EM3027IDSWS8 datasheet(20/28 Pages) EMMICRO

20 / 28 page

EM3027

 2013, EM Microelectronic-Marin SA

3027-DS.doc, Version 8.0, 25-Jan-13

www.emmicroelectronic.com

Power Management

I/O

Switchover

Logic, EEPROM,

Thermometer,

Voltage Monitor

Regulator

2.9V

Xtal

Oscillator

4x Trickle

charger

resistors

VCC

VBack

VReg

VHigh

Figure 6: Power Management

9.1

Power Supplies, Switchover and Trickle Charger

The device can be supplied from the VCC pin or from the

VBack pin.

The switchover block implemented inside the chip

compares VCC and VBack voltages and connects the

higher of them to the internal VHigh net that supplies the

chip.

Nevertheless, the communication pins (SCL, SDA or CS,

SCK, SI, SO) are supplied from the VCC pin. For that

reason, when serial interface (I2C or SPI) is used, the

chip has to be supplied from VCC. (i.e. VCC > VBack).

By setting of a trickle charger bit in register EEctrl, a

resistor can be inserted between VBack and VHigh voltage.

In this way, a rechargeable battery or a super-cap can be

charged from the VCC voltage, as long as VCC > VBack.

There are 4 selectable resistors connected in parallel

with typical values

of 80kΩ, 20kΩ, 5kΩ and 1.5kΩ. One

or more resistors can be selected by EEctrl bits setting.

If a Lithium battery shall be connected to VBack pin, a

protection resistor of value up to 1k

Ω can be connected

in series with it. In this way, in case of EM3027 device

damage resulting in short between both supply pins,

charging current from the VCC supply can be reduced to

its allowed maximum level as required by UL1642

standard.

5.5V

3.0V

4.0V

5.0V

2.0V

1.0V

Supply Voltage

2.2V

1.4V

EM3027 fully operating according datasheet

(clock, thermometer, thermocompensation)

Clock operating with thermocompensation using either

previously in fully operating mode measured or by user

stored temperature value; no EEPROM write

Serial communication

is enabled, if

VCC > VCCmin and

VCC > Vback

VCCmax

Vprog

EEPROM write if VCC > Vprog

min max

VCCmin

Figure 7: EM3027 operating Voltage Areas

EM3027IDSWS8 Datasheet(PDF) 20 Page - EM Microelectronic - MARIN SA

EM3027IDSWS8 Datasheet(HTML) 20 Page - EM Microelectronic - MARIN SA

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Datasheet Download

Link URL