MC34708 datasheet(73/159 Pages) FREESCALE

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Analog Integrated Circuit Device Data



Freescale Semiconductor

MC34708

Functional Block Description

7.5.6.9

VGEN1, VGEN2

General purpose LDOs, VGEN1, and VGEN2, are provided for expansion of the power tree to support peripheral devices, which

could include EMMC cards, WLAN, BT, GPS, or other functional modules. These regulators include programmable set points for

system flexibility. VGEN1 has an internal PMOS pass FET, and is powered from the SW5 buck for an efficiency advantage and

reduced power dissipation in the pass devices. VGEN2 is powered directly from the battery.

VGEN2 has an internal PMOS pass FET, which will support loads up to 50 mA. For higher current capability, drive for an external

PNP is provided. The external PNP is offered to avoid excess on-chip power dissipation at high loads and large differentials

between BP and the output settings. The input pin for the integrated PMOS option is shared with the base current drive pin for

the PNP option. The external PNP device is always connected to the BP line in the application. The recommended PNP device

VDAC LOW POWER MODE – DC - VDACMODE=1

VDAC

Output Voltage VOUT

•VINMIN < VIN < VINMAX ILMINLP < IL < ILMAXLP

VNOM – 3%

VNOM

VNOM + 3%

IDAC

Current Load Range ILMINLP to ILMAXLP

0.0

3.0

IDACQ

Low Power Mode Quiescent Current

•VINMIN < VIN < VINMAX IL = 0

8.0

µA

VDAC ACTIVE MODE – AC

VDACPSRR PSRR - IL = 75% of ILMAX 20 Hz to 20 kHz

•VIN = VINMIN + 100 mV

•VIN = VNOM + 1.0 V

VDACNOISE Output Noise Density, VIN = VINMIN IL = 75% of ILMAX

• 100 Hz – 1.0 kHz

•> 1.0 kHz – 10 kHz

•> 10 kHz – 1.0 MHz

-115

-126

-132

V/Hz

VDACSPURS Spurs

• 32.768 kHz and harmonics

-120

tON-VDAC

Turn-on Time

• Enable to 90% of end value VIN = VINMIN, VINMAX IL = 0

1.0

tOFF-VDAC Turn-off Time

• Disable to 10% of initial value VIN = VINMIN, VINMAX, IL = 0

0.05

VDACOS-

START

Start-up Overshoot

•VIN = VINMIN, VINMAX IL = 0

1.0

2.0

VDACLO

TRANSIENT

Transient Load Response

•VIN = VINMIN, VINMAX

1.0

2.0

VDACLI

TRANSIENT

Transient Line Response

•IL = 75% of ILMAX

5.0

8.0

tMODE-VDAC Mode Transition Time

• From low power to active VIN = VINMIN, VINMAX IL = ILMAXLP

100

µs

VDACMODE

RES

Mode Transition Response

• From low power to active and from active to low power

VIN = VINMIN, VINMAX IL = ILMAXLP

1.0

2.0

Table 62. VDAC Electrical Specification

Characteristics noted under conditions BP = 3.6 V, VBUS = 5.0 V, -40 C  TA  85 C, unless otherwise noted. Typical values

at BP = 3.6 V and TA = 25 °C under nominal conditions, unless otherwise noted.

Symbol

Characteristic

Min

Typ

Max

Unit

Notes

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