SE873 Family Product User Guide
Electrical Interface
1VV0301216
Rev.4
Page 33 of 69
2018-08-24
Power Supply
1.8 V Supply Voltage
Unlike previous GNSS receiver modules, the SE873 requires a single always-on 1.8 V supply.
Rather than having a “split” power supply design of main and backup, the module manages all of
its power modes internally. The module will power up into the state determined by the ON-OFF
pin (High: RUN; Low: HIBERNATE).
The power state of the SE873 can be determined by monitoring the “SYSTEM-ON” signal. A logic
low indicates the module is in OFF, RESET, HIBERNATE, or STANDBY; whereas logic high
indicates the module is in RUN state.
If the 1.8 volt DC supply is removed from the module (regardless of power state) it will lose current
RTC time and the contents of the internal SRAM. To execute an orderly shutdown, place the
module into the HIBERNATE state, then remove power. To prevent improper startup, keep the
power removed for approximately 10 seconds to reliably clear the SRAM contents.
The module monitors the 1.8 volt supply and issues an internal hardware reset if the supply drops
below 1.7 volts. This reset protects the memory from accidental writes during a power down
condition
.
This reset forces the module into a low power stand-by state.
To prevent the reset, the 1.8 volt supply must be regulated to be within ±50 mV of nominal voltage
(including load regulation and power supply noise and ripple). Noise and ripple outside of these
limits can affect GNSS sensitivity and also risk tripping the internal voltage supervisors, thereby
shutting down the module unexpectedly. Regulators with very good load regulation are strongly
recommended along with adequate power supply filtering to prevent power supply glitches as the
module transitions between power states.
The power supply voltage, including noise and ripple must be as specified below in
for all frequencies. To help meet these requirements, a separate LDO for the
module is suggested.
DC Power Requirements
Name
Min
Typ
Max
Units
V18
1.71
1.8
1.89
V
Max ripple: 54 mV (0 to 3 MHz), 15 mV (> 3 MHz)
Table 8-4 DC Supply Voltage
Power Supply Capacitance
Aluminum electrolytic capacitors are not recommended at the input to the module due to their
high ESR. Tantalum capacitors are recommended with a minimum value of 10uF in parallel with
a 0.1uF ceramic capacitor. Ceramic capacitors alone can be used, but ensure that the LDO is
stable with such capacitors tied to the output.
Summary of Contents for SE873 Series
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