Micrel, Inc. Supplier Page

MICRF507 Low-Power FSK Transceiver

Micrel's transceiver targeted at automated meter reading applications in the China SRD frequency band

Micrel, Inc. - MICRF507 Low-Power FSK TransceiverMicrel, Inc.'s MICRF507 is a fully integrated FSK transceiver with +10dBm power amplifier and transmit/receive switch. This device is targeted at automated meter reading (AMR) applications in the China Short Range Device (SRD) frequency band of 470MHz to 510MHz. The device supports data rates up to 20kbps with PLL divider modulation and up to 200kbps with VCO modulation. The receiver achieves a sensitivity of -113dBm at a data rate of 2.4kbps while only consuming 12mA of supply current. The integrated power amplifier (PA) delivers +10dBm of output power while only consuming 21.5mA of supply current. Power down supply current is a low 0.2µA while retaining register information and a low 280µA in standby mode where only the crystal oscillator is enabled.

The receiver of the MICRF507 utilizes a Zero IF (ZIF) I/Q architecture, integrating a low-noise amplifier (LNA) with bypass mode, I/Q quadrature mixers, three-pole Sallen-Key IF channel pre-filters, and six-pole elliptic switched capacitor IF filters, providing excellent selectivity, adjacent channel rejection, and blocking performance. FSK demodulation is implemented digitally, and a synchronizer, when enabled, recovers the received bit clock.  A Receive Signal Strength Indicator (RSSI) circuit indicates the received signal level over a 50dB range. An integrated Frequency Error Estimator (FEE) and crystal tuning capability allow fine tuning of the RF frequency.

The transmitter of the MICRF507 consists of an FSK modulator and power amplifier with output power adjustable from +10dBm to -3.5dBm in seven steps. Modulation can be achieved by applying two sets of PLL divider ratios or through direct VCO modulation by varying VCO tank capacitance.

Click here to view diagram

  • -113dBm sensitivity at 2.4kbps encoded bit rate
  • +10dBm power amplifier with seven gain steps
  • 53dB adjacent channel rejection at ±500kHz offset
  • 0.2µA power down current (registers retain settings)
  • 280µA standby current (crystal oscillator enabled)
  • Data rates up to 20kbps with PLL divider modulation
  • 50kHz to 350kHz programmable baseband bandwidth
  • 50dB Received Signal Strength Indicator (RSSI)
  • Three-pole Sallen-Key IF channel low-pass pre-filter
  • Six-pole elliptic switched capacitor IF low-pass filter
  • Available in 32-pin MLF® package (5.0mm x 5.0mm x 0.85mm)
  • -40°C to +85°C operating temperature range
  • Data rates up to 200kbps with VCO modulation
  • IF pre-amplifiers with DC-offset removal
  • Integrated transmit and receive (T/R) switch
  • Zero IF I/Q receiver architecture
  • FSK digital demodulator with clock recovery
  • 21.5mA transmit supply current at +10dBm
  • 12mA receive supply current
  • Frequency Error Estimator (FEE)
  • Reference crystal tuning capability
  • 2.0 to 2.5V supply voltage rangeRoHS Compliant
  • LNA with bypass mode
  • 59dB blocking at ±1MHz offset

Micrel P/N Digi-Key P/N Packaging Description Frequency Datasheet
MICRF507YML TR 576-3694-2-ND Tape & Reel TXRX FSK LOW PWR
470MHz ~ 510MHz Datasheet
576-3694-1-ND Cut Tape
576-3694-6-ND Digi-Reel®