300MHz–960MHz ASK Transmitter with I²C Interface

Description

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The MAX41461/MAX41462 is a UHF sub-GHz ISM/SRD transmitter is designed to transmit On-Off Keying (OOK) or Amplitude-Shift Keying (ASK) data in the 286MHz to 960MHz frequency range. It integrates a fractional phase-locked-loop (PLL), so a single, low-cost crystal can be used to generate commonly used world-wide sub-GHz frequencies. The fast response time of the PLL allows for frequency-hopping spread spectrum protocols for increased range and security. The chip also features preset modes with pin-selectable frequencies so that only one wire is required for external microcontroller interface. The only frequency-dependent components required are for the external antenna matching network. Optionally, the device can be put into programmable mode and programmed using an I²C interface. The crystal-based architecture of the MAX41461/MAX41462 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. A clock-out signal at 800kHz is also provided.

The MAX41461/MAX41462 provides output power up to +13dBm into a 50Ω load while drawing < 8mA (Manchester coded). The output load can be adjusted to increase power up to +16dBm, and a PA boost mode can be enabled at frequencies above 850MHz to compensate for losses. The PA output power can also be controlled using programmable register settings in I²C mode.

The MAX41461/MAX41462 also features single-supply operation from +1.8V to +3.6V. The device has an auto-shutdown feature to extend battery life and a fast oscillator wake-up with data activity detection.

The MAX41461/MAX41462 is available in a 10-pin μMAX package and is specified over the -40°C to +105°C extended temperature range. The MAX41461/MAX41462 has an ESD rating of 2.5kV HBM.

Design Solution: How to Maximize the Wireless Power Range of Your UHF Sub-GHz Short-Range Device ›

Key Features

• Low Implementation Cost
  • Bits-to-RF Single Wire Operation
  • Low Bill-of-Materials (BOM)
  • Uses Single, Low-Cost, 16MHz Crystal
  • Small 3mm x 3mm μMAX-10 Package
• Increased Range, Data Rates, and Security
  • Up to +16dBm PA Output Power
  • Fast Frequency Switching for FHSS/DSSS
  • Fast-On Oscillator: < 250μs Startup Time
  • Up to 200kbps NRZ Data Rate
• Extend Battery Life with Low Supply Current
  • < 8mA ASK Manchester Coded
  • Selectable Standby and Shutdown Modes
  • Auto Shutdown at < 20nA (typ) Current
• Ease of Use
  • Pin Selectable 300MHz–928MHz Frequencies
  • Pin Compatible ASK and FSK Versions
  • +1.8V to +3.6V Single-Supply Operation
  • Fully Programmable with 400kHz/1MHz I²C Interface

Applications/Uses

• Automatic Meter Reading (AMR)
• Building Automation and Security
• Garage Door Openers (GDO)
• Internet of Things (IoT)
• Radio Control Toys
• Remote and Passive Keyless Entry (RKE/PKE)
• Tire Pressure Monitoring Systems (TPMS)
• Wireless Sensors and Alarms