ZOE-M8 series - Hardware Integration Manual
UBX-16030136 - R07 Production Information Design-in
Page 7 of 32
Do not add any series resistance greater than 0.1 Ω to the V_CORE supply as it will generate input voltage
noise due to the dynamic current conditions.
If a DC/DC converter is not used, supply V_CORE with the same supply as used for the VCC.
2.1.3 DC/DC converter (only on ZOE-M8Q)
ZOE-M8Q comes with a built-in DC/DC converter to supply V_CORE, thus enabling significant power savings. For
more information, see the ZOE-M8 Data Sheet [1]. It requires an external inductor (L1) and capacitor (C1). For the
recommended inductor and capacitor, see Appendix A.4 and Appendix A.9.
Figure 1 : Circuit for DC/DC converter with ZOE-M8Q
The DC/DC converter block provides an energy conversion efficiency of up to 85%. The actual value depends on
the current drawn and which external inductor (L1) and capacitor (C1) are used.
To enable the DC/DC converter there are two options.
Option 1: In production, send a one-time command to the ZOE-M8Q, which enables the DC/DC converter
permanently in ZOE-M8Q’s internal OTP memory. The command to be sent is “B5 62 06 41 0C 00 00 00 03 1F
C5 90 E1 9F FF FF FE FF 45 79” and will be acknowledged (UBX-ACK). After doing a reset, it can be verified by
checking the UBX-MON-LLC message.
Ensure a stable VCC supply when sending the command to enable the DC/DC converter.
Option 2: Alternatively, if no SQI flash is used, the DC/DC converter can be enabled by defining the SQI flash pins
as shown in Table 1.
Pin # Name State Remarks
D1 SQI_D0 open Must be left open!
C1 SQI_D1 GND Must be connected to GND!
E3 SQI_D2 GND Must be connected to GND!
F3 SQI_D3 Open Must be left open!
E1 SQI_CLK GND Must be connected to GND!
D3 SQI_CS_N GND Must be connected to GND!
Table 1: Enable DC/DC converter
If the SQI flash pins are used to enable the DC/DC converter, ensure that the SQI flash pins are exactly set as
mentioned in Table 1, otherwise it can cause malfunction of the ZOE-M8Q.
2.1.4 Backup power supply (V_BCKP)
In the case of a power failure at main supply VCC, the backup domain and optional RTC oscillator are supplied by
V_BCKP. Providing a V_BCKP supply maintains the time (RTC) and the GNSS orbit data in backup RAM. This
ensures that any subsequent re-starts after a VCC power failure will benefit from the stored data, providing a
faster TTFF.
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