AS3661 datasheet(17/87 Pages) AMSCO

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AS3661

Datasheet - D e t a i l e d D e s c r i p t i o n

8.5 Modes of Operation

The following are the different modes of operation of AS3661

8.5.1 RESET

In the RESET mode all the internal registers are reset to the default values. Reset is entered always if Reset Register

(3DH) is written FFH or internal Power On Reset is active. Power On Reset (POR) will activate during the chip startup

or when the supply voltage VBAT fall below 1.5V (typ.). Once VBAT rises above 1.5V (typ.) POR will be inactivate and

the chip will continue to the STANDBY mode. CHIP_EN control bit is low after POR by default.

8.5.2 STANDBY

The STANDBY mode is entered if the register bit CHIP_EN or EN pin is logic low and Reset is not active. This is the

low power consumption mode, when all circuit functions are disabled. Registers can be written in this mode if EN pin is

logic high so that the control bits will be effective right after the start up.

8.5.3 STARTUP

When CHIP_EN bit is written high and the EN pin is high, the INTERNAL STARTUP SEQUENCE powers up all the

needed internal blocks (VREF, Bias, Oscillator etc.). Startup delay is 500 µs. If the chip temperature rises too high, the

Thermal Shutdown (TSD) disables the chip operation and chip waits in STARTUP mode until no thermal shutdown

event is present.

8.5.4 NORMAL

During NORMAL mode the user controls the chip using the Control Registers.

8.5.5 POWER SAVE

In POWER SAVE mode analog blocks are disabled to minimize power consumption. (see Automatic Power Save

Mode on page 19)

Figure 18. Mode Select

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