34716 datasheet(15/25 Pages) FREESCALE

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Analog Integrated Circuit Device Data

Freescale Semiconductor

34716

FUNCTIONAL DEVICE OPERATION

OPERATIONAL MODES

FUNCTIONAL DEVICE OPERATION

OPERATIONAL MODES

Figure 6. Operation Modes Diagram

MODES OF OPERATION

The 34716 has three primary modes of operation:

Normal Mode

In normal mode, all functions and outputs are fully

operational. To be in this mode, the VIN needs to be within its

operating range, both Shutdown and Standby inputs are

high, and no faults are present. This mode consumes the

most amount of power.

Standby Mode

This mode is predominantly used in Desktop memory

solutions where the DDR supply is desired to be ACPI

compliant (Advanced Configuration and Power Interface).

When this mode is activated by pulling the STBY pin low, VTT

is put in High Z state, IOUT2 = 0 A while VDDQ and VREF stay

active. This is the S3 state Suspend-To-Ram or Self Refresh

mode and it is the lowest DRAM power state. In this mode,

the DRAM will preserve the data. While in this mode, the

34716 consumes less power than in the normal mode,

because the buck converter and most of the internal blocks

are disabled.

Shutdown Mode

In this mode, activated by pulling the SD pin low, the chip

is in a shutdown state and the outputs are all disabled and

discharged. This is the S4/S5 power state or Suspend-To-

Disk state, where the DRAM will loose all of its data content

(no power supplied to the DRAM). The reason to discharge

the VTT and VREF lines is to ensure upon exiting, the

Shutdown Mode that VTT and VREF are lower than VDDQ,

otherwise VTT can remain floating high, and be higher than

VDDQ upon powering up. In this mode, the 34716 consumes

the least amount of power since almost all of the internal

blocks are disabled.

START-UP SEQUENCE

When power is first applied, the 34716 checks the status

of the SD and STBY pins. If the device is in a shutdown mode,

no block will power up and the output will not attempt to ramp.

If the device is in a standby mode, only the VDDI internal

supply voltage and the bias currents are established and no

further activities will occur. Once the SD and STBY pins are

released to enable the device, the internal VDDI POR signal is

also released. The rest of the internal blocks will be enabled,

and the buck converters switching frequency and the VDDQ

Soft start values are determined by reading the FREQ and

DDQ > = VUVR1

DDQ < = VOVF1

J < = 145˚C

TIMEOUT Expired

TIMEOUT

Expired

TIMEOUT

Expired

TIMEOUT

Expired

TIMEOUT

Expired

J < = 145˚C

TIMEOUT Expired

TT < = VOVF2

TT > = VUVR2

SD = 1 &

STBY = 1

3.0V < = V

IN < = 6.0V

J > = 170˚C

Shutdown

DDQ = Discharge

TT = Discharge

REF = Discharge

PG = 1

SD = 0 &

STBY = x

SD = 1 &

STBY = 0

SD = 1 &

STBY = 1

Standby

DDQ = ON

TT = OFF

REF = ON

PG = 1

Power Off

DDQ = OFF

TT = OFF

REF = OFF

PG = 1

IN < 3.0V

Normal

Fsw is programmed

LIM1 is programmed

DDQ and VTT tSS = 1

DDQ = ON

TT = ON

REF = ON

PG = 0

DDQ

Short Circuit

DDQ = OFF

TT = ON

REF = ON

PG = 1

TIMEOUT = 1

Channel 1

Overcurrent

DDQ = OFF

TT = ON

REF = ON

PG = 1

TIMEOUT = 1

Channel 1

Thermal Shutdown

DDQ = OFF

TT = ON

REF = ON

PG = 1

DDQ

Overvoltage

DDQ = ON

TT = ON

REF = ON

PG = 1

DDQ

Undervoltage

DDQ = ON

TT = ON

REF = ON

PG = 1

Short Circuit

DDQ = ON

TT = OFF

REF = ON

PG = 1

TIMEOUT = 1

Channel 2

Overcurrent

DDQ = ON

TT = OFF

REF = ON

PG = 1

TIMEOUT = 1

Channel 2

Thermal Shutdown

DDQ = ON

TT = OFF

REF = ON

PG = 1

Overvoltage

DDQ = ON

TT = ON

REF = ON

PG = 1

Undervoltage

DDQ = ON

TT = ON

REF = ON

PG = 1

J > = 170˚C

DDQ < = VUVF1

DDQ > = VOVR1

OUT1 > = ILIM1

For > = 10ms

OUT1 > = ISHORT1

TT < = VUVF2

TT > = VOVR2

OUT2 > = ILIM2

For > = 10ms

OUT2 > = ISHORT2

Normal

FSW is programmed

ILM1, is programmed

VDDQ and VTT tss = 1

VDDQ = ON

VTT = ON

PG = 0

Shutdown

VDDQ Discharge

VTT = Discharge

VREF = Discharge

PG = 1

VREF = ON

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