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SLOS758G – DECEMBER 2011 – REVISED MARCH 2020
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Detailed Description
Copyright © 2011–2020, Texas Instruments Incorporated
(1)
x = don't care
By default, the regulator setting algorithm sets the regulator outputs to a "Delta Voltage" of 250 mV below
VIN, but not higher than 5 V for VDD_RF and 3.4 V for VDD_A and VDD_X. The "Delta Voltage" in
automatic regulator mode can be increased up to 400 mV (for more details, see bits B0 to B2 in register
0x0B).
Power Amplifier Supply: VDD_PA
The power amplifier of the TRF7963A is supplied through VDD_PA (pin 4). The positive supply pin for the
RF power amplifier is externally connected to the regulator output VDD_RF (pin 3).
I/O Level Shifter Supply: VDD_I/O
The TRF7963A has a separate supply input VDD_I/O (pin 16) for the build in I/O level shifter. The
supported input voltage ranges from 1.8 V to VIN, however 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, VDD_I/O is directly connected to VDD_X while VDD_X also supplies the MCU. This ensures
that the I/O signal levels of the MCU match with the logic levels of the TRF7963A.
Negative Supply Connections: VSS, VSS_RX, VSS_A, VSS_PA
The negative supply connections VSS_X of each functional block are all externally connected to GND.
The substrate connection is VSS (pin 10), the analog negative supply is VSS_A (pin 15), the logic
negative supply is VSS_D (pin 29), the RF output stage negative supply is VSS_PA (pin 6), and the
negative supply for the RF receiver VSS_RX (pin 7).
6.4
Supply Regulator Settings
The input supply voltage mode of the reader must be selected. This is done in the Chip Status Control
register (0x00). Bit 0 in register 0x00 selects either 5-V or 3-V input supply voltage. The default
configuration is 5 V, which reflects an operating supply voltage range of 4.3 V to 5.5 V. If the supply
voltage is below 4.3 V, the 3-V configuration should be used.
The various regulators can be configured to operate in automatic or manual mode. This is done in the
Regulator and I/O Control register (0x0B) (see
and
).
Table 6-1. Supply Regulator Setting: 5-V System
REGISTER
ADDRESS
OPTION BITS SETTING IN REGULATOR CONTROL
REGISTER
(1)
COMMENTS
B7
B6
B5
B4
B3
B2
B1
B0
Automatic Mode (default)
0B
1
x
x
x
x
x
1
1
Automatic regulator setting with 250-mV difference
0B
1
x
x
x
x
x
1
0
Automatic regulator setting with 350-mV difference
0B
1
x
x
x
x
x
0
0
Automatic regulator setting with 400-mV difference
Manual Mode
0B
0
x
x
x
x
1
1
1
VDD_RF = 5 V, VDD_A = 3.4 V, VDD_X = 3.4 V
0B
0
x
x
x
x
1
1
0
VDD_RF = 4.9 V, VDD_A = 3.4 V, VDD_X = 3.4 V
0B
0
x
x
x
x
1
0
1
VDD_RF = 4.8 V, VDD_A = 3.4 V, VDD_X = 3.4 V
0B
0
x
x
x
x
1
0
0
VDD_RF = 4.7 V, VDD_A = 3.4 V, VDD_X = 3.4 V
0B
0
x
x
x
x
0
1
1
VDD_RF = 4.6 V, VDD_A = 3.4 V, VDD_X = 3.4 V
0B
0
x
x
x
x
0
1
0
VDD_RF = 4.5 V, VDD_A = 3.4 V, VDD_X = 3.4 V
0B
0
x
x
x
x
0
0
1
VDD_RF = 4.4 V, VDD_A = 3.4 V, VDD_X = 3.4 V
0B
0
x
x
x
x
0
0
0
VDD_RF = 4.3 V, VDD_A = 3.4 V, VDD_X = 3.4 V
