User's Manual

TRF7970A
www.ti.com SLOS743K –AUGUST 2011–REVISED APRIL 2014
Power Amplifier Supply: V
DD_PA
The power amplifier of the TRF7970A is supplied through V
DD_PA
(pin 4). The positive supply pin for the RF
power amplifier is externally connected to the regulator output V
DD_RF
(pin 3).
I/O Level Shifter Supply: V
DD_I/O
The TRF7970A has a separate supply input V
DD_I/O
(pin 16) for the built-in I/O level shifter. The supported
input voltage ranges from 1.8 V to V
IN
, not exceeding 5.5 V. Pin 16 is used to supply the I/O interface pins
(I/O_0 to I/O_7), IRQ, SYS_CLK, and DATA_CLK pins of the reader. In typical applications, V
DD_I/O
is
directly connected to V
DD_X
, while V
DD_X
also supplies the MCU. This ensures that the I/O signal levels of
the MCU match the logic levels of the TRF7970A.
Negative Supply Connections: V
SS
, V
SS_TX
, V
SS_RX
, V
SS_A
, V
SS_PA
The negative supply connections V
SS_X
of each functional block are all externally connected to GND.
The substrate connection is V
SS
(pin 10), the analog negative supply is V
SS_A
(pin 15), the logic negative
supply is V
SS_D
(pin 29), the RF output stage negative supply is V
SS_PA
(pin 6), and the negative supply for
the RF receiver V
SS_RX
(pin 7).
Copyright © 2011–2014, Texas Instruments Incorporated Detailed Description 17
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