LTC4449 datasheet(6/48 Pages) AD

6 / 48 page

LTC7872

Rev. 0

For more information www.analog.com

ELECTRICAL CHARACTERISTICS The

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C, VHIGH = 48V, VRUN = 5V unless otherwise noted. (Note 2)

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Synchronizable Frequency

SYNC = External Clock

750

kHz

Spread Spectrum Frequency

Modulation Range

VSYNC = 5V, RFREQ = 51.1k, MFR_SSFM = 0x00

–12

θ2 – θ1

Phase 2 Relative to Phase 1

180

Deg

θ3 – θ1

Phase 3 Relative to Phase 1

Deg

θ4 – θ1

Phase 4 Relative to Phase 1

270

Deg

θCLKOUT – θ1 CLKOUT Phase to Phase 1

Deg

Clock Output High Voltage

ILOAD = 0.5mA

V5 – 0.2

Clock Output Low Voltage

ILOAD = –0.5mA

0.2

SYNC Pin Input Threshold

SYNC Pin Rising

SYNC Pin Falling

1.1

SYNC Pin Input Resistance

100

kΩ

Power Good and FAULT

PGOOD Voltage Low

IPGOOD = 2mA

0.1

0.3

PGOOD Leakage Current

VPGOOD = 5V

±1

µA

PGOOD Trip Level, VFBHIGH/VFBLOW

With Respect to the Regulated Voltage

VFBHIGH/VFBLOW Ramping Negative

VFBHIGH/VFBLOW Ramping Positive

–10

PGOOD Delay

PGOOD Pin High to Low

µs

FAULT Voltage Low

IFAULT = 2mA

0.1

0.3

FAULT Voltage Leakage Current

VFAULT = 5V

±1

µA

FAULT Delay

FAULT Pin High to Low

120

µs

VLOW OV Comparator Threshold

1.15

1.2

1.25

VLOW OV Comparator Hysteresis

VOVLOW > 1.2V

µA

VHIGH OV Comparator Threshold

1.15

1.2

1.25

VHIGH OV Comparator Hysteresis

VOVHIGH > 1.2V

µA

VHIGH UV Comparator Threshold

1.15

1.2

1.25

VHIGH UV Comparator Hysteresis

VUVHIGH < 1.2V

µA

PWM Outputs

PWM Output High Voltage

ILOAD = 0.5mA

V5 – 0.5

PWM Output Low Voltage

ILOAD = –0.5mA

0.5

PWM Output Current in Hi-Z State

±5

µA

DIGITAL I/O: CSB, SCLK, SDI, SDO

VIL

Digital Input Low Voltage

Pins CSB, SCLK, SDI

0.5

VIH

Digital Input High Voltage

Pins CSB, SCLK, SDI

1.8

VOL

Digital Output Voltage Low

Pin SDO, Sinking 1mA

0.3

RCSB

CSB Pin Pull-Up Resistor

300

kΩ

RSCLK

SCLK Pin Pull-Down Resistor

300

kΩ

RSDI

SDI Pin Pull-Down Resistor

300

kΩ

LTC4449 Datasheet(PDF) 6 Page - Analog Devices

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