> 2.2 | GSM/GPRS vs. UMTS/HSDPA Power Supply Requirements

> Some Siemens wireless modules support GSM/GPRS as well as HSDPA and UMTS. The power supply requirements for HSDPA and UMTS differ from the GSM/GPRS requirements.
> As mentioned in Section 2.1 the supply current for GSM/GPRS transmissions includes maximum current bursts of up to 3.2A every 4.6ms. Because of a different transmission and modulation technology, this is not the case for HSDPA/UMTS transmissions. The supply current for HSDPA/UMTS is an averaged constant current. It depends on the output power level with no peak current pulses included. The maximum supply current for HSDPA/UMTS is less than 1A.
> Therefore, a power supply circuit for a combined GSM/GPRS/UMTS/HSDPA module must be able to supply up to 3.2A peak current (GSM/GPRS) and an averaged current of less than 1A (HSDPA/UMTS). This combination makes circuit design somewhat more complex and these issues should be taken into account.