WM_PRJ_Q2501_PTS_002
- 001
March
2004
confidential ©
Page:
18 / 79
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without prior written agreement.
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VBATT
IBATT
Uripp
Uripp
T = 4.615ms
T=577µs
Vmax
Vmin
In GSM or GPRS class 2 modes
In GPRS class 10 mode
Legend:
Figure 2: Typical Power supply voltage in GSM/GPRS mode
During these peaks the ripple (U
ripp
) on the supply voltage must not exceed a
certain limit (refer to document [2]).
Because VBATT supplies directly the GSM RF power amplifier component, it is
essential to keep a minimum voltage ripple at this connection in order to avoid
any phase error or spectrum modulation degradation.
On the other hand, insufficient power supply voltage could dramatically affect
some RF performances: TX power, modulation spectrum, EMC (Electro-
Magnetic Compatibility) performances, spurious emission and frequency error.
The power supply voltage features given in the table hereunder will guarantee
nominal functioning of the module.
Power Supply Voltage
V
MIN
V
NOM
V
MAX
U
ripp
max
VBATT
3.4 V (*)
3.6 V
4.5 V (**)
50 mVpp for freq<200 kHz
5 mVpp for freq>200 kHz
(*): This value has to be guaranteed during the burst (with 2.0 A Peak in GSM
or GPRS mode).
(**): max operating Voltage Stationary Wave Ratio (VSWR) 2:1.
Summary of Contents for WISMO Quik Q2501
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