MT3333 All-in-One GNSS
GPS TOW to accurately predict the signal code chip/phase. As a result, the code search range can be narrowed
down and a fast TTFF is achieved.
5.18. Power scheme
• Internal SMPS is used as the source power of the internal RF/BB LDO. It is also used as 1.8 volts I/O power,
external TCXO/LNA voltage source via built-in TCXO switch. The internal SMPS can switch to the LDO mode to
supply power to each of the about block
• The minimum/maximum input voltage of AVDD43_VBAT and AVDD43_DCV is 2.8/4.3 volts.
• The power-on reset voltage threshold of AVDD43_VBAT is 2.7 ± 0.1 volts. The maximum TLDO drop out voltage
at half load (25 mA ) is 0.2 volts. If one external LDO is used to provide power to MT3333, the 3.3 volts external
LDO will be recommended after taking TLDO drop-out into consideration.
• The power efficiency in SMPS mode will be better than that in the internal LDO mode.
• I/O supports 1.8 and 2.8 volts. The power comes from SMPS output for 1.8 volts application or TLDO output
(AVDD28_TLDO) for 2.8 volts application.
• The power for internal flash comes from AVDD28_TLDO.
• TCXO power is from AVDD_TCXO_SW that can select either from AVDD28_TLDO (2.8V) or from AVDD28_CLDO
(1.8V) by setting up power-on strap.
• RTC LDO input power comes from backup battery or uses coin battery.
• Here are 3 power schemes: low power (Figure 5-3), low cost (Figure 5-4) and external PMU (Figure 5-5).
• The power on and power off sequence of external PMU mode is shown in Figure 5-6.
Figure 5-3: Power supply connection (low power)
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