continued)
(Typical
Application Circuit,
50Ω system impedance, tuned for 315MHz to 433.92MHz operation, V
AVDD
= V
DVDD
= V
PAVDD
= +2.1V
to +3.6V, f
RF
= 300MHz to 450MHz, f
CRYSTAL
= 16MHz, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at V
AVDD
= V
DVDD
= V
PAVDD
= +2.7V, T
A
= +25°C, unless otherwise noted. All min and max values are 100% tested at T
A
= +125°C, and
guaranteed by design and characterization over temperature, unless otherwise noted.)
PARAMETER
Minimum SCLK Low to Falling-
Edge of
CS
Setup Time
Minimum
CS
Low to Rising-Edge
of SCLK Setup Time
Minimum SCLK Low to Rising-
Edge of
CS
Setup Time
Minimum SCLK Low After Rising-
Edge of
CS
Hold Time
Minimum Data Valid to SCLK
Rising-Edge Setup Time
Minimum Data Valid to SCLK
Rising-Edge Hold Time
Minimum SCLK High Pulse Width
Minimum SCLK Low Pulse Width
Minimum
CS
High Pulse Width
Maximum Transition Time from
Falling-Edge of
CS
to Valid GPO
Maximum Transition Time from
Falling-Edge of SCLK to Valid
GPO
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
SERIAL INTERFACE (SPI) TIMING CHARACTERISTICS (Figure 1)
t
SC
t
CSS
t
HCS
t
HS
t
DS
t
DH
t
CH
t
CL
t
CSH
t
CSG
C
L
= 10pF load capacitance from GPO to
DGND
C
L
= 10pF load capacitance from GPO to
DGND
10
5
20
5
10
5
40
40
40
50
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
t
CG
50
ns
Note 1:
Note 2:
Note 3:
Note 4:
Supply current and output power are greatly dependent on board layout and PAOUT match.
50% duty cycle at 10kHz ASK data (Manchester coded).
Guaranteed by design and characterization, not production tested.
Dependent on PCB trace capacitance.
CS
t
SC
t
CSS
SCLK
t
DS
SDI
t
CSG
GPO
t
CG
t
DH
t
CL
t
CH
t
CSH
t
HCS
t
HS
Figure 1. SPI Timing Diagram
4
_______________________________________________________________________________________
300MHz to 450MHz Frequency-Programmable
ASK/FSK Transmitter
Typical Operating Characteristics
(50Ω system impedance, V
AVDD
= V
DVDD
= V
PAVDD
= +2.1V to +3.6V, f
RF
= 300MHz to 450MHz, T
A
= -40°C to +125°C, unless oth-
erwise noted. Typical values are at V
AVDD
= V
DVDD
= V
PAVDD
= +2.7V, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX7057 toc01
MAX7057
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX7057 toc02
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
5.5
SUPPLY CURRENT (mA)
5.0
4.5
4.0
3.5
3.0
T
A
= +25°C
f
RF
= 315MHz
PA OFF
T
A
= +85°C
T
A
= +125°C
MAX7057 toc03
18
17
16
SUPPLY CURRENT (mA)
15
14
13
12
11
10
9
8
2.1
f
RF
= 315MHz
PA ON
T
A
= +85°C
12
11
SUPPLY CURRENT (mA)
10
9
8
7
6
5
T
A
= -40°C
T
A
= +125°C
f
RF
= 315MHz
50% DUTY CYCLE
T
A
= +85°C
6.0
T
A
= +125°C
T
A
= +25°C
T
A
= -40°C
T
A
= +25°C
2.5
2.0
2.1
2.4
2.7
3.0
3.3
3.6
2.1
2.4
T
A
= -40°C
2.4
2.7
3.0
3.3
3.6
2.7
3.0
3.3
3.6
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX7057 toc04
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX7057 toc05
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
6.5
SUPPLY CURRENT (mA)
6.0
5.5
5.0
4.5
4.0
3.5
3.0
T
A
= -40°C
2.1
2.4
2.7
3.0
3.3
3.6
T
A
= +25°C
T
A
= +125°C
f
RF
= 433.92MHz
PA OFF
T
A
= +85°C
MAX7057 toc06
MAX7057 toc09
18
17
16
SUPPLY CURRENT (mA)
15
14
13
12
11
10
9
8
2.1
f
RF
= 433.92MHz
PA ON
T
A
= +85°C
T
A
= +125°C
12
11
SUPPLY CURRENT (mA)
10
9
8
7
T
A
= -40°C
6
5
T
A
= +25°C
f
RF
= 433.92MHz
50% DUTY CYCLE
T
A
= +85°C
7.0
T
A
= +125°C
T
A
= +25°C
T
A
= -40°C
2.4
2.7
3.0
3.3
3.6
2.1
2.4
2.7
3.0
3.3
3.6
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
OUTPUT POWER
vs. SUPPLY VOLTAGE
MAX7057 toc07
OUTPUT POWER
vs. SUPPLY VOLTAGE
f
RF
= 433.92MHz
PA ON
T
A
= -40°C, +25°C
MAX7057 toc08
SUPPLY CURRENT AND OUTPUT POWER
vs. EXTERNAL RESISTOR
14
12
SUPPLY CURRENT (mA)
10
8
6
-10
4
2
0
f
RF
= 315MHz
PA ON
0.1
1
10
100
1000
-15
-20
-25
10,000
SUPPLY CURRENT
-5
15
10
OUTPUT POWER (dBm)
5
0
OUTPUT POWER
14
12
OUTPUT POWER (dBm)
10
8
6
T
A
= +125°C
4
2
0
2.1
2.4
2.7
3.0
3.3
T
A
= +85°C
f
RF
= 315MHz
PA ON
T
A
= -40°C
T
A
= +25°C
14
12
OUTPUT POWER (dBm)
10
8
6
4
2
0
T
A
= +125°C
T
A
= +85°C
3.6
2.1
2.4
2.7
3.0
3.3
3.6
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
EXTERNAL RESISTOR (Ω)
_______________________________________________________________________________________
5
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