7 MS2131 Power Design Guide
7.1 About This Chapter
This chapter describes the MS2131's power features and power supply requirements in
different scenarios and its power consumption data in sleep mode. For details about the power
supply circuit over which the host powers an embedded MS2131, see section 7.6 "Periphera l
Power Design Requirements."
7.2 MS2131 Power Supply
The working power of the MS2131 is provided through the USB port with an input voltage
ranging from 4.75 V to 5.25 V (typical value: 5 V).
7.3 MS2131 Power Requirements in 2G Mode
This section describes the MS2131 power features when in use in 2G mode. The power
consumption of the MS2131 increases with its transmit power. Transmit power, also called
uplink power, is the amount of power used during transmission from a wireless termina l to a
base station.
The Time Division Multiple Access (TDMA) uses GSM as the access method, and therefore,
the MS2131 transmits signals only in slots specified by the base station. Each GSM
transmission cycle has eight slots, 577 µs each. The MS2131 transmits power in one out of
the eight slots. As calculated, each GSM transmission cycle lasts 4.61 ms and the transmission
duration lasts 577 µs. This transmission mode is called "burst". The better signal reception
quality is, the less power consumption of the MS2131 will produce, and vice versa. The
maximum power consumption is 33 dBm (GSM900).
Figure 7-1 shows the GSM working principle.
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