CC256X_13 Datasheet, PDF (11/51 Pages) Texas Instruments – Bluetooth and Dual-Mode Controller

CC256x
www.ti.com
SWRS121C – JULY 2012 – REVISED OCTOBER 2013
3.3 Device Power Supply
The CC256x power-management hardware and software algorithms provide significant power savings,
which is a critical parameter in a microcontroller-based system.
The power-management module is optimized for drawing very low currents.
3.3.1 Power Sources
The CC256x device requires two power sources:
• VDD_IN: Main power supply for the Bluetooth core
• VDD_IO: Power source for the 1.8-V I/O ring
The device includes several on-chip voltage regulators for increased noise immunity and can be
connected directly to the battery.
3.3.2 Device Power-Up and Power-Down Sequencing
The device includes the following power-up requirements (see Figure 3-2):
• nSHUTD must be low. VDD_IN and VDD_IO are don't-care when nSHUTD is low. However, signals
are not allowed on the I/O pins if I/O power is not supplied, because the I/Os are not fail-safe.
Exceptions are SLOW_CLK_IN and AUD_xxx, which are fail-safe and can tolerate external voltages
with no VDD_IO and VDD_IN.
• VDD_IO and VDD_IN must be stable before releasing nSHUTD.
• The fast clock must be stable within 20 ms of nSHUTD going high.
• The slow clock must be stable within 2 ms of nSHUTD going high.
The device indicates that the power-up sequence is complete by asserting RTS low, which occurs up to
100 ms after nSHUTD goes high. If RTS does not go low, the device is not powered up. In this case,
ensure that the sequence and requirements are met.
nSHUTD
20 µs max
Shut down
before
VDD_IO
removed
VDD_IO
VDD_IN
SLOW CLOCK
FAST CLOCK
HCI_RTS
2 ms max
20 ms max
± 100 ms
CC256x ready
Figure 3-2. Power-Up and Power-Down Sequence
SWRS098-008
Copyright © 2012–2013, Texas Instruments Incorporated
Submit Documentation Feedback
Detailed Description
11