Specifications

Product Technical Specification & Customer Design Guidelines
Interfaces
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prior written agreement.
WA_DEV_Q64_PTS_001-003 January 9, 2009
3.2 Power Supply
3.2.1 Power Supply Description
The power supply is one of the key issues in the design of a GSM terminal.
Due to the burst emission mode used in GSM/GPRS, the power supply should deliver
high current peaks in a short time. During the peaks, the ripple (U
ripp
) on the supply
voltage must not exceed a certain limit (see
Table 1 Power supply voltage “Power
Supply Voltage”).
• In communication mode, a GSM/GPRS class 2 terminal emits 577μs radio
bursts every 4.615ms (see
Figure 2 below).
Uripp
VCC
Uripp
T = 4,615 ms
t = 577 μs
Figure 2: Power supply during burst emission
•
In communication mode, a GPRS class 10 terminal emits 1154 μs radio bursts
every 4.615 ms.
The VCC power supply input is only available for Q64 Wireless CPU
®
.
VCC:
• Directly supplies the RF components with 3.6 V. It is essential to keep a
minimum voltage ripple at this connection in order to avoid any phase error.
The RF Power Amplifier current (1.5 A peak in GSM /GPRS mode) flows with a
ratio of:
o 1/8 of the time (around 577 μs every 4.615 ms for GSM /GPRS cl. 2) and
o 2/8 of the time (around 1154 μs every 4.615 ms for GSM /GPRS
cl. 10).
The rising time is around 10μs.
• Is internally used to provide, via several regulators, the supply required for the
baseband signals.