User's Manual

TOBY-R2 series - Data Sheet
UBX-16005785 - R06 Interfaces
Page 10 of 41
2 Interfaces
2.1 Power management
2.1.1 Module supply input (VCC)
TOBY-R2 series modules must be supplied through the three VCC pins by a DC power supply. Voltage must be
stable, because during operation the current drawn from VCC can vary by some order of magnitude, especially
due to the surging consumption profile of the GSM system (described in the TOBY-R2 series System Integration
Manual [2]). It is important that the system power supply circuit is able to support peak power.
TOBY-R200 modules provide separate supply inputs over the three VCC pins:
 VCC pins #71 and #72 represent the supply input for the internal RF power amplifier, demanding most of
the total current drawn by the module when RF transmission is enabled during a voice/data call
 VCC pin #70 represents the supply input for the internal baseband Power Management Unit and the internal
transceiver, demanding minor part of the total current drawn by the module when RF transmission is
enabled during a voice/data call
2.1.2 RTC supply input / output (V_BCKP)
When VCC voltage is within the valid operating range, the internal Power Management Unit (PMU) supplies the
Real Time Clock (RTC) and the same supply voltage is available on the V_BCKP pin. If the VCC voltage is under
the minimum operating limit (e.g. during not powered mode), the V_BCKP pin can externally supply the RTC.
2.1.3 Generic digital interfaces supply output (V_INT)
TOBY-R2 series modules provide a 1.8 V supply rail output on the V_INT pin, which is internally generated when
the module is switched on. The same voltage domain is used internally to supply the generic digital interfaces of
the modules. The V_INT supply output can be used in place of an external discrete regulator.
2.2 Antenna interfaces
2.2.1 Antenna RF interfaces
The modules have two RF pins with a characteristic impedance of 50 . The primary antenna pin (ANT1)
supports both Tx and Rx, providing the main antenna interface, while the secondary antenna pin (ANT2)
supports Rx only for the LTE Rx diversity configuration.
2.2.2 Antenna detection
The ANT_DET pin is an Analog to Digital Converter (ADC) input with a current source provided by TOBY-R2
modules to sense the antenna presence (as an optional feature). It evaluates the resistance from ANT1 and
ANT2 pins to GND by means of an external antenna detection circuit implemented on the application board.
(For more details, see TOBY-R2 series System Integration Manual [2] and u-blox AT Commands Manual [1].)