R2000 datasheet(26/75 Pages) ETC

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Indy® R2000 Electrical, Mechanical, & Thermal Specification

5.5

Transmitter Modes

The Indy R2000 reader chip can operate in one of three transmitter modes, based on the power requirements and

the modulation scheme used. This section describes these modes.

5.5.1 Linear Mode

This is the default mode of operation. The R2000 Development Kit operates in this mode. The internal power

amplifier is biased class A (linear mode) for all transmit modulations.

5.5.2 Full Power Non-linear Mode (DSB-ASK)

To transmit the maximum allowable power of up to +30 dBm at the antenna, you must use an external PA. To

improve the power efficiency of the system, the chip uses a Class-C polar modulation approach. In CW mode, the

PA_out signal in the Indy R2000 drives the gate of the PA transistor into Class-C operation. A PA modulation DAC

amplitude modulates the drain of the PA transistor. Discrete devices are used to interface between the two different

voltage domains (see Figure 4-12). DSB-ASK is the only modulation supported in this mode.

Figure 4-12: Indy R2000 Reader Chip Transmit with External PA (DSB ASK)

transistor

modulation

transistor

to antenna

PA_bias

PA_out

PA_modulation

From

Indy R2000

Voltage

Converter

Voltage

Converter

5.5.3 Low Power Non-linear Mode (DSB-ASK)

The power control for this mode is similar to the full power mode, except that no external PA is used. Instead, an on-

chip PA with lower output power is used. DSB-ASK is the only mode available in this configuration.

Frequency generation

6.1

Internal synthesizer

Figure 6-1 shows the VCO tuning curves.

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