Texas Instruments SimpleLink CC2620 Technical Reference Manual page 416

Introduction
6.1.2.1 Internal DC-DC Converter and Global LDO
Normally, the VDDS supply pins of the CC26xx and CC13xx devices are powered from a 1.8-V to 3.8-V
supply (for example, batteries), and the VDDR supply pins are powered from the internal DC-DC
regulator.
Alternatively, the internal global LDO can be used instead of the DC-DC regulator, but this increases the
current consumption of the device. In this mode, disconnect DCDC_SW and connect VDDS_DCDC to the
VDDS supply. The Global LDO is connected internally to the VDDR pin, which must be connected
externally to the VDDR_RF pin. The Global LDO must be decoupled by a µF-sized capacitor on the VDDR
net.
6.1.2.2 External Regulator Mode
The CC26xx and CC13xx devices have an option to be supplied by an external regulator with a voltage
range of 1.65 V to 1.95 V. In this mode, the VDDS and VDDR pins are tied together. To enable external
regulator mode, the VDDS_DCDC pin and the DCDC_SW pins must be connected to ground, which
effectively disables both the internal Global LDO and the internal DC-DC regulator. Refer to the reference
design for a detailed description of connections and decoupling in the external regulator mode.
416
Power, Reset, and Clock Management
Copyright © 2015, Texas Instruments Incorporated
SWCU117C – February 2015 – Revised September 2015
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