AT86RF212 Atmel Corporation, AT86RF212 Datasheet - Page 6

• Manufacturer Part Number: AT86RF212
• Manufacturer: Atmel Corporation

Specifications of AT86RF212

• Max. Operating Frequency: 0 MHz
• Crypto Engine: AES
• Operating Voltage (vcc): 1.8 to 3.6
• Frequency Band: 700/800/900MHz
• Max Data Rate (mb/s): 1
• Antenna Diversity: No
• External Pa Control: Yes
• Power Output (dbm): 10
• Receiver Sensitivity (dbm): -110
• Receive Current Consumption (ma): 9.0
• Transmit Current Consumption (ma): 18 at 5dBm
• Link Budget (dbm): 120

2.2.1.2 RF Pins
RFN, RFP
A differential RF port (RFP/RFN) provides common-mode rejection to suppress the
switching noise of the internal digital signal processing blocks. At board-level, the
differential RF layout ensures high receiver sensitivity by reducing spurious emissions
originated from other digital ICs such as a microcontroller.
The RF port is designed for a 100 Ω differential load. A DC path between the RF pins is
allowed. A DC path to ground or supply voltage is not allowed. Therefore, when
connecting a RF-load providing a DC path to the power supply or ground, AC-coupling
is required as indicated in Table 2-2.
A simplified schematic of the RF front end is shown in Figure 2-2.
Figure 2-2. Simplified RF Front-end Schematic
RF port DC values depend on the operating state; refer to section 5. In TRX_OFF state,
when the analog front-end is disabled (see section 5.1.2.3), the RF pins are pulled to
ground, preventing a floating voltage larger than 1.8 V which is not allowed for the
internal circuitry.
In transmit mode, a control loop provides a common-mode voltage of 0.9 V. Transistor
M0 is off, allowing the PA to set the common-mode voltage. The common-mode
capacitance at each pin to ground shall be < 100 pF to ensure the stability of this
common-mode feedback loop.
In receive mode, the RF port provides a low-impedance path to ground when transistor
M0 (see Figure 2-2) pulls the inductor center tap to ground. A DC voltage drop of 20 mV
across the on-chip inductor can be measured at the RF pins.
Matching control (MC) is implemented by an adjustable capacitance to ground at each
RF pin as shown in Figure 2-2. The input capacitance can be changed within 15 steps
by setting a 4-bit control word (register 0x19, RF_CTRL_1); refer to section 7.2.3.
AT86RF212
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8168C-MCU Wireless-02/10