Product Brief AS3977

Revision No. 1.3, Date: 02-2007

Page 1 of 2

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merged, translated, stored, or used without the prior written consent of the copyright owner. To the best of its knowledge,

austriamicrosystems asserts that the information contained in this publication is accurate and correct.

1. General Description

The AS3977 is a low-power fully integrated ETSI, FCC

and ARIB compliant FSK transmitter capable of operating

at any ISM frequency in the range of 300 to 928 MHz. It is

based on a sigma-delta controlled fractional-N synthesiser

phase locked loop with fully integrated voltage controlled

oscillator. The power amplifier output is programmable

and can deliver output power ranging from –20dBm up to

+10dBm. An on-chip low drop-out regulator is available in

case an accurate output power independent of voltage

supply variation is required.

The output signal can be shaped using a programmable

Gaussian filter to minimise the occupied bandwidth and

adjacent channel power. The maximum data rate can be

up to 100 kb/s – depending on the required filtering.

The FSK frequency deviation is programmable up to a

maximum of 64kHz.

The crystal oscillator can handle a wide range of

frequencies. For narrow-band applications a temperature

sensor with digital read-out is included that allows

compensation of the crystal frequency drift due to

temperature variation.

The AS3977 is connected to an external microcontroller

via a bi-directional digital interface. The device operates

at very low current consumption with a power supply

range from 2.0V to 3.6V and can be powered down when

not in use.

The device is fabricated in austriamicroystems advanced

0.35um SiGe-BiCMOS technology.

2. Key Features

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Compliant to ETSI EN 300-220, FCC CFR 47 part 15

and ARIB STD-T67

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Multi-channel with narrow bandwidth

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300 – 928 MHz operating frequency range (ISM)

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Filtered FSK

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Data rate up to 100 kb/s

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FSK deviation programmable up to 64kHz

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Extremely low power consumption

3. Main Characteristics

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2.0 – 3.6V power supply

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Output power up to +10dBm

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Occupied bandwidth 8.5 kHz (4.8 kb/s, FFSK, ARIB)

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4. Additional Features

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Sigma-Delta controlled fractional-N synthesiser

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Resolution of synthesiser <100Hz

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Fully integrated PLL

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Fully integrated voltage controlled oscillator

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4kV ESD protection (1.5kV for analogue pins)

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Automatic antenna tuning

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12 – 20 MHz crystal oscillator

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On-chip temperature sensor with digital readout for AFC

purposes

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Integrated Manchester coder

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Digital lock detector

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Low drop-out regulator

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Bi-directional serial interface

5. Applications

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Remote keyless entry systems

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Short range radio data transmission

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Domestic and consumer remote control units

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Cordless alarm systems

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Remote metering

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Low power telemetry

Multi-Channel Narrowband FSK Transmitter

AS3977

PRODUCT BRIEF

PRODUCT BRIEF

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