Datasheet

Page 16 of 161
nRF8001 Product Specification
Revision 1.2
6 Analog and physical features
This chapter describes the analog and physical features of nRF8001.
The following analog features are included in nRF8001:
• Bluetooth low energy RF transceiver
• Three on-chip reference oscillators
• DC/DC converter for extended battery life with coin-cell batteries
• Temperature sensor
• Battery monitor
6.1 RF transceiver
nRF8001 includes an integrated RF transceiver which is compliant with the Bluetooth Core specification
v4.0 Volume 6, Part A. The RF transceiver requires the following external components to operate:
• 16 MHz crystal or external 16 MHz reference
• Resistor for setting internal bias currents
• Balun to match an antenna to the receiver/transmitter pins of nRF8001
6.1.1 Enabling the RF transceiver
All RF transceiver functionality and operation is controlled through the ACI. Configuring the GAP
parameters and entering a mode of operation through the ACI enables the transceiver to send
advertisement events and connect to a peer device. Data transfer is initiated after the negotiated Bluetooth
low energy setup procedures have been completed.
6.2 On-chip oscillators
nRF8001 includes three integrated oscillators:
• Low power amplitude regulated 16 MHz crystal oscillator
• Ultra-low power amplitude regulated 32.768 kHz crystal oscillator
• Ultra-low power 32.768 kHz RC oscillator with ± 250 ppm frequency accuracy
The 16 MHz crystal oscillator provides the reference frequency for the RF transceiver. The two low
frequency 32.768 kHz oscillators provide the protocol timing. Only one low frequency reference can be
used at any time. The choice of which reference to use depends on your application and will affect the
design cost and current consumption. The low frequency crystal oscillator clock can be driven by either a
32.768 kHz crystal oscillator or a 32.768 kHz external clock source.
6.2.1 Enabling the oscillators
The 16 MHz crystal oscillator is automatically enabled when nRF8001 requires it. The 32.768 kHz
oscillator is automatically enabled when nRF8001 is in a connection or advertising state. Both the 32.768
kHz and the 16 MHz reference sources and oscillator settings are set through the ACI, see Part B, section
22.3 on page 81.