General Description
The MAX7044 crystal-referenced phase-locked-loop
(PLL) VHF/UHF transmitter is designed to transmit
OOK/ASK data in the 300MHz to 450MHz frequency
range. The MAX7044 supports data rates up to 100kbps,
and provides output power up to +13dBm into a 50Ω load
while only drawing 7.7mA at 2.7V.
The crystal-based architecture of the MAX7044 eliminates
many of the common problems with SAW-based transmitters
by providing greater modulation depth, faster frequency
settling, higher tolerance of the transmit frequency, and
reduced temperature dependence. The MAX7044 also
features a low supply voltage of +2.1V to +3.6V. These
improvements enable better overall receiver performance
when using the MAX7044 together with a superheterodyne
receiver such as the MAX1470 or MAX1473.
A simple, single-input data interface and a buffered
clock-out signal at 1/16th the crystal frequency make the
MAX7044 compatible with almost any microcontroller or
code-hopping generator.
The MAX7044 is available in an 8-pin SOT23 package
and is specified over the -40°C to +125°C automotive
temperature range.
Features
●+2.1V to +3.6V Single-Supply Operation
●OOK/ASK Transmit Data Format
●Up to 100kbps Data Rate
● +13dBm Output Power into 50Ω Load
●Low 7.7mA (typ) Operating Supply Current*
●Uses Small, Low-Cost Crystal
●Small 3mm x 3mm 8-Pin SOT23 Package
● Fast-On Oscillator: 250μs Startup Time
Applications
●Remote Keyless Entry (RKE)
●Tire-Pressure Monitoring (TPM)
●Security Systems
●Garage Door Openers
●RF Remote Controls
●Wireless Game Consoles
●Wireless Computer Peripherals
●Wireless Sensors
*At 50% duty cycle (315MHz, 2.7V supply, +13dBm output power).
19-3221; Rev 5; 4/17
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
PART TEMP RANGE PIN-
PACKAGE
TOP
MARK
MAX7044AKA+T -40°C to +125°C 8 SOT23 AEJW
MAX7044
1XTAL1
ANTENNA
3.0V 3.0V
680pF
220pF
100nF 100nF
XTAL2
fXTAL
8
2GND VDD
7
3PAGND DATA INPUT
CLOCK
OUTPUT
(fCLKOUT =
fXTAL/16)
DATA 6
4PAOUT CLKOUT 5
DATA
CLKOUTPAOUT
1
+
2
8
7
XTAL2
VDD
GND
PAGND
XTAL1
SOT23
TOP VIEW
3
4
6
5
MAX7044
MAX7044 300MHz to 450MHz High-Efficiency,
Crystal-Based +13dBm ASK Transmitter
Typical Application Circuit Pin Conguration
Ordering Information
EVALUATION KIT AVAILABLE
VDD to GND .........................................................-0.3V to +4.0V
All Other Pins to GND .............................. -0.3V to (VDD + 0.3V)
Continuous Power Dissipation (TA = +70°C)
8-Pin SOT23 (derate 8.9mW/°C above +70°C) ..........714mW
Operating Temperature Range ......................... -40°C to +125°C
Storage Temperature Range ............................ -60°C to +150°C
Junction Temperature ...................................................... +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) ....................................... +260°C
(Typical Application Circuit, all RF inputs and outputs are referenced to 50Ω, VDD = +2.1V to +3.6V, TA = -40°C to +125°C, unless
otherwise noted. Typical values are at VDD = +2.7V, TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
SYSTEM PERFORMANCE
Supply Voltage VDD 2.1 3.6 V
Supply Current
(Note 2) IDD
fRF = 315MHz
VDATA at 50% duty
cycle (Notes 3, 4) 7.7 14.1
mA
PA on (Note 5) 13.8 25.4
PA off (Note 6) 1.7 2.8
fRF = 433MHz
VDATA at 50% duty
cycle (Notes 3, 4) 8.0 14.4
PA on (Note 5) 14.0 25.7
PA off (Note 6) 1.9 3.1
Standby Current ISTDBY
VDATA < VIL for
more than WAIT
time (Notes 4, 7)
TA < +25°C 40 130
nA
TA < +125°C 550 2900
Frequency Range (Note 4) fRF 300 450 MHz
Data Rate (Note 4) 0 100 kbps
Modulation Depth (Note 8) ON to OFF POUT ratio 90 dB
Output Power, PA On
(Notes 4, 5) POUT
fRF = 300MHz to
450MHz
TA = +25°C,
VDD = +2.7V 9.6 12.5 15.4
dBm
TA = +125°C,
VDD = +2.1V 5.9 9.0 12.0
TA = -40°C,
VDD = +3.6V 13.1 15.8 18.5
Turn-On Time tON
Oscillator settled to within 50kHz 220 µs
Oscillator settled to within 5kHz 450
Transmit Efciency with CW
(Notes 5, 9)
fRF = 315MHz 48 %
fRF = 433MHz 47
Transmit Efciency with 50% OOK
(Notes 3, 9)
fRF = 315MHz 43 %
fRF = 433MHz 41
MAX7044 300MHz to 450MHz High-Efciency,
Crystal-Based +13dBm ASK Transmitter
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Absolute Maximum Ratings
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.
Electrical Characteristics
(Typical Application Circuit, all RF inputs and outputs are referenced to 50Ω, VDD = +2.1V to +3.6V, TA = -40°C to +125°C, unless
otherwise noted. Typical values are at VDD = +2.7V, TA = +25°C, unless otherwise noted.) (Note 1)
Note 1: Supply current, output power, and efficiency are greatly dependent on board layout and PAOUT match.
Note 2: Production tested at TA = +25°C with fRF = 300MHz and 450MHz. Guaranteed by design and characterization over tem-
perature and frequency.
Note 3: 50% duty cycle at 10kbps with Manchester coding.
Note 4: Guaranteed by design and characterization, not production tested.
Note 5: PA output is turned on in test mode by VDATA = VDD/2 + 100mV.
Note 6: PA output is turned off in test mode by VDATA = VDD/2 - 100mV.
Note 7: Wait time: tWAIT = (216 x 32)/fRF.
Note 8: Generally limited by PCB layout.
Note 9: VDATA = VIH. Efficiency = POUT/(VDD x IDD).
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
PHASE-LOCKED LOOP (PLL)
VCO Gain 330 MHz/V
Phase Noise
fRF = 315MHz fOFFSET = 100kHz -84
dBc/Hz
fOFFSET = 1MHz -91
fRF = 433MHz fOFFSET = 100kHz -82
fOFFSET = 1MHz -89
Maximum Carrier Harmonics fRF = 315MHz -50 dBc
fRF = 433MHz -50
Reference Spur fRF = 315MHz -74 dBc
fRF = 433MHz -80
Loop Bandwidth 1.6 MHz
Crystal Frequency fXTAL fRF/32 MHz
Frequency Pulling by VDD 3 ppm/V
Crystal Load Capacitance 3 pF
DATA INPUT
Data Input High VIH
VDD -
0.25 V
Data Input Low VIL 0.25 V
Maximum Input Current 10 µA
Pulldown Current 10 µA
CLKOUT OUTPUT
Output Voltage Low VOL ISINK = 650µA (Note 4) 0.25 V
Output Voltage High VOH ISOURCE = 350µA (Note 4) VDD -
0.25 V
Load Capacitance CLOAD (Note 4) 10 pF
CLKOUT Frequency fXTAL/16 Hz
MAX7044 300MHz to 450MHz High-Efciency,
Crystal-Based +13dBm ASK Transmitter
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Electrical Characteristics (continued)
(Typical Application Circuit, VDD = +2.7V, TA = +25°C, unless otherwise noted.) (Note 1)
5
6
7
8
9
10
11
12
13
2.1 2.4 2.7 3.0 3.3 3.6
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX7044 toc02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +25°C
fRF = 315MHz
PA 50% DUTY CYCLE AT 10kHz
TA = -40°C
TA = +85°C
TA = +125°C
8
12
10
16
14
20
18
22
2.1 2.72.4 3.0 3.3 3.6
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX7044 toc03
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +25°C
fRF = 433MHz
PA ON
TA = -40°C
TA = +85°C
TA = +125°C
6
7
8
9
10
11
12
13
14
2.1 2.4 2.7 3.0 3.3 3.6
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX7044 toc04
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
TA = +25°C
fRF = 433MHz
PA 50% DUTY CYCLE AT 10kHz
TA = -40°C
TA = +85°C
TA = +125°C
8
10
14
12
16
18
2.1 2.72.4 3.0 3.3 3.6
OUTPUT POWER
vs. SUPPLY VOLTAGE
MAX7044 toc05
SUPPLY VOLTAGE (V)
OUTPUT POWER (dBm)
fRF = 315MHz
PA ON
TA = +25°C
TA = -40°C
TA = +85°C
TA = +125°C
8
10
14
12
16
18
2.1 2.72.4 3.0 3.3 3.6
OUTPUT POWER
vs. SUPPLY VOLTAGE
MAX7044 toc06
SUPPLY VOLTAGE (V)
OUTPUT POWER (dBm)
fRF = 433MHz
PA ON
TA = +25°C
TA = -40°C
TA = +85°C
TA = +125°C
-80
-78
-74
-76
-72
-70
2.1 2.72.4 3.0 3.3 3.6
REFERENCE SPUR MAGNITUDE
vs. SUPPLY VOLTAGE
MAX7044 toc07
SUPPLY VOLTAGE (V)
REFERENCE SPUR MAGNITUDE (dBc)
REFERENCE SPUR = fRF fXTAL
fRF = 433MHz
fRF = 315MHz
7
9
11
13
15
17
19
21
23
2.1 2.4 2.7 3.0 3.3 3.6
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX7044 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
fRF = 315MHz
PA ON
TA = -40°C
TA = +25°C
TA = +85°C
TA = +125°C
-3
-1
-2
1
0
2
3
2.1 2.72.4 3.0 3.3 3.6
FREQUENCY STABILITY
vs. SUPPLY VOLTAGE
MAX7044 toc08
SUPPLY VOLTAGE (V)
FREQUENCY STABILITY (ppm)
fRF = 433MHz
fRF = 315MHz
30
35
40
45
50
55
60
65
70
2.1 2.4 2.7 3.0 3.3 3.6
TRANSMIT POWER EFFICIENCY
vs. SUPPLY VOLTAGE
MAX7044 toc09
SUPPLY VOLTAGE (V)
TRANSMIT POWER EFFICIENCY (%)
fRF = 315MHz
PA ON
TA = -40°C
TA = +85°C
TA = +125°C
TA = +25°C
MAX7044 300MHz to 450MHz High-Efciency,
Crystal-Based +13dBm ASK Transmitter
Maxim Integrated
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Typical Operating Characteristics
(Typical Application Circuit, VDD = +2.7V, TA = +25°C, unless otherwise noted.) (Note 1)
20
25
30
35
40
45
50
55
60
2.1 2.4 2.7 3.0 3.3 3.6
TRANSMIT POWER EFFICIENCY
vs. SUPPLY VOLTAGE
MAX7044 toc10
SUPPLY VOLTAGE (V)
TRANSMIT POWER EFFICIENCY (%)
fRF = 315MHz
PA 50% DUTY CYCLE AT 10kHz
TA = -40°C
TA = +85°C
TA = +125°C
TA = +25°C
30
35
40
45
50
55
60
65
70
2.1 2.4 2.7 3.0 3.3 3.6
TRANSMIT POWER EFFICIENCY
vs. SUPPLY VOLTAGE
MAX7044 toc11
SUPPLY VOLTAGE (V)
TRANSMIT POWER EFFICIENCY (%)
fRF = 433MHz
PA ON TA = -40°C
TA = +85°C
TA = +125°C
TA = +25°C
15
25
20
40
35
30
55
50
45
60
2.1 2.72.4 3.0 3.3 3.6
TRANSMIT POWER EFFICIENCY
vs. SUPPLY VOLTAGE
MAX7044 toc12
SUPPLY VOLTAGE (V)
TRANSMIT POWER EFFICIENCY (%)
fRF = 433MHz
PA 50% DUTY CYCLE AT 10kHz TA = +25°C
TA = -40°C
TA = +85°C
TA = +125°C
-140
-110
-120
-130
-100
-90
-80
-70
-60
-50
-40
0.01 10.1 10 100 1 10
PHASE NOISE vs. OFFSET FREQUENCY
MAX7044 toc13
OFFSET FREQUENCY (kHz)
PHASE NOISE (dBc/Hz)
2
4
6
8
10
12
14
16
18
0 1 10 100 1000 10,000
SUPPLY CURRENT AND OUTPUT POWER
vs. EXTERNAL RESISTOR
MAX7044 toc14
EXTERNAL RESISTOR (Ω)
SUPPLY CURRENT (mA)
-16
-12
-8
-4
0
4
8
12
16
POWER
CURRENT
fRF = 315MHz
PA ON
OUTPUT POWER (dBm)
0
6
3
12
9
15
18
-10 -2 2-6 6 10 14
SUPPLY CURRENT vs. OUTPUT POWER
MAX7044 toc15
OUTPUT POWER (dBm)
SUPPLY CURRENT (mA)
fRF = 315MHz
PA ON
50% DUTY CYCLE
50kHz/
div
25µs/div
FREQUENCY SETTLING TIME
MAX7044 toc16
AM DEMODULATION OF PA OUTPUT
DATA RATE = 100kHz
MAX7044 toc17
5dB/
div
3.2µs/div
OUTPUT SPECTRUM
MAX7044 toc18
10dB/
div
0dB
100MHz/div
fRF = 315MHz
MAX7044 300MHz to 450MHz High-Efciency,
Crystal-Based +13dBm ASK Transmitter
Maxim Integrated
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www.maximintegrated.com
Typical Operating Characteristics (continued)
(Typical Application Circuit, VDD = +2.7V, TA = +25°C, unless otherwise noted.) (Note 1)
Detailed Description
The MAX7044 is a highly integrated ASK transmitter
operating over the 300MHz to 450MHz frequency band.
The IC requires only a few external components to
complete a transmit solution. The MAX7044 includes a
complete PLL and a highly efficient power amplifier. The
device is automatically placed into a low-power shutdown
mode and powers up when data is detected on the data
input. Once power is supplied to VDD, the DATA pin must
receive at least one logic pulse (low-high-low transition) in
order to properly initialize the device.
Shutdown Mode
The MAX7044 has an automatic shutdown mode that
places the device in low-power mode if the DATA input
has not toggled for a specific amount of time (wait time).
PIN NAME FUNCTION
1 XTAL1 1st Crystal Input. fXTAL = fRF/32.
2 GND Ground. Connect to system ground.
3 PAGND Ground for the Power Amplier (PA). Connect to system ground.
4 PAOUT Power-Amplier Output. The PA output requires a pullup inductor to the supply voltage, which can be
part of the output-matching network to an antenna.
5 CLKOUT Buffered Clock Output. The frequency of CLKOUT is fXTAL/16.
6DATA OOK Data Input. DATA also controls the power-up state. See the Shutdown Mode section.
7 VDD Supply Voltage. Bypass to GND with a 100nF capacitor as close as possible to the pin.
8 XTAL2 2nd Crystal Input. fXTAL = fRF/32.
-55
-52
-46
-49
-43
-40
2.1 2.72.4 3.0 3.3 3.6
CLKOUT SPUR MAGNITUDE
vs. SUPPLY VOLTAGE
MAX7044 toc19
SUPPLY VOLTAGE (V)
CLKOUT SPUR MAGNITUDE (dBc)
fRF = 315MHz
CLKOUT
PAGND
PAOUT
GND
DATA
XTAL1 /16
DATA
ACTIVITY
DETECTOR
LOCK DETECT 32x PLL
PA
CRYSTAL-
OSCILLATOR
DRIVER
XTAL2
VDD
MAX7044
MAX7044 300MHz to 450MHz High-Efciency,
Crystal-Based +13dBm ASK Transmitter
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Pin Description
Functional Diagram
Typical Operating Characteristics (continued)
The wait time is equal to 216 clock cycles of the crystal.
This equates to a wait time of approximately 6.66ms for
a 315MHz RF frequency and 4.84ms for a 433MHz RF
frequency. For other frequencies, calculate the wait time
with the following equation:
16
WAIT RF
2 x 32
tf
=
where tWAIT is the wait time to shutdown and fRF is the
RF transmit frequency.
When the device is in shutdown, a rising edge on DATA
initiates the warm up of the crystal and PLL. The crystal
and PLL must have 220μs settling time before data can
be transmitted. The 220μs turn-on time of the MAX7044
is dominated by the crystal oscillator startup time. Once
the oscillator is running, the 1.6MHz PLL loop bandwidth
allows fast frequency recovery during power amplifier
toggling.
When the device is operating, each edge on the data line
resets an internal counter to zero and it begins to count
again. If no edges are detected on the data line, the
counter reaches the end-of-count (216 clock cycles) and
places the device in shutdown mode. If there is an edge
on the data line before the counter hits the end of count,
the counter is reset and the process starts over. It may
be necessary to keep the power amplifier on steadily for
testing and debugging purposes. To do this, set the DATA
pin voltage slightly above the midpoint between VDD and
ground (VDD/2 + 100mV).
Phase-Locked Loop
The PLL block contains a phase detector, charge pump,
integrated loop filter, VCO, asynchronous 32x clock
divider, and crystal oscillator. This PLL requires no external
components. The relationship between the carrier and
crystal frequency is given by:
fXTAL = fRF/32
The lock-detect circuit prevents the power amplifier from
transmitting until the PLL is locked. In addition, the device
shuts down the power amplifier if the reference frequency
is lost.
Power Amplier (PA)
The PA of the MAX7044 is a high-efficiency, open-drain,
switch-mode amplifier. With a proper output matching
network, the PA can drive a wide range of impedances,
including the small-loop PCB trace antenna and any 50Ω
antenna. The output-matching network for an antenna
with a characteristic impedance of 50Ω is shown in the
Typical Application Circuit. The output matching network
suppresses the carrier harmonics and transforms the
antenna impedance to an optimal impedance at PAOUT,
which is about 125Ω.
When the output matching network is properly tuned, the
power amplifier transmits power with high efficiency.
The Typical Application Circuit delivers +13dBm at +2.7V
supply with 7.7mA of supply current. Thus, the overall
efficiency is 48% with the efficiency of the power amplifier
itself greater than 54%.
Buffered Clock Output
The MAX7044 provides a buffered clock output (CLKOUT)
for easy interface to a microcontroller or frequency-hop-
ping generator. The frequency of CLKOUT is 1/16 the
crystal frequency. For a 315MHz RF transmit frequency,
a crystal of 9.84375MHz is used, giving a clock output of
615.2kHz. For a 433.92MHz RF frequency, a crystal of
13.56MHz is used for a clock output of 847.5kHz.
The clock output is inactive when the device is in shut-
down mode. The device is placed in shutdown mode
by the internal data activity detector (see the Shutdown
Mode section). Once data is detected on the data input,
the clock output is stable after approximately 220μs.
Applications Information
Output Power Adjustment
It is possible to adjust the output power down to -15dBm
with the addition of a resistor (see R
PWRADJ
in Figure 1).
The addition of the power adjust resistor also reduces
power consumption. See the Supply Current and Output
Power vs. External Resistor and Supply Current vs. Output
Power graphs in the Typical Operating Characteristics
section. It is imperative to add both a low-frequency and a
high-frequency decoupling capacitor as shown in Figure 1.
Crystal Oscillator
The crystal oscillator in the MAX7044 is designed to
present a capacitance of approximately 3pF between the
XTAL1 and XTAL2 pins. If a crystal designed to oscillate
Figure 1. Output Power Adjustment Circuit
1XTAL1
ANTENNA
3.0V
3.0V
680pF
RPWRADJ
220pF
100nF
100nF
XTAL2
fXTAL
8
2GND VDD
7
3PAGND DATA INPUT
CLOCK
OUTPUT
(fCLKOUT =
fXTAL/16)
DATA 6
4PAOUT CLKOUT 5
MAX7044
MAX7044 300MHz to 450MHz High-Efciency,
Crystal-Based +13dBm ASK Transmitter
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with a different load capacitance is used, the crystal is
pulled away from its intended operating frequency, thus
introducing an error in the reference frequency. Crystals
designed to operate with higher differential load capacitance
always pull the reference frequency higher. For example,
a 9.84375MHz crystal designed to operate with a 10pF
load capacitance oscillates at 9.84688MHz with the
MAX7044, causing the transmitter to be transmitting
at 315.1MHz rather than 315.0MHz, an error of about
100kHz, or 320ppm.
In actuality, the oscillator pulls every crystal. The crystal’s
natural frequency is really below its specified frequency,
but when loaded with the specified load capacitance, the
crystal is pulled and oscillates at its specified frequency.
This pulling is already accounted for in the specification of
the load capacitance. Additional pulling can be calculated
if the electrical parameters of the crystal are known. The
frequency pulling is given by:
m6
pcase load case spec
C1 1
f x10
2CCCC
= −
++
where:
fp is the amount the crystal frequency is pulled in ppm.
Cm is the motional capacitance of the crystal.
Ccase (or Co) is the vendor-specified case capacitance
of the crystal.
Cspec is the specified load capacitance.
Cload is the actual load capacitance.
When the crystal is loaded as specified (i.e., Cload = Cspec)
the frequency pulling equals zero.
Output Matching to 50Ω
When matched to a 50Ω system, the MAX7044 PA is
capable of delivering up to +13dBm of output power
at VDD = 2.7V. The output of the PA is an open-drain
transistor that requires external impedance matching
and pullup inductance for proper biasing. The pullup
inductance from PA to VDD serves three main purposes:
it resonates the capacitance of the PA output, provides
biasing for the PA, and becomes a high-frequency choke
to reduce the RF energy coupling into VDD. The recom-
mended output-matching network topology is shown in
the Typical Application Circuit. The matching network
transforms the 50Ω load to approximately 125Ω at the
output of the PA in addition to forming a bandpass filter
that provides attenuation for the higher order harmonics.
Output Matching to
PCB Loop Antenna
In some applications, the MAX7044 power amplifier output
has to be impedance matched to a small-loop antenna.
The antenna is usually fabricated out of a copper trace on
a PCB in a rectangular, circular, or square pattern. The
antenna will have an impedance that consists of a lossy
component and a radiative component. To achieve high
radiating efficiency, the radiative component should be as
high as possible, while minimizing the lossy component.
In addition, the loop antenna will have an inherent loop
inductance associated with it (assuming the antenna
is terminated to ground). For example, in a typical
application, the radiative impedance is less than 0.5Ω, the
lossy impedance is less than 0.7Ω, and the inductance is
approximately 50nH to 100nH.
The objective of the matching network is to match the
power amplifier output to the small-loop antenna. The
matching components thus transform the low radiative
and resistive parts of the antenna into the much higher
value of the PA output. This gives higher efficiency. The
low radiative and lossy components of the small-loop
antenna result in a higher Q matching network than the
50Ω network; thus, the harmonics are lower.
Layout Considerations
A properly designed PCB is an essential part of any
RF/microwave circuit. At the power amplifier output,
use controlled-impedance lines and keep them as short
as possible to minimize losses and radiation. At high
frequencies, trace lengths that are approximately 1/20 the
wavelength or longer become antennas. For example, a
2in trace at 315MHz can act as an antenna.
Keeping the traces short also reduces parasitic
inductance. Generally, 1in of PCB trace adds about 20nH
of parasitic inductance. The parasitic inductance can
have a dramatic effect on the effective inductance. For
example, a 0.5in trace connecting a 100nH inductor adds
an extra 10nH of inductance, or 10%.
To reduce the parasitic inductance, use wider traces and a
solid ground or power plane below the signal traces. Using
a solid ground plane can reduce the parasitic inductance
from approximately 20nH/in to 7nH/in. Also, use low-
inductance connections to ground on all GND pins, and
place decoupling capacitors close to all VDD connections.
MAX7044 300MHz to 450MHz High-Efciency,
Crystal-Based +13dBm ASK Transmitter
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PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
8 SOT23 K8SN+1 21-0078 90-0176
MAX7044 300MHz to 450MHz High-Efciency,
Crystal-Based +13dBm ASK Transmitter
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│
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Package Information
For the latest package outline information and land patterns
(footprints), go to www.maximintegrated.com/packages. Note
that a “+”, “#”, or “-” in the package code indicates RoHS status
only. Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
Chip Information
PROCESS: CMOS
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
3 6/09 Changed part number in Ordering Information to lead-free and made a correction
in the Power Amplier (PA) section 1, 7
4 2/11
Deleted Maximum Crystal Inductance spec and Note 9 from the Electrical
Characteristics table and updated the Absolute Maximum Ratings, Shutdown
Mode, and Crystal Oscillator sections
2, 3, 7, 8
5 5/17 Updated Detailed Description section 6
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
MAX7044 300MHz to 450MHz High-Efciency,
Crystal-Based +13dBm ASK Transmitter
© 2017 Maxim Integrated Products, Inc.
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For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
