LTC3890 datasheet(5/34 Pages) LINER

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LTC3807

3807fa

For more information www.linear.com/LTC3807

The l denotes the specifications which apply over the specified

operating junction temperature range, otherwise specifications are at TA = 25°C (Note 2), VIN = 12V, VRUN = 5V, EXTVCC = 0V unless

otherwise noted.

TYPICAL PERFORMANCE CHARACTERISTICS

OUTPUT CURRENT (A)

FIGURE 12 CIRCUIT

100

0.1

0.01

0.001

0.0001

3807 G01

100

1000

10000

0.1

VIN = 12V

VOUT = 3.3V

BURST EFFICIENCY

FCM LOSS

PULSE-SKIPPING

LOSS

BURST LOSS

FCM EFFICIENCY

PULSE-SKIPPING

EFFICIENCY

OUTPUT CURRENT (A)

100

0.1

0.01

0.001

0.0001

3807 G02

VOUT = 8.5V

VOUT = 3.3V

VIN = 12V

Burst Mode OPERATION

FIGURES 12, 14 CIRCUITS

INPUT VOLTAGE (V)

100

3807 G03

VOUT = 3.3V

VOUT = 8.5V

ILOAD = 2A

FIGURES 12, 14 CIRCUITS

Efficiency and Power Loss vs

Output Current

Efficiency vs Output Current

Efficiency vs Input Voltage

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 LTC3807 is tested under pulsed load conditions such that

TJ ≈ TA. The LTC3807E is guaranteed to meet performance specifications

from 0°C to 85°C. Specifications over the –40°C to 125°C operating

junction temperature range are assured by design, characterization and

correlation with statistical process controls. The LTC3807I is guaranteed

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

LTC3807H is guaranteed over the –40°C to 150°C operating junction

temperature range and the LTC3807MP is tested and guaranteed over

the –55°C to 150°C operating junction temperature range. High junction

temperatures degrade operating lifetimes; operating lifetime is derated

for junction temperatures greater than 125°C. Note that the maximum

ambient temperature consistent with these specifications is determined by

specific operating conditions in conjunction with board layout, the rated

package thermal impedance and other environmental factors.

Note 3: 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 is 43°C/W for the QFN or 38°C/W for the

TSSOP.

Note 4: The LTC3807 is tested in a feedback loop that servos VITH to a

specified voltage and measures the resultant VFB. The specification at

85°C is not tested in production and is assured by design, characterization

and correlation to production testing at other temperatures (125°C for

the LTC3807E/LTC3807I, 150°C for the LTC3807H/LTC3807MP). For the

LTC3807MP, the specification at –40°C is not tested in production and is

assured by design, characterization and correlation to production testing

at –55°C.

Note 5: Dynamic supply current is higher due to the gate charge being

delivered at the switching frequency. See Applications Information.

Note 6: Rise and fall times are measured using 10% and 90% levels. Delay

times are measured using 50% levels

Note 7: The minimum on-time condition is specified for an inductor

peak-to-peak ripple current ≥ 40% of IMAX (See Minimum On-Time

Considerations in the Applications Information section).

ELECTRICAL CHARACTERISTICS

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

PGOOD Leakage Current

VPGOOD = 5V

±1

µA

PGOOD Trip Level

VFB with Respect to Set Regulated Voltage

VFB Ramping Negative

–13

–10

–7

Hysteresis

2.5

VFB Ramping Positive

Hysteresis

2.5

Delay for Reporting a Fault

µs

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