MAX7044, Crystal-Based, ASK Transmitter

By Maxim Integrated 74

MAX7044, Crystal-Based, ASK Transmitter

Maxim Integrated's MAX7044, crystal-referenced, phase-locked-loop (PLL), VHF/UHF transmitter is designed to transmit OOK/ASK data in the 300 MHz to 450 MHz frequency range. The MAX7044 supports data rates up to 100 kbps, and provides output power up to 13 dBm into a 50 Ω load while only drawing 7.7 mA at 2.7 V.

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 2.1 V to 3.6 V. 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
  • 2.1 V to 3.6 V single-supply operation
  • OOK/ASK transmit data format
  • Up to 100 kbps data rate
  • 13 dBm output power into 50 Ω load
  • Low 7.7 mA (typical) operating supply current
  • Uses small, low-cost crystal
  • Small, 3 mm x 3 mm, 8-pin SOT23 package
  • Fast-on oscillator: 250 μs 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

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