RV-3049 datasheet(21/65 Pages) MICROCRYSTAL

21 / 65 page

Micro Crystal

DTCXO Temperature Compensated Real Time Clock / Calendar Module

RV-3049

21/65

4. DETAILED FUNCTIONAL DESCRIPTION

4.1. POWER-UP, POWER MANAGEMENT AND BATTERY SWITCHOVER

The RV-3049 has two power supply pins:

•

VDD

the main power supply input pin

•

VBACKUP

the backup battery input pin

The RV-3049 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 VLOW1 and VLOW2 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

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.

The implemented backup switchover circuitry continuously compares VDD and VBACKUP voltages and

connects the higher of them to the internal supply voltage VINT.

The switchover hysteresis from VDD to VBACKUP and vice versa is typically 20mV.

When the device is operating at the VBACKUP supply voltage, non-used RTC functions are disabled to

ensure optimized power consumption:

•

SPI interface

Disabled when operating in VBACKUP mode

•

CLKOUT

Disabled when operating in VBACKUP mode

•

INT

Enabled even when operating in VBACKUP mode

•

Trickle Charge

Disabled when operating in VBACKUP mode

RV-3049 Datasheet(PDF) 21 Page - MICORO CRYSTAL SWITZERLAND

RV-3049 Datasheet(HTML) 21 Page - MICORO CRYSTAL SWITZERLAND

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