MAX7044_09 Datasheet, PDF (1/10 Pages) Maxim Integrated Products – 300MHz to 450MHz High-Efficiency, Crystal-Based +13dBm ASK Transmitter

19-3221; Rev 3; 6/09
EVAALVUAAILTAIOBNLEKIT
300MHz to 450MHz High-Efficiency,
Crystal-Based +13dBm ASK Transmitter
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 elimi-
nates many of the common problems with SAW-based
transmitters by providing greater modulation depth,
faster frequency settling, higher tolerance of the trans-
mit 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 microcon-
troller 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.
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
Typical Application Circuit
Features
o +2.1V to +3.6V Single-Supply Operation
o OOK/ASK Transmit Data Format
o Up to 100kbps Data Rate
o +13dBm Output Power into 50Ω Load
o Low 7.7mA (typ) Operating Supply Current*
o Uses Small, Low-Cost Crystal
o Small 3mm x 3mm 8-Pin SOT23 Package
o Fast-On Oscillator: 250μs Startup Time
* At 50% duty cycle (315MHz, 2.7V supply, +13dBm output
power)
Ordering Information
PART
TEMP RANGE
PIN-
PACKAGE
TOP MARK
MAX7044AKA+T -40°C to +125°C 8 SOT23-8 AEJW
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
Pin Configuration
100nF
220pF
ANTENNA
3.0V
680pF
f_XTAL
1
8
XTAL1 XTAL2
2
GND
7
V_DD
3 ^MAX7044 6
PAGND DATA
4
5
PAOUT CLKOUT
3.0V
100nF
DATA INPUT
CLOCK
OUTPUT
(f_CLKOUT =
f_XTAL/16)
TOP VIEW
+
XTAL1 1
GND 2
PAGND 3
MAX7044
PAOUT 4
8 XTAL2
7 V_DD
6 DATA
5 CLKOUT
SOT23
________________________________________________________________ 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.