LTC3412A datasheet(3/20 Pages) LINER

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LTC3617

3617fa

electrical characteristics The

denotes the specifications which apply over the full operating junction

temperature range, otherwise specifications are at TA = 25°C. PVIN = SVIN = 3.3V, RT = SVIN unless otherwise specified (Notes 1, 2, 8).

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

∆VFB(LINEREG) Feedback Voltage Line Regulation

SVIN = PVIN = 2.25V to 5.5V,

VDDQIN = 1.5V (Notes 3, 4)

0.2

%/V

∆VFB(LOADREG) Feedback Voltage Load Regulation

ITH from 0.5V to 0.9V (Notes 3, 4)

VITH = SVIN (Note 5)

0.25

Input DC Supply Current

Active Mode

Shutdown

VFB = 0.6V, VDDQIN = 1.5V (Note 6)

SVIN = PVIN = 5.5V, VRUN = 0V

1100

0.1

µA

RDS(ON)

Top Switch On-Resistance

PVIN = 3.3V

mΩ

Bottom Switch On-Resistance

PVIN = 3.3V

mΩ

ILIM

Top Switch Positive Peak Current Limit

Sourcing (Note 7), VFB = 0.5V

Top Switch Negative Peak Current Limit

Sinking (Note 7)

–12

–8

–5

gm(EA)

Error Amplifier Transconductance

–5µA < IITH < 5µA (Note 4)

200

µS

IEAO

Error Amplifier Maximum Output Current (Note 4)

±30

µA

tSS

Internal Soft-Start Time

VFB from 0.075V to 0.675V,

VDDQIN = 1.5V

0.4

0.85

fOSC

Oscillator Frequency

Internal Oscillator Frequency

RT = 370k

VRT = SVIN

0.8

1.8

2.25

1.2

2.7

MHz

fSYNC

Synchronization Frequency Range

0.3

MHz

VSYNC

SYNC Input Threshold High Voltage

SYNC Input Threshold Low Voltage

1.2

0.3

ISW(LKG)

Switch Leakage Current

SVIN = PVIN = 5.5V, VRUN = 0V

0.1

µA

PGOOD

Power Good Voltage Windows

VDDQIN = 1.5V, Entering Window

VFB Ramping Up

VFB Ramping Down

–3.5

3.5

–5

VDDQIN = 1.5V, Leaving Window

VFB Ramping Up

VFB Ramping Down

–8

–10

tPGOOD

Power Good Blanking Time

Entering and Leaving Window

105

140

µs

RPGOOD

Power Good Pull-Down On-Resistance

VRUN

RUN voltage

Input High

Input Low

0.4

Note 1: Stresses beyond those listed under Absolute Maximum Ratings

may cause permanent damage to the device. Exposure to any Absolute

Maximum Rating condition for extended periods may affect device

reliability and lifetime.

Note 2: The LTC3617 is tested under pulsed load conditions such that

TJ ≈ TA. The LTC3617E is guaranteed to meet performance specifications

over the 0°C to 85°C operating junction temperature range. Specifications

over the –40°C to 125°C operating junction temperature range are

assured by design, characterization and correlation with statistical process

controls. The LTC3617I is guaranteed to meet specifications over the

full –40°C to 125°C operating junction temperature range. Note that

the maximum ambient temperature is determined by specific operating

conditions in conjunction with board layout, the rated package thermal

resistance and other environmental factors. The junction temperature

(TJ, in °C) is calculated from the ambient temperature (TA, in °C) and

power dissipation (PD, in watts) according to the formula:

TJ = TA + (PD • θJA), where θJA (in °C/W) is the package thermal

impedance.

Note 3: This parameter is tested in a feedback loop which servos VFB to

the midpoint for the error amplifier (VITH = 0.75V).

Note 4: External compensation on ITH pin.

Note 5: Tying the ITH pin to SVIN enables the internal compensation.

Note 6: Dynamic supply current is higher due to the internal gate charge

being delivered at the switching frequency.

Note 7: In sourcing mode the average output current is flowing out of the

SW pin. In sinking mode the average output current is flowing into the SW

Pin.

Note 8: This IC includes overtemperature protection that is intended

to protect the device during momentary overload conditions. Junction

temperature will exceed 125°C when overtemperature protection is active.

Continuous operation above the specified maximum operating junction

temperature may impair device reliability.

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