Texas Instruments 2000 series, Справочное руководство

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High Performance RA-RFM RI-RFM-008B February 2002
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3.1 Power Supply Requirements
The logic and receiver sections of the RA-RFM must be supplied via the VSL and
GND pins with unregulated voltage.
The transmitter power stage is separately supplied via VSP and GNDP. As there is
no stabilization circuitry on the RA-RFM and as the transmitter power stage needs
a regulated supply voltage in order to meet FCC/PTT regulations, the supply
voltage for the transmitter power stage must be regulated externally. For the
voltage supply range please refer to chapter 2, Specifications.
Note:
The RA-RFM should not be supplied by switched mode power
supplies (SMPS) as most SMPS operate at frequencies of around
50 kHz. The harmonics of the generated field may interfere with the
TI-RFID receiver and therefore only linear power supplies, or SMPS
with a fundamental operating frequency of 200 kHz or higher are
recommended.
Noise from power supplies or from interface lines may interfere with receiver
operation. It is recommended to add additional filters in series to the supply and
interface lines if required by the application. For more details refer to Appendix 8,
Noise Verification and Appendix 9, Over
Voltage Protection.
In order to guarantee full RA-RFM performance, the power supplies should fulfill
the specifications for ripple voltage given in Table 13.
Table 13: Power Supply Ripple Specifications
Supply Type Maximum Ripple Voltage Allowable Ripple Frequency
Unregulated VSL supply 30 mV rms 0 to 100 kHz maximum
(sinusoidal)
Regulated VSP supply 50 mV rms 0 to 50 kHz maximum
(sinusoidal)