NRF902 Datasheet, PDF (8/13 Pages) List of Unclassifed Manufacturers – Single chip 868 MHz Transmitter

PRELIMINARY PRODUCT SPECIFICATION
nRF902 Single chip 868 MHz Transmitter
Power Down mode
Power Down mode is used to achieve very low current consumption. Effectively the
chip is disabled with minimal leakage current consumption, typically less than 10nA.
Operating in this mode when not transmitting data, i.e. low duty cycle systems can
significantly increase battery lifetime.
The resistor R1 connected from the crystal pin towards VDD supplies the crystal
oscillator with bias current (see Figure 9). When this resistor is connected to VSS or
left open, the chip enters Power Down mode. As shown in Figure 9 the resistor R1 is
connected to the “Power Down” terminal, this can be controlled by a micro-controller,
hence eliminating the need to switch off the power supply to the chip when not
transmitting. Start-up time when switching from Power Down mode to Transmit
mode is approximately 2 ms.
X1 13.567MHz
Power
Down
VDD
Clock
Output
VDD
R1
xtal ¹
R2
2
REXT
3
XO8
VDD ⁴
C1
C2
nRF902
8 _VSS
7 _ant1
6 _ant2
5 _FSK
Matching Network/
Antenna
Data
Input
Figure 9. FSK transmitter in Power Down mode
Nordic VLSI ASA
Revision: 1.0
- Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Page 8 of 13
April 2000