RV-3029 Datasheet, PDF (21/67 Pages) MICORO CRYSTAL SWITZERLAND – DTCXO Temperature Compensated Real Time Clock

Micro Crystal
DTCXO Temperature Compensated Real Time Clock / Calendar Module
RV-3029
4. DETAILED FUNCTIONAL DESCRIPTION
4.1. POWER-UP, POWER MANAGEMENT AND BATTERY SWITCHOVER
The RV-3029 has two power supply pins:
• V_DD
the main power supply input pin
• V_BACKUP the backup battery input pin
The RV-3029 has multiple power management function implemented:
• Automatic switchover function between main power supply and backup supply voltage. The higher supply
voltage is selected automatically, with a switchover hysteresis of 20mV
• Low supply voltage detection V_LOW1 and V_LOW2 with the possibility to generate an INT if the corresponding
control bits are enabled
• Functions requiring a minimum supply voltage are automatically disabled if low supply voltage is detected
• Interface and CLKOUT are automatically disabled when the device operates in backup supply mode
• Programmable trickle charge circuitry to charge backup battery or supercap
Backup Switchover Circuitry Disables non-used Functions
1 _{Trickle charge circuitry is enabled by software when selecting trickle-charge resistors. When back-up}
supply switchover-circuitry switches to the backup supply voltage, trickle charge function is disabled.
2 _{The implemented backup switchover circuitry continuously compares VDD and VBACKUP voltages and}
connects the higher of them to the internal supply voltage V_INT.
The switchover hysteresis from V_DD to V_BACKUP and vice versa is typically 20mV.
3
When the device is operating at the V_BACKUP supply voltage, non-used RTC functions are disabled to
ensure optimized power consumption:
• I2C interface
• CLKOUT
Disabled when operating in V_BACKUP mode
Disabled when operating in V_BACKUP mode
• INT
• Trickle Charge
Enabled even when operating in V_BACKUP mode
Disabled when operating in V_BACKUP mode
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