34708 datasheet(72/159 Pages) FREESCALE

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Analog Integrated Circuit Device Data



Freescale Semiconductor

MC34708

Functional Block Description

7.5.6.8

VDAC

The primary applications of this power supply is the TV-DAC. However, these supplies could also be used for other peripherals

if one of these functions is not required. Low Power modes and programmable standby options can be used to optimize power

efficiency during deep sleep modes.

An external PNP is utilized for VDAC to avoid excess on-chip power dissipation at high loads and large differentials between BP

and output settings. For stability reasons, a small minimum ESR may be required. External PNP devices must always be

connected to the BP line in the application. The recommended PNP device is the ON Semiconductor NSS12100XV6T1G, which

is capable of handling up to 250 mW of continuous dissipation at minimum footprint and 75 °C of ambient. For use cases where

up to 500 mW of dissipation is required, the recommended PNP device is ON Semiconductor NSS12100UW3TCG. For stability

reasons, an ESR of 110 m

 20%is required.

A short-circuit condition will shut down the VDAC regulator and generate an interrupt for SCPI.

The nominal output voltage of this regulator is SPI configurable, and can be 2.5 V, 2.6 V, 2.7 V, or 2.775 V. The maximum output

current along with an external PNP, is 250 mA.

Table 61. VDAC Voltage Control

Parameter

Value

Output Voltage

ILoad max

VDAC

2.500 V

250 mA

2.600 V

250 mA

2.700 V

250 mA

2.775 V

250 mA

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

GENERAL

VDACIN

Operating Input Voltage Range VINMIN to VINMAX

VNOM +

0.25

4.5

IDAC

Operating Current Load Range ILMIN to ILMAX

• Not exceeding PNP max power

0.0

250

VDACIN

Extended Input Voltage Range

• Performance may be out of specification

UVDET

4.5

VDAC ACTIVE MODE – DC

VDAC

Output Voltage VOUT

•VINMIN < VIN < VINMAX ILMIN < IL < ILMAX

VNOM – 3%

VNOM

VNOM + 3%

VDACLOPP Load Regulation

•1.0 mA < IL < ILMAX For any VINMIN < VIN < VINMAX

0.20

mV/mA

VDACLIPP

Line Regulation

•VINMIN < VIN < VINMAX For any ILMIN < IL < ILMAX

5.0

VDACSCTH Short-circuit Protection Threshold

•VINMIN < VIN < VINMAX Short-circuit VOUT to GND

ILMAX

+20%

IDACQ

Active Mode Quiescent Current

•VINMIN < VIN < VINMAX IL = 0

µA

34708 Datasheet(PDF) 72 Page - Freescale Semiconductor, Inc

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