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LM3478

SNVS085X – JULY 2000 – REVISED DECEMBER 2017

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Copyright © 2000–2017, Texas Instruments Incorporated

Electrical Characteristics (continued)

Unless otherwise specified, VIN = 12V, RFA = 40kΩ, TJ = 25°C

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

(5)

The over-voltage protection is specified with respect to the feedback voltage. This is because the over-voltage protection tracks the

feedback voltage. The overvoltage protection threshold is given by adding the feedback voltage, VFB to the over-voltage protection

specification.

(6)

The FA/SD pin should be pulled to VIN through a resistor to turn the regulator off. The voltage on the FA/SD pin must be above the

maximum limit for Output = High to keep the regulator off and must be below the limit for Output = Low to keep the regulator on.

VSL

Internal Compensation

Ramp Voltage

VIN = 5V

92

mV

VIN = 5V, −40°C ≤ TJ ≤ 125°C

52

132

VSL ratio

VSL/VSENSE

0.30

0.49

0.70

VOVP

Output Over-voltage

Protection (with respect

to feedback voltage) (5)

VCOMP = 1.4V

32

50

mV

VCOMP = 1.4V, −40°C ≤ TJ ≤ 125°C

25

VSSOP Package

78

VSSOP Package,

−40°C ≤ TJ ≤ 125°C

85

SOIC Package

78

SOIC Package,

−40°C ≤ TJ ≤ 125°C

100

VOVP(HYS)

Output Over-Voltage

Protection Hysteresis(5)

VCOMP = 1.4V

60

mV

VCOMP = 1.4V, −40°C ≤ TJ ≤ 125°C

20

110

Gm

Error Amplifier

Transconductance

VCOMP = 1.4V, IEAO = 100µA

(Source/Sink)

600

800

1000

µS

VCOMP = 1.4V, IEAO = 100µA

(Source/Sink),

−40°C ≤ TJ ≤ 125°C

365

1265

AVOL

Error Amplifier Voltage

Gain

VCOMP = 1.4V, IEAO = 100µA

(Source/Sink)

38

V/V

VCOMP = 1.4V, IEAO = 100µA

(Source/Sink),

−40°C ≤ TJ ≤ 125°C

26

44

IEAO

Error Amplifier Output

Current (Source/ Sink)

Source, VCOMP = 1.4V, VFB = 0V

80

110

140

µA

Source, VCOMP = 1.4V, VFB = 0V, −40°C

≤ TJ ≤ 125°C

50

180

Sink, VCOMP = 1.4V, VFB = 1.4V

−100

−140

−180

µA

Sink, VCOMP = 1.4V, VFB = 1.4V, −40°C

≤ TJ ≤ 125°C

−85

−185

VEAO

Error Amplifier Output

Voltage Swing

Upper Limit, VFB = 0V, COMP Pin =

Floating

2.2

V

Upper Limit, VFB = 0V, COMP Pin =

Floating,

−40°C ≤ TJ ≤ 125°C

1.8

2.4

Lower Limit, VFB = 1.4V

0.56

V

Lower Limit, VFB = 1.4V, −40°C ≤ TJ ≤

125°C

0.2

1.0

TSS

Internal Soft-Start Delay

VFB = 1.2V, VCOMP = Floating

4

ms

Tr

Drive Pin Rise Time

Cgs = 3000pf, VDR = 0 to 3V

25

ns

Tf

Drive Pin Fall Time

Cgs = 3000pf, VDR = 0 to 3V

25

ns

VSD

Shutdown threshold (6)

Output = High

1.27

V

Output = High,

−40°C ≤ TJ ≤ 125°C

1.4

Output = Low

0.65

V

Output = Low,

−40°C ≤ TJ ≤ 125°C

0.3

ISD

Shutdown Pin Current

VSD = 5V

−1

µA

VSD = 0V

+1

IFB

Feedback Pin Current

15

nA

TSD

Thermal Shutdown

165

°C

Tsh

Thermal Shutdown

Hysteresis

10

°C