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LT3435

3435fa

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

EA Source Current

FB = 1.15V

µA

EA Sink Current

FB = 1.35V

µA

VC to SW gm

6A/V

VC High Clamp

FB = 1.15V

2.1

2.2

2.4

IPK

SW Current Limit

●

5.2

6.5

Switch On Resistance (Note 9)

●

0.1

0.25

Ω

Switching Frequency

●

425

500

575

kHz

Maximum Duty Cycle

Minimum SYNC Amplitude

1.5

2.0

SYNC Frequency Range

575

700

kHz

SYNC Input Impedance

Ω

ICSS

CSS Current Threshold (Note 10)

FB = 0V

µA

IPGFB

PGFB Input Current

100

VPGFB

PGFB Voltage Threshold (Note 11)

●

ICT

CT Source Current (Note 11)

3.6

5.5

µA

CT Sink Current (Note 11)

VCT

CT Voltage Threshold (Note 11)

1.16

1.2

1.26

PG Leakage (Note 11)

0.1

µA

PG Sink Current (Note 11)

PGFB = 1V, PG = 400mV

100

200

µA

The

● denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TJ = 25°C. VIN = 12V, SHDN = 12V, BIAS = 5V, FB/PGFB = 1.25V, CSS/SYNC = 0V

unless otherwise noted.

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 LT3435EFE is guaranteed to meet performance specifications

from 0

°C to 125°C junction temperature. Specifications over the –40°C to

125

°C operating junction temperature range are assured by design,

characterization and correlation with statistical process controls. The

LT3435IFE is guaranteed and tested over the full –40

°C to 125°C

operating junction temperature range.

Note 3: Minimum input voltage is defined as the voltage where switching

starts. Actual minimum input voltage to maintain a regulated output will

depend upon output voltage and load current. See Applications

Information.

Note 4: Supply input current is the quiescent current drawn by the input

pin. Its typical value depends on the voltage on the BIAS pin and operating

state of the LT3435. With the BIAS pin at 0V, all of the quiescent current

required to operate the LT3435 will be provided by the VIN pin. With the

BIAS voltage above its minimum input voltage, a portion of the total

quiescent current will be supplied by the BIAS pin. Supply sleep current is

defined as the quiescent current during the “sleep” portion of Burst Mode

operation. See Applications Information for determining application supply

currents.

Note 5: Minimum BIAS voltage is the voltage on the BIAS pin when IBIAS is

sourced into the pin.

Note 6: This is the minimum voltage across the boost capacitor needed to

guarantee full saturation of the internal power switch.

Note 7: Boost current is the current flowing into the BOOST pin with the

pin held 3.3V above input voltage. It flows only during switch on time.

Note 8: Gain is measured with a VC swing from 1.15V to 750mV.

Note 9: Switch on resistance is calculated by dividing VIN to SW voltage by

the forced current (3A). See Typical Performance Characteristics for the

graph of switch voltage at other currents.

Note 10: The CSS threshold is defined as the value of current sourced into

the CSS pin which results in an increase in sink current from the VC pin.

See the Soft-Start section in Applications Information.

Note 11: The PGFB threshold is defined as the percentage of VREF voltage

which causes the current source output of the CT pin to change from

sinking (below threshold) to sourcing current (above threshold). When

sourcing current, the voltage on the CT pin rises until it is clamped

internally. When the clamp is activated, the output of the PG pin will be set

to a high impedance state. When the CT clamp is inactive the PG pin will

be set active low with a current sink capability of 200

µA.

ELECTRICAL CHARACTERISTICS

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