ZHCS363L August 2011 – March 2017 TRF7970A
PRODUCTION DATA.
The input supply voltage mode of the reader needs to be selected. This is done in the Chip Status Control register (0x00). Bit 0 in register 0x00 selects between 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.
As VDD_RF is increased, the system can become more susceptible to noise coupling on the RX lines. For minimum noise coupling, TI recommends using the value of 0x00. For improved range, higher VDD_RF voltages may be set, but complete system testing is required to determine the value which provides optimal performance.
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), as shown in Table 6-1 and Table 6-2.
REGISTER ADDRESS (hex) | 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 | 0 | 0 | Automatic regulator setting 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 |
REGISTER ADDRESS (hex) | 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 | 0 | 0 | Automatic regulator setting 400-mV difference |
Manual Mode | |||||||||
0B | 0 | x | x | x | x | 1 | 1 | 1 | VDD_RF = 3.4 V, VDD_A = 3.4 V, VDD_X = 3.4 V |
0B | 0 | x | x | x | x | 1 | 1 | 0 | VDD_RF = 3.3 V, VDD_A = 3.3 V, VDD_X = 3.3 V |
0B | 0 | x | x | x | x | 1 | 0 | 1 | VDD_RF = 3.2 V, VDD_A = 3.2 V, VDD_X = 3.2 V |
0B | 0 | x | x | x | x | 1 | 0 | 0 | VDD_RF = 3.1 V, VDD_A = 3.1 V, VDD_X = 3.1 V |
0B | 0 | x | x | x | x | 0 | 1 | 1 | VDD_RF = 3.0 V, VDD_A = 3.0 V, VDD_X = 3.0 V |
0B | 0 | x | x | x | x | 0 | 1 | 0 | VDD_RF = 2.9 V, VDD_A = 2.9 V, VDD_X = 2.9 V |
0B | 0 | x | x | x | x | 0 | 0 | 1 | VDD_RF = 2.8 V, VDD_A = 2.8 V, VDD_X = 2.8 V |
0B | 0 | x | x | x | x | 0 | 0 | 0 | VDD_RF = 2.7 V, VDD_A = 2.7 V, VDD_X = 2.7 V |
The regulator configuration function adjusts the regulator outputs by default to 400 mV below VIN level, but not higher than 5 V for VDD_RF, 3.4 V for VDD_A and VDD_X. This ensures the highest possible supply voltage for the RF output stage while maintaining an adequate PSRR (power supply rejection ratio).