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The regulators are not independent and have common control bits for output voltage setting. The
regulators can be configured to operate in either automatic or manual mode. The automatic regulator
mode setting ensures an optimal compromise between regulator PSRR and highest possible supply
voltage for RF output power. The manual mode allows the application to manually configure the regulator
settings.
SUPPLY
The regulator V
DD_RF
operation.
When configured for 5-V operation, the output voltage can be set from 4.3 V to 5 V in 100-mV steps. The current sourcing
V
DD_RF
capability for 5-V operation is 150 mA maximum over the adjusted output voltage range.
When configured for 3-V operation, the output voltage can be set from 2.7 V to 3.4 V, also in 100-mV steps. The current
sourcing capability for 3-V operation is 100 mA maximum over the adjusted output voltage range.
Regulator V
(pin 1) supplies voltage to analog circuits within the reader chip. The voltage setting is divided in two ranges.
DD_A
When configured for 5-V operation, the output voltage is fixed at 3.5 V. When configured for 3-V operation, the output voltage
V
can be set from 2.7 V to 3.4 V in 100-mV steps.
DD_A
NOTE: The V
DD_A
Regulator V
(pin 32) can be used to source the digital I/O of the reader chip together with other external system
DD_X
components. When configured for 5-V operation, the output voltage is fixed at 3.4 V. When configured for 3-V operation, the
output voltage can be set from 2.7 to 3.4 V in 100-mV steps.
V
DD_X
The total current sourcing capability of the V
NOTE: The V
DD_A
The V
pin (pin 4) is the positive supply pin for the RF output stage and is externally connected to the regulator output
DD_PA
V
DD_PA
V
(pin 3).
DD_RF
6.2.1 Negative Supply Connections
The negative supply connections are all externally connected together (to GND). The substrate connection
is V
(pin 10), the analog negative supply is V
SS
the RF output stage negative supply is V
V
(pin 7).
SS_RX
6.2.2 Digital I/O Interface
To allow compatible I/O signal levels, the TRF796x has a separate supply input V
input voltage range of 1.8 V to 5.5 V. This pin supplies the I/O interface (I/O_0 to I/O_7), IRQ, SYS_CLK,
and DATA_CLK pins of the reader. In typical applications, V
that the I/O signal levels of the MCU are the same as the internal logic levels of the reader.
6.2.3 Supply Regulator Configuration
The supply regulators can be automatically or manually configured by the control bits.
manual regulator settings for a 5-V system.
Table 6-4
and
Table 6-5
The automatic mode is the default configuration. In automatic mode, the regulators are automatically set
every time the system is activated by asserting the EN input high. The internal regulators are also
automatically reconfigured every time the automatic regulator selection bit is set high (on the rising edge).
Copyright © 2006–2017, Texas Instruments Incorporated
Table 6-1. Power Supplies
(pin 3) is used to source the RF output stage. The voltage regulator can be set for either 5-V or 3-V
and V
regulators are configured together (their settings are not independent).
DD_X
regulator is 20 mA (maximum) over the adjusted output range.
DD_X
and V
regulators are configured together (their settings are not independent).
DD_X
SS_TX
list the automatic mode gain settings for 5-V and 3-V systems, respectively.
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DESCRIPTION
(pin 15), the logic negative supply is V
SS_A
(pin 6), and the negative supply for the RF receiver input is
is connected directly to V
DD_I/O
Table 6-3
lists the manual regulator settings for a 3-V system.
TRF7960 TRF7961
TRF7960, TRF7961
SLOU186G – AUGUST 2006 – REVISED MAY 2017
SS_D
(pin 16), with an
DD_I/O
DD_X
Table 6-2
Detailed Description
(pin 29),
to ensure
lists the
11
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